jacking - up a caravan
Peter Shelley
caravan ? is it best to use a trolley jack or scissor jack ? and where
exactly is the safest and easiest place to place the jack on the caravan
without the risk of causing damage or injury, your replies would be greatly
appreciated thank you peter shelley
--
Peter Booth
it, I have a bad back and would struggle a little, bye for now...
Peter Shelley wrote in message <8uhhp5$ejh$1...@plutonium.btinternet.com>...
klyne
"> I may sound like a complete idiot, but what is the best way to jack-up a
> caravan ? is it best to use a trolley jack or scissor jack ? and where
> exactly is the safest and easiest place to place the jack on the caravan
> without the risk of causing damage or injury, your replies would be
greatly
> appreciated thank you peter shelley
Peter
It depends what sort of chassis you have. Al-Ko say that if you don't use
their own jack which fits a special bracket on the side of the chassis then
you should use the main axle as a jacking point. I could see a trolley jack
would perform the task more easierly but its a bit big to lug around with
you. I use a scissor jack when I put my van on axle stands for the winter
but it is a bit of a bind because you have lay under the van to complete the
task and you have to be very careful.
David - Milton Keynes
DaveK
"Peter Shelley" <Bette...@btinternet.com> wrote in message
news:8uhhp5$ejh$1...@plutonium.btinternet.com...
> I may sound like a complete idiot, but what is the best way to jack-up a
> caravan ? is it best to use a trolley jack or scissor jack ? and where
> exactly is the safest and easiest place to place the jack on the caravan
> without the risk of causing damage or injury,
>
raised,lower the corner steadies (not to support it, just to maintain it in
a steady position). Chock the wheel on the other side.
Alko make a jack specifically for lifting a caravan at the axle. The top
bracket is shaped to fit the oval shape of the axle tube. They are aware
that people don't jack up caravans properly and have redesigned the top
bracket with a steel fitting instead of nylon (which was ok as long as it
was used properly ).
I would advise never to jack a caravan as you would a car, it should only be
lifted at the axle, and then be steadied and secured.
It's not like dealing with a car puncture when ity happens on the road. The
axle will be lower than on most cars and you may need to pull the outfit
onto a ramp or block before you can get the jack under, hence the use of a
scissor jack. Have a warning triangle (two in Spain), torch and waterproofs
because it will be night-time and raining. It will also be on the side
nearest the traffic whichever country you are in.
DaveK
Barry
Bette...@btinternet.com says...
> I may sound like a complete idiot, but what is the best way to jack-up a
> caravan ? is it best to use a trolley jack or scissor jack ? and where
> exactly is the safest and easiest place to place the jack on the caravan
> appreciated thank you peter shelley
>
>
>
>
>
>
>
>
Having had the misfortune of having to struggle badly with a scissor jack
in a motorway service area on our second ever caravan trip, I bought the
Al-Ko side jack. It is very light and very easy to use, you can have the
caravan jacked up in seconds. It isn't cheap at around £65, but
definitely the tool for the job.
Barry
--
Email: barry(dot)eames(at)btinternet(dot)com
ray fisher
<Bette...@btinternet.com> writes
>I may sound like a complete idiot, but what is the best way to jack-up a
>caravan ? is it best to use a trolley jack or scissor jack ? and where
>exactly is the safest and easiest place to place the jack on the caravan
>without the risk of causing damage or injury, your replies would be greatly
>appreciated thank you peter shelley
>
caravan chassis. Alternatively any jack that has an appropriate cradle
to lift the axle (a trolley jack is ideal but heavy)- most car scissor
jacks are unsuitable because the cradle is unsuitable to lift a caravan
axle.
2 points to remember;
Always have the van hitched to a car before jacking.
Never rely on jacks if you are working underneath the van - make sure
you have axle stands in place.
--
ray fisher
preserve wildlife - pickle a hedgehog
Ian Gillis
cradle at the top to fit the axle. I found it ideal, apart from occasionally
having to pull the van up on levelling ramps before getting the jack under
(with the notorious Avon Supervan tyres I've had three blowouts, despite
scrupulously keeping to the 54psi pressure). Now I've changed the Disco for
a much more reliable Landcruiser, which has a screw-type bottle jack which
is a bit too tall. I've been looking out for a hydraulic bottle jack with an
axle cradle on the top. Most of the Halfords type have a chassis-perforating
button on the top that would slip off a 'van axle. The Disco jack (like all
Disco spares) costs a fortune. Anyone know of a suitable bottle jack - most
scissor jacks are pathetic, particularly in the first few inches of movement
when you really need the lifting power.
from Ian Gillis
Website:- http://www.ian-gillis.freeserve.co.uk
Nunc est bibendum!
Peter Shelley <Bette...@btinternet.com> wrote in message
news:8uhhp5$ejh$1...@plutonium.btinternet.com...
> I may sound like a complete idiot, but what is the best way to jack-up a
> caravan ? is it best to use a trolley jack or scissor jack ? and where
> exactly is the safest and easiest place to place the jack on the caravan
> without the risk of causing damage or injury, your replies would be
greatly
> appreciated thank you peter shelley
>
> --
>
>
>
>
>
>
Mary Fisher
ray fisher <carav...@ntlworld.com> wrote in message
news:a1sczIAW...@ntlworld.com...
> In article <8uhhp5$ejh$1...@plutonium.btinternet.com>, Peter
Shelley
> <Bette...@btinternet.com> writes
jack-up a
> >caravan ? is it best to use a trolley jack or scissor jack ?
and where
> >exactly is the safest and easiest place to place the jack on
the caravan
> >without the risk of causing damage or injury, your replies
would be greatly
> >appreciated thank you peter shelley
> >
the
> caravan chassis. Alternatively any jack that has an appropriate
cradle
> to lift the axle (a trolley jack is ideal but heavy)- most car
scissor
> jacks are unsuitable because the cradle is unsuitable to lift a
caravan
> axle.
> 2 points to remember;
> Always have the van hitched to a car before jacking.
Ray, this is interesting. What if you want to work underneath the
van when it's not hitched to the car - such as in our front
garden (the only place for it)?
> Never rely on jacks if you are working underneath the van -
make sure
> you have axle stands in place.
But you have to jack it up to get the stands in place ...
Mary
John Bretton
Get the corner steadies down just in case. Lift with the scissor jack until
you can get the bottle jack under and raise with both jacks in turn. This
provides total entertainment for all members of the family. As someone as
already said
* punctures in this country always happen on the off-side
* punctures abroad always happen on our near- side i.e. their off-side
* usually happens at night in the rain (but I had the pleasure of
getting a
puncture last summer in the morning sunshine - but it was on their
off-side!
Paul Cohen
da...@wkinnear.freeserve.co.uk (DaveK) uttered these words:
> >I use a trolley jack and axle stands at home. Once the caravan is
> raised,lower the corner steadies (not to support it, just to maintain
> it in
> a steady position). Chock the wheel on the other side.
I assume you intend to infer that the wheel should be chocked before you
start, not at the end. Also make sure the handbrake is applied firmly.
Paul C.
Paul Cohen
i...@ian-gillis.freeserve.co.uk (Ian Gillis) uttered these words:
> The Land Rover Discovery has a powerful but quite short bottle jack
> with a
> cradle at the top to fit the axle.
The Trooper's jack is ideal for jacking the van.
Paul C.
Paul Cohen
fisher) uttered these words:
> 2 points to remember;
> Always have the van hitched to a car before jacking.
Abbey recommend you unhitch. Makes sense to me.
Paul C.
ray fisher
Cohen <pco...@cix.co.uk> writes
AL-Ko say the van should be hitched.
If the van is hitched then the front is securely held in position by the
weight of the car and it will be almost impossible for the towhitch to
move sideways if the van decides to pivot around the wheel that is left
on the ground.
Try jacking one side of your van and see how little effort is needed to
push the back of the van sideways (and so topple the van off the jack)
once one wheel is off the ground and the front is not securely anchored.
Alex Heney
(Paul Cohen) wrote:
>In article <a1sczIAW...@ntlworld.com>, carav...@ntlworld.com (ray
>fisher) uttered these words:
>
>> 2 points to remember;
>> Always have the van hitched to a car before jacking.
>
>Abbey recommend you unhitch. Makes sense to me.
>
They are wrong.
Why does it make sense to you?
It is obvious common sense that you are better off with the van
hitched, and also what every book/magazine etc. that I have seen
suggests.
With the van hitched, it is not going to pivot around the one wheel
left on the ground, which would otherwise be too likely for my
comfort.
I would also suggest putting the corner steadies down, just as
insurance. Do *not* raise the van with them, but if they are down, and
something slips while jacking, they will probably stop the van landing
on you.
--
Alex Heney, global villager
If debugging is the process of removing software bugs, then programming must be the process of putting them in
Please remove NO and SPAM from above
address if replying by email.
Neil
Although I use one at home, a trolley jack is rather a heavy item for
caravanning use.
Instead, I carry a 1 ton Harvey Frost GPO registered design, screw jack in
the 'van. Must have bought it about 20 years ago from an army surplus
store, and it's been carried in and used on, just about every vehicle(and
caravan) I've owned since then, save the last 3 (Landrovers).
I can't fault it; 5 inches minimum height to 15 inches maximum height, cast
steel, should last forever. The cradle fits the caravan axle reasonably
well, and it has a nice long two-piece winding handle as well.
Neil
Ian Gillis wrote in message <8ui4p4$d7j$1...@newsg3.svr.pol.co.uk>...
Paul Cohen
fisher) uttered these words:
> Are you 100% sure about that ?
Yup - because after your post I went and looked in the manual at the
procedure for changing a wheel, so I'm quoting from the horse's mouth.
> AL-Ko say the van should be hitched.
Can't see why. On the one hand, as you say, it will mean that any tendency
for the van to develop a sideways swing will be countered. OTOH, jacking
will mean that the hitch and towball will be subjected to a strong
sideways and upwards force with nowhere to go - I can see the hitch being
badly damaged if the jack is raised a tad too high. Certainly, IME, I've
never had a problem jacking up the van to carry out maintenance without
having to hitch it up to the car.
Anyroad, it sounds like Alko and the van manufacturers need to get their
act together and start singing from the same hymn sheet considering the
potential danger of this operation. ATM, I'll go with Abbey's advice - if
the brakes are firmly applied and the wheel chocked, then no swing should
develop. BUT there needs to be sufficient noseweight to stop the van
tipping backwards, as the axle is mounted a few inches to the fore of the
wheel centre.
Paul C.
Paul Cohen
Paul Cohen
a.j....@btNOinterSPAMnet.com (Alex Heney) uttered these words:
> They are wrong.
Interestingly, the CC and Porter's Caravan Manual agree with you. (Well,
to be pedantic, they infer that it is desirable to leave the rig hitched,
not that it must be.)
> Why does it make sense to you?
See my reply to Ray.
> With the van hitched, it is not going to pivot around the one wheel
> left on the ground, which would otherwise be too likely for my
> comfort.
True, but OTOH, when you jack ISTM there will be additional strain insofar
as the van's hitch will be trying to lift the rear of the car as you go
on. This is not A Good Thing. Keep on jacking, and there *is* going to be
damage fersure.
I guess the *real* answer is to decide what's best in the circumstances,
taking into account gradient, quality of road surface, wind
speed/direction and so on. Then either leave it hitched, or turn/chock the
jockey wheel so that any swing is strongly resisted. The problem is,
manufacturers have to KISS (Keep It Simple Stupid), and it may be this
that gives rise to this conflicting advice.
> I would also suggest putting the corner steadies down, just as
> insurance. Do *not* raise the van with them, but if they are down, and
> something slips while jacking, they will probably stop the van landing
> on you.
Agreed.
Paul C.
DazB
"Paul Cohen" <pco...@cix.co.uk> wrote in message
news:memo.20001112...@pcohen.compulink.co.uk...
>
> Can't see why. On the one hand, as you say, it will mean that any tendency
> for the van to develop a sideways swing will be countered. OTOH, jacking
> will mean that the hitch and towball will be subjected to a strong
> sideways and upwards force with nowhere to go - I can see the hitch being
> badly damaged if the jack is raised a tad too high.
You'd have to jack it up a hell of a long way to any damage. Just get a old
hitch from somewhere and try it.... IMHO I reckon you would have to jack the
van up by around 2 - 3 feet at the axle before putting any strain on the
hitch... remember. it's designed to swivel in all directions.. You wouldn't
be lifting the 'van directly upright... you would be tilting it up from the
axle to the hitch, no more than when coming off a ferry!!!
Be safe.. leave it hitched... Again remember... at this point, we are
talking about being at the roadside changing a flat... If you going to work
on the 'van. for servicing etc, then it would be a slightly different
approach..
ray fisher
Cohen <pco...@cix.co.uk> writes
>
>> Are you 100% sure about that ?
>
>Yup - because after your post I went and looked in the manual at the
>procedure for changing a wheel, so I'm quoting from the horse's mouth.
>
>
>Can't see why. On the one hand, as you say, it will mean that any tendency
>for the van to develop a sideways swing will be countered. OTOH, jacking
>will mean that the hitch and towball will be subjected to a strong
>sideways and upwards force with nowhere to go - I can see the hitch being
>never had a problem jacking up the van to carry out maintenance without
>having to hitch it up to the car.
>
>Anyroad, it sounds like Alko and the van manufacturers need to get their
>act together and start singing from the same hymn sheet considering the
>potential danger of this operation.
I feel sure that if you ask Abbey direct they will say that the manual
doesn't say unhitch the caravan :-)
> ATM, I'll go with Abbey's advice - if
>the brakes are firmly applied and the wheel chocked,
Chocking the wheel will not prevent the jockey wheel from sideways
movement, especially when the wheel you are jacking clears the ground
and so effectively leaves with brakes only on the side you have chocked!
> then no swing should
>develop. BUT there needs to be sufficient noseweight to stop the van
>tipping backwards, as the axle is mounted a few inches to the fore of the
>wheel centre.
>
You shot yourself in the foot with your own logic on the last sentence.
With reasonable load on the nose (as there would be normally) how could
jacking one side possibly cause a >strong sideways and upwards force< on
the hitch - as you are jacking close to (or on the axle line) the
noseweight will keep the hitch firmly on the ball and sideways moment
will be negligible compared to normal towing forces.
Paul Cohen
fisher) uttered these words:
> I feel sure that if you ask Abbey direct they will say that the manual
> doesn't say unhitch the caravan :-)
Well, if you (or anyone else) has their number, I'll be only too pleased
to test the theory!
> You shot yourself in the foot with your own logic on the last sentence.
> With reasonable load on the nose (as there would be normally) how could
> jacking one side possibly cause a >strong sideways and upwards force< on
> the hitch - as you are jacking close to (or on the axle line) the
> noseweight will keep the hitch firmly on the ball and sideways moment
> will be negligible compared to normal towing forces.
Hmmm... if you extrapolate the jacking to absurdity, you will observe that
a line drawn through the hitch to the centre rear of the chassis is moved
away from the jack laterally, and upwards.
The lateral movement is not very significant with small amounts of lift.
But as for the upwards force... Let's do a bit of Blue Peter.
Take a VCR cassette which will represent the chassis, with a pencil
underneath to simulate the wheels. Balance the cassette so it is a little
nose heavy. Now lift one end of the pencil to jack it up. Notice how the
centre of the front of the cassette raises itself by half of the jacking
height? Now, simulate being hitched up by holding the front centre of the
cassette steady. Now jack it up. Notice what happens? It's *much* harder
to jack - that's because, if you notice, you are not only having to lift
the side of the van, but the far rear corner of the van as well, as the
front's got nowhere to go!
So, you are putting a negative strain on the hitch, and either you will
raise the rear of the car, or, if the car's really heavy, the far rear of
the van. Not good.
On my Dorset, in order to get at the spare slung under the n/s, you really
have to jack the bugger up *really* high in order to get the cradle clear
of the underside of the van to get at the spare. Nightmare.
Paul C.
Chris J Dixon
>In article <jY1CoKAy...@ntlworld.com>, carav...@ntlworld.com (ray
>fisher) uttered these words:
>
>The lateral movement is not very significant with small amounts of lift.
>But as for the upwards force... Let's do a bit of Blue Peter.
>
>Take a VCR cassette which will represent the chassis, with a pencil
>underneath to simulate the wheels. Balance the cassette so it is a little
>nose heavy. Now lift one end of the pencil to jack it up. Notice how the
>centre of the front of the cassette raises itself by half of the jacking
>height? Now, simulate being hitched up by holding the front centre of the
>cassette steady. Now jack it up. Notice what happens? It's *much* harder
>to jack - that's because, if you notice, you are not only having to lift
>the side of the van, but the far rear corner of the van as well, as the
>front's got nowhere to go!
>
>So, you are putting a negative strain on the hitch, and either you will
>raise the rear of the car, or, if the car's really heavy, the far rear of
>the van. Not good.
>
I'm not quite sure that your experiment is actually that
accurate.
Are you not considering two conditions here:
1 Caravan with normal noseweight parked with road wheels and
jockey wheel on ground.
2 Caravan attached to car.
Neither of these is represented by your cassette, until you
introduce, say, another pencil under the front centre, to
represent the jockey wheel or hitch. Having done this there is
no discernable difference.
In case 1, with normal noseweight, the jockey wheel will remain
firmly on the ground, and the hitch will remain at virtually the
same height throughout. (because of the overhang beyond the
jockey wheel, it might actually drop slightly during jacking)
In case 2, with the caravan hitched, the noseweight is still
present at the hitch. There is no way that this will ever go
away, and try to lift the car.
If you really want to go into the geometry of the situation,
because the centre of mass is normally higher than, and forward
of, the point about which the caravan is being pivoted, the
noseweight will increase slightly as the caravan is jacked up.
Interesting though this applied mechanics is, it is rather
missing the important safety issue here.
If you were to go through the back issues of the Caravan Club
magazine, you would find a strongly worded recommendation from
Alco that their jacks must never be used without the caravan
being hitched to the towing vehicle. This was in the context of
a pad on the jack failing due to the twisting of an unhitched
caravan. Any risk of this happening should clearly be avoided.
Chris
--
Chris J Dixon Nottingham UK
chris...@easynet.co.uk
Have dancing shoes, will ceilidh.
Paul Cohen
chris...@easynet.co.uk (Chris J Dixon) uttered these words:
> I'm not quite sure that your experiment is actually that
> accurate.
Mmmm... on second thoughts, I'm not sure either. If I was correct, then
when you jack unhitched, the jockey wheel would lift from the ground, and
therefore the van would only be supported from under the axle - clearly it
would have to be perfectly balanced not to topple back or forth. But in
fact it stays on the jockey wheel (hopefully!).
Therefore, I think I'm wrong - but thanks for talking it through, as I
think I've got a better understanding now.
> If you were to go through the back issues of the Caravan Club
> magazine, you would find a strongly worded recommendation from
> Alco that their jacks must never be used without the caravan
> being hitched to the towing vehicle.
Yes, I will follow this advice in future.
Paul C.
Alex Heney
(Paul Cohen) wrote:
>In article <51kr0tsogp41ejmdk...@4ax.com>,
>a.j....@btNOinterSPAMnet.com (Alex Heney) uttered these words:
>
>> They are wrong.
>
>Interestingly, the CC and Porter's Caravan Manual agree with you. (Well,
>to be pedantic, they infer that it is desirable to leave the rig hitched,
>not that it must be.)
>
>> Why does it make sense to you?
>
>See my reply to Ray.
>
I think you are exaggerating the effect of jacking (see below).
>> With the van hitched, it is not going to pivot around the one wheel
>> left on the ground, which would otherwise be too likely for my
>> comfort.
>
>True, but OTOH, when you jack ISTM there will be additional strain insofar
>as the van's hitch will be trying to lift the rear of the car as you go
>on. This is not A Good Thing. Keep on jacking, and there *is* going to be
>damage fersure.
>
Not really.
If your jack is under the axle (where it should be), then you are
lifting one side of the van, and most of that lift will effect itself
at the hitch as the cup pivoting around the ball. ONly a very small
amount of upwards force will be exerted, and I would think you will
have the wheel off the ground before the upwards force does more than
counteract the normal noseweight.
Yes, if you keep on jacking much after that, you could have problems,
but you shouldn't be jacking that far anyhow.
Remember, with the tyre at normal pressure, it only takes a lift of a
few inches for it to clear the ground.
--
Alex Heney, global villager
It's not hard to meet expenses, they're everywhere.
ray fisher
>> doesn't say unhitch the caravan :-)
>
>Well, if you (or anyone else) has their number, I'll be only too pleased
>to test the theory!
>
>> You shot yourself in the foot with your own logic on the last sentence.
>> With reasonable load on the nose (as there would be normally) how could
>> jacking one side possibly cause a >strong sideways and upwards force< on
>> the hitch - as you are jacking close to (or on the axle line) the
>> noseweight will keep the hitch firmly on the ball and sideways moment
>> will be negligible compared to normal towing forces.
>
>Hmmm... if you extrapolate the jacking to absurdity, you will observe that
>a line drawn through the hitch to the centre rear of the chassis is moved
>away from the jack laterally, and upwards.
>
>But as for the upwards force... Let's do a bit of Blue Peter.
>
>Take a VCR cassette which will represent the chassis, with a pencil
>underneath to simulate the wheels. Balance the cassette so it is a little
>nose heavy. Now lift one end of the pencil to jack it up. Notice how the
>centre of the front of the cassette raises itself by half of the jacking
>height? Now, simulate being hitched up by holding the front centre of the
>cassette steady. Now jack it up. Notice what happens? It's *much* harder
>to jack - that's because, if you notice, you are not only having to lift
>the side of the van, but the far rear corner of the van as well, as the
>front's got nowhere to go!
>
you would like to e-mail me I will attempt to explain where you are
wrong :-)
>So, you are putting a negative strain on the hitch, and either you will
>raise the rear of the car, or, if the car's really heavy, the far rear of
>the van. Not good.
>
But you will not be putting negative load on the hitch, otherwise if you
tried to jack as you suggest the hitch would lift and the van
overbalance backwards.
>On my Dorset, in order to get at the spare slung under the n/s, you really
>have to jack the bugger up *really* high in order to get the cradle clear
>of the underside of the van to get at the spare. Nightmare.
>
Hitches are designed to allow at least 35 degrees movement in all
directions - the van would tip on its side long before you could jack it
high enough to do any damage to the hitch !
ray fisher
<a.j....@btNOinterSPAMnet.com> writes
>If your jack is under the axle (where it should be), then you are
>lifting one side of the van, and most of that lift will effect itself
>at the hitch as the cup pivoting around the ball. ONly a very small
>amount of upwards force will be exerted, and I would think you will
>have the wheel off the ground before the upwards force does more than
>counteract the normal noseweight.
>
noseweight will increase slightly as the van is jacked. But at normal
jacking heights any effect will be negligible.
>Yes, if you keep on jacking much after that, you could have problems,
>but you shouldn't be jacking that far anyhow.
>
The main problem will be the van tipping onto it's side if you try to
jack much over 6ft :-)
>Remember, with the tyre at normal pressure, it only takes a lift of a
>few inches for it to clear the ground.
>
Even with a puncture and allowing for the suspension to drop 12" lift
should be more than enough.
Mary Fisher
I'm impressed and full of admiration! There aren't many people
who are prepared to be converted.
I was telling Spouse about this thread over the venison, he said
it was one of the things he learned on the towing course, that
you keep the 'van hitched when jacking.
When you come to think of it, at the roadside there's no point in
unhitching, it makes more work.
Mary
>
> Paul C.
>
>
Paul Cohen
fisher) uttered these words:
> Sorry Alex but you are incorrect - basic physics says that the
> noseweight will increase slightly as the van is jacked.
Why? The jacking point on my AlKo is infront of the wheel centre, giving
it a tendency in practise to tilt back when it's jacked. Is the axle tube
mounted behind the wheels on some models?
Paul C.
Paul Cohen
(Mary Fisher) uttered these words:
> I'm impressed and full of admiration! There aren't many people
> who are prepared to be converted.
Thanks Mary - I started off assuming the manual was correct, and
intuitively felt it was. But bouncing it back and forth now, it's obvious
it isn't.
Anyone who can't admit they're wrong when it is obvious to them that they
are is weak and foolish.
Paul C.
Paul Cohen
fisher) uttered these words:
> Obviously a few lessons in applied physics are called for here and if
> you would like to e-mail me I will attempt to explain where you are
> wrong :-)
Thanks for that very kind offer Ray, but I think my physics is quite
adequate, merely inappropriately and hurriedly applied this afternoon. But
as you will see passim, I have now rectified that.
But, one good turn deserves another. If you'd like to email *me*, I'll
attempt to explain how you might be able to reduce your level of pomp to
more manageable levels ;-).
> But you will not be putting negative load on the hitch, otherwise if you
> tried to jack as you suggest the hitch would lift and the van
> overbalance backwards.
Which actually is what it does on my van (as mentioned elsewhere) - but
that's because the axle tube is not in line with the wheels.
Paul C.
Martin Beenham
>as the van's hitch will be trying to lift the rear of the car as you go
>on. This is not A Good Thing. Keep on jacking, and there *is* going to be
>damage fersure.
Are you referring to a twin axle caravan? If so I can understand your
logic. On a single axle caravan there would be no lifting force on the
hitch since it is a three-point suspension - wheel, jack and hitch.
Jacking one wheel clear of the ground does not alter the geometry
sufficiently to change the nose weight appreciably.
It is very dangerous to jack a single axle caravan unhitched or without
the hitch anchored in some way and Alko specify jacking only a hitched
caravan. You can "get away with it" but it doesn't take much for the
jockey wheel to move if you do not jack exactly vertical. The danger and
likely damage to the van resulting isn't worth the risk.
Not having experience or knowledge of a twin axle rig I wouldn't comment
but can see the situation might be different.
--
Please replace 'spam' by 'martin' to reply by email. All mail to
sp...@aman.demon.co.uk is ditched without reading.
Martin Beenham
ian_w...@my-deja.com
Martin Beenham <sp...@aman.demon.co.uk> wrote:
> Not having experience or knowledge of a twin axle rig I wouldn't
comment
> but can see the situation might be different.
Why? OK you have 5 points of contact as opposed to three but, for all
practical purposes you can treat each pair of wheels as one entity.
When you jack it will lift one pair of wheels against a line from the
hitch/jockey to (roughly) the mid point of the opposite pair. What,
then is the difference. If the chassis were able to articulate then ok
but as it is you merely flex the suspenders a bit.
Sent via Deja.com http://www.deja.com/
Before you buy.
Mary Fisher
>
> Anyone who can't admit they're wrong when it is obvious to them
that they
> are is weak and foolish.
>
> Paul C.
Yes. It takes a strong character to admit that but not many know
it.
Mary
>
>
Paul Cohen
> Yes. It takes a strong character to admit that but not many know
> it.
<blushes> :-)
Paul C.
ray fisher
>fisher) uttered these words:
>
>> Sorry Alex but you are incorrect - basic physics says that the
>> noseweight will increase slightly as the van is jacked.
>
>Why? The jacking point on my AlKo is infront of the wheel centre, giving
>it a tendency in practise to tilt back when it's jacked. Is the axle tube
>mounted behind the wheels on some models?
>
be reasonably obvious :-)
hints:
Position of centre of gravity (don't forget the vertical position).
A colleague used to have a sign on his desk that read:
Please put brain in gear before engaging mouth.
I eagerly await the next 'bit of Blue Peter' (hopefully properly
researched this time).
Paul Cohen
fisher) uttered these words:
> If you draw a vector diagram of all the forces involved the answer will
> be reasonably obvious :-)
Well, yes, it is completely obvious. The CoG stays in the same place in
space. Move the point of lift *forward* and the back goes down. I can't
see what the issue is with this.
I should also point out that I did find out the axle tube is forward of
the wheels, hence leading to the above, the hard way (fortunately no harm
done).
So why, if you are correct, even though it was sitting quite happily on
the jockey wheel before I started, it rolled back onto the back steadies
when I jacked it up and the jockey wheel lifted into the air?
> A colleague used to have a sign on his desk that read:
> Please put brain in gear before engaging mouth.
Yes, and your point is?
BTW, Ray, just before you answer (if you do) - please do try really hard
to contain that rather unpleasant sarcastic streak. It is neither useful,
helpful or constructive to me, you or any other participants. It is just
tedious, and doesn't really impress anyone over the age of 7. If you want
to be sardonic, then at least do try and be witty and original with it.
Paul C.
Jon Beaumont
After my failed attempts to jack up my caravan this weekend (having put
it in storage for the winter I thought I'd be clever and put it on axle
stands), I wish I'd read this first.
I unhitched the 'van (handbrake on) and crawled underneath with a
scissor jack. two attempts with it slipping off the jack with my head
under the van convinced me it wasn't worth it.
I may have another attempt now leaving it hitched up, blocking the
wheels, and using bottle jack.
--
Jon Beaumont
smiler
"Alex Heney" <a.j....@btNOinterSPAMnet.com> wrote in message
news:51kr0tsogp41ejmdk...@4ax.com...
> On Sat, 11 Nov 2000 17:56 +0000 (GMT Standard Time), pco...@cix.co.uk
> (Paul Cohen) wrote:
>
> >In article <a1sczIAW...@ntlworld.com>, carav...@ntlworld.com (ray
> >fisher) uttered these words:
> >
> >> 2 points to remember;
> >> Always have the van hitched to a car before jacking.
> >
> >Abbey recommend you unhitch. Makes sense to me.
> >
>
> They are wrong.
>
>
> hitched, and also what every book/magazine etc. that I have seen
> suggests.
>
> left on the ground, which would otherwise be too likely for my
> comfort.
>
> insurance. Do *not* raise the van with them, but if they are down, and
> something slips while jacking, they will probably stop the van landing
> on you.
>
>
> Alex Heney, global villager
>
must be the process of putting them in
>
> address if replying by email.
>
>
I'm a bit late in catching on to this thread but personal experience leads
me to say .
DON'T EVEN THINK OF JACKING A CARAVAN UNLESS JOCKEY WHEEL IS SECURED.
I have been taking the van off its wheels for the winter for 25 years or so
and had no problem using scissor or trolley jacks. Some 5 years or so ago
in an effort to cut down on weight and to keep my knees dry should I have
to change a wheel , I bought the Alko jack that fits a bracket attached to
the chassis. I decided to use it for my annual winter preparation for the
first time last year.
First wheel , no problem, fitted an axle stand under the axle. Second wheel
, as soon as friction between the tyre and concrete slab was removed there
was an almighty swing of the caravan, no damage but the jack was jammed and
the axle stand had just two of its three legs in contact with the ground.
Sorting that out was interesting
The steadies were down on the non- lifting side and dragged. The swing was
halted by a clothes line which normally runs parallel to the rear of the van
and quite close to it for the 'smalls''
I read the jack instructions, which I had last read when I bought it and
they quite clearly state attach to the car before jacking.
I think the problem arose because the jack wasn't absolutely in the correct
position so that the lift wasn't absolutely vertical and was compounded by
the ease of rotation of the axle stand. (A point that I hadn't noticed
mentioned elsewhere)
I feel quite happy about using the Alko jack if changing just the one wheel
and the jockey is secure.
My winter preparation is done now by using my Mr Shifta. to hold the hitch
and a trolley jack
Cheers Happy Splashing
Smiler
smi...@halton.clara.co.uk (It's necessary to take my hat off the header
address -- usual anti spam measure)
ray fisher
<Bri...@louvre.co.uk> writes
the jack is suitable (has a wide and deep cup so that the axle cannot
slip off).
good luck.
ray fisher
Cohen <pco...@cix.co.uk> writes
>In article <0EDHPTA1...@ntlworld.com>, carav...@ntlworld.com (ray
>fisher) uttered these words:
>
>> If you draw a vector diagram of all the forces involved the answer will
>> be reasonably obvious :-)
>
>Well, yes, it is completely obvious. The CoG stays in the same place in
>space. Move the point of lift *forward* and the back goes down. I can't
>see what the issue is with this.
>
>I should also point out that I did find out the axle tube is forward of
>the wheels, hence leading to the above, the hard way (fortunately no harm
>done).
>
>So why, if you are correct, even though it was sitting quite happily on
>the jockey wheel before I started, it rolled back onto the back steadies
>when I jacked it up and the jockey wheel lifted into the air?
>
first post of the thread).
To behave as you state the CofG would have to be between the wheel line
and axle line (5" max?) on a properly loaded van it is far further
forward.
>> A colleague used to have a sign on his desk that read:
>> Please put brain in gear before engaging mouth.
>
>Yes, and your point is?
>
You have admitted that your first posts where incorrect - your Blue
Peter demonstration merely showed your lack of either knowledge or
thought and as you said you aren't in need of a basic physics lesson
then the only assumption I can draw is you aren't thinking :-)
>BTW, Ray, just before you answer (if you do) - please do try really hard
>to contain that rather unpleasant sarcastic streak.
You are the one reading sarcasm - I wonder why ?
F.U set to poster - seeing as the point about leaving the van hitched
has been accepted this will now become boring to most subscribers.
Graham Jones
<carav...@ntlworld.com> writes
>The AL-Ko jack fits special brackets that you need to mount on the
>caravan chassis.
Avery good bit of kit, got one!
>2 points to remember;
>Always have the van hitched to a car before jacking.
I fully agree with you here Ray. I used it on my old twin axle Transtar
(a word of caution to any twin axle users) make sure that the tyres are
running straight inline with no side wall deflection. If you jack up
without being hitched up and the tyres are out of line then the van will
twist sideways when the pressure is lifted from one side.
>Never rely on jacks if you are working underneath the van - make sure
>you have axle stands in place.
Excellent advise.
--
Graham Jones
(Medical Rescue)
ICQ 69660620
Graham Jones
<chris...@easynet.co.uk> writes
>In case 1, with normal noseweight, the jockey wheel will remain
>firmly on the ground, and the hitch will remain at virtually the
>same height throughout. (because of the overhang beyond the
>jockey wheel, it might actually drop slightly during jacking)
Sorry to butt in here, but there is no way on earth that I would lower
the jockey wheel when still attached to the car for jacking purposes.
Graham Jones
gillis.freeserve.co.uk> writes
>Anyone know of a suitable bottle jack - most
>scissor jacks are pathetic, particularly in the first few inches of movement
>when you really need the lifting power.
I think Alko used to do a very fine treaded scissor jack at one point?
Graham Jones
>Why? OK you have 5 points of contact as opposed to three but, for all
>practical purposes you can treat each pair of wheels as one entity.
>When you jack it will lift one pair of wheels against a line from the
>hitch/jockey to (roughly) the mid point of the opposite pair. What,
>then is the difference. If the chassis were able to articulate then ok
>but as it is you merely flex the suspenders a bit.
See my earlier post Ian.
Chris J Dixon
Nor, if you return to my original post and read it all, did I
suggest you should.
Paul Cohen
> It wasn't loaded with a positive noseweight
> (stated as needed in my first post of the thread).
Er, yes it was. That is why it sits on the jockey wheel when the van is
shipped.
> To behave as you state the CofG would have to be between the wheel
> line and axle line (5" max?) on a properly loaded van it is far
> further forward.
I repeat, not 'To behave', it *does* behave like that. It's not
surprising. Don't forget most of the really heavy stuff that is factory
installed is located over and around the axle. The CoG is *designed* to be
almost over the axle. 5" could well be (and in fact is) enough to change
shipping noseweight of 25kg to a small negative value.
Nevertheless, I'm sorry you didn't actually answer my question - perhaps
you couldn't or maybe you just neatly sidestepped it.
> F.U set to poster - seeing as the point about leaving the van
> hitched has been accepted this will now become boring
> to most subscribers.
I'm not sure what 'F.U' means in this context, but I wouldn't be so bold
as to make those sort of assumptions about this rather important subject.
Others can choose to ignore the posts if they wish.
Paul C.
ian willis
<g...@gavj.demon.co.uk> writes
>>practical purposes you can treat each pair of wheels as one entity.
>>When you jack it will lift one pair of wheels against a line from the
>>hitch/jockey to (roughly) the mid point of the opposite pair. What,
>>then is the difference. If the chassis were able to articulate then ok
>>but as it is you merely flex the suspenders a bit.
>
Read hitch OR jockey. In practice I side with the keep it hitched
brigade. However the basic logic of my statement is unaffected
whichever method is used. - The question was based around the
difference between single and twin axle when jacking.
--
ian willis i...@blackrock60.freeserve.co.uk
david
Had to have the tyres changed this year because of standing on them over
last winter. Reading these posts is a bit off putting when I will not be
able to connect to the car when jacking up.
I was thinking of useing a couple of spare axle stands under the axle. My
first thought was to use 'winter wheels' but insurence companies seem to
regard these as increasing the risk of stealing. Would have thought the
opposite as they would have to provide wheels it they were going to tow it
away.
--
Regards,
David
Mary Fisher
ray fisher <carav...@ntlworld.com> wrote in message
news:bp6cUpAS...@ntlworld.com...> >In article <0EDHPTA1...@ntlworld.com>,
answer will
> >> be reasonably obvious :-)
> >
> >Well, yes, it is completely obvious. The CoG stays in the same
place in
> >space. Move the point of lift *forward* and the back goes
down. I can't
> >see what the issue is with this.
> >
> >I should also point out that I did find out the axle tube is
forward of
> >the wheels, hence leading to the above, the hard way
(fortunately no harm
> >done).
> >
> >So why, if you are correct, even though it was sitting quite
happily on
> >the jockey wheel before I started, it rolled back onto the
back steadies
> >when I jacked it up and the jockey wheel lifted into the air?
> >
in my
> first post of the thread).
wheel line
> and axle line (5" max?) on a properly loaded van it is far
further
> forward.
>
>
> >> Please put brain in gear before engaging mouth.
> >
> >Yes, and your point is?
> >
> You have admitted that your first posts where incorrect - your
Blue
> Peter demonstration merely showed your lack of either knowledge
or
> thought and as you said you aren't in need of a basic physics
lesson
> then the only assumption I can draw is you aren't thinking :-)
>
>
> >BTW, Ray, just before you answer (if you do) - please do try
really hard
> >to contain that rather unpleasant sarcastic streak.
>
> You are the one reading sarcasm - I wonder why ?
I'm afraid he's not alone - I found it unecessarily unpleasant
too.
Mary
>
> F.U set to poster - seeing as the point about leaving the van
hitched
> has been accepted this will now become boring to most
subscribers.
Neil
david wrote in message <8v3c54$p68$4...@newsg3.svr.pol.co.uk>...
>Hi,
>Had to have the tyres changed this year because of standing on them over
>last winter. Reading these posts is a bit off putting when I will not be
>able to connect to the car when jacking up.
Try this if(like mine) your 'van is kept on a slight slope, and on a tarmac
drive:-
Obtain a 2 to 2.5 foot section of scaffold(or similar) pole, the same
diameter as your jockey wheel tube. Hacksaw or angle grind 4 to 6 large saw
tooth notches(so that the end resembles a hole saw with very large teeth.
Replace your jockey wheel with this pipe, and with a decent nose weight on
this, it won't move while you're jacking the 'van.
It works for me, 'cos if I were to hitch up with the 'van on the drive, I'd
be blocking the road ;-)
Neil
Mary Fisher
Neil <Har...@btinternet.com> wrote in message
news:8v9qs8$gm5$1...@plutonium.btinternet.com...
Sounds like a very good solution.
BUT.
What does 'er indoors think of the pattern on the tarmac?
Mary
>
>
>
Neil
Mary Fisher wrote in message <8vdkru$92v$1...@news5.svr.pol.co.uk>...
'Er indoors is never the one to sweep the drive ;-)
But seriously though, it has never made a noticeable mark except once or
twice in the very hottest of weather. Then the tarmac(it's not the fine
textured, decorative type) was "encouraged" back into place with a hammer!
Neil
Mary Fisher
>
> Mary Fisher wrote in message
<8vdkru$92v$1...@news5.svr.pol.co.uk>...
> >
> >Neil <Har...@btinternet.com> wrote in message
> >news:8v9qs8$gm5$1...@plutonium.btinternet.com...
>
> >
> >
> >BUT.
> >
> >What does 'er indoors think of the pattern on the tarmac?
> >
> >Mary
>
>
> 'Er indoors is never the one to sweep the drive ;-)
>
> But seriously though, it has never made a noticeable mark
except once or
> twice in the very hottest of weather. Then the tarmac(it's not
the fine
> textured, decorative type) was "encouraged" back into place
with a hammer!
>
> Neil
Like it :-)
M
>
>
>