[GMCnet] Lifting the rear of the coach

[Stu Rasmussen (97381.com) via Gmclist]

Greetings all,

I want to lift the rear end of the coach to do tire/brake/airbag/shock
absorber twiddling.

I have a Bendpak 14K 4-post lift and a 7K rolling jack accessory HOWEVER
the rolling jack does not go wide enough to get under the bogie
castings. (A bit of a disappointment, actually)

So my options are:

1: Lift with the rolling jack under the frame at the bogie position on
the crossmember (which will be right at the edge of the side frame rail
and looks pretty stout)

OR:

2: Get some honking large steel bar stock and fabricate a pair of new
lifting arms to fit the rolling jack and long enough to get directly
under the bogies at the lift points.

From a time/material standpoint #1 is the more attractive option but I
have read many places that the ONLY place to lift the rear is at the
approved jacking points.

So, which should I do?

Thanks in advance ~

Stu

As a PS, the lift/rolling jack combo also does not adjust wide enough to
lift the front at the approved points, another disappointment, I
probably should have saved the $$$.

It would have been much cheaper to get the jack adapter and a bottle
jack but more difficult to drop the fuel tanks for my creaky old bones.


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[James Hupy via Gmclist]

The jack attachment for the lift is not as wide as the distance between the
bogie boxes, correct? Is the lift itself capable, capacity wise, to lift a
12,000 pound coach? Same questions for the front end.
Then, after these questions are answered affirmatively, we can make
some suggestions.
Jim Hupy
Salem, Oregon

[Stu Rasmussen (97381.com) via Gmclist]

Yes, the lift total capacity is 14,000 pounds and the jack attachment is
rated at 7,000 pounds.

Yes, you are correct, the lifting arms on the jack attachment do not
adjust wide enough to get centered under the bogies.

Stu

[James Hupy via Gmclist]

Get a piece of .250" wall thickness rectangular steel tubing longer than
the distance between the bogies. Move the jack into position on the lift so
that it matches up with the bogies, place the tubing across the coach under
the bogies, lift until the jack makes firm contact with that tubing, then,
do something similar on the front, but lift on the frame where the front
clip and frame side rails meet. When you are sure that you cannot slip or
slide with the coach, then, and ONLY THEN think about lifting the coach
off the ground and crawling under it. I will look up your lift model later
and verify that what I just suggested is a truly safe way to proceed.
Jim Hupy
Salem, Oregon

On Thu, Jun 4, 2020, 3:19 PM Stu Rasmussen (97381.com) via Gmclist <

[Stu Rasmussen (97381.com) via Gmclist]

Thanks Jim,

The lift is at
<https://www.bendpak.com/car-lifts/four-post-lifts/hds-14/>

and the jack is
<https://www.bendpak.com/car-lifts/4-post-bridge-jacks/rbj7000/>

The trick is that the jack control is attached to the jack and you get
to lift while you're under the vehicle.

Thanks again.

Stu

[Matt Colie via Gmclist]

Stu Rasmussen wrote on Thu, 04 June 2020 17:12

> Greetings all,
> I want to lift the rear end of the coach to do tire/brake/airbag/shock absorber twiddling.
> I have a Bendpak 14K 4-post lift and a 7K rolling jack accessory HOWEVER the rolling jack does not go wide enough to get under the bogie castings.
> (A bit of a disappointment, actually)
> So my options are:
> 1: Lift with the rolling jack under the frame at the bogie position on the crossmember (which will be right at the edge of the side frame rail and
> looks pretty stout)
> OR:
> 2: Get some honking large steel bar stock and fabricate a pair of new lifting arms to fit the rolling jack and long enough to get directly under
> the bogies at the lift points.
> From a time/material standpoint #1 is the more attractive option but I have read many places that the ONLY place to lift the rear is at the
> approved jacking points.
> So, which should I do?
> Thanks in advance ~
> Stu
>
> As a PS, the lift/rolling jack combo also does not adjust wide enough to lift the front at the approved points, another disappointment, I probably
> should have saved the $$$.
> It would have been much cheaper to get the jack adapter and a bottle jack but more difficult to drop the fuel tanks for my creaky old bones.

Stu,

I also have a shop that has a compliment of less than capable equipment. My lift can only lift one end of the coach at a time and I have to be
creative with the other end.

The nature of the beast is such that you do not want to lift the coach weight directly on the frame ever except at the hard points. (I have seen lots
of coaches with the resulting damage.)
Ready?
I said lift the coach weight. If you are going to work at the rear, take the rolling lift all the way aft to that rear cross member. If you lift it
there, you are not lifting the whole (or even the rear half) of the coach weight. There is a considerable hard point where the rear cross frame bolts
to the stringers. Before I got the Merrill hitch installed, I lifted my coach (admittedly only a light 23) there several times. When I did this with
a 6 ton floor jack, I would put a 4x6 across and lift in the center and then crib under the bogey castings. When she was set on the cribbing -
usually two huncks of 4*6 - I would left the floor jack off and give the coach a solid body check. An acquaintance was watching this procedure and
asked if I were afraid I might knock the coach off the blocks. To this I replied,"I'm sure not worried now."

This never lift caused Chaumière any additional frame damage. (She came with some.) The notable point here is that you are not lifting as much
weight as you would have to when lifting any farther forward.

A warning about wood, it does not have a yield strength. When/If you hear a crack, that is it. You are done. Fifteen years later that 4x6 is still
here and has been used for other things.

Some time later (about three years after I bought the hitch at Berrien Springs) I mounted a Merril style (long story) hitch. Ever since I have very
successfully and safely used that as a rear jack point. It very effectively distributes the load on the rear most cross member. (It also severed me
well as a hook point to haul dear Chaumière out of the median in South Carolina.

I am sure you can do this, but it still requires that you use do care.

By the by, the approved lifting point in the front is the Entire front cross member. I have been picking coaches in the middle of that for a long
time and never witnessed any damage or distortion.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

[Jon Roche via Gmclist]

lifting in one spot with a floor jack, and I think lifting in two spots like you are trying to do, are quite a bit different.

many people worry about lifting points, so you don't twist or stress things. Some have experienced cracked windshields when jacking. The other
thing to worry about is our frames are not the stoutest to be a lift point. duration of that l

with that said, I think if you are lifting the back up, on two good points on the frame, you should be fine, but I would think some quick cribbing
and set the bogies on some blocks, or set the frame front and back of the rear tires would be just as well. if you jack in a poor spot, it
probably will not bend immediately, but if you leave it sitting on that poor location for a while the frame could bend.

I think just use a little common sense and be careful, you will not have any problems.

The downside to lifting the front of the coach by the crossmember(I prefer to jack from the front middle up if I can), is that you have to lift it
pretty high to get the wheels off. We just jacked up a coach wednesday that way, but took the wheels off quick, then lowered the coach down onto
some jackstands, did the brakes, then lifted it off the ground again in order to put the rims/wheels back on.

same thing with the rear, sometimes jack it up, yank the wheels, and lower it to a more desirable height. If you are not needing the bogies to drop
down, then use some bar stock to keep the bogies from dropping as you jack and you will not have to lift it to the sky to remove rims and tires.

the other thing to watch out for is airbag pressure pushing on the shock mounts. Jack it up, let air pressure out of bags.. Don't have 120 pounds
of air in the airbags with the wheels lifted off the ground.

another reason why I wish everybody had isolation valves on the air bags. the coach I was working on Wednesday did not- and the airsystem worked
only in "auto" and when you switched on of the switches to "up" you heard air leaving something..... not right, that is for sure! and I
honestly not sure if there was access to the compressor in order to take air pressure out of the bags.
--
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/

[Ken Burton via Gmclist]

I do not like to add any of that extra crap to the air bags because I do no like it bouncing around. I have seen one of them snap off flush with the
bag. (That brass is not all the strong) This was on a Black list call along side of the road about 30 miles away. I had to remove the entire bag
and bring it into the shop to remove the broken piece. I had another one that a guy brought in to my hangar because it was leaking. In the process
of trying to remove it we broke it off too. At least we did not have to drive back and forth to some roadside location to fix it.

If you want to remove the air in a bag simply remove the hose. It takes 30 seconds and one open wrench. I do it every time I jack one up.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

[Johnny Bridges via Gmclist]

I have a piece of truck spring cut to fit between both bogies so that they only drop a few inches. Air pressure is relieved before the spring is
tight though to lessen the load on it.


--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell

[James Hupy via Gmclist]

Stu, I looked very carefully at your lift and the cross lift jack. Where
the round rubber pads are located looks like it extends out a certain
distance, and then has limit stops. I think that the limit stops only go so
far out, and the GMC bogie boxes are farther apart than the limits on the
cross lift jack. Can you drive your GMC completely onto the lift, or is the
lift too short to accommodate the length of the coach. If that is the case,
perhaps you would have been better off with the "Limo" lift option for your
lift. It is longer, to accommodate extra length vehicles like extended cab
pick ups, RV's, and Limousines. If that is part of your problem, perhaps
Bend Pak might work you a swap. You might contact their customer service
department, and inquire how you might extend the frame jack width,
explaining about the extra width of the GMC bogie boxes. Worth a shot.
Otherwise, my suggestion of the heavy duty rectangular tube would work on
the rear. Looks like the frame jack will work as is on the front
crossmember that is the approved lift point to jack the coach in the front.
Just what I can see from here.
Jim Hupy
Salem, Oregon

[Stu Rasmussen (97381.com) via Gmclist]

Hi Jim,

The lift is actually long enough for a 26' coach to fit onto (but just
barely) with all wheels on the runways. Fits my 23' beautifully with
room to spare. The lift is just dandy, the rolling jack is the
disappointment - but I'll get over it.

My main reason for getting the standard length versus the extended lift
was that you have to derate the lift capacity of the lift as the
wheelbase of what you're lifting shortens - making the longer lift
marginal for my pickup or Kubota tractor that I also intend to be able
to work on using the lift. It was a compromise all around.

I found a source of suitable solid rectangular bar stock in Portland so
I can make new lift arms that will center under the bogies and all is
well.

Thanks!

Stu

[Stu Rasmussen via Gmclist]

Hi all,

It has been a while since I last posted on this subject and still have a problem.

The rolling jack extensions for the lift are fabricated and work fine but a new problem arises:

Lifting the rear of the coach while on the 4-post lift (after deflating the air bag) gets the tire off the runway but then the tire/wheel are an
additional 8" off the ground and heavy as the dickens. Awkward to remove and replace without additional muscle that I don't have.

So I got the 'tire lifter' from HF that would work fine but needs more depth than I have without building an extension of some sort at the +8" level.
Not impossible but still looking for the 'best way'.

I recall reading somewhere about a procedure of airing up the airbag to its fullest extent, cribbing under the bogie and then releasing the airbag
charge, which I understood was supposed to float the tire off the ground. Doesn't work for me - tire is still in pretty firm ground contact and does
not seem to want to budge and I am reluctant to just pop off the lugnuts for fear of a major OOPS! What am I doing wrong?

Thanks in advance

Stu
--
Stu Rasmussen W7QJ
Silverton, OR
'77 Birchaven

[Jon Roche via Gmclist]

Go buy some aluminum wheels. That will help. Amazing how heavy the steel
Rims/tires are.

You can make a bar, a leaf spring works well,
But needs to be a stout piece of steel plate.

Here is info:

http://www.gmcmhphotos.com/photos/g6509-blaze-orange-bogie-leaf-spring.html


Hopefully fires are staying away. Scott mills/crooked finger is way to close for comfort for silverton!

--
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/

[Jim Kanomata via Gmclist]

We sell those leaf spring helper bars.
We use them constantly in our shop as we do not need to jack the rear up as
much.

--
Jim Kanomata
Applied/GMC, Newark,CA
ji...@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502

[Stu Rasmussen (97381.com) via Gmclist]

Ah, thanks Jon - and thanks Jim Kanamota - you have _everything_ in
stock!

Aluminum wheels would be very nice but not in the budget until I
absolutely need to replace the tires. Even then I dread hearing my
wallet screaming long into the night.

I mis-remembered about lifting and re-searched the archive and found
this:

With either the OEM or upgraded systems, an important accessory is a
piece
of steel bar stock, 3/8"x2.5"x12"-14" (some use a piece of an old leaf
spring). After raising the coach to where the suspension arms are level,
slide that bar into the bogie beneath the suspension arms so that each
of
them is prevented from dropping lower. DUMP THE AIR from the air bags
before jacking further!!!. Now you'll only have to jack the coach about
1/2 as much as without that aid. The shock absorber will also be
protected
from excessive loading.

So it's off to my scrap bin for a small chunk of steel bar stock to make
the lifting bar. That should help immensely.

I'm not sure where the 'block up the bogie' memory item came from and
it's challenging to keyword search the forum sometimes.

Thanks again!

Regarding the wildfire situation, right now it looks like our evacuation
status is more yo do with bad air quality rather than actual fire
exposure - but we're ready to bugout in the partially operational GMC in
either event. Let's hope it rains soon. The winds have died down quite a
bit.

Stu

On 2020-09-09 15:56, Jon Roche via Gmclist wrote:
> Go buy some aluminum wheels. That will help. Amazing how heavy the
> steel
> Rims/tires are.
>
> You can make a bar, a leaf spring works well,
> But needs to be a stout piece of steel plate.
>
> Here is info:
>
> http://www.gmcmhphotos.com/photos/g6509-blaze-orange-bogie-leaf-spring.html
>
>
> Hopefully fires are staying away. Scott mills/crooked finger is way
> to close for comfort for silverton!

[Jim Kanomata via Gmclist]

We are the largest supplier and we help lot of people looking for parts.
Spende lot of times sourcing parts and getting on phone few hours a day and
making friends.

--
Jim Kanomata
Applied/GMC, Newark,CA
ji...@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502