front brakes binding after new master cylinder
strassenbaum
Seicento 1.1 2001.
Has just had a new master cylinder fitted.
Brakes OK when testing (cold) but on journey, fronts fail to release and
get very hot. Freeing off pipe unions at master cylinder OR waiting till
cold releases them.
Long version
My sisters seicento passed its MOT but she was told it needed the master
cylinder replaced. She took it in and has this done. about 10 days later
I got a call from her - stuck at side of road with the car smelling and
making a "funny noise". When I got there one brake was binding and I was
able to free it off by levering caliper away from pad. I moved the
piston many times thinking it was probably the cause. The problem
occurred again and so I replaced the flexible hose to that side - having
read they can sometimes break down inside and fail to release the
pressure. I also greased the caliper bolt and found I could press the
piston in ok with just finger pressure.
The car seemed fine under testing once I'd got it bled (difficult and I
had to use pressure for). The pedal was going down a long way and I was
planning to bleed more thoroughly, but that changed and brakes seemed to
be working well.
I was sceptical when told the same brake was heating again, however it
has happened again tonight. When I got there the brakes had freed off
and I had to do nothing more than tell her she could drive it home. I
told her not to use the brakes if possible, and she didn't - until she
met another car and had to draw into the side. About 300 yards both
front brakes were hot. I jacked it up and both sides were locked.
Momentarily freeing off the pipe unions at the master cylinder released
the pressure in the brakes immediately.
It looks as if the master cylinder is not letting the brake fluid back
in from the front wheels when the car is warmed up. What could cause this?
Adrian
saying:
> It looks as if the master cylinder is not letting the brake fluid back
> in from the front wheels when the car is warmed up. What could cause
> this?
ABS on it?
If it is, then gawd knows. If not, then a duff master is the most likely
cause. Just because it's new, doesn't mean it's good.
strassenbaum
No ABS and I don't know if the master cylinder is new - looks more like
recon to me.
steve robinson
Faulty replacement master cylinder , abs system not reset correctly
if fitted , incorrect fluid / contaminated fluid used
steve robinson
Take it back to the garage who fitted the new cylinder
Chris Whelan
> Short version
> Seicento 1.1 2001.
> Has just had a new master cylinder fitted. Brakes OK when testing (cold)
> but on journey, fronts fail to release and get very hot. Freeing off
> pipe unions at master cylinder OR waiting till cold releases them.
Only time I've had this was when the master cylinder was overfilled.
Chris
--
Remove prejudice to reply.
strassenbaum
Taking the top off did not release the pressure so although it is pretty
full, I don't think it can be that.
Chris Whelan
No, if it was pressurised you would be in trouble!
It still shouldn't be filled above the Max line though, and it's the
easiest of your options to try.
strassenbaum
OK - will try that, although if it is overfilling, it looks like the
garage is also of the overfilling school as I didn't fill it until after
the problem started. To be honest, I never even look for a max line -
just put in what seems right to me. I've never thought of it as a
potential problem before - so thanks.
Mrcheerful
when the brakes are stuck on, try undoing the bolts that hold the master
cylinder to the servo, if the brakes release then you know that the cylinder
is being slightly pushed all the time, which will stop fluid returning
easily, it will be worse when the system is hot. The brake pedal/linkage
may be pushing the cylinder slightly. The rod that pushes the master
cylinder may be adjustable. If so then back it off a little. best advice
though is to just take it back and let the supplier fix it.
Adrian
"new-to-you".
If it's a recon, it's even more likely. I had a pair of recon rear
calipers a few months back. One went straight back - stripped thread on
the handbrake adjuster.
Rob
had the same sort of thoughts.
Could be they didn't bleed the system enough and adjusted the rod to get
a peddle (pressure). hence blocking the return hole in the master cylinder.
When the air has settled out after a day or two hence the results.
strassenbaum
I phoned the garage who agreed to take it back and replace - then phoned
me back a bit later with the info that the supplier of the (confirmed
recon) unit states they've had a few faulty ones - and so he has ordered
a genuine part and intend to supply and fit it free. So this sounds good
news.
He did say there is no adjustment.
steve robinson
good result
Steve Firth
Very. The garage seems decent. If the end result is good, it may be worth
naming them.
Harry Bloomfield
> Momentarily freeing off the pipe unions at the master cylinder released the
> pressure in the brakes immediately.
>
> It looks as if the master cylinder is not letting the brake fluid back in
> from the front wheels when the car is warmed up. What could cause this?
Therefor it has to be a fault with the new master cylinder.
--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk
shazzbat
"strassenbaum" <1...@cl.ock> wrote in message
news:8snc0v...@mid.individual.net...
also be achieved by shimming. Not normally necessary, the only one I ever
had to adjust when changing a master cyl was one which had too much
clearance and gave a long pedal movement before operating the brakes ie the
opposite of your problem. Half a turn on the nut fixed it. This is probably
what your garage are going to do.
Steve
Chris Whelan
[...]
> There has to be adjustment.
Why?
> Usually on the servo actuating rod, but It
> could also be achieved by shimming. Not normally necessary, the only one
> I ever had to adjust when changing a master cyl was one which had too
> much clearance and gave a long pedal movement before operating the
> brakes ie the opposite of your problem. Half a turn on the nut fixed
> it. This is probably what your garage are going to do.
>
> Steve
I haven't seen an adjustable link to a brake master cylinder in years.
Things are manufactured to just fit these days. Even the accelerator
cable on my Focus has no adjustment.
shazzbat
"Chris Whelan" <cawh...@prejudicentlworld.com> wrote in message
news:ik85oc$h6q$1...@news.eternal-september.org...
> On Fri, 25 Feb 2011 11:11:43 +0000, shazzbat wrote:
>
> [...]
>
>> There has to be adjustment.
>
> Why?
>
seicento, but if there isn't some means of ensuring the correct clearance
I'll eat my toolbox.
Steve
Chris Whelan
I've browsed several threads on brakes here:
and looked at illustrations of Seicento master cylinders online, and from
what I can see, you might need to sharpen your false teeth!
shazzbat
I don't think so. I can't find a decent pic of a seicento servo, but this
from a clio clearly shows the adjustment I referred to. I'm confident
the seicento will have something very similar.
Steve
Chris Whelan
> "Chris Whelan" <cawh...@prejudicentlworld.com> wrote in message
> news:ik8iq7$87b$1...@news.eternal-september.org...
>> On Fri, 25 Feb 2011 15:26:58 +0000, shazzbat wrote:
>>
>>> "Chris Whelan" <cawh...@prejudicentlworld.com> wrote in message
>>> news:ik85oc$h6q$1...@news.eternal-september.org...
>>>> On Fri, 25 Feb 2011 11:11:43 +0000, shazzbat wrote:
>>>>
>>>> [...]
>>>>
>>>>> There has to be adjustment.
>>>>
>>>> Why?
>>>>
>>> Because if not you get the problem the OP has. I'm not familiar with
>>> the seicento, but if there isn't some means of ensuring the correct
>>> clearance I'll eat my toolbox.
>>> Steve
>>
>> I've browsed several threads on brakes here:
>>
>> http://www.fiatforum.com/
>>
>> and looked at illustrations of Seicento master cylinders online, and
>> from what I can see, you might need to sharpen your false teeth!
>>
>>
> I don't think so. I can't find a decent pic of a seicento servo, but
> this from a clio clearly shows the adjustment I referred to. I'm
> confident the seicento will have something very similar.
>
> tinyurl.com/6f3xrvz
>
>
> Steve
You may well be right; the thing is, you said "There has to be an
adjustment", but many (most?) modern cars don't have one, so it's
possible the OP's doesn't.
shazzbat
I don't accept that claim. Firstly because it's inconceivable that
manufacturers wouldn't build in a means of setting up to the correct
tolerance, and also because every servo that I see pics of when searching
seems to have the same or very similar arrangements.
Steve
strassenbaum
LOL! - whilst claiming to be fitting a brand new unit from Fiat! It is
not hard to imagine such a trick - would cost the garage nothing and
leave the customer thinking how generous they were - but I believe what
he says and the master cylinder is easy to get at and view - so easy to
see it it looks the same.
It wouldn't surprise me at all if this car didn't have adjustment. The
brake & clutch mechanism involves a LH drive conversion kit to transfer
the force from the RH pedals over to the brake master cylinder and the
clutch cable on the left - giving a lot of extra scope for wear, play
and failure I'd have thought. It is the first car I've seen with such a
nasty cheap method of producing a car for the UK market.
Rob
Wonder if they have a set-up procedure for the master cylinder.
I can't see any manufacturer having a perfect car which the master
cylinder will fit exactly each and every time. Could be shimmed.
Chris Whelan
[...]
> I don't accept that claim. Firstly because it's inconceivable that
> manufacturers wouldn't build in a means of setting up to the correct
> tolerance,
Why would you need to? It's less expensive to have no means of
adjustment. You only need to ensure that there is always some clearance -
perhaps 1 or 2mm. The difference in pedal position to when the brakes
start to operate between different vehicles would be negligible.
> and also because every servo that I see pics of when
> searching seems to have the same or very similar arrangements.
<Shrug>
Well, Fords don't have them, and the last m/c I changed was my Son's
Beemer, which also didn't have any adjustment.
Duncan Wood
shazzbat
> On Fri, 25 Feb 2011 19:13:36 +0000, shazzbat wrote:
>
> [...]
>
>> I don't accept that claim. Firstly because it's inconceivable that
>> manufacturers wouldn't build in a means of setting up to the correct
>> tolerance,
>
> Why would you need to? It's less expensive to have no means of
> adjustment. You only need to ensure that there is always some clearance -
> perhaps 1 or 2mm. The difference in pedal position to when the brakes
> start to operate between different vehicles would be negligible.
You ned to because it's absolutely vital to have some clearance, or you get
the OPs problem. Manufacturers have to allow for a range of variables in
manufacture, including sourcing parts from different suppliers, fitting
different m/cyl to different models in a range, changes from year to year in
one part or another. the list is endless. All of these things can affect the
clearance. There has to be a way of setting up.
>
>> and also because every servo that I see pics of when
>> searching seems to have the same or very similar arrangements.
>
> <Shrug>
>
> Well, Fords don't have them, and the last m/c I changed was my Son's
> Beemer, which also didn't have any adjustment.
>
Excuse me, mondeo, focus and Ka do, as do some beemers and volvos I looked
at this evening. Which fords are you referring to?
Steve
Paul
>>
>> Steve
>
> You may well be right; the thing is, you said "There has to be an
> adjustment", but many (most?) modern cars don't have one, so it's
> possible the OP's doesn't.
>
> Chris
>
Define modern - by a very strange co-incidence mate was descibing this
very problem on his ten year old Audi
Steve Firth
[adjusting disc brake clearances]
>
> You ned to because it's absolutely vital to have some clearance, or you
> get the OPs problem. Manufacturers have to allow for a range of variables
> in manufacture, including sourcing parts from different suppliers,
> fitting different m/cyl to different models in a range, changes from year
> to year in one part or another. the list is endless. All of these things
> can affect the clearance. There has to be a way of setting up.
I'm sorry but you don't seem to have a clue about how disk brakes work.
They have no adjusters because the don't need them. The design of a disk
brake makes them self adjusting. Otherwise one would have to continuously
adjust brakes as the pads and disks wear.
Applying pressure to the brake causes the slave piston to compress the pads
onto the disk. When the pedal is released the cylinder detracts slightly
leaving adequate clearance between disk and pad. As the pad wears the
extrusion of the cylinder takes up the slack but the rebound when the brake
us released always leaves the same clearance hence the brakes take up the
wear of the pad.
If the brake us binding then usually there's avproblem with the slave
cylinder. On recon brakes this is often pitting and corrosion that the
remanufacturer has not repaired properly. The corrosion stops the cylinders
from retracting as they should.
shazzbat
"Steve Firth" <%steve%@malloc.co.uk> wrote in message
news:909538562320414796.758704%steve%-mallo...@news.individual.net...
I suggest you read the thread before commenting furrther.
Steve
Adrian
they were saying:
> I'm sorry but you don't seem to have a clue about how disk brakes work.
> They have no adjusters because the don't need them. The design of a disk
> brake makes them self adjusting. Otherwise one would have to
> continuously adjust brakes as the pads and disks wear.
Umm, Steve... The question was whether the actuator rod between pedal/
linkage and master is adjustable. Not whether the wheel end is adjustable.
> If the brake us binding then usually there's avproblem with the slave
> cylinder.
Umm, Steve... It's definitely the master. That's all been gone through.
John Henderson
> Define modern - by a very strange co-incidence mate was descibing this
> very problem on his ten year old Audi
Brakes dragging?
I've read this thread with interest, having had dragging brakes
(with brake pedal feeling too high) on my 1996 VW Transporter
(disc brakes all round). This happened immediately after I
changed the brake fluid.
I bleed the brakes again, this time taking care to pump the pedal
more slowly in the process. That cured the problem, coincidence
or not.
The advice about pumping slowly was in the workshop manual for my
Nissan.
John
Grimly Curmudgeon
drugs began to take hold. I remember strassenbaum <1...@cl.ock> saying
something like:
>It wouldn't surprise me at all if this car didn't have adjustment. The
>brake & clutch mechanism involves a LH drive conversion kit to transfer
>the force from the RH pedals over to the brake master cylinder and the
>clutch cable on the left - giving a lot of extra scope for wear, play
>and failure I'd have thought. It is the first car I've seen with such a
>nasty cheap method of producing a car for the UK market.
It's not new, that method. Istr the early Fiesta or Polo did something
similar.
Adrian
sounding much like they were saying:
>>It wouldn't surprise me at all if this car didn't have adjustment. The
>>brake & clutch mechanism involves a LH drive conversion kit to transfer
>>the force from the RH pedals over to the brake master cylinder and the
>>clutch cable on the left - giving a lot of extra scope for wear, play
>>and failure I'd have thought. It is the first car I've seen with such a
>>nasty cheap method of producing a car for the UK market.
> It's not new, that method. Istr the early Fiesta or Polo did something
> similar.
It's far from unknown. My Saab's like that - to do it "properly" would
have required the heater box and (slightly more difficult) the cylinder
head to be moved to the other side of the car. '70s 2cvs did it for the
rod throttle.
Done properly, it's not the end of the world.
SteveH
Chris Bartram
> Adrian<tooma...@gmail.com> wrote:
>
>> Grimly Curmudgeon<grimly...@REMOVEgmail.com> gurgled happily,
>> sounding much like they were saying:
>>
>>>> It wouldn't surprise me at all if this car didn't have adjustment. The
>>>> the force from the RH pedals over to the brake master cylinder and the
>>>> clutch cable on the left - giving a lot of extra scope for wear, play
>>>> and failure I'd have thought. It is the first car I've seen with such a
>>>> nasty cheap method of producing a car for the UK market.
>>
>>> It's not new, that method. Istr the early Fiesta or Polo did something
>>> similar.
>>
>> It's far from unknown. My Saab's like that - to do it "properly" would
>> have required the heater box and (slightly more difficult) the cylinder
>> head to be moved to the other side of the car. '70s 2cvs did it for the
>> rod throttle.
>>
>> Done properly, it's not the end of the world.
>
> Isn't the MkI Golf and Scirocco the same, too?
master cyl was in the right place, but no room for a servo. Mind you, it
didn't need one if the brakes were in good order.
The Golf/Scirocco mechanism was criticised for the amount of give. It
was adjustable though. The clutch cable *always* used to pull through
the bulkhead too- most cars had repair plates fitted.
For a while, a tuner (Autocavan, IIRC) did a much more substantial
upgraded brake linkage. Quite expensive at the time, very hard to find now.