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Binding disk brake, 150 miles after MOT :(
- 08-20-2012
posted on August 20, 2012, 6:20 am
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many miles in it, only 150 since then in fact.
At the weekend I was on the motorway when I noticed a whistling sound
from the back; when I stopped I discovered one of the rear disk brakes
was binding and very hot. I called Autoaid out and the guy who attended
examined the calliper and disk and recommended trailering the car home.
I asked whether he thought this imminent failure should have been
picked up at the service/MOT and he said 'I'd have thought so, yes'.
He also said that the wheel nuts weren't tight enough; furthermore when
he drove the vehicle up the ramp on to his truck he had a hell of a job
getting the handbrake to stick and said that was wrong too.
So I'm just back from a return visit to the garage, and the conversation
went exactly as I could have predicted.
1. "Absolutely no way you could tell in advance that the brake was about
to bind. More likely to happen given your low mileage"
2. "The wheel nuts would have been tightened to the manufacturer's
specs, no more, no less"
3. "Well the brakes were buggered having binded, so not surprising"
In other words, one mechanic's view against another; and no-nothing me
caught in the middle.
I don't know whether to take the view of the garage (a local
independent, apparently well-respected I think) or the recovery guy.
I've only used the garage a couple of times before (and they were
apparently fine), after my previous (excellent) independent garage
relocated, and I don't know of anywhere else 'better' to try; ie I don't
want to leave this place if criticism is actually unfair. In the
meantime I took the vehicle away and am considering my options
Any thoughts?
Thanks
David
Re: Binding disk brake, 150 miles after MOT :(
If it was binding _when it went in_ for a service, I'd expect them to
pick this up (but not on an MOT). So this is either:
* It was binding before and they didn't notice.
* It started binding afterwards because there was a discarded MOT
inspector's stamp caught in the caliper
* It randomly started binding shortly afterwards, despite this only
being a short time.
Your call.
It's unusual to _remove_ nuts with a torque wrench, so how would he
know? However someone who is used to heaving on over-tightened and
seized nuts all day is going to be surprised when they meet one that's
tightened correctly to the fairly modest torques per spec.
Hard to say without knowing the handbrake design for this model, but
it seems likely.
You have a binding brake caliper and it needs fixing. All else is
likely to be unproductive.
Re: Binding disk brake, 150 miles after MOT :(
[...]
Yep, that doesn't sound unreasonable to me.
How did the recovery guy judge that the wheel nuts were too loose?
(Unless they were only finger tight, of course.)
Generally, wheel nuts are massively overtightened. If you do them up to
spec with a torque wrench, it never seems enough.
Again, you wouldn't expect a seized and overheated brake to work properly.
If those problems were predictable at service, it would have been in the
garage's interest to have advised you in case they got the extra work.
It would be difficult for the person conducting the MOT to have failed to
spot a brake defect; it's pretty much all done by machine.
Was the person who attended at the roadside actually a mechanic? AFAIK,
Autoaid just use a local breakdown service, and those guys are not
normally what one would think of as a mechanic.
If you have been happy with the garage up to now, I personally would get
them to quote for the repairs. As you have been a bit unlucky, they may
give you a favourable price.
Chris
--
Remove prejudice to reply.
Re: Binding disk brake, 150 miles after MOT :(
Ended up going back; they stripped it down and cleaned it all up
(without taking the opportunity to replace everything, which they warned
might be necessary) for £36, which I thought was a pretty good result,
and we're all friends again...
Thanks again all for the advice
David
Re: Binding disk brake, 150 miles after MOT :(
I've just changed a set of disks and pads for a car that had it's MOT
not long ago.
This car was laid up for a year or so, and what I believe to have
happened is that the pad material delaminated from the backing,
presuming from the expansion of rust between the two.
The result was metal to metal binding, the pad becoming lodged between
the calliper and disk, consequentially wearing the disk down to a few mm.
In short anything could happen, I'm sure the MOT testing station would
say if they could see anything untoward. Furthermore visibility of the
calliper/pad assembly is pretty much obscured by the wheel and
suspension components and disc protection/cover.
Sorry but I'd take it on the chin, and not pay too much attention to the
recovery guy.
Re: Binding disk brake, 150 miles after MOT :(
Brakes are more prone to seizing on a car that doesn't do many miles, and I
have heard of problems with Bosch rear callipers seizing on Zafiras. These
were replaced in production with Lucas rear callipers.
Mike
Re: Binding disk brake, 150 miles after MOT :(
Not a chance unless either the garage or the MOT station had a crystal ball.
Even I can't always tell what's going to happen six weeks in the future and
I'm psychic!
Anecdotal and pointless fretting about unless they were actually falling
off.
furthermore when
Hardly surprising if a rear caliper is now faulty which is what the
handbrake operates on.
You're overanalysing something that amounts to nowt.
--
Dave Baker
Re: Binding disk brake, 150 miles after MOT :(
years).
AA guy who came out said that the pads were within limits but over time the
disks have gained a groove where the pads wear them. With very little use,
the callipers are stiff and rust off the disks, which builds up between
infrequent uses - I can see it!, has probably got in and made things worse.
Also, as the disks are adjusted for pad wear, the callipers end up working
sections have had years to "rust" adding further to the problem.
Net result, the pads stick on instead of releasing properly.
His recommendation was to get the pads replaced more often. I got the pads
replaced with new, and adjusted of course, and everything is fine again.
Paul DS
Re: Binding disk brake, 150 miles after MOT :(
I'd say not. Neither of those involves getting the brakes hot - just a
check they are up to spec on the MOT and who knows on the service?
Some services require they are stripped and cleaned - maybe even the
brake fluid changed. Did the one you paid for include this? Your service
book should give details of the work meant to be carried out at the
various services. In other words all 'services' ain't the same.
Did he check the nuts with a torque wrench before undoing them? If not,
he's guessing. Also if a rear brake got cooked it's quite possible the
handbrake on that side suffered too.
Their comments have the same sort of validity as the recovery chap's. How
can whoever be sure a torque wrench was actually used? Nobody is perfect
so mistakes happen. And garages in general make far more than any other
trade - surprising given the rates they charge.
If you're generally satisfied with your garage stick with them. And you
can't really expect them to take responsibility for anything unless clear
cut. And often not even then...
--
*Nostalgia isn't what is used to be.
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
Re: Binding disk brake, 150 miles after MOT :(
The handbrake efficiency is an MoT item and it is doubtful whether this
would have seized to the extent of not working in 6 weeks.
The footbrake efficiency and balance is an MoT item but unless the
brakes were not operating efficiently or releasing at the time I would
imagine it would not fail. You would need to check what the service was
supposed to cover to ascertain whether it had not been carried out properly.
My first wife had a Fiat Uno with a a handbrake that was barely
efficient enough to pass an MoT with every part of moving perfectly
freely. A feature of that model I was told.
The foot operated brakes always applied correctly but the front
callipers were forever corroding outside the cylinder and causing the
brakes to bind,
Low mileage cars do tend to have more problems with things seizing,
condensation poling in exhausts etc.
Re: Binding disk brake, 150 miles after MOT :(
Many thanks for all the words of wisdom folks. Sounds like I'll be
giving the garage the benefit of any doubt, and taking the car back to
them to sort out.
(FWIW the 'recovery' guy *was* apparently a mechanic; he arrived armed
with two quotes, for either a roadside fix or a trailer job, depending
on what he found).
Thanks
David
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