ZX 1.4i new brakes overheating on offside front

DHJ · Unread post by **DHJ** » 24 Jul 2006, 19:35

(My first posting here. Originally posted at Honest John, they suggested trying here.)

9 months / 4000 miles ago I had a total brake failure on my 1997 Citroen ZX 1.4i, apparently due to fluid fade. The offside front got so hot that the disc turned blue and the insulation melted on the pad wear sensor wire. My local authorised Citroen independent diagnosed a faulty OSF caliper causing binding & consequent overheating, and replaced the front calipers, discs and pads both sides, plus offside front flexible hose. (Also rear cylinders and shoes as these were poor.)

The other day I had a loss of braking efficiency and a smell of friction material after coming down a big hill. I'd used a low gear to control speed but still had to brake fairly firmly behind a slow caravan. After parking shortly afterwards, I found that the offside front was very hot, considerably hotter than the nearside. I inspected the brakes next day and found that the offside disc had a continuous band of grey discolouration, over about a quarter of the width of the disc surface. Turning the disc by hand, it was a little stiff most of the way round but freer over say 60-90 degrees. The nearside disc had no discolouration and movement was freer and more even. A friend thought the discs looked slightly glazed. Plenty left on the pads, both sides. The plastic offside pad wear sensor connector block was partly melted away on the side facing the disc. I don't know whether this got replaced when the calipers were done.

The calipers are marked "REMAN", presumably remanufactured. I naively assumed I was getting new calipers, but AFAIR I wasn't explicitly asked or told. They have a Bendix logo and consecutive serial numbers.

I hadn't checked the wheel temperatures before this, but since then I found that after every journey the offside was quite a lot hotter than the nearside.

My main worry is that I once again have an overheating offside front, which previously resulted in a scary brake failure. What might cause the same side to overheat despite having new calipers, discs & pads both sides? There's no temperature difference between the back wheels, which I imagine there might be if the cause was weakness in one circuit? Perhaps it's just co-incidence and I got a dodgy reconditioned offside calliper.

I took it back to the garage today, they say they tried hard to find something wrong but couldn't. They cleaned & lubricated & made sure the calipers were operating freely. Also checked on rolling road. After the 1-mile journey home with only gentle braking, the offside front wheel nuts were uncomfortable to touch for more than 2-3 seconds, whereas the nearside were only starting to become uncomfortable after 8-10 seconds. I think I'll take it for a good old spin, then straight round to the garage and invite them to feel my nuts.

AndersDK · Unread post by **AndersDK** » 24 Jul 2006, 20:36

Glazed or overheated brake discs may be caused by even the smallest amount of grease or oil.
This will reduce friction so much that you automatically press the pedal harder to compensate - generating lots of heat on the discs and pads - which then distributes to the caliper and thereabouts.
In severe cases you can catch a fire in the underbody antirust layer nearby.

It should be pointed out that new discs ALWAYS comes with a spray of greasy rust protection - and during work with the brakes you always leave greasy fingerprints on the discs. These MUST be cleaned off at finish of the brakes job. I'm confident your garage knows about that.

Problems that could cause grease on/overheat your brake disc are :
1) split gaiter on the driveaxle CVjoint
2) leakage from the driveaxle CVjoint gaiter strap not being tight
3) bottom triangle/control arm swivel joint leaking - possibly a missing joint protective heatshield
4) leaking McPherson strut damper
5) leaking front wheel bearing
6) front wheel bearing defective leaving wheel incorrectly angled to the caliper/brakes components
7) foreign ingress from engine bay just above the wheel compartment
8 ) - or from the roads

Its quite easy to DIY inspect the above points - and not expensive to let your garage checking them.

Honestly I can't think of a failing recon brake caliper. These are always cleaned/inspected for bore/piston problems - then fitted with new seals all over. Some are sandblasted - others are painted.
But once exposed to overheating the seals are damaged - which will cause the piston not to retract correctly - leaving the pads out on the disc.

You are aware that new brakes should be allowed to bed in the first 150miles or so ? - to avoid overheated and ineffective brakes.

DHJ · Unread post by **DHJ** » 24 Jul 2006, 20:52

Thanks for the reply. Would the oil contamination theory fit with the difference in temperature between the two sides? The garage billed me for brake cleaner when the calipers were fitted. I was told at that time to let the new brakes bed in for about 300 miles, then bring the car back in to have the brake adjustment checked, which I did.

AndersDK · Unread post by **AndersDK** » 24 Jul 2006, 21:23

DHJ wrote:Would the oil contamination theory fit with the difference in temperature between the two sides?

Errr...
Thats exactly the point mate

DHJ · Unread post by **DHJ** » 24 Jul 2006, 23:26

AndersDK wrote:
DHJ wrote:Would the oil contamination theory fit with the difference in temperature between the two sides?
Errr...
Thats exactly the point mate

Oil contamination on nearside -> reduced friction nearside -> greater force applied to pedal -> increased braking effort & heat offside.
Have I got that right? If so, would you expect the uneven braking force to be apparent through pulling to one side on braking, or when tested on a rolling road?

AndersDK · Unread post by **AndersDK** » 24 Jul 2006, 23:39

No -

The contaminated side will glaze and produce more heat - as the piston will not retract fom the previous heat damage - causing a constant drag and then heat.
Should be seen on a brake test station. The glazed brakes will have less brakes Bhp.

The good side will brake like it should - eventually causing the steering to pull out of control - if the car has no ABS.

jeremy · Unread post by **jeremy** » 25 Jul 2006, 08:02

Presumably this car has the Bendix front calipers - which are in fact the same as those fitted to a BX without the handbrake mechanism. This then leads to the fact that there are really only 2 common problems - and yes one is the handbrake. The other is that these are sliding calipers with only one active piston and the only normal problem is the slide bushes wear over evry considerable miles and generally the first thing noticed is uneven pad wear.

I say all this just to point out that the Bendix caliper is generally a very reliable component and unless something crassly stupid has been done (which would probably be easily visible) its virtually impossible that one set of bits has been replaced with another having the same fault. (Incidentally I wouldn't worry about remanufactured parts - its an EEC initiative (OK that doesn't inspire confidence) but its done under proper conditions and inspections and is really reuse of the bits which don't wear like castings.

To check the slides on the caliper - remove pads and it should slide easily and without shake.

If the brakes are releasing properly (I'm not quite sure from what you say) then its not likely to be a hydraulic problem. If it is not releasing - it could be hydraulic - in which case has the master cylinder been changed recently or anyone worked on the brake pedal or its linkage? - (Diagonal split brakes - if the pedal linkage (servo as well) is maladjusted the piston in the master cylinder may not go back far enough to allow recuperator port to be uncovered - (yes I know back brakes should be affected but they may not work properly even if renewed).

Other possibilities are internally damaged brake hose (flap splits off inside layer and acts as a valve - caused by crushing pipe to prevent fluid loss while servicing) or even a squashed steel brake pipe.

DHJ · Unread post by **DHJ** » 25 Jul 2006, 09:13

AndersDK wrote:The contaminated side will glaze and produce more heat - as the piston will not retract fom the previous heat damage - causing a constant drag and then heat.

Thanks for clarifying.

AndersDK wrote:Should be seen on a brake test station. The glazed brakes will have less brakes Bhp.

The good side will brake like it should - eventually causing the steering to pull out of control - if the car has no ABS.

The brakes were tested on a rolling road yesterday as part of the garage's investigation, and no unevenness was found. The car has no ABS. It was a friend who thought the discs looked slightly glazed, both sides; the garage did not say this, they said they couldn't find anything wrong.

LeeDJC · Unread post by **LeeDJC** » 25 Jul 2006, 09:20

To be honest - I think this is being overcomplicated.

It sounds like a result of cheap pads and/or discs. When I used to have a 205 diesel when I was a poor niave student I used to replace with cheap pads, they stopped the car, but not very well 100% of the time. They were always OK at first but declined fairly rapidly.

I also used to get some if not all of the symptoms which you describe above.

I'd be tempted to go out and get set of decent pads & discs change them and see how you get on, particularly if the garage can't find anything mechanically wrong with the calipers. (Especially as you described a disc being difficult to turn part of the way but free the rest - sounds like warped discs to me - happens very easily with a cheap pad/disc setup)

As soon as I put on decent pads/discs on mine all of these problems went away.

DHJ · Unread post by **DHJ** » 25 Jul 2006, 09:32

jeremy wrote:Presumably this car has the Bendix front calipers

That's correct. Thanks for the info on these.

jeremy wrote:To check the slides on the caliper - remove pads and it should slide easily and without shake.

The garage say they cleaned & lubricated and found everything to be moving freely.

jeremy wrote:If the brakes are releasing properly (I'm not quite sure from what you say) then its not likely to be a hydraulic problem.

I'm not entirely sure either! The garage said they are, but when I inspected the discs I found that the offside one was a bit stiff to turn over about 3/4 of a turn, freer over the remaining 1/4 turn. I guess I'll have to keep checking it.

jeremy wrote:If it is not releasing - it could be hydraulic - in which case has the master cylinder been changed recently or anyone worked on the brake pedal or its linkage?

The master cylinder has not been changed while I've owned the car (nearly 4 years / 23000 miles), nor has anyone worked on the brake pedal or linkage.

jeremy wrote:Other possibilities are internally damaged brake hose (flap splits off inside layer and acts as a valve - caused by crushing pipe to prevent fluid loss while servicing) or even a squashed steel brake pipe.

The offside front flexible hose was replaced when the calipers were done 9 months / 4000 miles ago. No work has been done on the brakes since then, other than the garage checking, cleaning & lubricating yesterday. I'll look out for pipe damage or CV gaiter leaks etc.

Thanks again for the replies,

Dave

DHJ · Unread post by **DHJ** » 25 Jul 2006, 09:52

LeeDJC wrote:It sounds like a result of cheap pads and/or discs.

I'd hope not, as they were done by an authorised Citroen repairer, but who knows?

LeeDJC wrote:I also used to get some if not all of the symptoms which you describe above.

Did one side get substantially hotter than the other?

LeeDJC wrote:(Especially as you described a disc being difficult to turn part of the way but free the rest - sounds like warped discs to me - happens very easily with a cheap pad/disc setup)

I wondered whether the disc was warped. I guess I'll give it a few more jouneys to verify that the offside overheating is still present, check periodically how freely the wheels/discs spin and get it back to the garage. It's only 9 months since they replaced the calipers, pads & discs so this should be covered under guarantee.

Thanks,

Dave

LeeDJC · Unread post by **LeeDJC** » 25 Jul 2006, 10:52

LeeDJC wrote:I also used to get some if not all of the symptoms which you describe above.

Did one side get substantially hotter than the other?
[/quote]

Not that I recall, but then - I always changed both sides at the same time!

mezuk04 · Unread post by **mezuk04** » 25 Jul 2006, 11:18

Sounds like a silly suggestion, but

Could it be down to the wheel sensor wire?

On my ZX I couldnt work out why there was a smell of rubber burning and afterwards why their was so much heat coming off the drivers side wheel.

After inspection, after the pad wear light just came on out of the blue (after some heavy driving/braking) it seemed that the rubber had some how come off the sensor and the bare wire (from memory) was touching the brake disc which inturn melted a good amount of the rubber connector surround "thingy", bare wire wrapped with some electrical tape and all was well.

Just thought I should mention, just incase!

rabenson · Unread post by **rabenson** » 25 Jul 2006, 11:59

Been there, got the T shirt....

Had the same problem on my ZX 1.9D. Mine had the Girling calipers which are generally not considered as reliable as the Bendix ones.

Everything was tried - caliper stripped, cleaned and lubed, flexible hose replaced, new disk, pads etc but to no avail. Replaced the caliper and everything was fine.

18 months later and the same thing happened again! Living in a hilly area, I couldn't have a car with dodgy brakes so had caliper replaced immediately - no problems til I sold the car 2 years later.

Ron

DHJ · Unread post by **DHJ** » 31 Jul 2006, 15:40

Thanks for the replies. The offside front is still getting a fair bit hotter than the nearside every journey; the garage's clean & lube doesn't appear to have changed anything. Good news is that it doesn't get a lot hotter on a long trip than a short one. I took another look yesterday:

Offside: band of discolouration previously noticed on the disc had gone. Disc a bit stiff to turn by hand, freer over about 1/4 of a turn, as before. Could hear pad rubbing against disc as I turned it. Could see daylight between the inner pad and the disc - therefore not a hydraulic problem, I take it. Outer pad was in contact with the disc surface. These are Bendix single-piston calipers, presumably the inner pad is the one attached to the piston. So I'm guessing the piston is retracting OK, but the caliper isn't sliding as freely as it should - does that sound right, or have I misunderstood how these calipers operate?

Nearside: disc freer to turn than than offside. Could see a tiny bit of daylight between each pad and disc. Noticed that on turning disc, gap between disc and pad varied slightly, by a hair's breadth or two. Haynes gives max run-out as 0.2mm, I'd guess it was in that sort of range.

No signs of leakage from gaiters etc. I'm not sure what to do now, the garage have already pronounced that the calipers are operating correctly.