C8 Front Brakes Binding

[Gairloch]

Hi folks

 

Hoping that maybe someone has come across an issue I'm having with the C8 (2004 2.2hdi) and can maybe offer some words of advice.

 

Car failed MOT, needed pads and discs at front, also some rear brake cables. Long story short, I've replaced rear handbrake cables, drivers rear caliper, both front calipers, front discs and pads. Took it back for retest and it failed. The front brakes now binding on the test, in fact you couldnt even push the car - although it seemed ok on way to MOT station. So, after doing some research, I confirmed the cross rod to servo is moving (I cut a hole in passenger side bulkhead so I could see it!), so only thing left (or so I thought) was master cylinder. I changed master cylinder and although the pedal wasn't great after (bit of travel in pedal), it did pass MOT!

 

Hurray! Or so I thought. Today brake started binding again, couldnt get above 40mph, smoke from drivers front brake. Seems like the intermittant nature of the fault was all that allowed me to pass MOT test, and the orginal fault still persists.

 

Now, I've read that sometimes when you change pads and discs you can damage the servo. Seems like when you push the pistons in calipers back you can cause some damage internally. I did have problems pushing piston back at the time,hence why I changed calipers. But maybe I caused the fault when I changed the discs and pads at front?

 

Anyway, I'm thinking of having servo changed, but all indications are that I need to remove engine to do this - a considerable job! So before undertaking this, I'm asking if anyone else has come across this problem, how they rectified it, or indeed if anyone has changed a servo for these symptoms? Is servo failure possible considering the symptoms and the work carried out?

 

Any advice, greatly appreciated

 

Best regards,

Gairloch

Edited November 10, 2014 by Gairloch

[coastline taxis]

have you checked the slide mounts on the front calipers to see if there free. its the bit were the 2 caliper retaining bolts go into and has a rubber bellow on each one. you should be able to slide them in and out very easily whith the caliper removed

[Gairloch]

Hi, thanks for reply, I appreciate any input.

 

The caliper slides are free, don't think there's a problem there. I should have said in my original post - when the brakes sticks on, if I switch of the engine and press the brake, when the brake pedal is released the brake also releases, as if the vacuum has been exhausted. Oh, and I've also changed the servo valve.

 

Sorry, should have included this information in my original post.

 

Any help much appreciated

 

Best regards,

Gairloch

[coastline taxis]

Ok. check the flexi pipes as sometimes when they go they can turn into a sort of one way valve. get someone to press pedal and check for signs of bulging outward also try clamping them of at the very top were they met the metal brake pipe

[Gairloch]

Again, my fault for not fully detailing the work done (it's been so much!). I have 4 new flexi pipes on the car already in an effort to cure problem.

 

Thankyou for any further advice

 

Best regards

Gairloch

[paul.h]

My first thoughts are a caliper piston is seized/sticking and when you pushed it in to fit new pads a damaged/rusty/dirty part of the piston caused it to stick even more. If you did not use new calipers when the old were replaced, then these could also have the same problem. A bit more travel on the pedal after the work could be air still in the system or because the brakes are now free to move - but if you got air in the abs pump/valve system then it probably needs Lexia diagnostic equipment to bleed the air out.

 

Is it just one brake (you sometimes mention the driver's front and other times it is not clear) that binds or a front and opposite rear or both front or all 4 brakes ? If not sure, when it is binding, undo that brake bleed nipple to release the fluid pressure - if this then releases the brake you know it is fluid/pressure related and not a mechanical problem such as a sticking caliper piston.

 

Were the replacement parts all new ones or did you use second hand ones ? Could you move the caliper pistons in by hand without needing to use a clamp ? When you replaced the pads/discs were all the pads worn equally ? Was there any wear on the caliper /pads support brackets that could be causing the pads to not move easily ?

 

If it was a servo fault then I would think that would affect all 4 brakes, but if the brakes are stuck on you could try disconnecting its vacuum hose to see if it releases the brakes without having to touch the pedal.

[Gilbern Invader]

I recall someone on the peugeot website had this problem, turned out to be dry the cross shaft to the master cylinder sticking in the bearings. Can't rember how he got access to lubricate them