C4 VTR 2013 Brake Issue

[Daibach]

Foam pad

Thanks for that Marc. Would you be able to locate part numbers for the foam pads as per the attached photo. This is the driver's side one and I believe ( thanks to PaulC5) that there should also be one on the passenger side. The pad appears to be attached to the body at the top of the mudguard by means of a bright green plastic stud. This may possibly be a separate item to the pad. Thanks once again for your help.

[Daibach]

]SAM_6379.JPGHi Everyone, Just FYI I bought these new undertrays...bumper and engine...from Intercarparts and my garage reports that they fit well and all the holes line up. I just pass this info on because I thought the prices were reasonable and the delivery was next day, so it might be of use to somebody looking for the same bits.

[GiveMeABreak]

Thanks for that Marc. Would you be able to locate part numbers for the foam pads as per the attached photo. This is the driver's side one and I believe ( thanks to PaulC5) that there should also be one on the passenger side. The pad appears to be attached to the body at the top of the mudguard by means of a bright green plastic stud. This may possibly be a separate item to the pad. Thanks once again for your help.

Hi Dai

If you want part numbers, please can you request them in the main official part numbers thread, as I may not pick up the request elsewhere - just picked up this thread now.

Citroen, DS Automobiles and Peugeot Official Part Number Requests

(13) Foam

Right, part: 9809092980, £17.78
Left, part: 9809093080, £17.78

[Daibach]

Thanks yet again Marc. When you refer to left side and right side, I assume that for a UK market car right side is driver's side and left side is passenger side.

[GiveMeABreak]

Yes, that's correct Dai - so left and right as from the point of sitting inside the car.

[Daibach]

Thanks again, butty.

[Daibach]

Well, I am now getting random varying amounts of pedal travel before the brakes come on which is a bit scary in town driving ( especially at 20mph). I noticed today that if I push the brake pedal with the park brake on (separate drums to rear service brake discs I believe) and engine off it goes down along way with a hiss coming from somewhere behind the centre console ( or at least in that area). Do this a couple of times and the pedal goes solid.ie run out of vacuum boost. So does this mean a vacuum leak behind the panel somewhere or is this normal? Can anyone help please?

[PaulC5]

The C4s we've had did not have any drums at the back for the handbrake, it just worked on the caliper and disc. If you are only getting the vacuum hiss and going hard with a lot less travel with the engine off then this is normal for cars as you gradually use up the servo vacuum.

If not already done, the brakes might need servicing/cleaning in case they are a bit seized and also bleeding to remove any air. To bleed them fully though needs a diagnostic to get air out of the abs system.

[GiveMeABreak]

Yes, no drums on these, the parking brake cables just act on the rear calipers.

When did you last have the brake fluid changed? It is supposed to be done every 2 years and then must be bled correctly for both the primary and secondary systems - 1 using the manual bleeding, then secondly using the diagnostic tool for the ESP system. If this is not done you'll have problems for sure.

[Daibach]

Thanks for that info Paul. When I got the car in February this year I got my local garage to strip out and clean the brakes, lube up the slides, etc. So hopefully we can rule out that side of it. They did say that the rear discs were a bit scored, but it was not necessary to replace them just yet. I'm thinking that I should replace them anyway and also the rear pads. I am coming down in favour of a brake bleed too, since I feel that most of the stopping is happening on the front brakes. The pedal is doing all the expected things once I have dumped the vacuum out of the system, ie hard pedal at the top of the travel, with the pedal softening and increased travel as the vacuum builds. It seems to take a while to get a vacuum build up and I am wondering if there is a faulty non return valve somewhere. Also I reported hearing the sound of vacuum being released inside the car, but this sound is not there with the engine running. Am I right in thinking the vac tank is in the driver side front chassis member? Which is totally opposite to where I hear this vacuum/air release sound.

[Daibach]

Thanks for the info Marc. As I have said to Paul, I am coming down in favour of air in the system somewhere. I have only had the car since Feb this year, so from what you are saying it would be best to get the brake fluid flushed out and renewed. Then at least I've got a datum to start from. You mention needing diagnostics to bleed the brakes properly. Is this something that my local garage would either have or be able to access do you think? Also is any special equipment needed for this brake bleed? Finally, being a bit cheeky, can you explain to me how the park brake operates by moving the callipers. Thanks again.

[GiveMeABreak]

For normal braking using the foot brake pedal, the pads are just compressed and released by the piston under hydraulic pressure as you know. The handbrake operation basically has cables routed via cable guides to each of the rear calipers. The cables are attached to a mechanism on the caliper, such that when the handbrake is pulled, it rotates the screw-type piston, (the same as the hydraulic pressure would do when using the foot brake) and applies pressure on the pads. When released the pads ease off.

When you change the rear pads on this vehicle, this is why you need a piston wind back tool to screw the piston back to allow room for the new pads to fit in.