Tools for C5 rear brake de-corrosion and replacement

[frenchcarnut]

Hi, nice to see this forum is still going.

Okay, I've got brake squeal and grinding/binding from the rear. I no longer have a comprehensive tool kit, but does anyone know what tools I will need for this job? Mk I @ 36000 miles as of signature below

As for sorting out the probable and expected corrosion, one Swedish site suggests this should be left to Citroën <ahem> and quotes:

Important! Brakeproblem, backbrakes C5!

Citroen C5 has problems with the brakes on the back wheels. The brake blocks are sucessively tightening due to corrosion problems. The car will because of this take slightly more petrol for each mile as time passes. This is happening already in the first years of use and when the brake blocks are worn out and you need to switch them there might be a severe problem to do this without getting heavy troubles with the tightness mentioned. To change the blocks properly is almost impossible to do yourself since you have to remove the holder of the blocks and clean it and make it corrosion free and you have to know how to clean the parts properly. It is in some cases not at all certain that you can visibly see whats wrong. Because of this the blockswitch is something that almost in every case must be done by a Citroen garage if you dont get very precise information by asking the manufacturer or one of their representatives. If you do the work yourself or let an ordinary, non Citroen garage do the work you will not know of this problem and the brakes will not work properly after the change of blocks although everything might look ok during and after the repair. The corrosion problem will still be there, almost impossible to discover and the brakes will be tight and not working properly after the change. The tightness can be severe and as a result of this the brakes might get over heated and damaged and your car might take maybe .2-.3l more petrol per 10 km. The function of the brakes might in the long run be affected and your new brake blocks will be worn out in a very short time
A Citroen garage can switch the brake blocks and do the work of restoring the function since they know of this problem and also exactly how to fix it. The cost will however be high for this since they have to take the system apart and clean it by grinding it.
The mentioned problem has been confirmed by several representatives working with Citroen cars and in spite of their knowledge the Citroen manufacturer has choosen not to do anything about this. As a result of this you will have the same problem repeating itself since the corrosion will always appear and grow in the system even after it has been properly cleaned and repaired and seems to be working properly . There is reason to warn the buyer or car owner for this problem. It is not easily handled and the cost is high for reparation and fo extra petrol. Since there are no replacement parts available you can not permanently get rid of the problem

There are in some cases additional corrosion problems on the back brakes of C5 which sometimes are so severe that you have to switch the block holder because it gets very damaged and the pin that holds the brake blocks threatens not to stay in place. These problems are easily spotted and very obvoius. In this case Citroen has chosen to prolong the warranty. However as said above they dont provide replacement parts that are of a better quality and because of this the prolonged warranty is a kind of trap since you will have problems returning and when the car is older you will have to pay for this yourself.
We strongly urge Citroen C5 buyers and C5 owners to demand that the Citroen manufacturer does something about this problem

Is this just an overreaction?

[steelcityuk]

Pretty common on Xantia's and XM's. Even the Autodata discs list it as a common fault. Don't see why it should be left to Citroen dealers. Common sense, few tools and some copperslip should see the job done.

Steve.

[frenchcarnut]

Thanks Steve

[davek-uk]

The job of replacing the rear pads is simple enough. Removing the callipers if you have significant corrosion can be a problem, though. My callipers were so bad that one retaining bolt had snapped and another one was bent! It was one hell of a job to drill the broken bolt out...

You have to remove all of the corrosion before you put it all back together or it'll be as bad again very quickly.

I placed a thick sheet of plastic between the callipers and the arm. This seems to have done a good job as 3+ years later they are still perfectly aligned. If you can make a simple gaskit, don't rely on copperslip or grease to prevent similar corrosion in the future.

Dave

[CTR]

Some photos:

1. This is how it looks (that white stuff was upt to 3mm thick):


2. The corner of the caliper touch the inner surface of the wheel:

[frenchcarnut]

CTR and Dave, great stuff. Much appreciated.

I used to do all this stuff myself but eventually lost all my tools to over the years ( I won't explain). But what I'll do is take one of the rear wheels off and take some photos and see what people think.

[frenchcarnut]

From the Citroën garage manual - The comprehensive "on bench" process!! <gulp>

Rear brakes
ESSENTIAL: When refitting the rear brake caliper, coat the face which will be in contact with the suspension arm with sealing product of type FORMAJOINT 510.

New components:
Rear brake caliper (3).
Rear brake pads (4).

Old fitting.
(1) Rear brake caliper.
(2) Rear brake pads

New fitting
(3) Rear brake caliper; drilled with holes at «a» and at «b».
(4) Rear brake pads.

WARNING: Identify the type of fitting, prior to any operation. Two types of fixing may be found on the new, drilled brake calipers.
IMPERATIVE: The type of fixing screws should be identical, on RH and LH sides.
Fixing screws not bonded.
Do not bond during a repair (refer to the remove-refit method for the rear brake caliper).
Fixing screws bonded.
Bond during a repair (refer to the remove-refit method hereafter).
IMPERATIVE: The fitting of brake pads (2) is prohibited.
BRAKES

Raise and support the vehicle, rear wheels hanging.
Remove:
The rear wheels.
The rear brake pads(see corresponding operation).

Fit the pin (7).
Tighten the nut (8) so as to keep the two half-calipers tight.
Uncouple the supply pipe (5).
Plug the union and the brake caliper.
Undo the screws (6).
Remove the brake caliper (3).
WARNING: The holes should be cleaned without damaging them.
On the bench:
Force out the screws (6), with a hammer, in order to remove the used bonding on the screw
threads.
Remove the screws (6), using a punch.
Immobilise a 10 mm drill bit in a vice.
Clean the brake caliper fixing screw holes, using the 10 mm drill bit.
Remove the bonding plugs, at «a» and at «b».

IMPERATIVE: Do not use compressed air to clean the brakes.
1st possibility.

Clean the disc and the caliper using an approved cleaning product.
Leave to dry out.
Wipe with a cloth.
2nd possibility.
Use an approved de-dusting product (see Tools and Equipment catalogue).
Refitting.
WARNING: Systematically replace the brake caliper fixing screws.
On the screws (6) spray activation aerosol LOCTITE 7649.
IMPERATIVE: Coat the surface between the brake caliper and the rear arm with sealing
product of type FORMAJOINT 510.
Position the brake caliper.
Tighten the screws (6) to 7 ± 0,7 m.daN.
Couple the supply pipe (5).
Inject in the holes «a» product LOCTITE 121078, until product appears in holes «b».
WARNING: After injecting the product, clean the surfaces to avoid runs of product.
BRAKES

On product LOCTITE 121078, spray the activation aerosol LOCTITE 7649, at «a» and at «b».
Remove the pin (7).
Refit the new brake pads (see corresponding operation).
Bleed the braking circuit (see corresponding operation).

IMPERATIVE: Respect the times for setting of the product LOCTITE 121078. Respect the required distances, depending on the materials being used, in order to avoid any damage to surrounding components through heating.

Setting times:
Ambient temperature 75°C, 2 hours (with application of heat).
Ambient temperature between 10°C and 25°C, 12 hours (without application of heat).

Types of material to help setting (with application of heat):
TRISK short wave, model ETS HH02-850W, distance 20 cm from the brake caliper.
TECALEMIT lamp with 8 bulbs of 2000W, distance 45 cm from the brake caliper.
This is not an exhaustive list (see Tools and Equipment catalogue).
Refit the rear wheels. Lower the vehicle. Tighten the wheel bolts to 9 ± 1 m.daN. Replacement parts.

The Replacement Parts service only markets the components for the new fitting.