Discs & Pads

[Guest Kane]

Hi everyone, dose anybody have a step by step guide for replacing the front discs & pads or advice. (Xantia 2.0 HDi 90BHP 2000 W reg)

[Guest Colin Hunter]

I have a 110 and the brakes are different but I don't think that much to make a difference. In common with all activities which involve jacking the vehicle, always remember to make it SAFE by supporting it with "Axle" stands or blocks of wood before starting work. Don't rely on just a jack.

 

It is a good idea to take photos of the assembly with a digital camera or your phone before you start so that you can put the sensor wires and any other bits back the same way as the were. Otherwise make a simple drawing to remind you how it looked.

 

The first step is to remove the wires for the pad wear sensing from the plug on the suspension leg. Let them hang loose. You can remove the handbrake cable from the caliper if you find it obstructive. If you do remember to replace it afterwards.

 

The caliper is held on to the pad carrier by slides. The lower of the two slides has a bolt in the end which, when undone will free the caliper and allow it to swing upwards on the top slide. The pads can now be removed from the carrier. Take note of the way that the wear sensor wiring is arranged to each pad.

 

The caliper can be swung right up and slid out of the top slide. Hang it off something on a peice of strong cord or a cable tie to prevent straining the hose.

 

You will have to "Wind" the piston back into the caliper because of the handbrake mechanism. This can be done by using a proper wind back tool (Luxury!) or more slowly by the use of a peice of square steel which will fit between two of the diametrically opposed slots in the piston end. Wind it back as far as it will go, taking care not to damage the rubber boot on the piston. I used an old square file last time!

 

Unbolt the pad carrier from the swivel hub and clean up the areas where the pads fit in. Make sure the pads can move freely in the carrier.

 

The disc should now be exposed and ready for removal. There are (Should be) two countersunk screws holding the disc to the drive flange. They may be either torx or posidrive depending on what was used when the discs were last done. Remove them and the disc should now be able to be removed. You may need to give it a clout or two to free it from the hub.

 

Clean up the surface of the hub with a wire brush or suchlike and clean the protective film from the disc with a solvent. (Brake cleaner or methylated spirit).

Lightly coat the hub surface & and the matching inner surface of the disc with "Copaslip" (Copper grease) and re-assemble. If the retaining screws are sheared or have been missing it's not a problem as the wheel bolts will hold everything in place once the wheel is on. If the screws are OK replace them and do them up. Turn the disc and make sure it's running true. Citroen (And other manufacturers) will tell you to use a dial test indicator to ascertain the "Run-out" but if it looks straight it will most likely be OK.

 

Replace the pad carrier onto the swivel hub and tighten the bolts. There are torques that they should be done up to but usually people will tighten them more than enough with a normal spanner in the absense of a torque wrench. (70/80 lb/Ft)

 

Take the new pads and insert the wear sensor wires into them as the old ones were. Place them into the carrier, coating the mating surfaces with "Copaslip" again. ensure none gets onto the disc and friction surfaces of the pads.

 

You will see that the pad which fits against the Piston will have two "Nibs" on its back. Replace the caliper into the top slide After inspecting/cleaning the slide and applying yet more "Copaslip" to it. Inspect the small boots which seal both slides. With the caliper back in the top slide, rotate it downwards and watch as it engages with the pads. If the piston is not far enough back, screw it back a bit more, Making sure that two of the four slots in the piston engage with the two "Nibs" on the pad. Put a little "Copaslip" (Lovely Stuff!) on the back of each pad where it runs against the piston or caliper. This will help prevent squeal.

 

There should be a new bolt with a washer with two "Toes" on it in the kit. The toes fit into slots on the lower caliper slide. Put the bolt in place and tighten it up. (37lb/ft)

 

Re-route the sensor wiring and re-connect it to the plug on the suspension leg.

 

One down! One to go!

 

As I say, mine is a 110 and the brakes are different. You may find anti rattle shims and springs that I have not mentioned and the caliper may be secured by a knock out pin at the bottom rather than a bolt, but the principle is the same. Just put it back the way you found it and you won't go far wrong. Cheers Hope helps. :D

[Guest Kane]

Hi Colin, thank you very much for such an in depth reply.