Changing front disks and pads

stevee · Post by **stevee** » 28 May 2004, 03:36

Can anyone provide me with details of how to change the front disks and pads on a 1993 K reg 5door Xantia 1.8sx 5speed manual. Do i need any special tools?
Any help greatfully recieved.
Cheers
Steve.e.

NiSk · Post by **NiSk** » 28 May 2004, 04:17

Buy, steal, or download Haynes Xantia book of lies - most of what's said about the brakes i almost true. If you can't get the disc to separate from the hub:
Jack up and support the offending front wheel FIRMLY on axel stands.
Remove the wheel, undo the securing screw(s) between disc and hub, start the engine and engage a low gear. The disc will rotate. Apply the brakes gently but sufficiently for the disc to get hot, then jab the brake pedal. This nearly always released the disc.
The rest is a la haynes
//NiSk

Dave Burns · Post by **Dave Burns** » 28 May 2004, 04:37

Unhook the nipple on the handbrake cable from the caliper lever and pull the whole cable completely from the caliper.
Pull the R clip from the caliper retaining pin and punch the pin out, pull the flexible hose from its grommet on the strut then swing the caliper upwards, the piston now needs to be screwed back in by turning it clockwise while applying some pressure, do not try to force it back, it must be screwed back.
Undo the caliper mounting bolts (T55 Torx head) and hang the caliper from the strut with string or the like.
Remove the screws holding the disc (T30 head) and clout the disc with a hammer at the periphery to break it loose, pull it off and clean the hub drive flange so the new disc sits flat against its face, any trapped dirt or rust build up will cause you sever vibration problems as the brake disc will run out of true.
Clean the caliper slides of heavy rust where the pads sit, clean the new disc of its protective coating with petrol or some other safer non greasy solvent, lightly (very lightly) smear the drive flange with copper grease and bolt the new disc on ensuring that no dirt has got between the disc and the drive flange.
Refit the caliper to the hub carrier, smear copper grease on the pad slides making sure none of it contacts the new disc, fit the pads in the caliper, note the anti rotation peg on the back of the inside pad, position one of the slots in the piston to clear the peg as the caliper is swung back down, the peg must rest inside one of the slots when the caliper is in position, if it is not positioned correctly the piston will bear down on the peg instead of the entire pad, this will cause the piston to bind in its bore and the brake will overheat.
Refit the caliper retaining pin and its R clip, refit the flexible hose in its grommet, push the handbrake cable back into the caliper and hook the nipple into the lever.
Buy good quality discs and pads, have both wheels off the ground together, be aware of the rear of the car sinking (if yours does this), this may cause instability of the raised front end on stands.
When both sides have been done, check the handbrake cable freeplay, there should be between 3 and 5mm of play (travel) between the nipple and the caliper lever when at rest.
Before driving off, press the brake pedal with the handbrake in the off position, this will adjust the handbrake mechanism in the calipers aswell as placing the pads in close proximity to the discs.
I don't think the suggestion made by NiSK is very useful, it may in fact be extremely dangerous, with a wheel still on the ground the suspended wheel will rotate freely and little drive effort will be passed to the grounded wheel, until you press the brake pedal that is, then the suspended hub will be braked forcing some of the power to the other wheel, the car might then easily pull itself off the stand.
The disc will come free when its had enough hammer.
Dave

Kowalski · Post by **Kowalski** » 28 May 2004, 17:05

I agree with Dave on this one, it is dangerous unless you've got both driven wheels off the ground.
Some cars today have what they call an "electronic limited slip differential". This works by using the brakes on a spinning wheel so that more torque can be applied to the other non-spinning wheel. If for any reason the braking force applied to the supported wheel is greater than the other wheel, the car will be pushed forwards (or backwards) by the excess torque applied to the wheel still on the ground.
Personally, to shift a difficult disc, I would recommend getting the brake disc hot by driving and using the brakes, then having a go at removing it whilst it is still hot, this can often help but you have to be careful about getting burned by the brake components...

NiSk · Post by **NiSk** » 28 May 2004, 17:14

The method I recommended was suggested to me by a Citroën garage. I have used it to remove a VERY stubborn disc on an XM. I did say VERY firmly supported. The brakes should apply the force to both front wheels equally - otherwise you've got other problems. Belting hell out of a disc to dislodge it will do your wheel bearings absolutly no good at all!
//NiSk

adrianeaton · Post by **adrianeaton** » 28 May 2004, 18:20

Something I found necessary with GSF discs was to clamp the disc in place with a couple of wheel bolts with a stack or large washers under them while you put the disc retaining screws in. I didn't do this the first time and the (already warped) new discs just got worse and worse. Got another set and when I checked everything found that the hole drilled in the disc wasn't quite square to the thread in the hub - if you clamp it first as if the wheel were in place then tightening the small screws will keep it there.
No probs since, although it's a bit belt and braces for some. Did the same on the Xsara VTS at the back without trouble.
Adrian

AndersDK · Post by **AndersDK** » 28 May 2004, 18:46

From same experience with warped discs, I'd say NEVER tighten the small disc retaining screws. They are ONLY fitted to retain disc until wheel & bolts fitted.

bxbodger · Post by **bxbodger** » 28 May 2004, 19:08

If you have trouble getting the disc retaining screws out, and an impact driver won't shift them and you havent time or power to drill them out , then the Nisk method of applying the brakes with the motor running and in gear will shear them off as long as there are no wheel nuts in. then you can just put the new discs on and drill out the remains of the retaining screw when you have time.
All the screws do is hold the disc in place with the wheel off.

Dave Burns · Post by **Dave Burns** » 29 May 2004, 16:59

Citroen garages don't generaly have a good reputation in these pages, and if they suggest doing things like this its no wonder, perhaps they were taking the pi$$ and hoping you would cause some damage that they would be called in to repair.
Yes the brakes should provide the same force to both front wheels together, the mere fact that the wheel off the ground is still rotating with the brakes applied, and while under power means there insufficient force to prevent the grounded wheel also turning should enough power get transferred accross, plus its not a good idea to have a car vibrating away with the engine running on stands in the virst place, especially if its a diesel.
Unless you are a total thicket you don't belt hell out of anything on your car, getting a frozen on disc off is simply a matter moderate hammering with nothing bigger than a 1lb hammer all way around the disc face, the vibrations that this causes very soon breaks the rusts hold on the disc.
I have only ever had to replace two of my own front wheel bearings, one on a fiesta and one on a 205, both destroyed due to water getting in, the tell tale of this being the presence of rust.
But heyho I've replaced many a brake disc so any such hammering never did my bearings any harm, but then I don't go at it like a clown with a 7lb hammer either, there is enough bulk about the disc and hub to absorb the hammering without passing it on to the wheel bearings provided you don't go daft at it, deffinately don't hammer down on the edge of the disc, that doesn't help much at all.
Dave