Squeaky Xantia!

Post by **CitroJim** » 01 Jan 2007, 07:56

Split from another thread to save going OT..

Jim
could your squeeking rear brakes be a build up of corrosion between the rear calippers and arms
regards malcolm

Hi Malcolm,

Thanks. I'e been there a couple of times. Calipers and arms are as clean as a whistle and the pads are wearing evenly.

Any suggestions would be incredibly welcome so as to stop waking people up with them and I'd love to turn up at friends houses unannounced sometimes

It gets embarrasing when I'm doing Dads Taxi and the kids are already out waiting for me. "We heard you coming from miles away Dad!..."

Post by **Peter.N.** » 01 Jan 2007, 11:28

The remedy with drum brakes was to chamfer the leading edge of the lining, don't know if it would work with discs.

marty03321 · Post by **marty03321** » 22 Mar 2007, 13:42

Jim,
I have a 95 Xantia with an intermittent brake squeal, from the front though... I've had the calipers off loads of times trying to sort it, but no joy. A mechanic mate of mine says that the cause was due to Citroen using 2 different types of alloy when they fabricated the calipers and the hub carriers. I've reduced the squeal, however not totally by spreading copper filtrate (anti seize compound) over the mating surfaces every time I take the calipers off. Not too much as you don't want to get that stuff near your pads...
Hope this helps. Martin

jeremy · Post by **jeremy** » 22 Mar 2007, 13:57

Chamfering can work with disc pads - you may be able to remove the sharp edge with a sharp knife or wood chisel -does not produce dust like filing or sanding!

Are the new pads the same make as the old ones? Different makes may be a slightly different shape and for example rub on a rusty section of disc near the centre? I had this on our ZX - which would barely stop till I realised what was happening and replaced discs and pads.

AndersDK · Post by **AndersDK** » 22 Mar 2007, 15:41

Brake pads should have a hard rubber like padding on rear from factory. Looks like a thick layer of paint. This prevents the high frequency rattles from the pad contacting the disc and piston - reponsible for the squealing.
Any rusty part of the disc will not make the noise, but merely rub down the pads within a few miles.

Its still possible to purchase antirattle padding at brakes specialists. This is a dense fibre like sheeting which can be cut to fit between pads and pistons. It may even work with padding made up from mild steel - i.e. a tin can.
Works a miracle.

Post by **CitroJim** » 22 Mar 2007, 17:37

Thanks all, I really must get back to this problem. The Activa continues to steal all of my time at the moment. It's brakes are as quient as the proverbial mouse.

The TD has quite well worn rear discs and there is a quite obvious lip between the unworn edge and the working surface and I've noticed the lip becomes very highly polished so on that basis I reckon a chamfer operation would do the trick as that would prevent the pad contacting the lip as hard as it otherwise would. I noticed the squeal became much, much worse when I accidentially switched the pads from side-to-side so the pads were working more on the lip. After switching them back to how they were it was silent for many days before the squeal returned.

I suppose I should really replace the discs but apart from the wear they are in otherwise excellent condition with no scoring or pitting.

Anders, yes I recall back in the dim and distant past that disc brakes when they were unusual on cars used to have very thin anti-squeal shims between the pad and piston. I have not seen a brake set-up with these shims for donkeys years now.

citronut · Post by **citronut** » 22 Mar 2007, 19:00

when i fit new pads to a car that the discs have any raised sections at the inner and or outter edges,i allways put a bevel on both edges of the new pads with my angel grinder,it also pays to use resonably good quality pads wich have a high copper content
regards malcolm

ps.
GS/As and CXs have the metal shims on the rear pads

Mandrake · Post by **Mandrake** » 23 Mar 2007, 00:22

Squealing from rear discs in my experience is usually due to the raised lip that forms on the outer and inner edge of the discs as they wear. (Mainly the outer lip, which can become quite sharp)

If the lip isn't too serious you can just chamfer the edge of the pads a bit so the pad doesnt touch the sharp lip. (I tend to do this anyway)

If the lip is quite high then this will only be a temporary cure that will last about 3-6 months, because as the pads wear down they will lose their chamfer and start squealing again - and you have to chamfer them again and get another 3-6 months.

The leading and trailing (narrow) edges of the pads should be given a very slight chamfer (1mm or so) just so there is no sharp edge on the pads, but the long edges that are against the sharp lip on the disc will probably need quite a lot of chamfer if the discs are well worn - when you hold the pad in place on the disc by hand the pad should rest flat and true on the disc and NOT touch the lip at all, and have at least 1mm of clearance from the lip so that they will not start touching again until the pads have worn a reasonable amount.

I pretty much guarentee this will cure your squealing - for a few months anyway.

I have exactly the same issue on mine, and after 6 months of no squealing it is JUST starting to squeal slightly again, but I'm too stingy to buy new rear discs at the moment, so I will probably chamfer the pads again.

The permanent cure is to get the lip machined off the edge of the discs, or fit new discs.

Regards,
Simon

jmd · Post by **jmd** » 27 Mar 2007, 01:07

I take away the edges of the lip from the disc's on both front and rear discs with an angle grinder, whenever I am renewing pads, and have got no squeals for a few years, also use copper grease on the backs of the pads when renewing. The front brakes are the real offenders, as the rear ones only come into play at high speeds or under load. With noise travelling back it may give the impression that the sound is coming from the rear,

alan s · Post by **alan s** » 27 Mar 2007, 02:26

Last pads I fitted were to a VTS Xsara and in the instructions, they suggested champhoring the edge of the pad off where it hits any raised outer edge. I did it on these but on the Xantia, I did as has been suggested and used an angle grinder on the outer edge.
IMO, the guy who suggested the different metals as the cause was grasping at straws otherwise they'd ALL do it.

Alan S