Xantia - reassembling rear brakes

Stempy · Post by **Stempy** » 26 May 2009, 12:16

Just looked in the BOL and it shows a pic with the shim area nearest the ground and the small tang uppermost. So if you're happy to believe Haynes then that's the way it should be.

VertVega · Post by **VertVega** » 26 May 2009, 17:11

Rear brake pad shim fits as shown in the picture. At least they were like that in my Xantia.
I tried to edit this picture and the blue colored "thing" is supposed to be the shim

Last two sets I have bought didn't have any shims but instead they were replaced by some kind of a surface material added on the back side. They work fine.

AndersDK · Post by **AndersDK** » 26 May 2009, 21:09

doesnt matter really as all the shims do is to take the pads a bit out of true preventing them from hi-frequent vibrations.

Also the shims wont stay in the caliber if fitted upside down at least not until the longbolt is fitted

Mandrake · Post by **Mandrake** » 02 Jun 2009, 02:36

AndersDK wrote:doesnt matter really as all the shims do is to take the pads a bit out of true preventing them from hi-frequent vibrations.

A bias shim like that does matter which way up it is - I've seen one Xantia where the bias shim on ONE rear brake pad was upside down and the other three were the right way around and the pads whose shims were correct looked normal, but the one whose shim was upside down had a HUGE angle on the surface of the pad, there was about a 2mm thickness difference between the two sides of the pad

I couldn't believe just how non parallel the pad surface was, I wish I had taken a photo.

The idea of a bias shim is to apply more pressure on the trailing side of the pad in the direction of normal rotation, and putting it on backwards will apply more pressure on the leading side and cause it to dig in, resulting in very uneven wear...

So yes, it does matter

Regards,
Simon

KP · Post by KP » 02 Jun 2009, 09:39

To be honest how many people have replaced more than 1 set of rear pads on the same car??

I can only imagine people who tow caravans or heavey trailers using the pads a decent amount as some xantias i've had still had original discs and pads at the rear!!!

Also does anyone else notice that the pads they remove always have lips on, only 1 of the xantias i've changed rear pads on has had no lip and i've always thought it was due to the corrosoin on the caliper causing it to run untrue and thus be off the disc?

f00lzz · Post by **f00lzz** » 02 Jun 2009, 11:37

KP wrote:To be honest how many people have replaced more than 1 set of rear pads on the same car??

My V6 required new pads AND discs at the rear after 3 yrs and 30k miles... since changing them, the replacement pads and discs show no sign of wear after a further 70k... something was obviously amiss somewhere.

Ian