Copy and pasted from a small blog type thing I did
Here....
Postby richarduk » Mon May 12, 2008 12:55 pm
Time for an update, been a couple of weeks since the work on the steering, not changed the front tyres yet, got a biding rear brake to fix first.
I've order up some new pads and started the job of dropping down the diff. I'm expecting the cailliper in question, the near side one, to have either the handbrake linkage to be seized or something more serious causing it to bind. It does not bind too much but enough for you to feel it dragging and for it to over heat the brake. Odd thing it does not do it all the time and once cooled down will be ok for a while. When it does bind the wheel is hard to turn by hand so does need doing.
Here is what inboard disks look like.
The callipers are on the top with a big plate that holds the diff in place in the way.
There are three bolts to be removed from the diff before removing the plate, you need to do this because if you unbolt the plate from the car first its hard to get a good purchase on the bolts to undo them, the diff moves about far too much. Once these bolts are done you can remove the stabiliser rod and the two long bolts that attach the plate to the bodywork, the nuts to these are accessed from the boot under two plates.
Also you need to release the brake pipe from its bracket so that the pipe is not stretched. Just need to loosen of the bolt, not the pipe though!
Image
Once this is done the diff can be lowered down on a jack, the jack can be removed once lowered down, the half shafts will keep it in place.
You may be able to see in this picture that the callipers look like they've been reconditioned, up close they look in very good condition. So thats a nice surprise so I remove the pads, there are two bolts that hold the outer pads in place and two bolts on the front and read edge of the brake that holds in a plate that in turn holds in the inner pads.
With the pads removed I spot the 1st problem, could be the cause, the piston on the problem calliper is 180 degrees out. The pistons on these brakes wind in and out for adjusting back the handbrake auto adjuster. To do this is an L shapped plate on the end, this should be pointing up to the body of the car, on the problem calliper its pointing down. The other problem is that the flex pipes are not very good condition, I've ordered two new ones. There are two on the back, one from the body to the offside calliper on the diff and then another to the nearside calliper.
With the old pads out its obvious the nearside ones have over heated and both sides are not in a very good shape, this could have been to do with the time being off the road and the disks rusting up then driving the car to clean them up. I expected this and had always planned to change the pads once the disks were clean.
Looking at the new and old together they don't look too warn.
Now with the pads out I check all the handbrake linkage over, every thing is moving fine and the callipers are free to move on their pivot pins. Also the pistons wind back easily, did with my hands there are in such good nick.
I put in the new pads and put it all back together, whilst doing this I took the chance to paint up the plate.
Time for a test drive, I drive for about ten mins and then return home, no noise from the rear and does feel good. But when I jack her up the near side rear is still binding, not as bad as before but enough for me not to be happy. So I jump on the net and post to the p6roc forum and ask the oracle. I get an answer back quickly, it seems the 2nd problem I found, the old brake flex pipes could be the cause. Seems because there are two to the nearside, one via the offside it is common for the pipes to create a kind of 'one way' valve when they get old. This sounds a good candidate but will not know till next Saturday and they are replaced. There isn't anything else it can be!
All in all was a good Sunday spent working on the P6 coming in doors to a roast and scrap heap challenge.
