New On Forum - Rear Brakes Slow to Respond Xanti Esta - Help

moonster72 · Post by **moonster72** » 02 Aug 2011, 17:39

Hi there im very confused i have a Xantia Estate that has just failed its MOT on the rear brakes being slow to respond - they are working just not imediate when you apply the brake, thats what the MOT station has told me. The car has not been used for 4 or 5 months.

My next question is that a local French car specialist states the rear height corrector needs to replaced at a cost of £235+vat.

My evening last night was spent googling and the only references i can find to delayed rear brakes are down to bleeding and air locks in the hydraulics and absolutely nothing to do with height corrector so why is the local specialist so convinced its a scrap height corrector?

Can anyone shed any light, my first go is to bleed brakes as this is easiet and i guess the next step is to clean the height corrector as per
CitroJim and his super website

http://www.eastment.net/hcrefurb/hcrefurb3.htm

Any advice anyone can give would be much appreciated.

Moon

Xaccers · Post by **Xaccers** » 02 Aug 2011, 18:53

Definitely bleed the brakes.
Also, pop one of the wheels off:
Set car on high
Slacken wheel bolts a bit
Put axle stand under either the jacking point at the back on that side, or a solid part of the car (where the cross bar bolts to the subframe is good)
Set car on low and stand back in amazement as it cocks it's leg and lifts the wheel off the ground

Once the wheel is off, get your head over the top of the brake disc where it passes through the caliper and look to see if it runs at an angle.
Chalk like corrosion builds up between the caliper and arm pushing the caliper out at an angle reducing their efficiency.
Remove the calipers and chip off the build up, then refit with plenty of grease between the arm and caliper to prevent it building up again.
Careful though as if the stress on the bolts is too much they can sheer which is a pain.

Open the boot, with the engine running, sit in the boot and wait for the car to rise back up, it shouldn't take more than a few seconds to react. If it does, then there's nothing wrong with your actual height corrector.
The linkages may be in need of some lube though.

moonster72 · Post by **moonster72** » 02 Aug 2011, 19:55

Brilliant XAC

Thank you for the advice im gonna be busy this weekend, i think i may change the fluid at the same time and clean filters cant hurt.

Have been doing Citrobics and jumping up and down in the boot and car does move up and down to compensate as it should.

Im just not very sure of a French Specialist who seemed to go for the most expensive option first?

Once again thankyou, will let you know how i get on.

Moon

Xaccers · Post by **Xaccers** » 02 Aug 2011, 20:06

Call me cynical but I'm always dubious of "specialists" when it comes to cars.

lexi · Post by **lexi** » 02 Aug 2011, 21:06

Maybe check accumulator sphere as well as the above stuff. Any regular ticking from it?

Post by **myglaren** » 02 Aug 2011, 21:53

moonster72 wrote:Brilliant XAC

Thank you for the advice im gonna be busy this weekend, i think i may change the fluid at the same time and clean filters cant hurt.

Have been doing Citrobics and jumping up and down in the boot and car does move up and down to compensate as it should.

Im just not very sure of a French Specialist who seemed to go for the most expensive option first?

Once again thankyou, will let you know how i get on.

Moon

If you are going to change the LHM it would be a good opportunity to flush the system with Hydrorinçage.
Available from GSF, among others.

There is a thread describing how to do all this that would be worth looking through in advance to familiarise yourself with the procedures.
Here

Derekofpriory · Post by **Derekofpriory** » 02 Aug 2011, 22:03

You must have found a very strict tester, our rear brakes were slow to get to full effectiveness on our last MoT, but were passed because they were up to standard eventually. Looking on here, the consensus was that the anti sink sphere had failed.

Xaccers · Post by **Xaccers** » 02 Aug 2011, 22:26

lexi wrote:Maybe check accumulator sphere as well as the above stuff. Any regular ticking from it?

Good point, let the engine idle and listen for a loud tick/click from the front accumulator sphere.
There should be at least 30 seconds between ticks, otherwise it needs replacing, and if it needs replacing then most likely the rear accumulator (known as anti sink sphere) will need replacing. There's a trick to it involving a 9mm flare spanner, so do a search for 9mm flare spanner and you'll find one of my posts covering it.
Sphere changing is a doddle if you make your own tool or buy a proper one from pleiades, or a tool from fleabay.

moonster72 · Post by **moonster72** » 03 Aug 2011, 19:35

Hello all, just been out playing and doing Citrobics.

The car does not drop overnight, goes up and down and does everything as it should or seems to.

Ive timed the clicking and you get a click every 18 seconds and this seems pretty regular, car drives fine so do i need to change spheres just yet?.

Ive got fluids arriving tommorow (top tip GSf will deliver to your workplace) so thats my 1st job.

2nd Job clean calipers
3rd job grease up linkages on height corrector

lets see how that works for MOT man.

Cheers for the input, im determined to fix this.

Moon

VertVega · Post by **VertVega** » 03 Aug 2011, 19:45

moonster72 wrote:.. Ive timed the clicking and you get a click every 18 seconds and this seems pretty regular, car drives fine so do i need to change spheres just yet?. ...

18 secs means that you need a new accumulator sphere

Xaccers · Post by **Xaccers** » 03 Aug 2011, 20:01

VertVega wrote:
moonster72 wrote:.. Ive timed the clicking and you get a click every 18 seconds and this seems pretty regular, car drives fine so do i need to change spheres just yet?. ...
18 secs means that you need a new accumulator sphere

Which means it's probably also time to replace the rear accumulator sphere too. Don't forget the 9mm flare spanner!

davek-uk · Post by **davek-uk** » 04 Aug 2011, 08:37

Definately clean up those rear clipers! Leave them too long and they'll push around until the retaining bolts snap. You'll see the problem with the rear wheel off. As Xac says, the corrosion is chalk like and builds up in a wedge. Scrape all this off and use something between the caliper and the rear arm to prevent another build up – some use copper grease but I made up a gasket out of a thick sheet of plastic.

Note that the rear calipers are in two halves, held together buy a small nut and bolt. You'll need to remove this to withdraw the pads (if needed) but put it back on whilst working on the caliper to stop the two halves seperating when the caliper is unbolted from the rear arm.

Dave

Clogzz · Post by **Clogzz** » 04 Aug 2011, 14:14

Since it’s an estate, load some ballast into the back for MOT day, it helps the rear brakes a lot.

Post by **myglaren** » 04 Aug 2011, 17:34

I was messing around with some clear silicon sealer yesterday and it occurred to me that this would perhaps be a suitable material to prevent the electrolytic corrosion between the caliper and trailing arm.

I was supposed to take my car in to have the rear calipers removed, cleaned up and replaced, plus a few other odds & sods but have to postpone as the car is needed as a taxi on Sunday, so will be the next weekend instead.

I'd do it myself but I know that I will never shift them. The guy doing it has heat, breaker bars and rattle guns so stands a better chance.

I think I will give the silicon a try. What could possibly go wrong

Dommo · Post by **Dommo** » 04 Aug 2011, 18:28

You just need a breaker bar and smooth pressure, rattle guns would work but I'd rather the breaker bar method, its much less aggressive!