SirG

Hi guys.

At first, I have to say that I did try to use the search function on this forum, but as I have said earlier it sucks HARD! If I type search words that is bound to get a lot of hits it just returns with "No matches" etc.

Its a negative spiral actualy, no matches caused by to many hits leads to new topics (like this one) witch add to the problem in the first place. Anyways ...

I have a S2 RST and have fittet cossie brakes in all the corners. 4wd calipers with 2wd discs in front, and 2wd calipers and discs rear. Calipers rear is mounted on a bracket from burtonpower.

When I bled the brakes for the first time the car was on axle-stands, resulting in the rear weight-dependent valves where not open. I bled the front calipers with no problem, the pedal was hard and stayed hard. Then I was going to bleed the rear brakes and moved the rear axle-stands form the jackpoints to the rear traveling arm (believe its called that) so that the weight-dependent valves stayed open. Bled the rear calipers, until only fluid come out of the bleed nipple. But the pedal drops to the floor every time I try to brake. If I pump the pedal very fast I might be able to build up some pressure with the engine turned off, but running it is not possible at all. After I get that pressure, I release the pedal and if I press it back in the pressure is gone and the pedal slams to the floor agian.

The solution I've used so far is simply disconect the pushrod arms to the rear brake valves. Now I got a good hard pedal again, but the rear brakes is not in use obviously. If I press real hard on the pedal I can feel that the valves is "leaking" cause the pedal moves slowly inwards. My big worry is the MOT test I have to pass to get my number plates back due to a 2 year rebuild of the car.

Now im using the original rubber flexi hoses, but I do believe that braided steel hoses might make the pedal feel a bit harder, but Im sure it does not fix the rear caliper brake problem. My guess is that the ridiculos large pistons (in RST world) is using to much fluid so the system cant build up a good pressure. But is there any way to fix this problem? Is there another master sylinder I could use witch is bolt-on and deliveres more fluid?

This really worries me cause I have sold the original RST brakes and can not mount them before the MOT. And they are not sold around every day here in Norway.

Please help!

Thanks!

SirG

BUMP

jon@work

iTrader: (5)

if you look at the rear calipers when you are trying to bleed them - you may well see that the bleed nipple is not the highest point of the caliper

if this is the case, then remove one of the caliper mounting bolts so you can twist the caliper so that the nipple is the highest point then bleed as usual then replace bolt

Alex_86

iTrader: (2)

or u could use a wilwood break stablisator thing.
Norwagian:
bremsene bak har en tedens til ĺ lĺse seg bak uten en sĺnn bremse sak, der du kan stabelisere trykket pĺ kaliperne bak. Har selv cossi bremser over alt som du har med stĺlombunde slanger. ĺ mine bremser konstant bak,men stĺr pĺ noen bukker nĺ sĺ erikke sĺ farlig. Men den kan lette ĺ stramme trykket. du fĺr den hos burton

AX Cossie

Surely you should start bleeding the caliper furthest away from the MC?
So rear left, rear right, then front left and finally front right if the MC is on the right hand side of the car.

If you start at the front there will still be air in the system.

Ive got a screw type bias valve for sale if interested, its 2nd hand buts still works a treat. Ł25 delivered.

sas

I have a very simular set on my ERST and the brake system works fine.

There are a few things that might help you bleed up.

Gently tap all the brake line all the way along and tap the calipers. This helps dislodge any air bubbles.

Adjust the rear load valves so that the rear calipers see full line pressure. (the same effect as a fully loaded car)

Last resort is to remove the rear calipers from there brackets to ensure that bleed nipple is right at the very top and bleed.

S.

SafeChav

It will be the rear calipers causing you the problems as said.

Spending Ł16 on a Eazi Bleed will be the best money you ever spent. And unless you have brackets that mount the calipers at 12 o'clock the bleed nipples wont be at highest point.

I had this same problem with my car i was pulling my hair out especially after spilling brake fluid all down the engine bay changing the master cylinder, only to still have the problem.

The pedal will probably still feel a bit rubbish after they are bled properly though due to the size of the pistons on the rear calipers.

SirG

Okay. Thanks a lot for the tips. I ordered braided brake hoses to all corners yesterday. Now I can bleed the rear calipers properly 'cause I will be able to hold the caliper at 12 o'clock like said in this thread Now I have a solid brake pipe bend from the shock absorber which obviously is not suitable to bend before bleeding