Antti O

My rear brakes scuffle (not releasing 100%)
Standard load compensators (brake bias valves) in rear axle. No ABS system anymore.

-Sierra cosworth 2wd rear discs
-Sierra cosworth 2wd rear pads
-Sierra cosworth 2wd rear calibers & repair kit 60£ from local scrapper & bigg red brakes, -Sandblasting & Zinc coating
-Brackets
-Braided hoses for rear disc conversion
-RS2000 handbrake cable


all assembled and brakes bleeded properly.
But.. rear brakes scuffles (not release properly) until releasing pressure from the calibers bleed screw. What a hell?

s1cab

iTrader: (1)

if they're rubbing u can wind the piston back a bit thats what i done.

Antti O

Hi!

Can you explain? My rear calibers are reconditioned and like a new.
You mean that i should push rear caliber piston in little bit?

s1cab

iTrader: (1)

u need a tool for winding back the calliper it wont just push back like the fronts.

s1cab

iTrader: (1)

yeah just wind it in a bit till theres clearence

Antti O

Still cannot understand how it will help.. but i have to try.

s1cab

iTrader: (1)

because you set the gap between the disc's and pads so they dont touch but get as close as posible

studabear

disconnect the handbrake cable see if the problems still there

S1

Couple of possibilities I can think of. If you're still running the rear load sensors then you need to bleed the brakes with the weight on the suspension so the allow fluid through.

What master cylinder you running? I recently did a master change on my Fiesta only to find the brakes were almost locked all the time. Turned out the pushrod in the servo needed shortening slightly to prevent it pushing on the master as it was bolted up.

As previously suggested it could be the rear calipers need winding in. You can buy a specialist tool or wind it in yourself. You need push the piston in dead hard whilst turning it at the same time. Can be a git to do but once you have the knack its easy.

s1cab

iTrader: (1)

What master cylinder you running? I recently did a master change on my Fiesta only to find the brakes were almost locked all the time. Turned out the pushrod in the servo needed shortening slightly to prevent it pushing on the master as it was bolted up.

i had the same prob ages ago. but i have heard people say on here dont adjust that rod unless u really have to

Antti O

I have standard S2 Turbo 25mm master cylinder & standard s2 turbo servo. I also have rear axle standard weight compensators in place and now the car is jacked up and rear is in the air.
I will try rear calibers winding today, but i doubt it will help because when we assembled rear calibers pistons were pushed in the bottom.

G2RSR

what ever you do, do buy a adjustable brake bias valve i know so many people who have totaled there cars just by fitting rear disc breaks back of car over taking the front

Antti O

I am aware of that. If i have to install brake bias valve, can someone tell which is the best way to do it? Because i believe in rst there is no separate front/rear brake lines. There is 2 different brake circuits like this:

1. Passenger rear and driver front
2. Passenger front and driver rear

So i have to make new brake lines.. or something

S1

When I converted my FRST to rear discs with a bias valve, I used a Mk5 escort ABS master cylinder with only two outlets and ran a split front/rear system. The bias valve is in the line that runs to the rear.

I saw in a magazine once they joined the lines under the car and then fitted the bias valve. To my mind it was a bodge as they effectively did away with the two circuits meaning that in the event of a line hose bursting or line getting damaged you end up with no brakes at all. If you're gonna do it then do it properly and run new lines in, as it is the youngest ERST is coming up for 20 years old so probably in need of replacement hard lines anyway?

Antti O

Hi!

Tonight we work with brakes and tried different setups.
Without any brake bias valves rear brakes lock before fronts, not good.
With original brake bias valve and some adjusting rear end not lock before front and thats good, they rubbing really little and wheel spins easily if you spin with hand in air after applying brake.
So i believe with little work and adjustment i can have brake balance with original bias valves.

Antti O

Without brake bias valves! Really bad setup!



This is with original S2 turbo brake bias valves adjusted to the max limiting.

JesseT

Testing the brake bias on a gravel "special stage" is not optimum. On tarmac you will make the rear go much lighter under braking.