Hi, I am using the standard sierra mcyl (less servo) and cannot get the rear brakes to provide any sort of stopping force! Could they just need
bedding in?I dont think its bleeding as the pedal pumps up solid after 2 strokes.The Cortina fronts are as taken from the scrappie (do they need
reconditioning?)
I believe that the mcyl less servo can be a bit tricky to set up - is their one designed for use without a servo, available on another car that would
be a direct replacement?
Any help gratefully recieved!!!
have you got a balance valve?are the flex,s ok and not squashed,is the master cylinder any good,are you getting any fluid to the rears????
Cheers,
The mcyl is new, and the flexis are from lolocost. I have fitted a tilton lever reducing valve which is set at no reduction!
When I press max pressure on the pedal you can still grip the wheel and turn it (although it does take a bit of effort)!
I take it a lot of builders have used this setup succesfully.(couldn't afford a balance bar set up)
The rear pads are new, as are the self adjusters; which you can hear click up on the initial application of the pedal after fitting.
Still driving me mad! - Just sheared an exhaust stud aswell!- can these be easily drilled out?
Thanks for your reply
There is plenty of fluid coming out of the rear bleeds- have put nearly half a gallon through it! One thing however- the rear brakes are on upside down i.e. cycls at the bottom!but as they are horizontal in terms of feed and bleed I didn't think this should matter. Could be proven wrong of course!!!
make sure your shoes are adjusted up at the self adjusters not the h/brake cable
quote:
pedal pumps up solid after 2 stroke
there is a brake bias cylinder which goes in line to push 25% more barking to rear I think you need to fit this to pass SVA. Its a small device about
the size of two golf balls!!!
have you got enough leaverage from the pedal onto the push rod????
pete
Slowbuild -
The Sierra mcyl was designed for use with a booster, which provides the backstop for the pistons. By removing the booster you eliminate the
backstop.
The booster output rod (which abuts the primary piston) is factory-set to +/- 0.15mm. You will need to replicate this condition, with any linkage
between brake pedal and mcyl piston. You will also need to ensure that the mcyl pistons return sufficiently to release the brakes.
After reaching your hard pedal condition, do your brakes release immediately with pedal release?
P.S. You could try using Mk.1 Fiesta non-servo mcyl, but check the displacements relative to your brakes.
[Edited on 21/2/03 by Dick Axtell]
quote:
Originally posted by Barker
there is a brake bias cylinder which goes in line to push 25% more barking to rear I think you need to fit this to pass SVA.
sounds like either the pressure reducing valve is doing too much or the master piston is coming to the end of its travel before it should,you got them
plumbed in the right way round?
The brakes do seem to release as soon as the pedal is released.There is plenty of travel in the mcyl as when released you can manually rotate the pushrod so there is no residual pressure on the mycl when the brake is released.Maybe if I remove the rear drums and allow the self adjusters to click up a couple of times this will hold the shoes a little closer to the drums resulting in less travel required to apply pressure????? - Could give it a try -If not may have to resort to the fiesta mycl but is that not a diagonal split system? can it be altered to suit??
The self adjusters could be the problem,i had this problem on a car once where the ratchet system was failing
.
I was driving around with the handbrake on a couple of notches to give better braking.
I see what you mean but the adjusters are brand new genuine ford! £25 aswell!!!
They do seem to work as you can hear them clicking up on initial application after overhaul - having said that the wheels rotate very freely as if
they are too much released when there is no pressure on the brake pedal! Can you see now why its driving me so mad!!!!
The bias valve is correctly fitted!
quote:
Originally posted by slowbuild
One thing however- the rear brakes are on upside down i.e. cycls at the bottom!but as they are horizontal in terms of feed and bleed I didn't think this should matter. Could be proven wrong of course!!!
I'll second what JGG said. Also (though I don't believe this is your problem), don't expect too much from a totally new brake system until the brakes
bed in a bit.
you could try a pressure bleeder,that will blast out any air in the system
have you definatly got all the springs on right??
adjust up your shoes till their just rubbin the drums i find best way is 2 big screwdriver to lever them apart
have just read my note - the compensator gives bias to the front NOT the rear - sorry guys
pete