Best to use something else
Hi guys,
One of my back wheels locks before the front on heavy breaking. Is there some sort of SVA friendly restrictor valve that I can fit to the rear line to
stop this? Or anything that I can change on the drum?
My setup is:
Sierra master cylinder
Sierra rear drum brakes
Wilwood front calipers.
Thanks.
there's various inline adjustable ones, I'd fit it in the engine compartment to keep Mr SVA happy
Strange that drums are locking up before discs..... Adjustor valves are available... might be worth making sure everything is set up and bedded in first though. Normally drums are suitably pants to lock up about half and hour after discs have locked.....
quote:
Originally posted by Mr Whippy
there's various inline adjustable ones, I'd fit it in the engine compartment to keep Mr SVA happy
You may also be able to fit smaller bore slave cylinders in the rear drumbrakes.
Take one of your current slave sylinders to your local motor factor and ask. Ford use the same or similar fixings for all thier models,
Fiesta/Focus/Sierra etc... and you may find a smaller cylinder (on both sides) will cure the problem.
The Sierra rear restrictor is a G-Valve and has to be installed at an angle to give the correct level of restriction.
Best to use something else
quote:
Originally posted by Snap-off
quote:
Originally posted by Mr Whippy
there's various inline adjustable ones, I'd fit it in the engine compartment to keep Mr SVA happy
Mr SVA said that it must not be adjustable. He mentioned that there was a restrictor valve fitted in some sierra models in the rear line. Anyone know anything about it?
quote:
Originally posted by Mr Whippy
all brakes are adjustable to some degree, just normally you don’t fiddle with them when moving.
quote:
Originally posted by Mr Whippy
quote:
Originally posted by Snap-off
quote:
Originally posted by Mr Whippy
there's various inline adjustable ones, I'd fit it in the engine compartment to keep Mr SVA happy
Mr SVA said that it must not be adjustable. He mentioned that there was a restrictor valve fitted in some sierra models in the rear line. Anyone know anything about it?
sure he didn't mean adjustable while driving along? hence putting it in the engine compartment, all brakes are adjustable to some degree, just normally you don’t fiddle with them when moving.
Are you sure the front brakes are OK?
Mine has standard sierra fronts and rear drums with no pressure limiting valve and the fronts always lock first.
As you have Wilwoods I should have thought these would be more powerful than standard brakes and so should lock well before the drums.
Stu
I'd double check, think of the bias bar cars that are passing the SVA, all they have to do is pin the adjuster.
how bedded in are the front brakes? They may have slight contamination and will get better with more use.
[Edited on 11/7/08 by Mr Whippy]
quote:
Originally posted by whitestu
Are you sure the front brakes are OK?
Mine has standard sierra fronts and rear drums with no pressure limiting valve and the fronts always lock first.
As you have Wilwoods I should have thought these would be more powerful than standard brakes and so should lock well before the drums.
Stu
if your master cylinder is dual circuit have you connected front and rear pipes the correct way round.Mine is the the old escort one and not sure what the sierra one is like
need to look at the basics first, like may be 1 caliper not operating properly, is you master cylinder set up front/rear or the standard sierra opposite sides. i think on most fords each section of the master cylinder piston would have been to oposite fron/rear sides with restrictors in the rear pipe to limit pressure to the rear which may now answer why, have you tried jacking up the front and get someone to apply the brakes a bit at a time and try and spin the wheels and se if they start to bite at the same time with same force?
quote:
Originally posted by will121
need to look at the basics first, like may be 1 caliper not operating properly, is you master cylinder set up front/rear or the standard sierra opposite sides. i think on most fords each section of the master cylinder piston would have been to oposite fron/rear sides with restrictors in the rear pipe to limit pressure to the rear which may now answer why, have you tried jacking up the front and get someone to apply the brakes a bit at a time and try and spin the wheels and se if they start to bite at the same time with same force?
Hi had my rears lock first as well with a standard sierra master cylinder, that said, I've got cosworth disks on the back.
I used a willwood adjustable bias valve and made a bracket so that a roll pin would lock it off. I passed the SVA OK with this, though it does sound
that your tester is into every detail.
Cheers
Ian
quote:
Originally posted by Snap-off Mr SVA said that it must not be adjustable. He mentioned that there was a restrictor valve fitted in some sierra models in the rear line. Anyone know anything about it?
Bleeding the brakes won't fix it.
If only one rear is locking it points to corner weights try jacking the springs up just a little at that corner.
If you want to fit a pressure reducing valve in the rear brake line either fit a Fiat Uno or Fiat Ritmo/Starda or Lada Riva one (very cheap from
Brakes International) or go to the scrappies and get one off an early Mondeo without ABS -- it is bolted straight on the master cylinder outlet but
remember to cut through the pipe and take the tube fitting with it.
[Edited on 11/7/08 by britishtrident]