I ask you all , oh knowers of all things car related:
Does this sound like a shagged servo?
Intermittantly the brake pedal goes straight to the floor on Roland's Locost. The master cylinder is new (on my advice), there are no leaks in
the system, brakes have been bled umpteen times so we're clutching at straws really.
The system is all Mkll Escort BTW.
This happens regularly and has prevented Roland using the car recently - missed taking it to Stoneleigh.
Help, like.
Marcus
Put your foot on the pedal without the engine running and it should be solid.
Keep your foot on the pedal and start the engine and you will find the pedal goes soft. If it goes right to the floor with the engine running, it
means that your servo is knackered. If it goes to the floor without the engine running, then suspect your master cylinder.
One other thing to check is a non-return valve in the servo vacuum line. Sometimes they fail.
[Edited on 14/5/2006 by nitram38]
Pedal sometimes goes to the floor even when engine turned off. My initial thought was the master cylinder, so I told him to buy a new one. He found a
new, old stock one - never been on a car for £40, fitted it and still the same. Testing the servo by pumping up and starting the engine, the pedal
does move, indicating the servo is ok, BUT the problem persists.
I've tried everything I know, hence the post!
Marcus
If it does it with the engine off, then it is your master cylinder. The rubbers inside are probably failing.
My thoughts exactly, BUT the master cylinder has been replaced with a new one and the problem is still there.
It's a wierd problem.
Marcus
It could still be faulty.
Have a go at buying a service kit and changing the seals yourself. It is pretty easy to do.
Found this: Click
[Edited on 14/5/2006 by nitram38]
Hmm, if it was old stock, the bores could be rusty I suppose, causing the seals not to - well - seal.
I think he's more inclined to return cylinder rather than try to fit a new seal kit.
Is there anything else it COULD be before we go along this track - however silly?
Marcus
Seal kit is the cheapest option.
Should only cost a few pounds.
Try changing your original cylinder seals first. If when you open it, the seals are obviously worn or falling apart, (compare them to your new ones)
then change the seals. If they look good, then suspect that the bore is worn, so replace the cylinder.
You should not cut corners with brakes, so a new master cylinder is best of all.
Never used them but you could try these LINK
[Edited on 14/5/2006 by nitram38]
quote:
Is there anything else it COULD be before we go along this track - however silly?
I agree, not cutting corners is the way. We didn't and bought a new master cylinder. Looks like it must be duff, think we'll try another -
as long as we can return this one!
Marcus
Did it come with a reservoir or did you use your old one. My brother in law had a similar problem with his and it was the grommets where the reservoir pushed into the cylinder.
Before replacing the m/cyl;
Disconnect all the brake pipes at the m/cyl' and fit bleedscrews in their place.
Then press the brake pedal; if it's solid there's no problem with the m/cyl' if it sinks to the floor then there MAYBE a problem with
the m/cyl'.
Check all the silly things like pedal linkage, clevis pins etc... before replacing the master cylinder.
Easier than blanking off m/cyl, just clamp off the flexy hoses, if you still have the problem you either have a knackered m/cyl or a massive leak which would be obvious. Servo is irrelevant to this problem
Clamping the hoses is a no no because they're all goodridge jobbies (and new) so balooning also isn't the problem.
The reservoir was new with the m/cyl, BUT the unions are smaller than the old unit. We've now fitted the old reservoir, checked the new cylinder
- bores immaculate, as you would expect, seals perfect, so it can only be something like air in the system as there are no leaks anywhere.
Going to have another bleeding session and totally renew fluid just in case. Will report back soon.
Marcus
A direct acting servo fault can't make a pedal go all the way to the floor. Different with a old style remote servo.
A few very simple tests.
Try this one both with and without servo assistance.
First get someone to watch the level in fluid resevoir very carefully -- might help if you fill it right to the very top. Now put steady but gentle
presure on the brake pedal, if the fluid level increases the recuperating seal/valve in the master cylinder is u/s.
If that dosen't show a fault check for small leaks at the all the pipe unions -- get somebody to but a lot of steady pressure on the system.
If that dosen't show anything if the car has proper rubber-fabric brake hoses clamp off all the goses to isolate the master cylinder and then
test the pedal.
If the car has braided hoses the only way to test the mastercylinder is to fit bleed nipples to each port - give it a qiuck bleed and pressure test
it.
quote:
Originally posted by Marcus
Clamping the hoses is a no no because they're all goodridge jobbies (and new) so balooning also isn't the problem.
The reservoir was new with the m/cyl, BUT the unions are smaller than the old unit. We've now fitted the old reservoir, checked the new cylinder - bores immaculate, as you would expect, seals perfect, so it can only be something like air in the system as there are no leaks anywhere.
Going to have another bleeding session and totally renew fluid just in case. Will report back soon.
Marcus