Marcus
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| posted on 14/5/06 at 03:22 PM |
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Brake Servos
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
Marcus
Because kits are for girls!!
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nitram38
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| posted on 14/5/06 at 03:35 PM |
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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]
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Marcus
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| posted on 14/5/06 at 03:42 PM |
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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
Marcus
Because kits are for girls!!
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nitram38
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| posted on 14/5/06 at 03:51 PM |
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If it does it with the engine off, then it is your master cylinder. The rubbers inside are probably failing.
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Marcus
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| posted on 14/5/06 at 03:53 PM |
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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
Marcus
Because kits are for girls!!
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nitram38
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| posted on 14/5/06 at 03:57 PM |
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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]
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Marcus
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| posted on 14/5/06 at 04:07 PM |
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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
Marcus
Because kits are for girls!!
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nitram38
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| posted on 14/5/06 at 04:17 PM |
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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]
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omega 24 v6
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| posted on 14/5/06 at 04:20 PM |
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quote:
Is there anything else it COULD be before we go along this track - however silly?
Unless youve got an intermittent leak then probably no. I'd go for another master cyl as well just as a check. Even if it's new it could
still be faulty.Did you bleed the brakes using the pedal (seal reversal) Or is it possible that ocassionally one of the flexis is
failing(ballooning)under higher pressure (thinking possibly the rears, under greater breaking force the pressure to them would be higher anyways). Is
it really that intermitant or can you tie it to particular scenarios?
You did say any ideas however bizarre. StillI think it'll be the m/cyl.
Good luck
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Marcus
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| posted on 14/5/06 at 04:20 PM |
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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
Marcus
Because kits are for girls!!
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Peteff
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| posted on 14/5/06 at 05:46 PM |
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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.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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JAG
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| posted on 14/5/06 at 06:12 PM |
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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.
Justin
Who is this super hero? Sarge? ...No.
Rosemary, the telephone operator? ...No.
Penry, the mild-mannered janitor? ...Could be!
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russbost
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| posted on 14/5/06 at 09:35 PM |
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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
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Marcus
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| posted on 15/5/06 at 08:01 AM |
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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
Marcus
Because kits are for girls!!
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britishtrident
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| posted on 15/5/06 at 08:51 AM |
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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.
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britishtrident
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| posted on 15/5/06 at 08:57 AM |
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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
From hard experience I know new Goodridge hoses are MUCH more likely to give a problem than proper brand new OEM hoses.
Seen a couple of Goodridge hoses that were badly assembled, If using them again I would always bench test before fitting to a car.
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