ZX 1.9D Aura 1992
Something's wrong with my brakes now!! With the engine running the pedal goes almost to the floor before meeting resistance, but if I press it down fully, then release, then press again - it's fine. I.E as if I have to pump them up.
Is it possible something wasn't put back right when the gearbox was replaced last week??
Where should I start looking!?
Appreciate any help.
S.
Excessive Brake Pedal Travel
Moderator: RichardW
Start with the obvious :
check the brake master valve fluid reservoir level.
Have engine stopped - work the pedal several times until it get's hard.
Then press down & HOLD the pedal down - while you start the engine.
You should then feel the pedal move up against your foot pressure - indicating the vacuum servo charges right after engine start.
check the brake master valve fluid reservoir level.
Have engine stopped - work the pedal several times until it get's hard.
Then press down & HOLD the pedal down - while you start the engine.
You should then feel the pedal move up against your foot pressure - indicating the vacuum servo charges right after engine start.
Try pulling the handbrake on fully then backing if off a notch or the until the wheels are just free to move. Try your footbrake and see if it bites in the right place.
If it makes a noticeable difference, then your rear shoes are out of adjustment.
(Anders - wouldn't the pedal SINK a little rather than rise if you test the brake servo that way on a ZX?)
If it makes a noticeable difference, then your rear shoes are out of adjustment.
(Anders - wouldn't the pedal SINK a little rather than rise if you test the brake servo that way on a ZX?)
Even though i did a fatal mistake in my explanation on the vacuum servo test - you managed to check it out OK [:D][:)][8D][^]
Now you know 2 facts :
1) the fluid level is ok
2) the vacuum servo is ok
The pedal pressure is un-affected of any "preload" to the rear brakes (handbrake) - since brake force to the rear wheels is very weak.
The only remaining possibility is air in the system - and then next question - where from ?
I'd immediately suspect the brake master valve then - a known problem issue in the AX - with a similar (if not the same) system.
N65216 BRAKE MASTER CYLINDER ZX 20.6mm 27.50
This is the standard ZX brake master valve - NO ABS - NON-Estate.
NOTE : It's no longer possible to find rep kits for brake master cylinders - for reasons of narrowed safety regulations.
Now you know 2 facts :
1) the fluid level is ok
2) the vacuum servo is ok
The pedal pressure is un-affected of any "preload" to the rear brakes (handbrake) - since brake force to the rear wheels is very weak.
The only remaining possibility is air in the system - and then next question - where from ?
I'd immediately suspect the brake master valve then - a known problem issue in the AX - with a similar (if not the same) system.
N65216 BRAKE MASTER CYLINDER ZX 20.6mm 27.50
This is the standard ZX brake master valve - NO ABS - NON-Estate.
NOTE : It's no longer possible to find rep kits for brake master cylinders - for reasons of narrowed safety regulations.
Could I just clarify, if you apply the footbrake and keep your foot on the pedal, does the pedal slowly continue to sink to the floor (may take a minute or two), or does it sit there rock solid but too close to the floor for comfort?
If the former, then I'd agree with Anders - master cylinder. If it doesn't move, I'd try clamping off the flexible hoses one at a time to see if the excessive travel could be traced to a particular corner of the car.
If the former, then I'd agree with Anders - master cylinder. If it doesn't move, I'd try clamping off the flexible hoses one at a time to see if the excessive travel could be traced to a particular corner of the car.
Brake hose clamp picture: http://www.justoffbase-tools.co.uk/tool ... 563P1505M0
Don't use a G clamp or mole grips as it'll damage the hose. At a push you could use mole grips with the jaws protected by a copper pipe cut in half and reversed i.e.
Jaws) |hose| (Jaws
Sorry the ascii art is so poor, the ")" and "(" represent the halves of the copper pipe, its there to spread the load on the hose.
A balooning pipe would likely give a springy or spongy pedal so its probably not that, but I'd clamp each off one at a time to see if anything feels different at the pedal when the clamp is on then concentrate my efforts there.
One other thought, do the brakes actually stop the car OK? If not it could be a failure of one of the split braking circuits.
Don't use a G clamp or mole grips as it'll damage the hose. At a push you could use mole grips with the jaws protected by a copper pipe cut in half and reversed i.e.
Jaws) |hose| (Jaws
Sorry the ascii art is so poor, the ")" and "(" represent the halves of the copper pipe, its there to spread the load on the hose.
A balooning pipe would likely give a springy or spongy pedal so its probably not that, but I'd clamp each off one at a time to see if anything feels different at the pedal when the clamp is on then concentrate my efforts there.
One other thought, do the brakes actually stop the car OK? If not it could be a failure of one of the split braking circuits.
arry_b - yeah the brakes do stop the car fine.
Thanks all for your help. Unfortunately I now don't have any time to spare so a friend of mine who happens to be a mechanic is gonna look at it.
Expect I'll be back here shortly asking for more help as I noticed a 'knocking' sound at the front of the car when going over some potholes today.
S.
Thanks all for your help. Unfortunately I now don't have any time to spare so a friend of mine who happens to be a mechanic is gonna look at it.
Expect I'll be back here shortly asking for more help as I noticed a 'knocking' sound at the front of the car when going over some potholes today.
S.