Please Help! Ongoing Brake Problem

[Tuccy]

Guys is there a way to disable or bypass the abs system on my willy3 ?
im almost at the point of banging my head of the wall with my brakes

it all started ages ago just after i bought the car.
basicially what happens is this:
if i press my brake pedal it does right to the floor with very little effort and the brakes dont really apply, it only slows the car very gently, if i press the pedal to the floor then release it and press it again immediately i get brakes that are excellent, ie first press of the pedal nothing really happens, but on second press brakes are like amazingly good.

ive bled the brakes, this seems to cure the problem for a few days or maby a week before if starts being silly again, ive completely drained the brake fluid and replaced it with new stuff, same thing happens, temporary fix only, ive replaced my master cylinder with a new one, still the same thing, im NOT loosing fluid anywhere, no leaks anywhere, ive clamped all the flexi lines to check the new master cylinder but it seems ok, ive stripped all the callibre`s and freed them all up, this hasnt helped either.. im simply lost as to what is causing this..

all bleed nipples are tight, but could the brake system be drawing air through the threads of the brake nipples, should i remove them and copper thread grease them?

Having said this the pedal does NOT feel spongie like it would if there was air in the system which is a contradiction because if i bleed the system it temporarly cures the prob lol :twisted:

would the equaliser valve on the rear of the car being set wrong cause this prob? should i re-adjust the equaliser valve? im asking this because the car was lowered when i got it and i havnt checked if the valve was set to suit the lowering...

also ive fitted all new brake pads all round on the car too..

please help its driving me nuts here :(

any ideas are much appreciated.. and a big thankyou in advance for any suggestions or ideas :)

[northy]

im having trouble too with my rear brakes on my 3 mate, no matter what i do i carnt get the drivers rear to bleed. Its not even getting to the caliper....further investigations are needed on my part.

Is your abs working ok pal ?

[BristolSam16v]

Sounds a bit like the caliper isnt in contact with the pad so on the first press it makes contact 2nd press you get full effect?

[Tuccy]

im having trouble too with my rear brakes on my 3 mate, no matter what i do i carnt get the drivers rear to bleed. Its not even getting to the caliper....further investigations are needed on my part.

Is your abs working ok pal ?

hey northy how do i tell if the abs is working ok,?? sorry if that seems like a silly question

if i was to jump on my brakes (TWICE at the min lol) it feels like there is a
virrbating feeling coming through the brake pedal, although ive never managed to lock any of the wheels, dunno if this is because my abs is working or just because my brakes are really bad and just aint workin :?

[northy]

abs = anti lock brakes.

So if its working at normal braking they will feel normal

Hard braking the pedal will vibrate as the abs stops the wheels from locking.

There is a fuse to disable the system though but u need it functional for mot tests

the pedal should not need pumping. when u have been doing the bleeding as u keepin the fluid topped up and no air comes out ?

what method of bleeding are u doing

[Tuccy]

yeah northy i feel the vibrating in my pedal under hard braking so i may assume my abs is working...

i have tried two ways of bleeding,
the first way i started with the wheel closest to the master cylinder and worked away from the cylinder ending with the furthest wheel away from it.

and then when the problem reoccured about a week later i did the same thing but this time i started with the wheel furthest away from the master cylinder and worked my way round each wheel till i ended with the wheel closest to the master cylinder..
at all times i was very very careful to keep the resivoir topped up.

ive tried the two person bleedind ie me bleeding the nipples while a friend pressed the pedal for me. and ive bought a oneway bleed pipe and bled them myself too :?

im puzzeled with this lol :oops:

[Tuccy]

i removed the abs fuse you mentioned northy and tried my brakes, its just the same with the fuse removed :?

[MAXIBOY]

hi mate

have you put a dial gauge on the discs and checked for run out and are all wheel bearings in good condition.

new to make sure the discs aren,t warped..

[drsmith1979]

i have a brand new willy 3 (abs) rear bias valve boxed from renault, had it on special order as we couldnt bleed the passenger rear caliper, however, after it settled over a day, it bled fine. cant take it back as it was special order. i think they are nearly £100 from Renault, if anyone wants a shiny new one, you can have it for £80.

Northy if you want it i can deliver 8)

[Tuccy]

hi mate

have you put a dial gauge on the discs and checked for run out and are all wheel bearings in good condition.

new to make sure the discs aren,t warped..

i will check now as have borrowed a dial guage from my dad, so i will post my findings a bit later. this guage measures in 0.01mm segments so it should be very accurate, is there a rough quide as to what measurments would be acceptable and which would not?

many thanks for all the help and suggestions so far guys i really appreciate your help :D

[northy]

with the abs off the pedal should be one constant pressure and not be really vibratey and notchey like when the abs is on.

Are all your calipers bolted up tight. disks ok, pads correct and fluide on max ?

if not go to kwick fit and get a free brake check

[MAXIBOY]

hi mate

have you put a dial gauge on the discs and checked for run out and are all wheel bearings in good condition.

new to make sure the discs aren,t warped..

i will check now as have borrowed a dial guage from my dad, so i will post my findings a bit later. this guage measures in 0.01mm segments so it should be very accurate, is there a rough quide as to what measurments would be acceptable and which would not?

many thanks for all the help and suggestions so far guys i really appreciate your help :D

hi mate run out should be 0.07mm maximum

[Tuccy]

thanks for all the pointers guys :)

all my discs are ok, they all measure roughtly the same when checked with the guage (0.01mm)

all calibres are tight, all sliders are free, wheel bearings seem ok

so i got my hands on a pressure bleeder kit and bled the brakes with it.
because before i had been doing them the old fashioned way

brakes seem perfect again, but i wont really know for a week or so to see if they gradually die again, like they usually do. :roll:

fingers crossed
thanks again guys :P :P

[Tuccy]

:shock: :x Same thing again :cry:

any other suggestions guys?

im at a loss here :evil:

[Lunner]

Maybe tehre is a leak in the ABS unit

Have you checked your brake lines for corrosion

When you bleed the brakes do you get air bubbles coming out

[kenny]

Might be barking up the wrong tree but it's obviously pulling air in, It's not likely to be a metal component as split of any kind would see fluid expeled under pressure and you have said there is no fluid loss, so it has to be a seal somewhere. It's not likely to be a caliper etc as they are also under pressure and you would see fluid loss there. What about the seal between the reservoir and master cylinder, as you press the pedal and fluid moves through the pipework there could be a small amount of negative pressure at that point if the reservoir cap, which has an air hole is blocked. A blocked cap will mean air has to enter the reservoir from somewhere else. I would be amazed if this were the case as the air would then have to get past the master cylinder seals and into the system. It might be clutching at straws, but it's easy to check and I recon you must be pulling your hair out now

[Lunner]

new master cylinder comes with new seals for this though

What fluid are you using?

Solid pipes might be rusted and allowing weapage, in which case you wouldn't notice it, but if fluid can get out it can get in when pressure is released.....i think

[kenny]

It might come with new a seal, but it's only got to stop a viscous fluid from escaping, there's no pressure there. It could still be weapage, but there will be at least a small loss of fluid, maybe not noticable, but to stop this line of thought it's easy to check the reservoir cap.

[Twincam]

not sure whether it is relevent to any of you but are you using a one man bleeder?

These kits work fine unless your bleed nipple isnt tight in the caliper. I had a problem trying to bleed a system with one and just couldnt sort it turned out when i was lifting my foot off the pedal air was being sucked back up from around the threads

best kits are the pressure bleeders, I have my brake lines running through the car, through a bias valve then through my vertical hydraulic handbrake on the road rally clio. Was a nightmare to bleed to get all the air out. Used a pressure bleeder and pumped the brake peddle and pulled the handbrake to get all the air out

Works well :D

[Lunner]

Agreed pressure bleeders are the ones, just need to get a decent seal on the resovoir

[eternalife]

Are you using standard calipers?
Standard brake lines?

[Tuccy]

Thanks for all the pointers guys, its getting to the point where i will take the car off the road for a day or two and go over it with a fine toothed comb :twisted: this will be a nightmare for me as i only have 1 car and need it daily :twisted:

i will check the resivoir cap as mentioned, as a run down here is everything i have tried so for

car is a 1995 williams 3
brake calibres, lines etc are all standard

tried various types of bleeding including
the 2xperson method (a friend pressing and releasing brake pedal and me doing the nipple bleeding)

the one man bleed pipe with a one way valve fitted

and the preasure bleeder method
all the above provide a temporary fix only :shock:

i have removed all bake nipples and applied a bit of copper thread grease to there threads

i tried releasing the brake lines of the top of the abs unit (simply to attempt bleeding from here like you would bleed a diesel engine which had run out of fuel) but these are very tight and im afraid i might damage or break them so i gave up with that idea

checked all calibres are tight and all sliders are free

there isnt enough disc warp as all discs are around a 0.01mm tollerance when checked with a guage

wheel bearings seem ok

master cylinder has been replaced with a new one

i thought i might have flipped the seals in the master cylinder but if i clamp all the brake likes the master cylinder seems fine, so ive ruled that out.

fitted new prake pads all round (just because i had the calibres off to clean and free them anyway)

i bled 2 bottles of brake fluid through the system using the bleed method, was just trying to be sure i had nearly all the old fluid out of the system and all new stuff in there instead.

Using brand new bottles of fluid at all times, throwing bleed fluid out and not reusing it as some do, using comma dot 4 fluid

i feel its drawing air into the system from somewhere as the bleed methods do provide a temporary fix, then after a few days to a week i gradually feel the brake pedal loosing its responsivness.

the master cylinder did come with new rubber seals for the resivoir but i will check the cap is clean and clear.

im feeling this is a silly problem, which will be easily fixed, its just finding the problem thats a nightmare.

if i have to i will get car on the ramp and renew all the brakelines.
im determined to fix the problem, and thanks to all the help on here im sure i will eventually get it sorted..

think ive covered everything, and thanks again for all the pointers guys :P

[Purple]

if i press my brake pedal it does right to the floor with very little effort and the brakes dont really apply, it only slows the car very gently, if i press the pedal to the floor then release it and press it again immediately i get brakes that are excellent

Are you running some high specs racing pads? Or standard renault? Racing pads might not be clamping properly in the cold weather until you warm them up with the initial brake application.

My other guess is that one of pistons or guides are not sliding cleanly. Try checking them again. It could be when you bleed the brakes, you give the piston and sliders a good workout, thus reducing the problem for a while.

[number1]

I scrapped my last valver cos of this problem, but i reckon it was a dodgy master cylinder... changed it once and once bled would be ok for a few days then onto the emergency brakes again.... kept getting air in the system... gave up when the gearbox gave up aswell...

Stress!!!

[Tuccy]

if i press my brake pedal it does right to the floor with very little effort and the brakes dont really apply, it only slows the car very gently, if i press the pedal to the floor then release it and press it again immediately i get brakes that are excellent

Are you running some high specs racing pads? Or standard renault? Racing pads might not be clamping properly in the cold weather until you warm them up with the initial brake application.

My other guess is that one of pistons or guides are not sliding cleanly. Try checking them again. It could be when you bleed the brakes, you give the piston and sliders a good workout, thus reducing the problem for a while.

No just replacment FERODO pads all round, i will go over the calibres and sliders again, im really beginning to wonder if i was unlucky and got a dodgy new master cylinder :?

well had to bleed them again today just to get brakes back, still wondering whats causing my problems :evil:

[Tuccy]

if i press my brake pedal it does right to the floor with very little effort and the brakes dont really apply, it only slows the car very gently, if i press the pedal to the floor then release it and press it again immediately i get brakes that are excellent

Are you running some high specs racing pads? Or standard renault? Racing pads might not be clamping properly in the cold weather until you warm them up with the initial brake application.

My other guess is that one of pistons or guides are not sliding cleanly. Try checking them again. It could be when you bleed the brakes, you give the piston and sliders a good workout, thus reducing the problem for a while.

No just replacment FERODO pads all round, i will go over the calibres and sliders again, im really beginning to wonder if i was unlucky and got a dodgy new master cylinder :?

well had to bleed them again today just to get brakes back, still wondering whats causing my problems :evil:

[Tuccy]

woops sorry for double post

cant find a edit or delete option :oops:

[1fast6]

Have you replaced the pedal servo?

[Lunner]

With a dodgy servo the pedal will sink to the floor when pressure is applied, rather than being spongy, and i can't see how bleeding would help, defo think its air getting into the system somewhere

What brake fluid are you using, dot 5 or 5.1, can never remember which absorbs air like there's no tomorrow