Celica Gen 6 Brake Problem

[The Scotsman]

Hi All

Ive owned my 96 Celica ST for the past 3 years,recently its developed a brake problem

when you brake their is a noise like the teeth on the abs ring arent being grabbed properly,have replaced the discs and pads all round but to no avail

has been into 3 garages and they cant pinpoint the problem im now at the stage of replacing all four calipers and bleeding the brakes,if this doesnt work im lost as to what to do next,sometimes when you brake the pedal goes solid then you have to pump it to get it to work,the ABS light only comes on when you start the car then goes off

any suggestions would be greatly appreciated

Thanks

Scott

[GT4 BOOSTER]

the abs ring is fixed to the cv joint , it does not grab anything , the abs sensor sits opposite this ring and when the gap in the teeth is opposite the sensor abs is off ,when its opposite a tooth the abs is on . changing the pads ,discs and calipers has no bearing on the abs rings.

try bleeding all calipers if the pedal still aint right , id imagine its either the slave cylinder or master cylinder at fault.

[The Scotsman]

the abs ring is fixed to the cv joint , it does not grab anything , the abs sensor sits opposite this ring and when the gap in the teeth is opposite the sensor abs is off ,when its opposite a tooth the abs is on . changing the pads ,discs and calipers has no bearing on the abs rings.

try bleeding all calipers if the pedal still aint right , id imagine its either the slave cylinder or master cylinder at fault.

Thanks very much for your advice.

If bleeding / replacing cylinders do not remidy the problem Do you think it could be the servo or are these pretty realiable?

Thanks

[GT4 BOOSTER]

if the brakes work ok at first then you have to pump the pedal , it sugests an air leak somewhere , when a servo fails you usually hear air rushing from it , most have a tiny hole at the bottom which vents rather than the servo exploding so to speak , it also could be the rubbers in the master cylinder or the slave cylinder have failed , sometimes pushing the pistons back in the calipers is enough to make the rubbers flip ,due to the pressure of the fluid returning to the brake fluid resovoir. im still not sure what your problem is though as you mention a noise and then brakes failing in the same question .

[The Scotsman]

Thanks very much for all that info,very interesting! I see what you mean about pushing the pistons to 'reverse' the rubbers. Its mainly the pedal goin to the floor that im worried about,not the noise. I've changed all the calipers and fully bled through twice with engine running. The pedal is slightly harder but then pushes right to the floor again. Im starting to think its the master cylinder,as when I pump the pedal it gets slightly harder. I can hear some air when I push the pedal. Could this mean the servo is knackered or is this normal? Think I will replace the master cylinder and see what happens. Any other ideas? Thanks again very much for your advice. Really appreciate it!

[GT4 BOOSTER]

if you could locate a servo with a master cylinder attatched - happy days - if not try a new master cylinder ( lots on eBay ) , sounds to me when its under pressure its failing .

when you push back the pistons in future , use a length of fish tank airline on the bleed nipple going into an old bottle - this prevents the pressure build up on the braking systems components.

[The Scotsman]

if you could locate a servo with a master cylinder attatched - happy days - if not try a new master cylinder ( lots on ebay ) , sounds to me when its under pressure its failing .

when you push back the pistons in future , use a length of fish tank airline on the bleed nipple going into an old bottle - this prevents the pressure build up on the braking systems components.

Hey,

I managed to get a brake master cyclinder from a local scrappy. Fitted it and bled the brakes through...still no luck,the pedal still goes to the floor, although there is some pressure. When the engine is off the pedal is quite solid, as soon as start the engine to bleed the system the pedal pushes to the floor...im wondering if this is the servo due to the vacum from the engine not producing enough through the servo...!? I have now replaced all calipers & front disc's and pads and master cylinder...is the servo only thing left...?

Also ran into another problem...the n/s rear disc seems to be jamming due to the brake shoes inside, even when the hand brake is off... how do i adjust the hand brake shoes as i cant get the disc off?

Thanks again!

[GT4 BOOSTER]

if the rear drum/disc combo is old ,chances are the handbrake shoes have worn a nice deep edge on the inside , think what you need to do is back the handbrake off as far as possible on the adjuster to get the shoes to relax a little ,then its a case of trying to pull off the disc/drum the best you can , if you can sneak a screwdriver inside to lever down on the shoes till you get some clearance maybe .

is there also not a rubber bung in the front or at at the rear of the disc/drum for you to adjust the rear shoes ?? ( working from memory here ) you may be able to acces this and hold down the shoes as you pull off the disc/drum .