brake issue - need some help

[welsha]

rev3 turbo - done all the BGB checks and as far as I'm aware everything works ok. Engine off pedal rises when after pumping then sinks when engine started.

The issue - when I press the brakes the travel is a bit and the feel is soft. If I immediately lift off the brakes and then press down the travel is shorter and pressure firmer. What tests can I do to id where the issue lies?

New std pads and bled system has not changed this behaviour. Brakes work hard when pressed but the 2nd press behaviour does bother me

[BSM]

I would say either warped discs as an extreme, poss sticky caliper, they are known for it. Then I'd look at your flexi's for bulges. It is a clear symptom of air in the sytem, the check you did with engine off then on is for the servo operation.

What is new and what is old? What have you changed that has caused this to happen? New discs and pads? new caliper on one side? Handbrake cable been changed?

Post up your full details and we'll see where we can get fromt here mate.


BSM

[welsha]

had the car 5 years always had this issue.

Brake fluid has been changed within 18 months, system bled many times since

front - discs new on 2 years ago pads last year - std toyota pads. Calipers cleaned up but yeah they are likely goosed as with the carrier

rear - new caliper passenger side original discs AFAIK std Toyota pads last year

[T.I.M]

I get a similar problem, and I too think its to do with the calipers. they are really bad for seizing on. I've had 3 MR2s and only one didn't suffer from the calipers either partially or fully seizing. think this stickyness of them could be the problem.

[welsha]

brakes are not seizing on as far as I can tell but likely the calipers and carriers are past their best. Big brake kit anyone?

[BSM]

Could sell you an ST205 set of calipers an discs if you're interested? ;)

[millentubby]

I'd refurb the BMC seals and overhaul the calipers.

[Portgordon]

The caliper sticking slightly after the first pedal press would explain the less travel required for the second press would it not? :hmm:

[welsha]

Could sell you an ST205 set of calipers an discs if you're interested? ;)
i know the calipers need a special mounting bracket made up and the disc hat is too tall for my 8" front rims - pity but cheers.


The caliper sticking slightly after the first pedal press would explain the less travel required for the second press would it not?
certainly might be, the first press forces everything to line up with the disc then the 2nd press actually makes it all work.

Colin - the front calipers were overhauled by Calum 2 years ago but aye the whole caliper / carrier setup is past it's best.

i just don't want to spend money I don't have changing parts that are not faulty but if I do need to change the calipers then might as go and put on some 4pots and bigger discs. 320mm anyone?

[welsha]

can I block off the brake booster in the engine bay thus allowing me to check that's not an area of issue? I am right in thinking the brakes will still work but will take a fair old push to work?

[BSM]

Yes quite true, this servo just assists the pedal pressure. if you take the vac hose off all you will have is raw brakes, pedal to caliper with no pressure assistance. Give it a go and see what issues you have.

[welsha]

coolio, I was er kinda drunk at the weekend there so will need to do it this weekend. The feedpipe is the one that runs round under the drivers side inspection panel?