Brakes????

[rice_eg]

hey all,

i just got my licence back and i've noticed that when i drive now and am at a set of lights or idling my brake pedalgoes further and further in. I changed the pads today and its stops mad. But the same problem keeps hapening.

any ideas?

mate said that is the master cylinder but theres no leaking fluid. Fluid levels stay the same.

also, i've bleed em too.

cheers

(eh vti)

[Sexc86]

Its the Mastercylinder.

Its the seals inside, doest mean you have to be actually leaking fluid out of your resoviour.

[Limbo]

you need to rebuild the master cylinder. There is a post in the DIY on how to do this

[JohnL]

The fluid (and pressure) leaks past the seals and then back into the reseviour, hence no fluid loss. It's a dangerous condition and needs to be fixed asap.

It may happen more in hot weather or after the MC has been sitting in a hot engine bay when the car is parked. My best guess as to why this sometimes happens is that when the MC is colder the cylinder bore is X diameter, but when it's hotter the metal expands and the diameter becomes X+. The seals may be old and hard, and not able to 'spring' outward to seal adequately when the MC expands. The diameter difference between a cooler and hotter MC may only be very slight, but enough to be the difference between sealing and leaking slightly.

[bennjamin]

did this happen before thebrake fluid change ?

i doubt its your master cylinder - its more than likely user error. You need to rebleed the fluid and make sure there is no air bubbles thru the system. How did you bleed ?

[rice_eg]

cheers guys,
i bleed them for ages. I changed the calipers a month ago but i didnt notice the brakes done that before the calipers were changed.

I hope its something small........

Whats the best way to bleed them?

I had somone pump the brakes and held, then realease the pressure from the 10mm nipple on the caliper. Both sides. Havent doen the rears though.

Could that be it?

[SuiJin]

u need to bleed all the brakes... == u got air in there.

[bennjamin]

Could that be it?

yes it COULD be that.

do it again - you should do it furthest away from the MC (master cylinder) and work your way back in.

So REAR LEFT , REAR RIGHT , FRONT LEFT , FRONT RIGHT.

Make sure there is solid brake fluid coming thru the tube/pipe before you ask your friend to "hold" to the floor as you tighten.

[aaronng]

I had somone pump the brakes and held, then realease the pressure from the 10mm nipple on the caliper. Both sides. Havent doen the rears though.

This method CAUSES leaking master cylinders. You should open the nipple, and then pump the brakes. Time for a rebuild.

[wynode]

A 'leaking' master cylinder won't show a loss of fluid. What happens is the fluild is bypassing the seals.

See this thread for the proper method on 'pumping' the brake pedal.

http://www.ozhonda.com/forum/showthr...ht=brake+fluid

[Davo]

i am also having this issue in my crx. is it possible that the brake boost is faulty too???

[JohnL]

The pedal merely being soft with excessive travel is most probably a symptom of air in the hydraulics. This tends to be a fairly consistant problem, i.e. the pedal is always soft and the system needs bleeding

If the pedal sometimes feels soft with excessive travel, but sometimes feels firm with 'normal' travel (or close to it), and particularly if the softness sometimes manifests as a progressively 'sinking' pedal when say waiting at the lights, then the problem is most probably an internally leaking MC, and the MC needs to be replaced.

It wouldn't be impossible to have both problems simultaneously.