92 prelude SI /w h22 swap.

Last summer on extremely hot days (90 degree+) the breaks would go to the floor on occasion, then i just let off and press again and it pumps it out...

Almost like break fluid has air in it or something?

But now...out of no where on a semi-cool humid day...its happening again.

The thing is...it doesn't always do it, its rare...but then CONSTANT for an entire day.

Master cylinder? just bleed the lines?

Does the liquid in the lines thin out on hot days, causing this problem? or is it a master cylinder issue?

ugh...I have had another h22 swap done, brakes blead, and it seems to still do it 3-4x a year.

 

it is most likely the master cylinder, check for wetness under the dash.

 

sounds very much like the master cylinder, even without any under dash leak it could be faulty.


at the very least its easy to replace.

good luck

 

it seemed like the brakes to the floor happened almost always when i had the clutch all the way down as well.

when i break without the clutch in, i dont know if i have ever experienced this problem.

but i should only need the brake MC, not clutch MC?

 

The two are completely seperate systems. You should just need a brake master cylinder.

I would check over things first and make sure that is actually the problem. Go look at all your brake fittings.