one way valve

[_Wing_]

one way valve

I was at eastern creek the other day and after the straights my pedal would almost hit the floor and do nothing. If I released and jumped back on it was rock hard. Has anybody experienced a leaky or slow one way valve in their brakes?

[Dale FZ1]

Sounds like pad knock off, Wing.

[Duncan]

Or possibly also simply boiled brake fluid (the better the fluid the more water it absorbs so the more often it needs bleeding).

I have had a split line to the brake booster (in an Emo 9) and the pedal was rock solid but did pretty much nothing when I stomped it, it's quite a distinctive feeling and not what you are describing. Oh and for fun it happened to me at 250 at bathurst in the chase....Modern braking systems are not designed to work without the booster so they don't have much pedal leverage on their own.

[niZmO_Man]

Bleed the ABS.

[Dose Pipe Sutututu]

Did you wrap brake lines near your turbo setup? Also worthwhile making a basic heat shield using ACL shield to cover the ABS unit.

Sounds like cooked brake fluid.

[_Wing_]

When it first happened I thought it was pad knockoff too but I've just upgraded to version 3 of the evo 350mm brembos and as the day went on, I took note that after hard cornering, like turn 6, the brakes were fine going around turn 7 / corporate hill and then into turn 8 hairpin too, so definitely not pad knockoff.

The brakes were bled a few weeks before 2 man style which I've done hundreds of times already, but how do you bleed the ABS? It could be boiling, but I don't understand how boiling fluid would be ok on the next corner.

No extra heat shielding added, but it's a good idea. That reminds me, I need to wrap the wiring around the turbo side!

The thing is that on short straights the brakes were fine, it wheelspins 3rd gear so not much boost is produced until the long straights, which got me thinking that a fraction of the 25psi boost was making it's way back through the old one way valve. I THINK remember reading here that someone had the same issue...

[Dose Pipe Sutututu]

Phil's S15 has 25psi going into it.. no issue what so ever..

I suspect boiling fluid and you're heating up your ABS unit.

Bleed ABS unit easy, crack open the lines up top of the unit and bleed as you would bleed a set of calipers without a one-man bled tool, i.e. pedal down, crack line, close line, pump pedal, pedal down, crack line, close line.. ra ra ra.

[_Wing_]

I'll give it a go, cheers