Pump my brakes

[briitts]

Ohh err

Right, I have had this problem with my brakes for about 2 years, its only a problem on the track as it means I have that less braking time as I have after I have pumped the brakes once.

They are not spongy, even before I have pumped them, and work fine just have a lot of travel. I have had them bled upteenth times and nothing works.

I have 310mm Hi Specs with Pagid pads.

Could it be the master cylinder, and if so is there a way of testing it?

 

[jonee]

r

if the pistons in the new calipers are bigger in surface area then you will have extra pedal travel.

 

[Fast Guy]

If it's only on the track ie after lots of hard braking, it could be moisture in your fluid boiling, but if you've bled them enough you'll have fresh fluid throught out the system. It may simply be the fluid itself boiling when it's getting hot.

What brake fluid do you have?

 

[ard1ey]

I have this problem (does yours do it on the road as well :?: ) and I've seen it mentioned on here a few times. I'm convinced the pads are being knocked back away from the disk somehow, but I'm yet to pin down why

There's some mention of the problem on the Stoptech website.

 

[jonee]

r

i forgot to ask if you have fitted metal braided brake lines.

if not then try them as they do stop the pedal travel due to brake pipe expansion

 

[antgtir]

Id go with the above, 1st change your hoses for braided ones then change your fluid for a higher grade. This option first will be cheaper than trying to source and upgrade the master cylinder.

 

[briitts]

Firslty it happens not just on the track but on the road even from cold, so basically all the time. I have braided lines already.

To be honest I am thinking its something to do with the pads being knocked back like matey said. I think its a fault in the calipers as my R was one of the first to have the Hi Spec kit.

Incidentally, when I am on track I have never had any fade or any problems with them, its just that initial first pump.

 

[Fast Guy]

its only a problem on the track as it means I

I misinterpreted this bit

 

[ard1ey]

Yep, I have braided brake lines and new fluid as well. My calipers are the Godspeed ones though, so perhaps the pinchers aren't to blame.

Still, keeps it interesting I suppose . At some point I think I'll try a new master cylinder (or seal kit) and see if that improves matters.

 

[Olly]

britts, do your pads move freely with plenty of copper slip on the edges? cos if they stick when they suddenly move it can cause this, i have willywoods and had a similar thing, also when bleeding have you tried pumping up the pedal till hard and holding it down, then person number 2 cracking off the bleed nipple let the fluid out then do it back up, pull the pedal up and do the others and it should make a differance, did for me when i was bleeding my wilwoods only way to get all the air out normal foot or machine bleeding not enough. 8)

 

[LeeSmith]

I remember reading on here a while ago that the ABS won't work well with larger brakes as the control unit doesn't have a self learning capability, it only knows how much to fill the std calipers & only fills the larger ones to the capacity of the smaller calipers!

Basically when it locks the pressure building back up takes longer and therefore your braking distance is greatly increased :shock:

 

[GTIR-LOZ]

sorry to drag up old posts but did this ever get fixed as i suffer from this still and cant figure it out