taylor

My 97my impreza has the newer 2pots + x drilled and grooved discs, upgraded pads and goodridge hoses.

My brakes are still crap! There's very little power for the first 2" and I can press the pedal right to the stop.

The systems been bled, so it's not that.

Surely by adding an extra pot I must need extra displacement, hence the need for a larger master cylinder.

I've never read anything on here to suggest that this is the case, so am I barking up the wrong tree?

Cheers
Taylor

Dyney

:confusesd: Where did you add an extra pot?

Pavlo

I think you mean 4 pots, 2 each side of the caliper?

You need to bleed the brakes again, and again, and again if necessary. You will also need to bleed the whole system, front and rear, in diagonal pairs, start with the rear caliper first.

paul

taylor

Sorry. I should have said that I've gone from the old 2 pots to the new Post 98 4 pots. I've bled them and the local garage has bled them. My question is: Surely by adding volume, (by having more slave cylinders) you must then require extra displacement. Otherwise, the pedal will shoot through it's travel without fully pressurising the calipers.

Or am I missing something?

Pavlo

yes you're missing something.

with the 2 pot sliding caliper the pistons have to go twice as far, volume is the same.

Your brakes need bleeding again. Also make sure you do some ABS stops between bleed sessions.

I bled mine 3 time, did the abs thing, then bled them twice again.

Also make sure the bleed nipple is on the top of the calipers, people have been known to fit them upside down.

Did I mention you need to bleed your brakes again?

Paul

taylor

Cheers Pavlo, You sound like you know what you're talking about.

So does this apply to after market calipers also. ie AP's. Same volume just greater surface area?

Pavlo

Many of the aftermarket calipers have same or slightly greater piston area. Stoptech has lower piston area to compensate for larger disk and maintain the same brake balane.

Newer subaru 4 pots on older car is a popular way to go though.

When bleeding my brakes , I eventually fed the front caliper output to the master cylinder. BUT, this was after flushing and bleeding about three times, so the fluid was all new, coming out nice and clean. I did this for about 5 minutes each side until I couldn't hear the air moving through the lines.

I was like you, thought i bled them fine till I went on the road and tried them, aaaaaargh!

"eazi-bleed" type device might make it easier, but I did okay without, and some say you don't have the control. Make sure the pipe on the bleed nipple goes up then down so you don't suck any air in.

Paul

Pavlo

did this get anywhere, I'm curious.