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Posted by: germaneighter Jan 8 2008, 11:27 PM

I finally installed a 19mm MC to match the SC front brakes I installed last year. I have new brake lines front and year. No leaks anywhere that I can tell. I used a pressure bleeder with ATE Super Blue. Bleed brakes for 12 rounds and still am getting bubbles. Pumped brake pedal hard in between each round to free up any air trapped in proportioning valve. I bleed the MC connections prior to bleeding each wheel.

When I first push on the pedal it goes down quite a ways. second pump is much higher and stiffer but there is still some sponginess. Any suggestions?

thanks,

Posted by: Jeff Hail Jan 9 2008, 12:29 AM

Air still in the proportioning valve assy which is the highest point in the system. Let sit overnight with the resevior cap off. If problem persists re-blead again (R rear first, L rear 2nd, R front and L front). Make sure you are bleeding both sides of each caliper especially the top bleeder's. Then if problem is still present may have a bad seal in the in the MC bore. Also recommend if replacing different type of fluid (4 vs 3) that you purge all the old fluid out of the system completely until your eye's see blue.

Posted by: Blood red 914-6gt Jan 9 2008, 01:18 AM

Could be the proportioning valve, but one way that we do it at our shop is with having two people. On sits in the driver seat to pump up the pedal. Generally three pumps or four. Starting at the passenger rear have the other guy crack the bleader and then close. Do this five times. Go to the drivers front and do the same. Then the drivers read and then the passenger front. If the pedal is still not hard do it one more time. This is the most effective way to get a very solid pedal.

Posted by: SirAndy Jan 9 2008, 01:24 AM

with the above procedures ...

Posted by: sww914 Jan 9 2008, 02:58 AM

Me too.
I haven't seen power bleeders work well unless the only thing that you're doing is flushing the system with new fluid. The 2 guys with feet method is the only thing that usually works right when you've introduced a bunch of air to the system.

Posted by: SLITS Jan 9 2008, 08:11 AM

I use a electric vacuum pump (hospital aspirator). Hook it up, turn it on and keep filling the reservoir. Never had a problem. At start, I crack the outlet lines on the MC and let them drip for a while to fill the MC bore. Sequence I bleed in is RR, LR, RF, LF.

Pressure bleeders are a PITA.

Posted by: Root_Werks Jan 9 2008, 10:03 AM

2 person bleed works best, simple no need to buy anything. My wife has gotten good at it.

Posted by: Cap'n Krusty Jan 9 2008, 10:09 AM

"Pumped brake pedal hard in between each round to free up any air trapped in proportioning valve."

Therein MAY be the problem. You pump the pedal SLOWLY between openings of the system. You have to allow the fluid time to fill the master cylinder. I allow 2-3 seconds between each pump of the pedal. Might wanna try that. The Cap'n

Posted by: germaneighter Jan 9 2008, 11:23 AM

Ok thanks for the help and advice. I usually use the wife. She too, knows the drill well. But brother in law gave me the presure bleeder for a birthday present. Wanted to give it a try.

dg

Posted by: Dr. Roger Jan 9 2008, 04:38 PM

wouldn't improper rear caliper venting clearance have the same symptoms?

Posted by: Phoenix 914-6GT Jan 9 2008, 04:42 PM

You may have a point. I have never had that problem thus never had to think about that.

Posted by: Dr. Roger Jan 11 2008, 04:00 AM

Since my car was in the air tonight, and she just got new Shea-bilt real calipers, I tested my theory.

All that was done on the cars brakes so far was throughly bleed using the two person method. Then adjust venting on the outer/rear calipers. but not the inner adjusters.

I needed to pump up brakes after the steps stated above to get pedal.

I adjusted the inner adjusters, because I didn't know I had to... =), and the pedal is now right up there as it should be. Sweeet!


*****Note: Eric's inner adjuster modification is absolutely fantastic. Period. Got both adjustments done in about 4 minutes.