Carrera Proportioning Valve and check valve for 951 Calipers on 911

MotoSook · 09:18 PM

Well, it's the night before a DE and I'm almost ready...but!!!!

It's late and I have to be on the road in 6 hours or so, so tried something figuring it would be a quicky. I took the proportioning valve apart and took the spring out of it. There is a ball check in the assembly too, so I left that alone figuring that it would keep the rear pads on the rotor when the MC isn't pressed. I've worked with regulators and check valves all my professional career, and I do not believe that the ball is the regulating portion of the valve. The spring appears to press on a plate that would seem to be the pressure limiting device; however, I'm still locking up the front 951 calipers up front very easily. The rear still has the Carrera rear caliper.

Seems there are more than a handfull of guys running the 951 front with Carrera rear. Are you guys locking up easily with the whole proportioning valve removed?

If you did remove the whole proportioning valve (eliminating what I think is the check valve), are you having issues?

I'll probably drill out the whole damn thing tomorrow or put a jumper in its place...then just saywhatthefuch.

So! Anyone play with the p-valve at all....or did you all just eliminate the thing?

ianc · 10-06-2006, 09:32 PM

Took apart your proportioning valve figuring it would be a quicky?

Souk, you're mad!

ianc

MotoSook · 10-06-2006, 09:55 PM

LOL...mad and tired

I didn't want to have to deal with making a coupler to replace the p-valve. Oh well...back out to the garage I go...taking the damn thing out and making/finding a coupler.

bigtom03 · 10-07-2006, 12:29 AM

did the same two weeks ago. used a tilton adjustable valve for my 996 on c1 brake.

to fit the tilton valve in, that is shorter than the original, it is much more easy to make a slightly longer brakeline from m/c to where the proportioning valve used to sit than trying adaptors.

optimal bias is two steps before fully open.

Bill Verburg · Bill Verburg's Garage

Quote:

Originally posted by Souk
I took the proportioning valve apart and took the spring out of it. There is a ball check in the assembly too, so I left that alone figuring that it would keep the rear pads on the rotor when the MC isn't pressed. The spring appears to press on a plate that would seem to be the pressure limiting device; however, I'm still locking up the front 951 calipers up front very easily. The rear still has the Carrera rear caliper.

Gut it, you don't want any restriction on the free flow of brake fluid.

MotoSook · 09:57 AM

I gutted it, but I would have had to drill the ball out. I tested it with the ball and it was not doing what I thought it was doing. I gave the P-engineers a little too much credit on the design. so I just removed the whole thing.

After I removed it at 2AM and studied it some more, I realized the ball is the part of the "restriction" in the regulator/proportioning valve. I had a new rear brake hose in stock, so I just looped it and used it to span the gap left by the P-valve.

It was too late to do much test driving (it would have been the third test drive! No so much a quickie job

), so I just when to bed. At the track the brakes performed just beautifully. I use to have to bleed my brakes after every session at this particular track, now the car stops better. I can brake later and with more control which was great for my corner speed. The fronts can still be locked up at just about any time, but I got use to it after the first lap or two. I just had to make myself use less force on the pedal than I was use to with the stock calipers.