Swapping proportioning valve for "T" fitting... |
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Swapping proportioning valve for "T" fitting... |
Wanna9146 |
Jul 14 2008, 10:10 PM
Post
#1
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Member Group: Members Posts: 235 Joined: 19-January 08 From: Florida Member No.: 8,595 Region Association: South East States |
I read on this forum recently about someone swapping out their proportioning valve for a "T" fitting.
Does anyone know the size/thread count of the correct "T" fitting? Any fabrication required? |
r_towle |
Jul 15 2008, 10:29 AM
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#2
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Custom Member Group: Members Posts: 24,661 Joined: 9-January 03 From: Taxachusetts Member No.: 124 Region Association: North East States |
The proportioning valve is really a simple piston and spring.
I have never met a bad one. If you still have mushy brakes its because you have not bled the air THROUGH the proportioning valve. This is not as easy as it sounds. the spring requires 750 PSI to activate, and most people dont get that when bleeding brakes. It can be done using the old school two person brake bleeding system, but honestly I have never had success with that, nor a power bleeder, nor a miti vac bleeder. The reason I suspect that I have never had success is because I am the bleeder, not the pumper. If I was pumping, I would pump them till they were firm and then try to push the pedal through the floor...that will do it. The only way I know I have rid myself of the nasty bubble is to bleed them the best I can, then go for a ride and STOMP on the brakes about ten times...this produces the required PSI to move the air past the valve. Then I go home and bleed them again, and I am all set to go. Be careful because when you finally get the air bubble past the valve, it will feel like you have almost no brakes at all...pedal to the floor. I stay close to home...its a ten minute ride. Rich |
Wanna9146 |
Jul 15 2008, 10:37 AM
Post
#3
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Member Group: Members Posts: 235 Joined: 19-January 08 From: Florida Member No.: 8,595 Region Association: South East States |
The proportioning valve is really a simple piston and spring. I have never met a bad one. If you still have mushy brakes its because you have not bled the air THROUGH the proportioning valve. This is not as easy as it sounds. the spring requires 750 PSI to activate, and most people dont get that when bleeding brakes. It can be done using the old school two person brake bleeding system, but honestly I have never had success with that, nor a power bleeder, nor a miti vac bleeder. The reason I suspect that I have never had success is because I am the bleeder, not the pumper. If I was pumping, I would pump them till they were firm and then try to push the pedal through the floor...that will do it. The only way I know I have rid myself of the nasty bubble is to bleed them the best I can, then go for a ride and STOMP on the brakes about ten times...this produces the required PSI to move the air past the valve. Then I go home and bleed them again, and I am all set to go. Be careful because when you finally get the air bubble past the valve, it will feel like you have almost no brakes at all...pedal to the floor. I stay close to home...its a ten minute ride. Rich Yep, I've tried all this (contrary to the other posters in this thread who think I'm a dumbass who doesn't do his research). So, I'm assuming (shhh...don't tell "Rhodyguy" I'm assuming something...he doesn't approve!) the proportioning valve is stuck solid. The calipers & master cylinder were totally gunked-up. I didn't even think about removing the proportioning valve when I had everything apart (as you said...it's just a simple spring/piston...not much to go wrong). As I have to move the car around, I figure I'll throw in the "T" so at least it's driveable until I do my 911 brake conversion (sooner/later). Can the proportioning valve be "saved" by removing/cleaning? Not sure what's involved in a rebuild...(off to do more homework) |
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