Powermaster to vacumm brake conversion

[Robert Dean]

So I did the conversion from the power master to vacuum brakes. Everything went well and I'm confident that I've got everything bled out. By confident i mean i went around the whole car probably four times to make sure there is no more air left in the system. I also replaced the rear brake shoes along with rear wheel cylinders and got everything adjusted properly. The problem I'm having now is that i have really good front brakes but hardly any rear brakes. I feel like i have a proportioning valve problem but I'm not entirely sure. Just wondering if i should have changed the proportioning valve when i did the vacuum converion, just because of the different brake systems and maybe the difference between the power master and vacuum brakes require a different proportioning valve. Or would that original valve work fine with the vacuum brakes and i just have a faulty valve? If anyone has any info at all on my situtation I'd appriciate any advice.

 

[kjizzle]

I never changed the proportioning valve. Every kit that I've ever seen leaves the stock one on there. Did you bench bleed the new master cylinder? You can get air trapped in there that can be a damn pain in the ass to bleed out.

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[Robert Dean]

I never changed the proportioning valve. Every kit that I've ever seen leaves the stock one on there. Did you bench bleed the new master cylinder? You can get air trapped in there that can be a damn pain in the ass to bleed out.

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Yes, I did bench bleed the master cylinder before i installed it.

 

[kjizzle]

You could just have a crappy valve. It happens. Kirban sells a brass one, if I remember right. I'd wait for someone else to chime in first, though, before you blow money on a part that you don't need.

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[Robert Dean]

Also when I was bleeding the brakes out I made sure to hold the pin in on the proportioning valve with a clamp because i was told that air can get trapped in there as well. When I did that though i noticed that the pin didn't stick out very far anyways and also seemed kind of sticky. Didn't think much of it at the time, but now that i have this issue i'm thinking that could be a problem.

 

[Robert Dean]

Do you know if there is an adjustable valve available that fits without having to modify the way it mounts on the car or anything?

 

[kjizzle]

I got nothing, sorry. I've never had to mess with it. I swapped over to vacuum years ago and it went pretty smooth.

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[cj92345]

mine went also no problem, I didn't even bleed the brakes

 

[turbo chris1970]

mine went also no problem, I didn't even bleed the brakes

I swapped over as well and I kept the original valve also I just disconnected all power master electrical hoses no problems

 

[Boxcars]

If you had no problem with the proportioning valve before the swap, it's probably not the proportioning valve. Not that it's better, but I usually gravity bleed. Just open the petcocks and let 'em drip. These problems happen some time. When I changed over to LS1 12" disc brakes on my GN, it wouldn't stop worth a shit. Ultimately, it was the auto zone pads. Went to Hawk pads, and they fixed it for me.

 

[turbo chris1970]

If you had no problem with the proportioning valve before the swap, it's probably not the proportioning valve. Not that it's better, but I usually gravity bleed. Just open the petcocks and let 'em drip. These problems happen some time. When I changed over to LS1 12" disc brakes on my GN, it wouldn't stop worth a shit. Ultimately, it was the auto zone pads. Went to Hawk pads, and they fixed it for me.

Thanks bro I got them all fixed thanks for the advice ,ChrisChris