Powermaster problem

[MSKBuick]

I know it says to check the link for powermaster diagnosis, but any quick thoughts as to what would cause intermittent lose of power brakes, and now when I loose the power brakes the brake light comes on when I step on the brakes and out when letting off. I replaced the pump about two months ago. I am not sure if the accumulator is going and with the cost of it I am about ready to convert to vacuum if I can find a brake pedal from some where then buy the powerbooster and reservior from a parts store. Any thoughts or thoughts on the vacuum conversion?

[Keller]

any quick thoughts as to what would cause intermittent lose of power brakes, and now when I loose the power brakes the brake light comes on when I step on the brakes and out when letting off....
There are only a few basic components of the system,and you've already replaced one. The only other big electrical one is the pressure switch. Granted, its not available from GM anymore....

You really need to go through the diagnostic tree. Even the distribution block can light the brake warning light.

[MSKBuick]

Thanks for the advice, I will go through the trouble-shooting list and see if I can pin point the problem part.

[turbojd]

When I converted my power master brake system to vacuum, I re-used the power master brake pedal. After you bolt in the new vacuum booster you will see that the pivot point for the connection is in a different spot, I just took the power master pedal and lined it up to the booster, then I marked it where it had to be re-drilled, I drilled a new hole re-installed the pedal and checked it for proper fitting, it's no big deal.

[MSKBuick]

I am thinking about attempting that, I was going to purchase a powerbooster with reservior from the a parts store, like NAPA, but I am not sure what vehicle; buick, chevy (camero, monte carlo) or what year to get. Also, where would I get the check valve that is mentioned in the vacuum conversion kits for turbo buicks?

[Keller]

Why not get one for a V8 Regal? Maybe even the inline check valve, too?

[MSKBuick]

Does it matter what year? Also were do I get the inline check valve? Is there a certain part number.

[turbojd]

When I went to the parts store I used a master cylinder from a 1987 Monte SS, you can also use that car as a donor for a brake pedal as well if you don't want to re-drill the powermaster pedal.

[MSKBuick]

Use the single or dual diaphragm booster and any idea about where to get the check valve?

[turbojd]

You want the dual diaphram booster.

[turbojd]

Check valve came with my booster. You can probably get one from GM if you need to.

[Keller]

Dual diaphragm is smaller in diameter, giving more room on the firewall. A single diaphragm may not even fit.

Both the check valve and inline filter are commonly available.
http://www.partsamerica.com/productdetail.aspx?MfrCode=RAY&MfrPartNumber=CV89000
http://www.partsamerica.com/productdetail.aspx?MfrCode=RNB&MfrPartNumber=80195&CategoryCode=3110

[MSKBuick]

Thanks for the help guys. I think I am still going to convert to the vacuum system, but I did notice that when I pump on the brakes with the powermaster system (ignition off) that I could hear a whoosh/hissing noise coming from the powermaster assembly. I wonder if the problem is an internal leak in the powermaster body. I will probably set the unit on the shelf in case I ever want to restore the car to original and see if there is a internal rebuild kit for it should I ever want to restore it. Again thanks for the help on the vacuum conversion, I think I am going to convert to it.

[Keller]

I will probably set the unit on the shelf in case I ever want to restore the car to original and see if there is a internal rebuild kit for it should I ever want to restore it.
There was one. GM on longer sells it. Given that Karps Brake Service in California and Cardone are still rebuilding Powermasters, someone either still has stock, or is making the parts.