Turbo Buick Forums banner
1 - 6 of 6 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
Progress has been slow as hell on the '85 GN. Too many other projects and the owner's health isn't helping. We finally got the interior finished. Refreshed the carpet, new seat cushions and covers, headrest covers, new door panel inserts, and a few other details. The inside looks killer! That being said we moved on to other details. This thing barely stops. After some research here I am now aware of the Powermaster brake system issues. Got it, when they fail you have stopping issues. Here is my question: Under the hood bin the master cylinder/brake booster area We have 2 weatherpack connectors that go to nothing. one of them is a 3 pin flat and the other is a 4 pin flat connector. I can't find anything of where they go to. I am thinking someone before us may have tried the vacuum conversion in the past and missed something. The brake pedal has almost no movement at all, engine running or not. Please help me understand what to look for to assess what is going on and where to start/go with getting things right with the brakes.

Thanks in advance.
 

·
YOU KNOW MY NAME!
Joined
·
5,673 Posts
I tossed my PM years ago...and swapped out to vacuum. One or more weatherpack connectors are still there. They plug into the PM...as far as I remember.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #3 ·
I dug into my friend's factory service manual. Found that the OE parts are definitely not in the car. So those connectors are for the PM brakes. So this leaves me wondering if the booster is bad or was the vacuum conversion not done correctly. Where should the vacuum for the booster be coming from? I guess that is the best place to start troubleshooting.

All the problems I had figuring out the vacuum system on the car are now clear. Needing a new port for the vacuum boosted brakes has been throwing me for a loop for some time. This may also explain why it randomly won't return to idle, but then again maybe not.
 

·
Registered
Joined
·
2,008 Posts
Breaks

If this is a hot air car ,i think you can tap into the pcv valve,but you have to block off the pcv some how so you don't suck in oil.
 

·
YOU KNOW MY NAME!
Joined
·
5,673 Posts
I dug into my friend's factory service manual. Found that the OE parts are definitely not in the car. So those connectors are for the PM brakes. So this leaves me wondering if the booster is bad or was the vacuum conversion not done correctly. Where should the vacuum for the booster be coming from? I guess that is the best place to start troubleshooting.

All the problems I had figuring out the vacuum system on the car are now clear. Needing a new port for the vacuum boosted brakes has been throwing me for a loop for some time. This may also explain why it randomly won't return to idle, but then again maybe not.
I'm not familiar with the hot air engines. What you basically need is manifold vacuum to run the brake booster. Brake booster hoses have a filter...to catch any contaminates. You need a brake pedal, booster and master cylinder from an 80's GBody to swap over.
 

·
Registered
Joined
·
73 Posts
What you basically need is manifold vacuum to run the brake booster. Brake booster hoses have a filter...to catch any contaminates. You need a brake pedal, booster and master cylinder from an 80's GBody to swap over.
Correct. Factory G-body's with Vacuum brakes pull the vacuum off the intake. I have a bunch of G-body vacuum brake parts if you need something....
 
1 - 6 of 6 Posts
Top