Vacume brake conversion WTF???

[turbov6joe]

I bought a new vacume brake conversion from G-Body and just went to install the master cylinder and booster only to find that it has 4 studs sticking out the back of the booster and does not appear to be compatable with the 2 studs that are currently sticking out of the firewall from the OE unit...am I missing something here....WTF???

It appears to me that the firewall has 4 plastic looking caps/plugs that line up with the new booster...surely I don't have to drill those out do I

I need some guideance ASAP, of all things I have never done to these cars, this is one of them!

[turbov6joe]

Disregard, I fingered it out. What a PITA job!!

[zeus87gn]

Powermaster doens't look too bad now, eh?













Sorry, just had to get one in.

[chrisgarrett]

Originally Posted by turbov6joe

Disregard, I fingered it out. What a PITA job!!

I'm going to be doing this conversion soon. I've noticed that about the bolts. What's the solution?

[QUIP'6']

Originally Posted by zeus87gn

Powermaster doens't look too bad now, eh?












Sorry, just had to get one in.

till it goes out at 100 plus mph

[chrisgarrett]

Originally Posted by chrisgarrett

I'm going to be doing this conversion soon. I've noticed that about the bolts. What's the solution?

Never mind. I just read the answer somewhere else.

[jcawley3]

what was the solution?

[chrisgarrett]

Originally Posted by jcawley3

what was the solution?

Here's a copy of the entire install. You have to remove the mounting plate from under the dash.

Vacuum Brake Install

Step-by-step instructions for the swap from the PM:

"The first thing to do is to remove the powermaster system. This is accomplished by removing the 15mm nuts securing the PM to the firewall. They are located on each side of the brake pedal. There are four. Two on each side. Remove these, using a long extension, deep 15mm socket and ratchet. Unfasten the brake lines from the MC and disconnect the booster rod from the brake pedal. Unplug the electrical connections from the PM and remove the PM.

Next job is to swap out the PM brake pedal. In order to do this, you need to drop the saddle that the pedal is attached to. The four studs that held in your powermaster are the main fasteners that holds the saddle in place. After removing the PM the mounting bracket, there is till one more bolt holding the saddle in place. Looking directly at the brake pedal shaft, the bolt is threaded vertically up at the top of brake pedal. Only the head is visible. You should remove the brake light switch and the other switch above it that rest against the brake pedal shaft. Though they appear to be threaded in, they just pull out from the saddle. Take a long 3/8" extension with a 13mm socket. The bolt is about a half inch left of the pedal. Remove this bolt and the saddle will be free. You can remove the saddle completely and make sure the booster bolts align with the holes in the saddle. You may have to tap them with a hammer to align. This will make putting it in easier.

A word about the booster....the rod has a seal inside the booster and sometimes in installation or transit, it can somehow become cocked and cause a vacuum leak. Before bolting the booster in place, run a vacuum to the check valve from your engine, start the car and make sure the booster isn't leaking. I check them right before I ship them but this problem arises from time to time. You'll find it very difficult to push the rod in when there is no vacuum to it. When you start your motor, and apply vacuum, it's pretty easy to push in the rod.

OK, now with the new brake pedal installed, you can install the booster. Make sure the pin is in the recess in the frontcenter of the booster. It can fall out. It just slides in loosely. Install the booster into the firewall and through the saddle and install the 15mm nuts inside the firewall.

Next, you need to bleed the MC. Place it in a vice just tight enough to hold it in place. Use those cutoff lines I included. Use a tubing cutter to access open ends. Fit a hose tightly over each of the lines and run the other end of the hoses into the reservoir. Fill with clean brake fluid and then use a rod to push on the plunger of the MC. This will pump the air and old fluid into the reservoir. Keep pumping it until all air is removed and clean brake fluid is observed.

When this is done, you can attach the MC to the booster, reinstall the brake lines and you may be done. If there was no air in your brake lines before you attached the new MC, you will have a hard pedal. If there was air in your lines, your brake lite will probably be on, your brake pedal will be low and will pump up. This indicates air in your lines and you'll have to bleed all your wheels.

If you don't have a TTA vacuum block, you'll have to get your vacuum from the PCV vacuum hose. Purchase a 3/8" vacuum Tee from any parts store. Basically, cut into the pcv hose a couple inches above the pcv valve and install the T in that line. Run a 3/8 fuel hose for vacuum. Run it to the check valve on the booster. This will provide adequate vacuum for your vacuum brake system."

[GNocide]

Originally Posted by lpaulabbott

till it goes out at 100 plus mph

ill bet everyone of them has fluid that looks like Pepsi instead of clean clear brake fluid.

[87NAT]

You forgot the part on the install about becoming a contortionist to get the new brake pedal hooked up under the dash.

[turbov6joe]

The only reason I went with the vacume conversion was my PM setup is on its way out the door and replacement parts are too expensive and hard to find. This job was more a PITA then it was hard. I'm getting too old and my back is too f'ed up to be up side down under the dash dicking with the bolts and what not. Anyhow, it's in and looks good....now it's time to do the braided lines, S-10 wheel cylinders, and drilled rotors. I can't believe that after 17 years of wrenching on these cars this is my first vacume brake conversion

[zeus87gn]

Originally Posted by lpaulabbott

till it goes out at 100 plus mph

I hope that wasn't on the street!!!

[turbofish38]

Originally Posted by chrisgarrett

Next job is to swap out the PM brake pedal. In order to do this, you need to drop the saddle that the pedal is attached to. The four studs that held in your powermaster are the main fasteners that holds the saddle in place. After removing the PM the mounting bracket, there is till one more bolt holding the saddle in place. Looking directly at the brake pedal shaft, the bolt is threaded vertically up at the top of brake pedal. Only the head is visible. You should remove the brake light switch and the other switch above it that rest against the brake pedal shaft. Though they appear to be threaded in, they just pull out from the saddle. Take a long 3/8" extension with a 13mm socket. The bolt is about a half inch left of the pedal. Remove this bolt and the saddle will be free. You can remove the saddle completely and make sure the booster bolts align with the holes in the saddle. You may have to tap them with a hammer to align. This will make putting it in easier.

I do not know why John does the pedal R&R this way. Time consuming IMO. Okay here is how I do it. First locate the pivot bolt. Take a 11/16" box wrench or one those new ratchet box wrenches and put it on the left side which should be the nut head. There aint much room to swing it but that doesn't matter. Take a 3/8 drive ratchet with a 8" or so extension and a 5/8" socket. Pull down the cruise control module that sits above the gas pedal. Now put your wrench up above the module bracket until it seats on the bolt head end. The first click is tough as it breaks the torque loose. After that just ratchet the nut off. Once the nut is off pull the hairpin off that holds the rod to the pedal. Use a screwdriver to pry the rod off the pedal if you have to. Once the rod is loose pull the bolt out. The pedal should drop free. I've done this a hundred times and it should only take you 10 minutes at the most. Now on the reinstall attach the rod first before you put the pivot bolt back in. It's always tighter on the nut end so keep the nut on the left side. Plenty of room on the right side for even the ham fisted amongst us. To do it Johns way there just isn't a lot of room to handle that bracket.

[GNVYUS 1]

Ya this job is a PITA, yet a lot of people will say it's a cake walk.

[T-CHRGD]

Originally Posted by turbov6joe

I can't believe that after 17 years of wrenching on these cars this is my first vacume brake conversion

I Can't Believe it's been 17 years Since I converted mine !!

[turbov6joe]

In years past I would buy the dealer only service kit and rebuild the master cylinder and call it good for a while. Since the price of replacement parts has gone through the roof and the availability of parts in a worse state of affairs, the vacume brakes were a no brainer for me.

[POWERBRAKEBOB]

The Hydroboost bolts right in without changing the pedal. It runs off of the power steering pump, and needs no vacuum, which is hard to find on a turbo six. That's why Buick never installed a vacuum booster on these cars. Vacuum boosters need vacuum. Adding a vacuum pump is a waste of money, because it is noisy, and it can not pull the volume of air out of the booster to operate in traffic. The Hydroboost can deliver 2000psi to the calipers, compared to the 800psi the vacuum booster puts out. The units we use are new, and usually last 200,000 miles, with just an occasional fluid change. The car performs better than you could image with confidence in the brake system.