Vacuum Brake Conversion

[JAMCAR223]

I have done this swap on my car ( Powermaster TO vacuum ), and the smaller line connects to the rear port ( closest to firewall ), and the larger line connects to the front port of the master cylinder. I read these same posts with conflicting info, and next time at the junkyard, I confirmed it.

 

[earlbrown]

no, that doesn't really help. Because that contradicts the two pictures posted above.

Not really. If you look at the powermaster picture, it's 100% factory.

On the vac picture the rear port on the master cylinder is now at the same place the PM front port used to be. (The booster moves the master cylinder away from the firewall) The large line wants to reside where the booster is now.

 

[Tori]

Not really. If you look at the powermaster picture, it's 100% factory.

On the vac picture the rear port on the master cylinder is now at the same place the PM front port used to be. (The booster moves the master cylinder away from the firewall) The large line wants to reside where the booster is now.

I don't know what you're saying here...... final placement means nothing. Are you saying the big line goes to the rear, or to the front ? You cannot tell me the big line isn't shown at the front in both pictures, where as the text tells you to swap positions.

I CANNOT BELIEVE HOW DIFFICULT THIS HAS BECOME. SMH.

 

[earlbrown]

The booster is about 4" thick. Therefore the vac master cylinder is further away from the firewall.

It just so happens it moves about the same distance as the gap between the lines. Now the vac master cylinders rear line occupies the same coordinates as the PM's front line.

The side effect the the larger line (that's now the front) needs to be curved to mate up to it's new home.

If you were doing the conversion it's be easy to see. It would look just like my pic with the unbent disconnected large line.

 

[Tori]

The booster is about 4" thick. Therefore the vac master cylinder is further away from the firewall.

It just so happens it moves about the same distance as the gap between the lines. Now the vac master cylinders rear line occupies the same coordinates as the PM's front line.

The side effect the the larger line (that's now the front) needs to be curved to mate up to it's new home.

If you were doing the conversion it's be easy to see. It would look just like my pic with the unbent disconnected large line.

Good god man, i know that your saying the booster pushes things outward from the firewall, but how does this answer the question? I know that one line has to be moved a little bit to reach the master, but does the fat line get moved to the back ?

For what it's worth, i've done the conversion. I have the fat line at the front, but the instructions say to swap it opposite of the way the PM is plumbed.

 

[earlbrown]

You just contradicted the hell out of yourself with that last one.

So you realize that things move around when you change things. And you realize, from experience, that the lines have to swap sides. And you realize that the pictures match real life, not mental images....


...how about we not clutter up my how-to thread anymore?

 

[Tori]

I didn't say "move around" i said i understand that it moves forward.

DO YOU NOT SEE THAT THE PICTURES IN YOUR THREAD CONTRADICT YOUR THREAD ?

LET ME SPELL IT OUT FOR YOU ONE. MORE. TIME.

1. ORIGINAL CONFIGURATION OF POWERMASTER SHOWS THE FAT LINE AT THE FRONT. - ( agree ? ) -

2. YOUR INSTRUCTIONS SAY TO SWAP THE LINES - ( agree ? ) - Quote "Notice the front and real lines have been swapped relative to the Powermaster. Front is not rear and rear is not front.

3. THEN, YOUR FINAL INSTALL PICTURE OF THE MASTER WITH VACUUM BOOSTER STILL SHOWS THE FAT LINE AT THE FRONT.

WHY IS THIS SO HARD TO ADMIT ? WTF !

 

[gusszgs]

Tori........I've done this. The larger line goes to the front port on the vac master cylinder. I think what Earl is referring to is the WHEN the PM was installed the front port is where the rear hook up would be on the vacuum unit.
The confusion is just in the wording.......deep breaths and stick to the "KISS" rule.
This is a great helpful thread by Earl for those who haven't done the conversion.

 

[Tori]

Thanks Jim, I appreciate your post. I hated to see this turn so sour, that was not my intent at all. I actually did an install write up when i did mine too. I've been questioning my vacuum brakes for a while now as the performance just isn't what it should be. When i came across this post it made me wonder (and hope) i'd done something wrong. Maybe at the least, it'll be clear for someone else in the future that the fat line stays in the front.

Cheers Earl !

 

[gusszgs]

Thanks Jim, I appreciate your post. I hated to see this turn so sour, that was not my intent at all. I actually did an install write up when i did mine too. I've been questioning my vacuum brakes for a while now as the performance just isn't what it should be. When i came across this post it made me wonder (and hope) i'd done something wrong. Maybe at the least, it'll be clear for someone else in the future that the fat line stays in the front.

Cheers Earl !

Hey, it's all good. I was struggling with my Vac brakes holding as well (pushing through the lights at track @ 0-2 psi) I bled and bled, and have all the tricks done to the rears. Long shoes adjusted tight, S-10 cylinders, all 3 Russell brake lines ect....
Turns out my issue was I bought a good used vac MC but did not do a proper bench bleed on it prior to installing. That was my issue the whole time............now I can hold 20 psi off the foot brake if I want.

 

[turbobob924]

Late but subscribed

Sent from my SM-G955U using Tapatalk

 

[3-5.0]

Not to stink up your thread as I find (good) vendors for these car to be important and hopefully will give you biz in the future but is this kit by chance the same one as Kirban used to sell?

I (perhaps mistakenly in hindsight we'll see) bought his kit several years ago as it was marketed in a positive light as re-using the turbo pedal and came with a machined vacuum block kit. I can't find instructions anywhere but besides the booster assembly and a hose the kit came with a new pin and cotter key and now I'm assuming it needs to be located precisely, drilled and then welded as per your style instructions.

 

[earlbrown]

I'm sure some of the parts are similar. I think Kirbin sends a TB block and I send a SS tee that taps into the PCV line (or a threaded barb for those that want to drill and tap the manifold) I think running the vac line under the coil pack looks better instead of going over the DS valve cover.

There's two ways to locate the pin location. One is to install the booster, pull the pedal against the brake switch and scribe the location.

The other is to get a rule and put it on your pedal and punch the pin location based on my picture.


What's really odd is that a N/A pedal is drilled for a PM pin so there's already a hole in the right place. It'd be nice if the PowerMaster pedal was pre drilled for a vac conversion pin.

 

[captndave737]

I added a second pin to my original Buick pedal. Now it's set up for powermaster or vacuum brakes.

Or Hydraboost!

 

[3-5.0]

Thanks for the reply Earl. I appreciate it.

 

[sdteb]

anyone have these pics so to see the conversion?

 

[626gn]

anyone have these pics so to see the conversion?

What specific pics you need?

 

[earlbrown]

anyone have these pics so to see the conversion?

if I find them on an old hard drive, I'll make another thread somewhere and make sure they don't go missing again.

Otherwise, I'll just have to wait until I do another conversion to take them again. Its been many years since I did this to my GN and I haven't had to touch the brake system since the initial install.

 

[87nationalturbo]

Did everyone just pull the lower 30 amp powermaster fuse and leave it out or is there another fuse I need to pull to run Earls kit?

 

[626gn]

Did everyone just pull the lower 30 amp powermaster fuse and leave it out or is there another fuse I need to pull to run Earls kit?

I just left mine in...you don't need to pull any fuse when converting to vacuum.