vacuum brake conversion kit

[Steve Wood]

everything hooks up with no problem.  The hole in the pedal is in the wrong place to provide the correct leverage and throw on the pushrod. 

[SuperSix]

What is the difference on the brake pedal/arm? Cant look at car as its in the body shop. I'm assuming the vacuum brake booster actuator arm wont just hook up to powermaster brake pedal/arm??
 
Would save some gymnastics under the dash if it would!

Dammit - I can't remember why - but they are NOT interchangeabl e. I know the brake arm / shaft attaches at a different spot, causing a different angle.

[Steve Wood]

yeah

here is a write up  http://www.gnttype.org/techarea/brakes/Powermaster_to_vacuum.html

I have done it in less than two hours from start to end....once I spent a lot more time because the pedal bolts had a couple of tinnerman nuts as lock nuts and I was too stubborn to get out of the floor and get some side cutters to snip them off.

I like to replace the vacuum block on the plenum with one that has a vacuum port aimed at the brakes.  Others have tee'd into the pcv line.  Many think it is better to install a new master cylinder...it might be, but some of this new stuff ain't worth a damn so I guess it is a personal choice.

You don't need to brake lines from the mc downward...you can just bend the originals a little so they line up with the new mc location

It used to cost less than $100 if you go to the wrecking yard for the pedal.

Some use the original pedal and drill a new mounting hole in it...should be a template somewhere online that shows where.

It takes King Kong to  stand on the pedal if the system fails....that is for sure.   I went up a curb one day to keep from hitting a school bus....

If you install the new booster, get under the dash, see where the pushrod lines up with the pedal, mark the location on the old brake pedal, take the old brake pedal off and drill a hole at the right place, then you can remount it and use it.   Just be sure the push rod is not being depressed at all when the brake pedal is not being touched in order to prevent the brakes from partially locking after the pedal has been released following a stop

[Shimy87]

Thanks guys, I have the pedal that came with the vacuum set-up, was just looking to be lazy. I hate under dash work, back cant take it anymore . Got all old stuff out of a stripped car that didnt have a dash so removal was easy access. I hope old booster is good, dont know how to test it? Going to get a new MC, $35 with core swap, so cheap that its easier than cleaning up and painting old one.
 
 
Thanks!!

[Steve Wood]

don't throw the old m/c away.

You can apply a vacuum to the booster and see if it will hold it

[Shimy87]

Stupid question time, how can I do this?

[Steve Wood]

well, you could use a Mitey Mite or you could hook a vacuum line from your engine to the booster's check valve for a few seconds, then disconnect it.  After a couple of minutes, pull the check valve out of the booster and see if you hear the air hiss as it fills the booster.

I have seen very few that failed.  If they do, it is usually just the check valve.

[Shimy87]

stupid question #2, I'm assuming the check valve the round plastic thing coming out of the metal booster body that the hose connects to. This just pulls out?? The directions you sent me mention replacing a check valve, this is it?
 
Thanks again!!

[Steve Wood]

yes

[Shimy87]

finished swapping the pedal/parts yesterday. Got a new master cylinder but used the old booster ( mistake ) changing the frickin pedal is the worst part. One item that should be added to the tools needed list is patience, which I have little, cause anyone over 6 feet and 200 lbs will need lots and lots for that portion of the job. Also good call on the side cutters, had to fight with one of those nuts also. Anyway got it all done and bled and fired it up and the booster is bad  , why didnt I test that dam thing!!! Ordered a new one and its back under the frickin dash tommorrow to replace that.
 
Of all the things I've done so far on the GN, this one is by far the biggest PIA!

[Steve Wood]

You sure that booster is bad?  I know it is possible, but, I have never seen one fail

[Steve Wood]

I am a bit over 200 lbs and 6 ft tall...when I started getting older, I always pull the seat out to make it more comfortable... otherwise it takes 15 minutes to find a way to wiggle out

[Pyro6]

I agree with Steve, you may have gotten a bad one but highly unlikely. Make sure you have enough vacuum tested AT the supply side of the check valve, 18 inches. The booster should store enough vacuum for 4-5 pumps. Start the car, let it run couple minutes, shut it off. Pump the brakes 4-5 times, start the car, should feel the pedal drop a little. I also started to put the OEM style filters in the feed line to protect further as the cars get older. 6 bucks, cheap insurance. Back under my rock.

[Shimy87]

Taking the seat out was contemplated, hindsight says that would have been a much better option. The booster is bad for sure, I pulled straight vacuum right from the port to it and when you start the car you can hear it hiss under the dash. Its sucks but changing it wasnt the worst part, you can kneel outside the car and lean in and get to those nuts, and there should be enough play to just unbolt the MC and move it out of the way to replace the booster. New one is supposed to be in Friday morning

[Shimy87]

Everyone keeps telling me what a terrible idea it is to tee off the brake vacuum line? The PCV valve port is where I'm pulling vacuum. The conversion write up tee's into that line, can i pull vacuum to the PCV valve from a different line and run straight from old PCV port to booster?