Brake booster install pics

[GMCMAX]

I converted the 69 to power brakes today, still drum drum. Used a 1/2 ton booster I bought off the parts board.
Parts list: booster & bracket+pushrod, new pushrod boot, vacuum T fitting, 2 ft vacuum hose, booster vacuum check valve if needed.

As it was


The old vacuum connection for the trans, need to install T fitting to hook booster to.


New fitting installed


Have to disconnect push rod under dash for m/c


I removed the pedal stop plate under the dash for working room. The bolt will hit the column, remove the master cyl nuts first so you can push the pedal way down for clearance.


Master cylinder unbolted and moved out of way


Booster bolted to firewall with master cyl, don't forget to get a pushrod boot for power brakes, it's different. Hook the pedal up first, before bolting the unit in, so you can have the pedal down to put the pivot bolt in.


Together inside with new pedal pad


Hooked up outside with vacuum line to new fitting.


Oh yeah, don't forget to adjust the brakelight switch because th e pedal will be slightly lower.

[Lippyp]

Hopefully I'll be doing just this soon. Did you need to lengthen any brake lines or was their enough slack to just slip the booster in behind the master? Did you need to re-bleed the brakes afterwards?

[GMCMAX]

Lippyp- the lines were long enough, just had to carefully bend and reposition them forward, and since I didn't disconnect them from the master cyl, no bleeding involved!

[VA72C10]

can you show a pic of the pushrod boot? I am a noob and don't know where that is so i don't know what to look for when i'm picking up parts for this. Thanks!

[GMCMAX]

Boot pops into hole in the firewall where the pushrod comes through to the pedal, pic #6
Picture of boot i bought: http://www.gmcpauls.com/pictures/47-...tpowerbstr.jpg

[69TowRig]

Originally Posted by Tynee

So, here's a question. I did this ac ouple months ago, and in the process realized a had a leaking brake hose on the driver's front, so I assumed that was what was causing my brake pedal not to come back up to the top.

Well, I replaced the hose last weekend, and still can't get the pedal back to the top without pulling up with my toe. It'll come up enough to release the brakes, but that's it.

Anybody know what's wrong here? I adjusted the length of the pushrod to both extremes with no change.

I would change the passenger hose as well. It may be collapsing internally and that will partially drag the brake as well as not let the MC return. I had a boss one time that had a hose collapse on the driver's front and would lock up the brake on that wheel. It took a while for it to settle and return. He drove around with the parking brake a lot before he got it fixed!

[steelhorse]

Did you use the same hole in the brake pedal?I heard you need to use a different hole in the lever for power brakes.

[GMCMAX]

Same hole,, tread lightly on the pedal till ya get used to it.......

[blazer72]

Have you experienced any vacuum issues?? I only ask because I've had a few mechanic buddies of mine tell me the brake booster needs it's own dedicated vacuum source. On my stock power brake trucks, the brake booster vacuum is tapped into the backside of the carb. My edelbrock has a port, but it's not the same size as the stock line/tube I pulled from the donor truck.

Just curious. Oh, and I sure wish I would've read your last tech tip before I thought I had finished. had to drop the column and the rod after I was "done" to adjust the switch. I do that kinda stuff alot.

[GMCMAX]

No vac problems as of yet, my carb didn't have the port iirc, the fitting I used was from a manifold in the shed and looked right.
Only problem I've heard was Longhorn Man lost the booster diaphragm and the vacuum leak fried the piston on the cylinder under the fitting (see pic 2&3) because the fitting is on the intake runner leading to that cylinder. Connected to the carb would distribute a vacuum leak across all cylinders.

[ZZ4Blazer]

Originally Posted by steelhorse

Did you use the same hole in the brake pedal?I heard you need to use a different hole in the lever for power brakes.

I was wondering this as well. I've always heard the pedals were different(atleast different mouting position) for different leverage on power vs manual brakes.

I've got a 67 im gonna be swapping to pb's using the booster and such off my 68. But gonna use a 80's master since Im swapping to those discs in the front. Im gonna try and compare the brake pedals and see if they're actually any different. Good to hear the swap is pretty straight forward.

[ERASER5]

Originally Posted by ZZ4Blazer

I was wondering this as well. I've always heard the pedals were different(atleast different mouting position) for different leverage on power vs manual brakes.

They are. If you look at the booster bracket for our trucks, there is linkage that changes the effective leverage of the pedal.

If you were working on a Chevelle, you would drill a new rod mount hole in the pedal to change the leverage.

[Luvlegs]

My personal experience was great - it was a piece of cake - I spent a week cleaning my stuff up and then a week contemplating doing it... hemming and hawing... it took all of about 45 mintues I think to do it and that was because I looked it over 3 times afterwards to see if I missed anything.
Watch your first trip on the road - I about put myself and the steering wheel through the windshield - to me, it makes a WORLD of difference.
As for a leaking diaphram buring up a valve, would that be why the check valve is in place where the hose meets up with the booster? Or as later models have one inline before the booster?

[Brad]

Originally Posted by ERASER5

They are. If you look at the booster bracket for our trucks, there is linkage that changes the effective leverage of the pedal.
If you were working on a Chevelle, you would drill a new rod mount hole in the pedal to change the leverage.

So which hole is for pdb- bottom or top, and how far is the 2nd hole from the other hole? I think I need to make another hole in mine and move the rod...

[ERASER5]

The truck brake linkage has only one mounting hole on the pedal arm. It is best to look at another truck to get the linkage geometry correct.

[GMCMAX]

LUV, the check valve holds vacuum in the booster, if the engine stops, you still have booster power for one stop....the hydroboost has an accumulator for that same reason, it's that gold colored 4" long can that sticks out of the h/b unit.