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Power brake booster

Posted: October 10, 2014, 3:05 pm
by CraigM
I am in the process of redoing the brakes in my '65 and decided to go with power drums all around. I read (or maybe misread) that the '68-72 booster/mc combos bolt right up so i got the brackets from a '70 and bought a new '68 booster/mc unit.
The problem i am having is the push rod is about an inch or so too long for the pedal. The only way to get it connected is to turn on the truck to activate the booster, then push the rod in and connect it ro the pedal but this seems wrong.
Any ideas? I dont have a way to shorten and weld the existing rod. If i bought a '65 booster would that bolt up and work with the '68 m/c i have now? Kind of at a loss as i tried the adjustable threaded rod route but couldnt find the correct clevis end so i teturned it for the non adjustable one i have now.
I am not opposed to buying a different booster i just need some guidance on what to do.

Re: Power brake booster

Posted: October 10, 2014, 6:27 pm
by tomsrod
As I remember, the best setup is the 1967 dual bowl master cylinder along with a 1967 set of brackets from a master cylinder with a power booster. Those brackets should take care of the pushrod length issue you are having. Not too sure why 1967 works best, but it did for me. I'd do a search of the hints and tricks section for "power brake booster". Pat

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Re: Power brake booster

Posted: October 10, 2014, 7:15 pm
by tomsrod

Re: Power brake booster

Posted: October 11, 2014, 9:07 am
by CraigM
Right on. Thanks for the info.

Re: Power brake booster

Posted: October 11, 2014, 7:19 pm
by William-in-St George
Craig, Don't get to tangled up in this year of manufacture stuff. Basically it'll drive you nuts. Between the booster and MC is an adjustable rod (kind of a goofy nut looking deal). This adjusts the free play necessary for the boosted brakes to release. Have a look at this rod and loosen it and run it all the way in. Your pedal booster rod may line up after you adjust this. When you convert to power brakes from non boosted brakes you need to change the pivot point on the brake pedal arm. Non boosted brakes require much more leverage than boosted brakes so usually the mount point for the booster rod is lowered by simply drilling a new hole about an inch lower on the brake pedal arm and about a 1/4 inch closer to the firewall.

Re: Power brake booster

Posted: October 14, 2014, 9:59 pm
by 66camperspecial
I used a 70 booster in my 66 and had to add spacers between the bracket and firewall and between the bracket and booster to get the pedal where I liked it.

Re: Power brake booster

Posted: October 16, 2014, 1:50 pm
by CraigM
Thanks for the tips. I'm gonna play around with these suggestions and see what works out. Will post an update when I get to it next weekend.

Re: Power brake booster

Posted: October 25, 2014, 9:29 am
by CraigM
So i decided to go the route of using spacers and it worked out pretty good. I did not measure where the pedal sat before installation so I'm not sure if the pedal sits higher or if it just seems like it. Anyways, I went to Lowe's and bought some 1" steel sleeve spacers and longer bolts. I think they were 2 1/2", and put those between the firewall and brackets. Then I used nuts that came off of a donor booster and put those between the MC and brackets (you could also use washers). They are about 1/4". So in all a 1 1/4" of spacing to get it where it felt right.

Here is a picture of the spacers from the passenger side:

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Still have to bench bleed it but here is the finished product. Plumbed all new lines front to back.

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Re: Power brake booster

Posted: October 25, 2014, 7:55 pm
by Truckfarmer2
The nice thing about adding spacers instead of cutting the rod is if something fails in the middle of nowhere, you can simply replace it with no modifications.