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mothermuxer · 06-28-2004, 10:52 PM

Hey.
I've read around the board about smaller power brake boosters (dual diaphragms) increasing braking power. Would LOVE to swap out my exsisting booster (the big ol' stock one from my 75 T/A) to a smaller one. So... was wondering if there were any boosters available from different makes/models that would work in this application? Kinda like taking a 3rd Gen. Firebird's smaller booster, and making it fit in/on a 2nd Gen. Just curious.....
-j

mothermuxer · 06-28-2004, 10:52 PM

Hey.
I've read around the board about smaller power brake boosters (dual diaphragms) increasing braking power. Would LOVE to swap out my exsisting booster (the big ol' stock one from my 75 T/A) to a smaller one. So... was wondering if there were any boosters available from different makes/models that would work in this application? Kinda like taking a 3rd Gen. Firebird's smaller booster, and making it fit in/on a 2nd Gen. Just curious.....
-j

mothermuxer · 06-28-2004, 10:53 PM

I should add that my "old stock one" is actually a new replacement, but the same size as the original. My original one bit it.

PMDRACER · 06-30-2004, 04:07 PM

Check my personal website. I detail how to swap in a '78-'87 A/G-body 10" dual-diaphragm booster to an A-body, but it should be the same for your F-body.
Click Here

mothermuxer · 07-01-2004, 02:16 AM

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by PMDRACER:
Check my personal website. I detail how to swap in a '78-'87 A/G-body 10" dual-diaphragm booster to an A-body, but it should be the same for your F-body.
http://home.socal.rr.com/tigerefi/ <HR></BLOCKQUOTE>

That's funny... I was just doing this EXACT thing! Found an article in Car Craft, and I spent a few hours in my local U-Pickapart, and found all sorts of great stuff. Using a dual diaphragm booster from an 81 Cutlass, and a m/c from an 89 Firebird. I just need to remove the old booster and install. Hopefully, it'll give me some extra "oomph". Even after replacing EVERY brake component, it still doesn't feel quite right. I should be eating the dashboard by now when I stop.
Thanks for the input!
-joe

67cruiser · 07-01-2004, 03:26 AM

your in luck, i just did the same with my 67 gto. it had a 12 inch booster and i swapped it for a smaller 8 inch off a 78 trans. am it was a bolt on swap, no problems so far. master cylinder was also a bolt on deal. good luck and hope the info helped!

mothermuxer · 07-01-2004, 05:55 PM

It would have been easier for me to find an 8" booster from a '78 T/A, but boneyard doner cars are scarce in LA. Also, the local parts places (NAPA, PepBoys, AutoZone, Kragen) seem to be useless when it comes to older musclecars. I'm sure if I had a Honda...

Hopefully, this booster/master combo works. I've replaced EVERYTHING in the brake system, but it still feels underpowered. 16" of vacuum from the manifold; 20" from an installed vacuum pump. It should all work fine, but.... we'll see.

67cruiser · 07-01-2004, 06:01 PM

Just took 78 out of the box, same size as my 67 gto,s, just reordered a 81 witch is smaller and the only yr. by itself, hope this works!!

mothermuxer · 07-01-2004, 11:45 PM

Did you notice an improvement in overall braking power? Was the swap noticeable? Do tell...

-j

pontiac-fanatic · 07-03-2004, 06:43 AM

When i replaced the booster on my 75 TA, i went to the local parts store and told them i wanted one for an 80-81 turbo Ta with 4-wheel disc brakes----its a bolt-on, and is about 8.5 inches wide. Braking power seemed to be only a little better. good luck---

67cruiser · 07-03-2004, 08:47 AM

Hay Pontiac Fan. i just ordered the same one, hopes its as easy as you say. I tryed a Bran new 85, trans am, shaft was to short, then i went with a 78 thru 80 same size booster as whats on my 67 gto, Now i just ordered a 81 turbo trans am, should be in soon and keeping my fingers crossed!! Stay in touch on this never ending story! LOL

mothermuxer · 07-03-2004, 04:37 PM

Holy Shazbot!!! I just finished installing that 81 Cutlass dual diaphragm booster with a 1989 Firebird m/c in my 1975 T/A. Wow... stops like a Cadillac!!! 1000% difference than the last "correct" booster & m/c. No more using my entire leg to "stop" the car.

hey 67... I had to modify the shaft to fit in my car. Not too hard: cut the clevis pin off, and thread the end with a 3/8x16 die. Then, cut off the entire shaft from the old booster. Thread that end, and use a coupling nut to connect them.

When you install the booster, before you disconnect the brake pedal from the shaft, tie a piece of string from the brake pedal to the steering wheel. When you take out the booster, the pedal will be in the same place.. that way you can adjust the length of the new shaft to match the old one.

[email protected] · 02-14-2005, 08:50 PM

Hey guys,
I know this is an old post, but has anyone tried a booster from a 93-up f-body and maybe a master cylinder from an 82-92 f-body? I'm going to do the front drum to disc swap as well as add power brakes to my 68 firebird. Just looking for suggestions.

Thanks

mothermuxer · 02-14-2005, 09:48 PM

I originally looked at 90's f-body boosters, but the mounting bracket is different. I guess it would work, but it was easy as pie to use the Olds booster. MC is from an 89 F-body. Make sure the MC is from a disc/drum setup, and get the right combination valve.

scottk · 02-14-2005, 09:53 PM

Dont know about the booster, but the post above yours replaced the master with one from an 89 Firebird.

I am not surprised he had such a dramatic decrease in effort. That master offers quite a bit more line pressure... about 25% more, and has a step bore and special valve for high volume too.

The step bore master has a large diameter end where it fits in the booster. The 93+ did not use a step bore, so the 82-92 master probably would not fit that booster without modification.

As far as the booster, I have no idea if the angle is correct to get a straight shot for the pushrod.

LOPEZ5 · 02-19-2005, 08:45 AM

hey guys,
not to change directions on this topic, but I'm wondering what it takes to convert from manual to power brakes...is it just adding the booster and changing the m/c? Or am I oversimplifying it? Thanks...

LOPEZ5 · 02-19-2005, 09:00 AM

oh yeah, the car I'd be upgrading to pwr brakes is a 72 LeMans Sport. Would I have to upgrade the front to disc rotors also? thanks

Skip Fix · 02-22-2005, 12:42 PM

When I changed my 78 to the 4WD dual diaphragm I had to order a rod for the booster to M/C from Pontiac. The "big" regular booster had one built in but the dual did not.Do the new replacements come with one?

[email protected] · 02-28-2005, 10:27 AM

Well guys,
I'm converting my 68 bird from non-power drum/drum to power disc/drum. I bought a dual diaphram booster off of an 87 bonneville, and I'm on the hunt for the 3rd gen f-body master cylinder. Since I'm converting to power brakes, I have to drill the holes in the firewall to mount the booster to. I'm not sure how simple this is going to be, but I think I can do it. If you guys have any additional info on this I would appreciate it. I'll keep you posted on how it turns out.

Thanks
Bob

[email protected] · 02-28-2005, 08:09 PM

I've heard that origninally on power brake cars that there was a bracket that stepped the booster away from the firewall. Has anyone seen these reproduced, or does anyone know where I could get one? Thanks in advance.

Bob

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