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Old 08-10-2022, 05:18 PM   #1
don t. - 72gmc
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Brake booster install

70 GMC C20

Never played w/a booster before.

Bought a new one...



Old booster rod length is 8 3/4" from housing to end of rod.
New rod was to long....


Removed old rod, installed on new booster.
Slid rod in hole. Bolted booster to firewall.
Bolted rod end to brake pedal, installed cotter pin.

Anything I should be worried about?

Thanks much...Don.
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Old 08-10-2022, 06:07 PM   #2
leftybass209
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Re: Brake booster install

make sure that the linkage doesn't contact the firewall when you have the pedal height where you want it. I just did a conversion with an 8" booster and that's one of the things the instructions pointed out. I had to cut the booster rod about 1".

Might be different for the brackets on the 11" booster.

Best of luck!
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Old 08-11-2022, 12:12 AM   #3
ProjectHarold72
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Re: Brake booster install

Getting ready to do the exact same thing in my 72. Never done it before but have researched the heck out of it online and hoping that will be enough to make it all come together. I'm sure you have seen this already but be sure you bench bleed the master before hooking up your lines. Good luck on your install!
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Old 08-11-2022, 08:08 AM   #4
don t. - 72gmc
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Re: Brake booster install

Initially, I was a bit worried about the size difference between old and new, but it bolted on w/no issue. I was thinking of cutting it but it was a ton easier to swap em.

Yep bleeding everything is a week or so out.

Thanks much...Don
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Old 08-11-2022, 09:32 AM   #5
72SB
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Re: Brake booster install

While the rods may be different lengths....make sure the booster brackets are also (read are new ones longer?) as you may need the one that came with the new booster

I just replaced my non power MC with a power MC/Booster (CPP) and it was plug & play relative to using the rod that came with new booster.

You do want to remove MC from new booster and bench bleed it before installing on truck
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Old 08-11-2022, 04:01 PM   #6
Sheepdip
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Re: Brake booster install

Someone chime in if I'm 180 out, but I was under the impression the dual diaphragm like the old one shown here was for added stopping power for loaded 3/4- and 1-ton trucks

I'm sure the single will work but not as engineered by GM
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Old 08-11-2022, 09:25 PM   #7
Accelo
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Re: Brake booster install

I surely am interested in the difference between the firewall to the master cylinder overall length differences.
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Old 08-14-2022, 08:43 AM   #8
don t. - 72gmc
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Re: Brake booster install

Quote:
Originally Posted by Sheepdip View Post
Someone chime in if I'm 180 out, but I was under the impression the dual diaphragm like the old one shown here was for added stopping power for loaded 3/4- and 1-ton trucks

I'm sure the single will work but not as engineered by GM
I was a bit concerned when I received the part, the overall difference between the 2. I checked the site I purchased, overall did a google. From what I could tell, the new part is all that is available. As you stated, my C20 will not do the work it once did, and should be fine.


Quote:
Originally Posted by Accelo View Post
I surely am interested in the difference between the firewall to the master cylinder overall length differences.
I'll get you the measurements tomorrow.
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Old 08-15-2022, 02:52 PM   #9
don t. - 72gmc
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Re: Brake booster install

Quote:
Originally Posted by Accelo View Post
I surely am interested in the difference between the firewall to the master cylinder overall length differences.
From the firewall to where the master mounts to the new booster = 9 3/16"

Same measurement of the old booster is a bit short of 10", maybe 9 7/8"

HTH...Don.
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Old 08-15-2022, 06:02 PM   #10
Accelo
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Re: Brake booster install

Thanks Don.
Not enough to account for my lines being so far off.
Has to be in the lines not the master/booster set up.
Cheers
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