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Old 01-11-2021, 06:28 PM   #1
cericd
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1970 C/10 Brake Booster Bracket Question

I have a 1970 C/10 that originally came with manual drum brakes front and back. I am adding a front disc brakes and a factory Delco/Moraine brake booster, new master cylinder and disc/drum prop valve. When I was getting parts together for this upgrade I purchase a set of brake booster brackets from someone here on the forum and there were two booster support brackets included. I can't figure out where they bolt up to the firewall. I'm thinking that these support brackets may have come along in 1971 with the addition of factory disc brakes.

Did pre-1971 trucks with drum brake boosters not have these brackets?

Are they necessary now that I have a booster and front disc brakes?

Here's a picture of the support brackets I'm referring to.
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Old 01-11-2021, 06:33 PM   #2
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Re: 1970 C/10 Brake Booster Bracket Question

I had power drum brakes on my '70 C20 and converted to front disc. It never had those brackets, and the first time I saw it was in '80.
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Old 01-11-2021, 06:35 PM   #3
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Re: 1970 C/10 Brake Booster Bracket Question

I've found pics of how the were installed on other trucks. Here are a couple examples I have found but I can't see exactly where they attach.
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Old 01-11-2021, 08:19 PM   #4
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Re: 1970 C/10 Brake Booster Bracket Question

Talking to people locally, I'm getting conflicting info on whether or not I need to add those brackets. Some people are telling me that they are definitely needed for support. But I thought that they had drum brake trucks with boosters before these brackets were created.
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Old 01-11-2021, 09:08 PM   #5
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Re: 1970 C/10 Brake Booster Bracket Question

Maybe it's a requirement for manual transmission-equipped vehicles? Not that pushing in the clutch pedal is going to place that much more force on the firewall.
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Old 01-11-2021, 10:12 PM   #6
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Re: 1970 C/10 Brake Booster Bracket Question

The round bracket goes from where the booster bolts to the fire wall brackets and it bolts to the fire wall. My set up came off a C20 which I installed on my C10 and it came with the round bracket. The C20 booster is bigger than the C10.
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Old 01-12-2021, 11:14 AM   #7
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Re: 1970 C/10 Brake Booster Bracket Question

Both my 72 C/10's have the braces,,,The round rod braces the booster via the top left bracket bolt on the back of the booster and attaches to the firewall behind the hinge. The flat brace attaches to MC bolt, (left side) and runs down, again attaching to the firewall below the unit...
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Old 01-12-2021, 11:22 AM   #8
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Re: 1970 C/10 Brake Booster Bracket Question

Another look...
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Old 01-12-2021, 12:11 PM   #9
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Re: 1970 C/10 Brake Booster Bracket Question

My 72 had them...I'd put them on. More is better in this case and their not hard to install. I am curious about their concourse correctness through the years though. Here's a pic and a close-up that should help.
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Old 01-12-2021, 08:24 PM   #10
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Re: 1970 C/10 Brake Booster Bracket Question

Hey everyone, thanks for the info and pics.

I have scoured the forum for more information on this subject and here's what I've come up with so far.

The circular hole in the "round" bar brace attaches to the back of the booster at the upper, driver's side bolt (see the first image). The oblong hole in the bar attaches to an existing bolt sticking out of the firewall, above and to the right of a rectangular hole used for the e-brake (see the second image).

The "flat" channel iron style brace attaches to a bolt on the front of the booster just in front of the prop valve bracket, (also see the second image).

Okay, so this is where things get sketchy. The other end attaches to the firewall to a point above and to the right of the corner of the driver's side cab rail that attaches the cab to the frame, (also shown in the second image). My 1970 C/10 doesn't have a hole or bolt in that location. It seems that this was a '71 and up thing. I have included a picture from member FirstOwner69's firewall which shows some dimples in that area and I have circled (in yellow) the dimple that I believe coincides with where the hole/bolt would be on a later truck (see the third image).

I have also included an image of the firewall on member GASoline71's 1972 GMC and have circled the two mounting spots in red. From what I've found, his truck would have had the hole from the factory (fourth image).

I also came across a post http://67-72chevytrucks.com/vboard/s...90&postcount=7 where a member added a booster and the braces to a 1968 pickup. If you look carefully, you can see there are even more differences in the firewall.

Hopefully this information will be of some help to others.

I would like to have found a couple of close-up pics of that lower mounting spot from the inside and outside of a '71 or up cab. Just to see how it was originally attached and if there is any bracing inside the cab there.
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Old 01-12-2021, 09:18 PM   #11
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Re: 1970 C/10 Brake Booster Bracket Question

To anybody that says that the "brackets" aren't necessary, GM went to a lot of trouble and expense to put those brackets on the trucks. If they weren't needed they wouldn't be there.
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Old 01-12-2021, 10:14 PM   #12
rechinca
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Re: 1970 C/10 Brake Booster Bracket Question

I’d throw them on. I don’t know the real reason, just speculate to help with the pressure on the firewall. I had cracks on my firewall around the emergency brake mounts. Here is a shot showing how mine are mounted, you might have to zoom in. I’ll take a couple more when I get home.
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Old 01-12-2021, 10:26 PM   #13
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Re: 1970 C/10 Brake Booster Bracket Question

Quote:
Originally Posted by BigBird05 View Post
To anybody that says that the "brackets" aren't necessary, GM went to a lot of trouble and expense to put those brackets on the trucks. If they weren't needed they wouldn't be there.
Agreed. Back in the day, they measured parts cost at the .1 cent level. Adding those brackets was many dollars territory.

And yet, there are millions of trucks (like mine) that never had those brackets. We just haven't figured out the design criteria.
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Old 01-13-2021, 01:16 AM   #14
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Re: 1970 C/10 Brake Booster Bracket Question

More info in these old threads.

https://67-72chevytrucks.com/vboard/...d.php?t=653806
https://67-72chevytrucks.com/vboard/...d.php?t=156683
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