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Old 04-12-2019, 10:26 AM   #1
Tortelvis
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Need Power Brakes

Hi Ya'll, I have 1970 C20. Looking to upgrade to power brakes using drums all the way around until I feel like dishing extra for the discs. Anyone done this conversion? Thanks!
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Old 04-12-2019, 10:30 AM   #2
GASoline71
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Re: Need Power Brakes

All you need is a stock booster, booster bracket and brake pedal rod. The rebend your lines as the booster will stick out further from the firewall..

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Old 04-12-2019, 11:06 PM   #3
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Re: Need Power Brakes

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Originally Posted by GASoline71 View Post
All you need is a stock booster, booster bracket and brake pedal rod. The rebend your lines as the booster will stick out further from the firewall..

Gary
Plus a vacuum line to a vacuum source. The earlier small block trucks got vacuum from the intake port to the right rear of the carb. Same port where the transmission line went to. I BELIEVE the later years (maybe with the addition of discs in 1971) the vacuum source was at the bottom rear of the carb. Perhaps someone can verify.
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Old 04-13-2019, 11:52 AM   #4
Tortelvis
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Re: Need Power Brakes

Great info, thanks Guys!!
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Old 04-13-2019, 12:26 PM   #5
jocko
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Re: Need Power Brakes

Member Captainfab offers an alternative firewall bracket for this conversion. Just add booster and do the above things that were mentioned. His bracket tucks the booster closer to the firewall. Might require some thinking for proper pedal rod length but no rocket science involved. If you google him on here you will find it. Stock is a perfectly fine setup also, mentioning in case you can’t find it or prefer it closer to the firewall.
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Old 04-13-2019, 02:08 PM   #6
May70
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Re: Need Power Brakes

Funny I was just thinking the same thing for my 70 c20
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Old 04-13-2019, 02:51 PM   #7
RichardJ
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Re: Need Power Brakes

The MC for manual brakes have a deep hole for the brake rod. The MC for power brakes have a shallow hole to mate with the adjustable pin in the front of the booster.
CPP sells universal MC's with a plug that drops in so it can be used for manual or with a booster. I've made plugs like that from aluminum rod. Bull nose one end and drill a shallow dimple on the other end so the booster pin can't wonder off center. CPP adds an O-ring, but there is no need.
The important thing is that you measure the booster pin and the MC hole depth accurately. This is important even if you get a power MC.
They have a tool for this measurement, but with care can be checked with basic measurement tools.
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Old 04-14-2019, 02:27 AM   #8
rechinca
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Re: Need Power Brakes

And do yourself a favor, don’t skimp out on the brackets. Buy the correct OEM used one as well as the brace. My trucks PO had his mechanic install a cheap $20 set of brackets which caused him to booger well a bastardized rod together to the pedal. Looks like crap and is really unsafe. While you’re at it buy a new boot for the pushrod too. It’s cheap and might as well do it while you are at it. The cheap brackets the PO used on my truck are bending so I bought the right setup from members here on the board in the classified section. They can be had for about $50. A little work and paint and they look like new.
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Old 04-14-2019, 10:14 AM   #9
Jim Boy
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Smile Re: Need Power Brakes

If you have an eight cylinder engine you will be ok. Be aware that if you have a six cylinder and you use a stock eleven inch booster with stock brackets it will hit the air cleaner. You will either have to raise the air cleaner or find an offset one. You could also consider using a smaller diameter booster. My two cents. Have a good day.

Last edited by Jim Boy; 04-14-2019 at 10:16 AM. Reason: sp
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Old 04-14-2019, 10:21 AM   #10
Jason Banks
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Re: Need Power Brakes

Make sure you get the C20 Parts. I believe the wheel cylinders have larger diameter than 1/2 ton and require a specific master cylinder and the C20 booster is a larger dual diaphram unit.

Last edited by Jason Banks; 04-14-2019 at 01:05 PM.
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Old 04-14-2019, 04:18 PM   #11
bill3rail
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Re: Need Power Brakes

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Originally Posted by Jim Boy View Post
If you have an eight cylinder engine you will be ok. Be aware that if you have a six cylinder and you use a stock eleven inch booster with stock brackets it will hit the air cleaner. You will either have to raise the air cleaner or find an offset one. You could also consider using a smaller diameter booster. My two cents. Have a good day.
Or a smaller diameter air cleaner.
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