Author Topic: 74 c15 brake booster conversion  (Read 1356 times)

Offline Swampyankee74

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74 c15 brake booster conversion
« on: August 27, 2022, 11:07:35 AM »
My 74 c15 has no brake booster. I would like to replace the entire brake system and put a brake booster on. There are a million companies that sell parts to do this. My plan is all new rotors calipers, either copper nickle or stainless break lines, rebuild the the rear drums, and a break booster. Who makes quality products to do this? And does anyone know of a complete kit for this? I really can't afford wildwood, but want a good quality product and there is a ton of options out there. Any input would be helpful.

And where is the best place to pull vacuum from for the booster?

Offline Shifty

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Re: 74 c15 brake booster conversion
« Reply #1 on: August 27, 2022, 01:04:54 PM »
First, you will need to determine JB3 or JB5 brakes (if you can't find it on the option sticker, it comes down to width of the front rotor (1.04" front rotor, 2" wide rear shoe is JB3, 1.25" front rotor, 2-3/4" wide rear shoe is JB5).

Quick scan shows that both boosters are still available from Cardone.

Vacuum source is off the intake manifold.

Honestly, unless you're going with a ton of horsepower, good-working OE brakes work fine for most applications, and replacement parts are much easier to find and/or diagnose, and this from a serious "over-braker" (big-brake fiend)
87 V20 Standard Cab Longbed (current)

87 R30 3+3 Longbed (days of yore)

98 C2500 ext cab longbed

Offline Swampyankee74

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Re: 74 c15 brake booster conversion
« Reply #2 on: August 27, 2022, 01:36:32 PM »
Truck has jb5 brakes.1.25" rotors. Isn't a ton of horse in the truck yet, but that is the plan for it. Brakes are pretty rough on the truck. If I'm gonna redo them, I want them to handle any drivetrain I throw at it. . Plan for this winter is breaks, steering and suspension overhall.i will check out Cardone. Thank you shifty

Offline Shifty

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Re: 74 c15 brake booster conversion
« Reply #3 on: August 27, 2022, 03:29:45 PM »
Cardone P/N#54-71008

Cheers!
87 V20 Standard Cab Longbed (current)

87 R30 3+3 Longbed (days of yore)

98 C2500 ext cab longbed

Online VileZambonie

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Re: 74 c15 brake booster conversion
« Reply #4 on: August 27, 2022, 07:52:04 PM »
The Factory dual diaphragm booster is all you need. It's enough to allow you to skull punch the windshield with your head if you press hard. Don't look for "kits" look for factory fit like shifty said.
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Swampyankee74

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Re: 74 c15 brake booster conversion
« Reply #5 on: August 27, 2022, 08:43:41 PM »
I want to put OE parts in this truck. I can't find anywhere that GM still makes any of these parts. There is a ton of companies that make these parts, with an aray of prices. Just looking to find who makes a good quality product. I will definitely check out that Cardone. I was looking for a kit, thinking it may be cheaper to go that way considering I'm replacing all of it instead of buying parts individually.  But I'm not trying to nickle and dime it, just want a nice functional break system

Offline Swampyankee74

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Re: 74 c15 brake booster conversion
« Reply #6 on: August 27, 2022, 09:35:09 PM »
Just ordered off of rock auto a remanufactured Cardone brake booster and a new acdelco master cylinder.  Thank you both for your help

Offline Shifty

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Re: 74 c15 brake booster conversion
« Reply #7 on: August 29, 2022, 09:07:18 AM »
Cheers!
87 V20 Standard Cab Longbed (current)

87 R30 3+3 Longbed (days of yore)

98 C2500 ext cab longbed