Power drum brakes - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**dmjlambert** · 07-21-2016, 01:36 PM

If I like the 4 wheel drum brakes just fine on my 1969 CST/10 and want to add power brakes, is it as simple as going up to autozone and getting a booster and connecting it? Just re-bend or replace the metal brake lines and add a vacuum hose? This is what I see available and price is affordable at $150. Are there any things to be aware of?

BILT4ME · 07-21-2016, 04:05 PM

I posted the following in a different thread. make sure you get the CORRECT MC for your combination. Verify wheels cylinder diameters from each application to compare:

Something that no one has really mentioned here:
Is that the CORRECT master cylinder for the truck? Many of these trucks have been bought/sold many times. Each owner does something to it. If someone has replaced the MC with one for disc brakes and the truck only has drum brakes, it will NOT operate correctly, and the MC will push MORE fluid for a disc brake setup than a drum brake.

It is the opposite for a drum brake MC being installed on a disc brake setup. The brakes will be insufficient because there is not enough volume for the disc brakes.

Just a thought. BTDT, done the research to confirm.

**dmjlambert** · 07-21-2016, 08:19 PM

The way I know to verify is to observe that my 69 truck has 4 drum brakes on it now, and I bought new master and wheel cylinders for it about a year ago by going into O'Reilly's and telling them what truck I have, and asked for the parts. The parts fit OK and the brakes work fine. I am the second owner of the truck and it looks to me like the PO didn't do much to the truck except drive it, and he parked it in 1986.

When I login to the Autozone web site and tell it what truck I have, and pick a power booster, it says the part fits the truck. Since 69 pickups did not come with disc brakes, I suppose the one I'm picking (pictured in my above post) should be for drum brakes. I thought perhaps I should pick the one that comes with a master cylinder in case the non-power-brakes master cylinder I have now is not compatible with the booster. I wish I knew more about this, but I'm a newbie. If there are flaws in my thinking or if anybody has hints/tips for a newbie please let me know.

Shady Rascal · 07-21-2016, 08:25 PM

You need significantly more than the booster itself. The booster mounts to the firewall on a pair of brackets with a bellcrank setup between them for the pushrod. There are also braces that bolt from the booster to the firewall.

07-21-2016, 01:36 PM	#1
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,817	Power drum brakes If I like the 4 wheel drum brakes just fine on my 1969 CST/10 and want to add power brakes, is it as simple as going up to autozone and getting a booster and connecting it? Just re-bend or replace the metal brake lines and add a vacuum hose? This is what I see available and price is affordable at $150. Are there any things to be aware of? Attached Images

07-21-2016, 04:05 PM	#2
BILT4ME Registered User Join Date: Jul 2016 Location: Olathe, KS Posts: 267	Re: Power drum brakes I posted the following in a different thread. make sure you get the CORRECT MC for your combination. Verify wheels cylinder diameters from each application to compare: Something that no one has really mentioned here: Is that the CORRECT master cylinder for the truck? Many of these trucks have been bought/sold many times. Each owner does something to it. If someone has replaced the MC with one for disc brakes and the truck only has drum brakes, it will NOT operate correctly, and the MC will push MORE fluid for a disc brake setup than a drum brake. It is the opposite for a drum brake MC being installed on a disc brake setup. The brakes will be insufficient because there is not enough volume for the disc brakes. Just a thought. BTDT, done the research to confirm. __________________ 1970 GMC K2500 Dis-use is harder on a car than mis-use.

07-21-2016, 08:19 PM	#3
dmjlambert Senior Member Join Date: Apr 2016 Location: Cypress, TX Posts: 3,817	Re: Power drum brakes The way I know to verify is to observe that my 69 truck has 4 drum brakes on it now, and I bought new master and wheel cylinders for it about a year ago by going into O'Reilly's and telling them what truck I have, and asked for the parts. The parts fit OK and the brakes work fine. I am the second owner of the truck and it looks to me like the PO didn't do much to the truck except drive it, and he parked it in 1986. When I login to the Autozone web site and tell it what truck I have, and pick a power booster, it says the part fits the truck. Since 69 pickups did not come with disc brakes, I suppose the one I'm picking (pictured in my above post) should be for drum brakes. I thought perhaps I should pick the one that comes with a master cylinder in case the non-power-brakes master cylinder I have now is not compatible with the booster. I wish I knew more about this, but I'm a newbie. If there are flaws in my thinking or if anybody has hints/tips for a newbie please let me know.

07-21-2016, 08:25 PM	#4
Shady Rascal Registered User Join Date: Feb 2016 Location: Weatherford Texas Posts: 306	Re: Power drum brakes You need significantly more than the booster itself. The booster mounts to the firewall on a pair of brackets with a bellcrank setup between them for the pushrod. There are also braces that bolt from the booster to the firewall.



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