1970 C30 disc Brake swap

[wshymas]

I have a 1970 C30 I want to replace the front brakes. I have been doing some searching and reading. My truck has power brakes and from what I have read i can swap from the a arms out (with tie rodends) or swap a complete assembly.
1. Do I need to make any changes to the brake booster I have now?
2. Will I need to add a new divider/proportioning valve?
I think mine is just a divider block.
Thanks for the info and help.

[kwmech]

I recently did my 69, I ended up swapping just about everything to get it right. My truck needs to stop when I want it to. Especially being a 1 ton flat bed. I use it and haul heavy. You will have to step up to about 1978 parts for availability. I also had to have some custom rubber brake hoses made.

[Aruba1]

First thing is first: you have a 1/2 braking system. Apparently a lot of 3/4 and 1 ton had their braking system downgraded during prior ownership. See my thread of 1/2 ton versus 3/4 and 1 ton.

http://67-72chevytrucks.com/vboard/s...d.php?t=666291
The first image shows the 1/2 MC at the top and the 3/4 ton at the bottom. The latter got bigger bore and I believe the brake booster is a bit different. The other give-away is the proportional valve, on the larger MC the rear reservior is connected to the front piece of the valve. You can either go with the bigger system (Autozone got a MC and booster setup for $119) or get a 1/2 ton to match to your booster. I recommend that you go with the former.

On mine I installed front brake system and the rear brake system off a 1989 C3500 4 dr and I didn't have to change the proportional valve. It works like a charm but now I am hunting for a P/S system and a hydro-boost setup to go with my MC. If you want brakes, that is the best way to go.

[kwmech]

Never heard of that. The differences I have seen is whether or not the truck was built with the Bendix brakes or the Delco Moraine

[SS Tim]

Originally Posted by Aruba1

First thing is first: you have a 1/2 braking system. Apparently a lot of 3/4 and 1 ton had their braking system downgraded during prior ownership. See my thread of 1/2 ton versus 3/4 and 1 ton.

http://67-72chevytrucks.com/vboard/s...d.php?t=666291
The first image shows the 1/2 MC at the top and the 3/4 ton at the bottom. The latter got bigger bore and I believe the brake booster is a bit different. The other give-away is the proportional valve, on the larger MC the rear reservior is connected to the front piece of the valve. You can either go with the bigger system (Autozone got a MC and booster setup for $119) or get a 1/2 ton to match to your booster. I recommend that you go with the former.

On mine I installed front brake system and the rear brake system off a 1989 C3500 4 dr and I didn't have to change the proportional valve. It works like a charm but now I am hunting for a P/S system and a hydro-boost setup to go with my MC. If you want brakes, that is the best way to go.

It appears you missed the fact he is converting a 70 factory drum/drum truck to front dics brakes. While on your page Jocko points out the differences between a 71-72 1/2 and 3/4 ton it does not show this C30 as incorrect or "downgraded".

The drum and combination valve as they sit are correct for a 70 C30 or C20.

As kwmech pointed the later parts are easier to find doing a swap and even a hydroboost can be installed.

The factory service manuals might be a good place to start for both what you ahve and where you want to go.

RTFM ... Read The Factory Manuals... download 'em here

[wshymas]

Will a van front end work for a brake swap? It is a 83 van 3/4 ton with school bus breaks JD5.