Another brake question.

[Dieselmh]

I've read through 6 pages of brake threads, but still haven't found exactly what I'm looking for. I've got a 1970 K5 with 1 ton running gear, 44s, and disc brakes all around. My booster and MC are stock 1/2 ton units that were made for drum brakes. I can stop the truck, but panic stops are out of the question. I'm looking for suggestions on the best and/or easiest upgrade. If I go with a 1 ton setup from a 1970 K30, it should bolt up to my bracket on the firewall, but won't it be made for drum brakes? Will it work for my discs? If I go with a 1 ton setup from a 1972 K30, it should work just fine for discs, but it won't bolt to my firewall without a different bracket and support rods. I haven't been able to find the bracket/rods anywhere locally. Does anyone make reproductions of these? Is there a different/better option that will stop my Blazer properly, yet still bolt to my factory 1970 booster bracket? I don't want to go hydro, and while I don't normally mind "fabbing" my own brackets, I don't really want to trust my brakes and my life to my skills. Any suggestions, information, and criticism are welcomed with open arms.

 

[MNorby]

mine is a 71 so it was factory front disks but I am running tons with disks all around now. I used a 3/4 ton i think MC and boost (dual vs single diaphram i think) and it bolted up for the most part. I also eliminated the factory prop valve and just use a basic wilwood prop valve in the rear brake line and just tuned till all 4 locked about equal.

 

[AJs72K5]

1-ton booster swap write-up I did: LINK

Touches on everything I did for the brake system.

 

[Dieselmh]

Yep, your's was one of the threads that I read. That still doesn't help me find the brackets that I can't find. Thanks, though.

 

[bp71k5]

Is there a different/better option that will stop my Blazer properly, yet still bolt to my factory 1970 booster bracket?

You didn't say what you did to the proportioning valve. Also what kind of calipers are on the rear?

The drum proportioning valve typically needs to be removed or modified. Bleeding it well enough can be tough.

Also, if you are using the ebrake calipers from an eldorado, the ebrake needs to be hooked up and used to keep the rear calipers adjusted.

I can't help with the booster bracket, but you can swap the pushrod between either booster if one isn't the right size.

 

[Dieselmh]

My proportioning valve is already gone. I guess that was another quality mod done by the PO. I'm running 3/4 ton calipers in the rear, and using a driveline e-brake. I didn't know that the pushrods could be swapped from the half ton booster I have to a new 1 ton booster. IIRC, the bolt pattern is different on the two boosters, though, so I'd still have to get the correct bracket to bolt it up. Thanks for the info.

 

[bigblock72]

The bolt patterns are the same on all of the boosters. The difference is in the length of the brackets, I believe AJ pointed this out in his thread. If you have the longer disc brake booster brackets/linkage then you're set.

The other option is to go to hydroboost, it's a little more involved than a 1 ton booster but you'll have the best brakes possible.

 

[70jimmy]

Yep get the brackets off a newer truck 71 or 72.

I used 1 ton stock stuff on mine and used adjustable proportioning valve and residual pressure valve in the rear brake line and just kept playing with it.

Definately have great brakes now.