Disc Brake Conversion

[Steeveedee]

I'm trying to use the link for brakes, but it doesn't work. I get this message below. And I can't paste the screenshot into the contact field information.

Anyway. I'm looking to upgrade my '70 C20 Chevy (8 lugs) to disc brakes. I don't see anything at Summit except 6 lug stuff. I know what I need, just need to know where to get it. I think maybe the least expensive would be to dogrob the parts from a truck that will fit mine- what years, I don't know. I also don't know if they will work with 16.5" steel wheels, but I think they should. If I still worked as a mechanic, I'd know this information cold, but I left that occupation as a living in 1984 when I went to work as an engineer.

Any pointers?

Thanks in advance.

[DBK81]

Go to CPP they have lots of quality options.

[b.sharp]

I believe you can use 71-72 8 lug spindles out and change the upper/lower ballpoints. I know you can swap the73/87 front crossmember but do not know if you can swap any of the individual parts or not. There are a lot of knowledgeable people on here. Maybe one of them will chime in.

[Voodoo556]

The 16.5's will clear the calipers, so will 16's.
15's will too, with a sh*t pot of grinding, which I don't understand why anyone would do.

Little pricey
https://www.performanceonline.com/63...-deluxe-8-lug/

A guy sent me this about doing a disc swap back when I was asking.

OPTION 1: get the spindles only from a 71-72 up truck, get new ball-joints to match the year of the spindles, new calipers or rebuild, turn rotors or buy new rotors, new bearings, throw it together. Use the donor upper ball joint, taper is different on upper, lower is the same. Use the donor lines, you'll need a disc/drum proportioning valve, don't skip this unless you enjoy changing calipers a lot! The control arm bushing are a bear to remove, they screw in/out and the lower arm bushing bolts have a small weld bead on each. Not sure if it was factory or not. Retorque to 230 ft/lb.
OPTION 2: get a whole crossmember from a later model truck.

I'm sure someone will chime in and give you more info. Good luck.
.

[Steeveedee]

Originally Posted by Voodoo556

The 16.5's will clear the calipers, so will 16's.
15's will too, with a sh*t pot of grinding, which I don't understand why anyone would do.

Little pricey
https://www.performanceonline.com/63...-deluxe-8-lug/

A guy sent me this about doing a disc swap back when I was asking.

OPTION 1: get the spindles only from a 71-72 up truck, get new ball-joints to match the year of the spindles, new calipers or rebuild, turn rotors or buy new rotors, new bearings, throw it together. Use the donor upper ball joint, taper is different on upper, lower is the same. Use the donor lines, you'll need a disc/drum proportioning valve, don't skip this unless you enjoy changing calipers a lot! The control arm bushing are a bear to remove, they screw in/out and the lower arm bushing bolts have a small weld bead on each. Not sure if it was factory or not. Retorque to 230 ft/lb.
OPTION 2: get a whole crossmember from a later model truck.

I'm sure someone will chime in and give you more info. Good luck.
.

Thanks! The second option is kind of what I'm looking for. Given that the brakes pull to the right, I know I've got to get into it and fix that. Also, given that I know that I did the last brake job on it for my FIL about 16 years ago (he didn't drive it much), it probably needs wheel bearings and wheel cylinders, as well. I'll have to check ball joint play. The truck has 200+k miles on it, and I don't know if the front end has ever been overhauled. Going to discs wouldn't be that much more expense, if I had to buy ball joints, anyway, for instance. To do it all, I'm probably looking at $2k in parts. I will do the labor, except for the alignment.

A crossmember from a later truck sounds nice, too. Especially if it had all the parts in question in better condition. I hate to do that though, that is heavy work for my back that I trashed doing that kind of work, years ago.

[michael bustamante]

if you need the 3/4 ton lower control arms just let me know

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[hugger6933]

Any of the post you read about changing to disc from the 73-87 trucks will work on the 3/4 and 1 ton stuff too you just need to make sure your doing 3/4 to 3/4 or 1 ton to 1 ton same as you would make sure it is 1/2 ton stuff if you were doing a 1/2 ton. Does that make sense? You can get your stuff from a donor [newer truck] and then break down the components so your not dealing with a bunch of weight at once and not having to remove the motor to change crossmembers. You can change the control arms out and then put the newer spindles back just as if you were rebuilding the front. If you turned wrenches long ago it is still the same stuff it was back then just older and greasier. Good luck Jim

[Steeveedee]

Originally Posted by hugger6933

Any of the post you read about changing to disc from the 73-87 trucks will work on the 3/4 and 1 ton stuff too you just need to make sure your doing 3/4 to 3/4 or 1 ton to 1 ton same as you would make sure it is 1/2 ton stuff if you were doing a 1/2 ton. Does that make sense? You can get your stuff from a donor [newer truck] and then break down the components so your not dealing with a bunch of weight at once and not having to remove the motor to change crossmembers. You can change the control arms out and then put the newer spindles back just as if you were rebuilding the front. If you turned wrenches long ago it is still the same stuff it was back then just older and greasier. Good luck Jim

Makes sense, and yes, it is a lot greasier than back then.

[Tim67]

I recently put disc brakes on my 67 GMC C20. I used the disc brakes off of an 83 Chevy 3/4 ton. We used 83 spindles, ball joints, the whole tie rod (inner tie rod end, connector, and outer tie rod end), rotors, calipers, and brake hoses.

[Mmorgan32]

I bought the 8 lug kit from pol. It came with everything I bought new hard lines too. I haven't installed it yet but the only thing extra I had to buy is springs and shocks. It took forever to get delivered but I feel it's worth the money since it also came with a new master cylinder, booster, tie rods, and ball joints.

[Tim67]

I had an 83 Chevy that I had rolled which I took the parts I needed from. I also used the master cylinder from the 83. I found a 72 brake booster and mount at a junkyard and used it.

[Steeveedee]

Originally Posted by Tim67

I had an 83 Chevy that I had rolled which I took the parts I needed from. I also used the master cylinder from the 83. I found a 72 brake booster and mount at a junkyard and used it.

Was the booster change due to the '83 having Hydra-Boost? I currently have power drum brakes.

Thanks for the responses folks, I appreciate it.

[Tim67]

I needed the mount and booster so it would sit low enough to not hit the hood and I decided to see if the 83 master cylinder would work with the 72 mount and booster, becuase it didn't have a master, which it did.

[Steeveedee]

Ended up with the POL kit. Came with bent seals and caps, and missing parts. Had to flog it some, but it's OK, now. I rebuilt the front end while I was in there. All the stuff was original from 1970- riveted ball joints and all! It rides a lot better, now, as I also put new shocks on. Now that I have a new travel trailer, I have to go through it to make it more than a sad driveway queen.

[Jose's 69]

I also bought the kit from POL. It came with everything to pretty much rebuild the front end, rotors, calipers, booster and prop valve. I live like 45 minutes away so I picked it up. Gave me the wrong bearings but they replaced it no problems. I also bought the front pre bent brake lines. No issues.

[NC_John]

Originally Posted by DBK81

Go to CPP they have lots of quality options.

We must have very differing definitions of "quality."

[chevylemon]

On my 68 c30, I ended up buying a 73 suspension clip for $80. Going to my napa and buying everything brand new putting it all together and then bolting it in, in an afternoon. Total bill was about $340. Lifetime warranty on bearings, seals, calipers, pads, and steering linkage if you go with ncp(better line).

[davepl]

On my '70 I bought a complete front disc setup (spindles, control arms, tie rods, everything but the crossmember) for $300 delivered and rebuilt and installed it, works great, and it's factory-engineered for this truck, so you really can't go wrong with factory parts if the interchange is right!

That requires, of course, that you can find one. But since ALL trucks went disc, pretty much any rusty old beater C20 on a farm has the parts you need.