C20 to C10 5 bolt disc brake conversion

[airkore65]

I have an 8 lug drum brake C20 and would like to convert to 5 lug disc brake. Will the C10 upper and lower control arms with spindles and rotors mount on the C20 frame?
Thanks for any help and direction.

[dmack91]

If you are talking about getting same year parts and swapping them into the factory crossmember, I can't help. I can say that I converted mine using an 84 C10 donor truck. Simply swapped the entire assemblies. It was a direct bolt-in, with the exception of opening up one of the holes on each side.

[SCOTI]

Yes, C10 parts can be swapped over to the C20 frame/crossmember. On the 73-87/91 models, I know the upper a-arm frame studs are larger for the HD trucks vs the half ton trucks. Not sure about the 67-72's.

It's easy enough to overcome by using the correct upper disc brake BJ for a half ton spindle on the C20 upper arm.

[kwmech]

You can use the same C20 upper arm, just swap out the ball joint. Lower arm has to be replaced b'cuz of ball joint diameter

[connorm]

From my understanding the control arms are the same with different ball joints. I swapped from a 1970 C20 drum brake front end to a 1971-72 C20 disk brake front end. My understanding of it was the crossmember and control arms were the same, but ball joints, spindles, steering, etc. were different. I have never tried switching ball joints, spindles, etc. but that is my understanding. I only switched the whole crossmember because I got a deal on a fully rebuilt one.

[azsnow]

Solid info here. Easiest route’s still the full C10 crossmember swap if you can find a donor, saves chasing part numbers and ball joint sizes later.

[connorm]

Originally Posted by azsnow

Solid info here. Easiest route’s still the full C10 crossmember swap if you can find a donor, saves chasing part numbers and ball joint sizes later.

Correct. But if you swap to a 1967-70 or 1971-72 spindle, just give them that year for parts (I believe those are the year cut offs). Once you modify any part of your vehicle keep notes on which parts to buy, and keep a copy of them in the vehicle. If you're going through the headache of doing it once, make it easier the next time. Whether it you, your child, or the next owner. They will thank you.