8 lug to 6 lug

[thompson1122]

I just bought a 1999 Silverado 2500 crew cab short bed with a 454 in it. I do not like the 8 lugs on it. The plan is to switch it to 6 lug and put in a set of newer 6 lug wheels. It is 2wd. I can just change out the spindles, rotors and calipers for the front. I want to put rear disc brakes on the rear. I think a guy used a rear axle out of 2004 Silverado and put it in the rear of his regular cab OBS. Was there a rear made with rear disc for my truck or do I buy a rear disc conversion kit or can I swap the rear axle from a newer 2000 and up model?

[95 S_Trucker]

If the truck is a 99, Its a C2500 LS. It doesn't have a Silverado badge anywhere on it. It would be 8500-8600 GVW. The rear axle should be a corporate 14 bolt 10.5" full floating axle.

For the front, you can swap all control arms and knuckles and brakes from a 88-98 2wd 6 lug truck.

For the rear, you can swap a different axle. You may need different u bolts if the tube is a different diameter. You will probably need a conversion universal joint.

If you swap to disc brake axle, you can remove the 15PSI residual pressure valve from your ABS unit. You will need 2PSI residual pressure valves to prevent caliper pushback. They can be mounted anywhere in the rear brake line circuit. It doesnt have to go in the same place as the 15 PSI valve. You can use your original brake master cylinder and ABS unit.

The largest GM trucks to have 6 lug in this era had 7200 GVW. Keep that in mind as you will reduce payload and braking effectiveness. Your c2500 weights around 6000 pounds empty. That doesn't leave much for payload or passengers

It may be better to look for a set of 8 lug wheels you like.