help i search drum brakes updated to disk with a 5x4 3/4 lug

[mr mike]

I have Search the Forums and need to to know If i am good to go

Ok so I have a 1969 short bed 3 on the tree with a 327 v8
I have drum brakes front and back and, I would like to do the disk brake swap
so I can put some rims on the truck and get a brake job update at the same time, But The rims that i have are 20" 5 x 4 3/4 the same as a Camaro.

So is this what i need

The 73-87 truck spindle or Belltech 3" drop spindle that uses the A-6 inner bearing as long as it has a 1-1/4" bore

the Camaro 1" 5X4.75 bolt circle rotor

Camaro rotor will work on the 73-86 spindles if the 81-86 calipers are used as well.

stock brake pads for a 81 to 86 camaro

What else do i need to get a brake booster or something
I can not recall

but some day i plan go doing air ride and some 24" rims but as of now i am planing on just stuff some 20" under it Got them so cheap I lol just thinking about it and getting it as low as i can. If any one can help I would real love the help thanks mike


I found this info when I was Search the Forums


Now we all know that the 73-87 front crossmember and suspension components can be swapped into the 60-72 trucks. The 73-80 Chevrolet C10 pickups used a 1.28 rotor. Then in 81-86 GM switched to a 1" rotor. I did a bit more digging and found that the calipers are different for the 1" rotor but use a common bolt pattern with 73-80 so, it looks as if the 91 Camaro rotor will work on the 73-86 spindles if the 81-86 calipers are used as well. Also the flexible brake line will need to be changed if you have the 73-80 caliper as one of the calipers uses American standard thread and the other uses a metric thread. The parts house could not tell me which one used what thread but that they were different. I will figure that out when I purchase the parts. I have not done this yet but it does look like it will work. fones1966 a member here PMed me telling me about this possibility and I want to thank him for that. I just thought I would post this information in case there were others that could use it. Olympic Brake here in Washington is who provided this information. One note I want to point out is the specs that I have all show the same bearings on all three rotors. I was told by fones1966 that the 73-80 1.28 rotor used a A-5 inner bearing so that bearing would have to be replaced when switching to the Camaro rotor but, what I found was the 73-80 heavy duty 1.28 rotor used the A-5 inner bearing and the 81-87 light duty rotor used the A-6 as shown in the specs I have provided. I hope this information is helpful. Here are the specs on both the truck and Camaro rotors:

73-80 Truck rotor specs are:

Height 4.88
Diameter 11.85
Min. Thickness 1.220
Hub 3.06
Outer bearing A-3
Inner bearing A-5
Seal Part # 8871
Bolt Circle 5X5

81-86 Truck rotor specs are:

Height 4.63
Diameter 11.86
Min. Thickness .96
Hub 3.20
Outer bearing A-3
Inner bearing A-6
Seal Part # 8871
Bolt Circle 5X5

91 Camaro 1LE Performance Package rotor specs are:

Height 4.65
Diameter 11.85
Min. Thickness .97
Hub 2.78
Outer bearing A-3
Inner bearing A-6
Seal Part # 8871
Bolt Circle 5X4.75



Well after much research and comparisons this is what I have come up with. I would like to thank gringoloco he helped me out here. The 73-87 2-1/2 drop spindle from CPP uses the A-5 inner bearing that has a 1-3/8" bore. This spindle uses the 1-1/4 rotor with the 5X5 bolt circle. This is the same size spindle as the OEM as well. Belltech has a 3" drop spindle that uses the A-6 inner bearing that has a 1-1/4" bore. This spindle uses a 1" rotor and there for can either be used with the light duty truck 1" 5X5 bolt circle rotor or the Camaro 1" 5X4.75 bolt circle rotor. There it is. This is the only way that I found to switch from the 5X5 bolt circle to the 5X4.75 bolt circle using the OEM rotors. Hope this helps