Gbody rotors all the same?

[just plain john]

I swapped the GN rear today into my El Camino today, and ran into an issue I hadn't thought of. I have Weld Draglites on the car. When I went to mount the wheels, I found that the wheel studs are 1/2 inch, not 7/16 like the stockers. I also have Belltech drop spindles on the front, and they spec the same part number for G bodies as well as earlier S10 trucks. Do Regal rotors have 1/2 inch studs? I was going to do the complete brake system, and the back brakes are done (S10 manual brake wheel cylinders). Now the fronts. Is the Regal rotor an easy swap? I don't know what bearing sizes are involved, but I do know my 81 model has different larger bearings than the 78 and 79 El Camino. Turbofish38, are you listening?

 

[just plain john]

Hmmm, wait a minute. I can press in new studs, right?

 

[just plain john]

A quick look at autozone.com says the part numbers for rotors for the 87 TR and 90 s10 Rotors are the same, but the 81 El has a different number listed. Maybe because of the wheel stud diameter? My stock rotors fit on the S10 spindles, despite the part number so I'm guessing the others will work after all.

 

[spidereyes]

Actually the studs aren't 1/2'' there metric 12mm with a 1.5mm thread pitch. this was on Gbodys from about 81 or 82 up and the earlier cars used standard 7/16th studs, if the studs are factory originals on the car they should have either an S for standard or an M for metric stamped in the end of the stud. hollander lists that all Gbody rotors from 82 and up interchange and that 79,80 and 81 fit by including lug nuts. 78 appears to be an oddball and only fits 78 I assume thats because of the different spindles and smaller wheel bearings. Hope that helps.

 

[Roc87]

I believe 81 was the last year of SAE studs, then in 82 they switched to metric. Other than that, the rotors and drums should be identical for all G-bodies.

 

[just plain john]

Cool, that's the answer I was looking for.

 

[turbofish38]

Stupid Question? You aren't doing a 12" rotor upgrade are you? The reason I ask is because the 12" B-Body(Impala) rotor would have 1/2" studs depending on the year. Not to mention the wrong bolt pattern.

As far as G-Body rotors goes.
78-81 use 7/16" studs
82-88 use 12mm
The 1978 only rotor uses a different outer wheel bearing. 79-88 use the same bearings.
And 82-05 S-10 and 82-92 F-Body use the same rotor with 12mm studs.

 

[just plain john]

No Eric, I could just use the ones I have but since I'm going to replace the stock set up, I'll just get the rotors with the 12mm studs. I'm pretty anal about the detail stuff, and even though no one else would know the front and back studs are different it would bug the hell out of me.