J20 Disk brake conversion wheel studs

Modified FSJ Tech Area
Post Reply

Topic author
SJohn
Vendor
Posts: 283
Joined: Sun Nov 03, 2019 4:10 pm

J20 Disk brake conversion wheel studs

Post by SJohn »

I am converting my 1986 J20 to disk brakes in the rear and after realizing the rotors mount to the back of the hub I need longer wheel studs. But why do none of the hundreds of disk conversion kits out there include the wheel studs or even tell you what to get? There seems to be no information about what studs are needed so is everyone reinstalling the old studs? That doesn't seem like a great idea now that the splines are pushed farther out of the hub so does anyone have a part number for the right wheel studs to use?
Thank you
Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

1986 J20 LS Swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=17875

1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981

RamJetFSJ
Posts: 431
Joined: Fri Mar 22, 2013 12:36 pm
Location: Carpinteria, CA

Re: J20 Disk brake conversion wheel studs

Post by RamJetFSJ »

What kit are you using? I don’t think the rotors mount to the back of the hub on rear axle conversions. They may use a rotor from the front (which would mount to the back of the hub), but not on the rear axle. That would require completely removing the axle shaft to change the rotor.
80 Wag in 73 attire, Ram Jet 350 power

Topic author
SJohn
Vendor
Posts: 283
Joined: Sun Nov 03, 2019 4:10 pm

Re: J20 Disk brake conversion wheel studs

Post by SJohn »

I am using the sneveys offroad caliper bracket and the rest are all gm parts. All kits use the GM 3/4 ton front rotor mounted to the back of the hub. This is the same for just about any make dana 60 and older 14 bolt axles. The gm rotor is not big enough to fit around the hub so it is mounted to the back. I have not found anywhere where someone has used a rotor that will fit over the hub like your standard rotors on any other car.
Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

1986 J20 LS Swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=17875

1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981

RamJetFSJ
Posts: 431
Joined: Fri Mar 22, 2013 12:36 pm
Location: Carpinteria, CA

Re: J20 Disk brake conversion wheel studs

Post by RamJetFSJ »

My bad, overlooked the j20/Dana 60 part. Only have experience with D44 and M20/23. That’s what I get for replying to a thread before finishing my coffee. Carry on!
80 Wag in 73 attire, Ram Jet 350 power

rocklaurence
Vendor
Posts: 2565
Joined: Sat Mar 30, 2013 6:53 am

Re: J20 Disk brake conversion wheel studs

Post by rocklaurence »

That doesnt sound right--rotor mounts to the back of the hub?

Topic author
SJohn
Vendor
Posts: 283
Joined: Sun Nov 03, 2019 4:10 pm

Re: J20 Disk brake conversion wheel studs

Post by SJohn »

Yes on dana 60 disk brake conversions the rotor mounts to the back of the hub unless there is a rotor that will fit over the hub but that would require a different caliper bracket. But I was able to find the correct wheel studs to correctly make this work. I found 1978 k20 rear wheel studs for 11" brakes work great. Part number 610-188.
Image
Image
Image
Image
Owner/Operator/Chief Engineer of Johnson Production FSJ Parts
https://www.johnsonproductionjp.com/

1986 J20 LS Swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=17875

1981 Cherokee Chief - Rustard - 2JZ swap
https://www.fsjnetwork.com/forum/viewto ... 12&t=22981

rocklaurence
Vendor
Posts: 2565
Joined: Sat Mar 30, 2013 6:53 am

Re: J20 Disk brake conversion wheel studs

Post by rocklaurence »

I never noticed that... I always assumed that they mounted from the front.

threepiece
Posts: 430
Joined: Mon Apr 20, 2020 8:33 am

Re: J20 Disk brake conversion wheel studs

Post by threepiece »

Back of the hub? What you fellows are referring to as “back side” is actually the “inboard” side. As car guys and mechanics we all should know that all references are made from the driver seat: front, back, inboard, outboard, right side, left side. This way there is no misunderstanding, Driver side in some countries is the right side.
I used to name my FSJ’s after their previous owners, I realized I had too many with five named Rick.

Dang raccoons again!

Rust is a color too.
User avatar

Phils67
Posts: 1011
Joined: Sat Mar 24, 2018 3:11 pm

Re: J20 Disk brake conversion wheel studs

Post by Phils67 »

I just did this a few months back. The GM ones mentioned earlier are correct. The rotor mounting behind the hub is also correct. Its the same rotor used on a J20 front, at least using the cuthroat4x4 kit I used. Make sure you have the brackets clocked to where the caliper won't interfere with the springs. Thats the only issue I've had, my calipers mount super low. Almost like when they drilled the holes they should have drilled then between the current mounting holes. If i move it up a hole i can't get my upper slide bolt out. Image

Sent from my SM-G970U using Tapatalk

1967 Gladiator J2000, 1998 4.0L OBD2, T18, D20 twin sticks, D44HD/D60, Detroit lockers, 3.73s, 4wheel disc brake, FSSR, Dakota digital, etc.
Post Reply