Wilwood rear disc help.......

-
D

DGrace

Well-Known Member
Joined
Aug 19, 2009
Messages
154
Reaction score
46
Location
Snow Hill, NC
Just got around (could finally scrape enough $ together) to install my Wilwood rear disc kit. Bought the Moser housing & axle package (Trutrac, 33 spline) - upon installing the caliper, I notice that without any shims installed, the caliper can't center on the rotor (outboard pad is too tight). It appeared that the rotor wasn't sitting flat against the axle. Determined that the 3" studs were causing the interference. I verified by tapping the studs in a tad and was able to center the rotor with one shim. Not sure how to correct this properly. Moser only shows the 3" stud with the Mopar .685 knurl. I was going to go with the screw in studs but was advised by Moser that they may interfere with the internal parking brake mechanism. Should I "machine" (careful grinding) the stud or possibly open the rotor hole for clearance? Really at a loss & thought someone may have experienced this. Any help appreciated - as always.
 
I have Wilwood discs on my Demon, but I have a Dana under it. Mine has 3" studs also & I didn't run into any interference. Maybe post a few pictures so we can see what you are seeing.
 
Sounds like the shoulder on the wheel studs is larger than the holes for the wheel studs in the rotor?

If that’s the case, DO NOT alter the studs. The right way to do it would be to ream the holes in the rotor until the rotor sits flush against the axle flange. Other option would be to drill them slightly larger, the smallest you can make them and have them clear would be best. As long as the axle register matches the hub bore in the rotor having the wheel stud holes slightly larger shouldn’t hurt anything, it won’t move when everything is tightened. Having the rotor flush against the axle flange is very important.

But that assumes the rotor isn’t hanging up on something else. The other usual culprit is the center register on the axle. Same deal, leave the axle alone and have the rotor clearanced. Harder than the wheel stud issue though, if it’s more than what you want to take out with some sandpaper the center hole should be machined so it stays concentric to the axle register.
 
72bluNblu said:
Sounds like the shoulder on the wheel studs is larger than the holes for the wheel studs in the rotor?

If that’s the case, DO NOT alter the studs. The right way to do it would be to ream the holes in the rotor until the rotor sits flush against the axle flange. Other option would be to drill them slightly larger, the smallest you can make them and have them clear would be best. As long as the axle register matches the hub bore in the rotor having the wheel stud holes slightly larger shouldn’t hurt anything, it won’t move when everything is tightened. Having the rotor flush against the axle flange is very important.

But that assumes the rotor isn’t hanging up on something else. The other usual culprit is the center register on the axle. Same deal, leave the axle alone and have the rotor clearanced. Harder than the wheel stud issue though, if it’s more than what you want to take out with some sandpaper the center hole should be machined so it stays concentric to the axle register.
Click to expand...
Yes, the tapered area of the stud (between the knurl and the threads) is too big. I tapped them in a bit and everything lined up. Is enlarging the holes something I should have a machine shop handle? Thank you for your help.
 
DGrace said:
Yes, the tapered area of the stud (between the knurl and the threads) is too big. I tapped them in a bit and everything lined up. Is enlarging the holes something I should have a machine shop handle? Thank you for your help.
Click to expand...

I had to enlarge the holes in the rotors to get my rotors to sit flush on the flange for the same reason. The center register hole kept everything lined up though. Not a big deal. I used a hand drill and a step drill bit.
 
jbc426 said:
I had to enlarge the holes in the rotors to get my rotors to sit flush on the flange for the same reason. The center register hole kept everything lined up though. Not a big deal. I used a hand drill and a step drill bit.
Click to expand...
Same for me,a little die grinder and carbide bit work,a few minutes and done, Don't forget the center register adapter.

20170524_174212.jpg
 
jbc426 said:
I had to enlarge the holes in the rotors to get my rotors to sit flush on the flange for the same reason. The center register hole kept everything lined up though. Not a big deal. I used a hand drill and a step drill bit.
Click to expand...
Ok, thank you. I just didn't want to mess anything up - took too long to save up for them....
 
Demonracer said:
I have Wilwood discs on my Demon, but I have a Dana under it. Mine has 3" studs also & I didn't run into any interference. Maybe post a few pictures so we can see what you are seeing.
Click to expand...

dana1.jpg
 
DGrace said:
Thank you, and yes, I'm using the adapter.
Click to expand...

Just did a set on an 8.75 with the bigger stud shoulders and had to take out the stud holes to 5/8. (used a drill press)
Also had to slightly open the center register also, but it was close enough that a mototool with a sanding drum was enough.
The axles were from Dr. Diff and they had a larger center register.
It all went fine in the end.
 
DGrace said:
Yes, the tapered area of the stud (between the knurl and the threads) is too big. I tapped them in a bit and everything lined up. Is enlarging the holes something I should have a machine shop handle? Thank you for your help.
Click to expand...

As others have already pointed out it's not really necessary to have a machine shop do it. I would use a drill myself just so the hole is round (vs a die grinder). Drill press would be ideal but a handheld drill would work fine. Step drill would be a good way to do it if you could find one close to the right diameter. I'd want to keep the holes as small as possible, but with a good center register it isn't super critical.
 
72bluNblu said:
As others have already pointed out it's not really necessary to have a machine shop do it. I would use a drill myself just so the hole is round (vs a die grinder). Drill press would be ideal but a handheld drill would work fine. Step drill would be a good way to do it if you could find one close to the right diameter. I'd want to keep the holes as small as possible, but with a good center register it isn't super critical.
Click to expand...
Thank you. I got a 5/8" reamer and enlarged the hole and purchased an Irwin 5 piece countersink kit (Lowes - $20) - used the 3/4" bit and slightly chamfered the hole - fits like a glove. Thank you to all that replied! I can do a few things, just need a little (knowledgeable) direction. <><
 
Last edited:
mopardude318 said:
How did y’all hook up your parking brake? Did you use the wilwood brake cables?
Click to expand...
I haven't, and probably won't. I didn't want a parking brake but they didn't have an 11" rotor kit without one. I was informed that a 12" rotor wouldn't fit my wheels (or it would have been less room than they recommend).
 
The wilwood setup has a parking brake. I just don't use it. I would imagine you hook the factory cable to it in one way shape or form.
 
You must log in or register to reply here.
-

Back
Top