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1974 Vette Wilwood front brake kit 140-12040DR
Anybody run into this problem?
Replacing the front brakes on the Vette with Wilwood setup. The top bolt of the mounting bracket is a 11/16-16 1 1/2in long Torx and torques to 140ft-lbs!!
The problem is that when the necessary spacers are put in to line things up, there are only 3 threads engaging in the hole. Even my mind knows that 3 threads won't take 140ft-lbs. Waiting on call from Wilwood. Maybe they have a 2 or 2/14 in bolt?? Anybody solve this issue? (There are spacers for the spindle mounting.)
Hi,
McMaster doesn't carry that thread size bolt. Closest they have is 3/4-18 hex socket FH. Only 11/16-16 bolt I found are from GM and Wilwood (they had them custom-made for their kit). And neither GM nor Wilwood has any length options. Kit was assembled according to Wilwood directions, by me and a mechanic friend. From the pics I sent to Wilwood, they said "it looks like you're doing it right.". Other after-market brakes each have their own way of dealing with the bolt issue. Aerospace uses an adapter for 11/16 down to 7/16 bolt. Strange wants you to remove the spindles and send to them so they can helicoil it down to a 5/8 bolt. And those 2 manufacturers each have a 40-60 ft lb torque spec. Bottom line - after much more discussion with Wilwood, the brakes were returned to Wilwood. I bought the Aerospace kit. Installing this week.
I'm familiar with the problem....You won't find a longer 11/16 bolt. Nor have them made is difficult at best with the CS head.
The fix was to turn up a 9/16-18 insert. Open up the current thread on the mill to .750 (the dia of the material used) Then weld the insert just below the mount surface.
This will then convert the part to a more common (yet hard to find) 9/16 flush head cap screw. The next issue will be the plate itself. Arguably the seat angle will be the same and the bolt will work but it will be smaller than the existing hole...but being countersunk and tight against the barrel spacer...and having two more bolts to secure it....unless you really try to; you won't break anything. The other option is of course to replace the plate with the new smaller hole and countersunk flush spec for the new bolt.
You need me to make any of that happen for you; it's what we do here.
I'm familiar with the problem....You won't find a longer 11/16 bolt. Nor have them made is difficult at best with the CS head.
The fix was to turn up a 9/16-18 insert. Open up the current thread on the mill to .750 (the dia of the material used) Then weld the insert just below the mount surface.
This will then convert the part to a more common (yet hard to find) 9/16 flush head cap screw. The next issue will be the plate itself. Arguably the seat angle will be the same and the bolt will work but it will be smaller than the existing hole...but being countersunk and tight against the barrel spacer...and having two more bolts to secure it....unless you really try to; you won't break anything. The other option is of course to replace the plate with the new smaller hole and countersunk flush spec for the new bolt.
You need me to make any of that happen for you; it's what we do here.
Appreciate the info and the offer of help. But, I've returned the brakes to Wilwood and bought brakes from Aerospace Components. They approach the bolt problem differently (they supply an adapter from 11/16 down to 9/16). We'll put that together today or tomorrow and see what happens.
Appreciate the info and the offer of help. But, I've returned the brakes to Wilwood and bought brakes from Aerospace Components. They approach the bolt problem differently (they supply an adapter from 11/16 down to 9/16). We'll put that together today or tomorrow and see what happens.
walt z.
A way to accomplish it yes. I hadn't really considered a double side threaded insert but like a keensert it would do the job.
12-13-2021, 06:35 PM
Wilwood brakes on 74.
