Hey guys I'm doing my Wilwood brakes 140-11275 and I'm about to modify the spindles and have a question for anybody that's done these brakes. When the 2 holes get drilled out the instructions say to countersink the holes .438 x 90*, how important is it too do that with a 90* countersink?? I only ask because I've only got a 82* bit and couldn't find any 90* bits anywhere in my area.

Thanks guys for the input. Oh and I attached a picture from the Wilwood instructions.

 

I had a hard time finding that stuff so I had a machine shop do the drilling/counter sinking. I trimmed the caliper ears off and cleaned them up. I had wilwood 6 pistons up front w 13 inch brakes and 4 piston 12 inch in the rear. I used the wilwood adjustable prop valve and the stock master. It stops crazy fast. You're gonna dig it.

 

I'm trying to wrap my brain around why it needs to be done?? It's flat on the spindle and the caliper brackets are also flat with no bolt shoulders or anything like that. Yea I can't wait to get these on they look badass and will go great with everything else I've put on my car

 

If the Wilwood bracket bolts on the outer side of the spindle I don't see why you would need the countersink. If the Wilwood goes on the inner side the bolt would also have to bolt on from the inner side and again the countersink would serve no purpose. ??? Maybe someone smarter than I can enlighten us.

 

Mine were not countersink. I have front #140-11275. They show a countersink in figure #1, but below, in figure#2, they show a regular flat hex bolt with a washer (#2 230-10025 Bolt, 3/8-24 x 1.25 Long, Hex Head & #3 240-10190 Washer, .391 I.D. x .625 O.D. x .063 Thick). I can confirm that I have flat hex screws with washer holding the bracket. A countersink on the hole would be useless as it is sandwiched between the spindle and bracket. Photo#1 further below shows that.

 

Yes exactly where my thoughts are! As you can see from the exploded diagram the caliper bracket bolts to the face of the spindle. I'm headed down to go cut the ears off the spindles and drill and tap them. I'll give the brackets and calipers a test fit

 

Okay perfect! I've got the same kit as you. Thank you very much sir!! I wonder if the instructions are an older revision and they never bothered to remove that from them??

 

Get in touch with Scott at Big Brake Upgrade. TGO name is BBU.COM . I see on his website that he offers a countersunk option for some of the brackets he sells. He should be able to explain the purpose.

I'm just guessing here, but I think it has something to do with the position of the hex head when the bracket bolt is fully tightened into the spindle. Sometimes the hex head of the bolt can be in such a position where one of the points of the hex head might interfere with the attachment of the caliper to the bracket. A countersunk bolt will prevent such a fitment issue, or it can relieve such an existing fitment issue. If such a fitment issue doesn't happen, then it wouldn't be necessary at all. But without a countersunk bolt, then I guess it's a roll of the dice whether or not the hex head of the bracket bolt will fit without creating the issue.

 

they are probably saying to countersink to get a good thread start, avoiding feather burrs, etc

 

Thanks for all the input guys!! Appreciate it. I just finished installing them. They went on without a hitch. And damn do they look good. I mocked up everything before finalizing and to make sure the calipers were centered on the rotor. Nothing interfered torqued it all down.

This was probably the easiest thing I've done to this car since I bought it like 17-18 years ago. Anybody else looking to upgrade to 12.19" front discs this is your sign.

 

Nice! You'll love them.

 

I had stock style slotted rotors and SSBC dual piston calipers and with the bearings in the rotors still and all the other hardware weighed everything together in the Wilwood box and it came out to an even 55.2 lbs! I really wish I weighed the new Wilwood stuff before installing it to see what the difference was