Just put on a lift and while putting everything back on the passenger side brake caliper wont bolt down. The top bolt tightens down, the bottom will go finger tight and if when put a wrench on it, it pops loose. We cleaned all the boots, bolt slides and bolt holes, cut down a new bolt to fit the thread pattern and size, and still the same thing. Any ideas what else i need to do to fix this?

 

Sounds like you stripped the threads on the mounting hole on the knuckle. You cut down a new bolt? Did you deburr it or anything before you reassembled?

 

Thread in the knuckle sound stripped. Helicoil.

 

Helicoil, or some other threaded insert, or replace the knuckle. Your choice.

 

Yeah it was past midnight so we found another bolt close and ran it through a die to cut the threads down.
Yeah we cleaned EVERYTHING before we put it all back together. Everything was so stuck we didn't want to have that go down again for the next time. I assumed it was stripped or or fouled up somehow, was just out of ideas to solve the problem besides a while new knuckle. How strong is the helicoil going to be?

 

Helicoil will be just fine. Finding one the right size though, that's another thing. May not be readily available locally depending on the size. You may have to order it. If you can't get it and you need it quickly, you might just have to get the knuckle and do it that way. A lot of work to do it that way though. Either way, it's going to suck. You have to drill the hole and tap it for the insert, then install with a special tool. You may not have ideal clearance to get it done, you won't know until you try, unless someone else here can chime in that has done it. Good luck.

 

Helicoil should be easy to find. Most local parts stores should carry them. I have had one in one of my caliper mounting holes for a year with no issues and have installed quite a few at work. It is pretty common. It is a pretty small bolt. Think it is m8-1.25.

 

I've used many helicoils and other inserts over the years. It isn't difficult, UNLESS it's in a spot that's hard to get to. Never had to put one on a knuckle. It may be easy as pie. I have had difficulty in the past finding certain sizes locally, if it's a common size, though it shouldn't be a problem.

 

How close? Did you try to install a SAE threaded fastener in a metric threaded bore, maybe that's the whole problem.

 

No we cut it down to a m8x1.25. I appreciate all the input, ill be going to the parts store tomorrow to get it and ill let ya know how it goes. Buddy says it should be easy, so we shall see

 

This worked just fine. Auto zone special. Make sure to use drill nits that get bigger and bigger to ream out the hole. That way it stays straight. I locktited it just for kicks. Take off the rotor a day drill and tap from that angle and not from the inside.

 

I grabbed the tap with some needle nosed lock vise pliers. The little piece to hold the tap is crappie. Make sure to oil the bit and tap to get the junk out. Blow it out when you're done.

Good luck all.

 

I have a stripped caliper hole in the knuckle as well. Almost all auto parts stores that have helicoils (or other brand name) will have them for M8/1.25, as its a really common size. I went down and got a pack from Advance the day it happened, but haven't put it in yet. However, I found out that it is common for them NOT to have the drill bit size you need. Had to go to the hardware store for that.

When the knuckles get a little rust on them, the caliper holes suffer quickly, the metal is pretty low quality, so those little threads factory tapped right into the knuckle don't stand a chance. If you have an XJ with rusty knuckles, and your caliper slide bolt holes are not stripped, you might consider hitting them with fluid-film (or whatever) to keep the threads alive in there.

 

Take a look at your knuckle... turns out my issue wasn't JUST the bolts..
I found a thread that showed how the knuckles can wear a little divot where the tabs on your brake pads slide on it. I looked at mine... they were worn into horrible grooves. I wire brushed them and filled them in with weld. Even from my crappie 90$ welder it worked OK. Then I filed them down with a hand file. They slide nice now.