Retapping brake caliper mount threads on truck? (2 Viewers)

[heydanno]

Stripped threads for the front brake caliper mounts is a common issue on our trucks (see: here here here here here here). It has happened to me, and I'm looking for guidance that I haven't been able to find in any other threads. I'm pretty much settled on the Helicoil approach. My question is: has anyone successfully done this job with the knuckle still mounted on the truck? How about with the rotor still mounted? I'm mostly wondering about the likelihood of drilling a straight hole for the helicoil and not run into the rotor, etc. Others have alluded to doing the job in 15 minutes, but I guess I'm just not that confident in my ability to drill straight enough for tapping without it being on a drill press. Any advice appreciated.

As an aside, my little trick in an emergency is to get a slightly longer 12mm bolt than the standard 38mm. 40mm is about perfect. I found that the extra length was sufficient to bite on the few remaining good, non-stripped threads at the very end. It won't last long, but it could get you home in a pinch.

Thanks!

 

[snowboardonsnow]

I wouldn't trust helicoil on my brakes. I just had this happen to me, I simply drilled and tapped it with a bigger bolt. 9/16ths? maybe I don't remember. Drill out the caliper bigger and don't forget to drill the bracket that holds the dust shield as well. The drill will bite like a mother fxxxer because its just a hair bigger, I used a 1/2 right angle drill because my 1/2 drill has been known to break arms

BTW I still havnt found a decide tap and die set for a decent price so just run down to the auto parts store and rent one (its free) and yes I did all this with everything still on the vehicle minus the rotor, take that off.

 

[Randy88FJ62]

Three out of the four caliper holes on my knuckles are drilled to accept 1/2-20 helicoils. I have been running this setup for over two years without issue. I was able to drill them from the back and tap them in place without removing the tires or any other parts.

If you are worried about the bolts coming out you can drill lockwire holes and wire them together like the original FJ40 brakes came from the factory. It's very effective in aerospace applications.

If you are leery of helicoils and want to go the extra mile, look into keenserts. We use them to repair cast aluminum housings where I work. Approved for FAA use, we use them for flight critical repairs.

 

[ntsqd]

A Heli-Coil is stronger than the original threads when the original threads were in a lower strength material. With a Heli-Coil you get the advantage of more surface area engaged with the base part (like when using a larger bolt) without needing to create unique calipers (by drilling the ears larger) and non-std bolts. Those bolt holes in the caliper need to be fairly precise because they also locate the caliper correctly over the rotor. Getting a rebuild with drilled holes would really piss me off.

A Keen-sert is even better than a Heli-Coil, but either will do this job.

If you let it the drill will follow the existing hole. Tapping is where you're more likely to go astray.

 

[FJ60Cam]

I went the helicoil route and don't remember encountering any difficulties. You shouldn't have any problems drilling it straight. The old hole will line up the bit.

You shouldn't have to disassemble much to drill it out. Doubt you'll hit the rotor either. Even if you do bump into it, it probably won't do any damage.

 

[heydanno]

Great, thanks for the tips guys. I like the lockwire approach, too. I guess I'll give it a go with an original-size Helicoil and see what happens.

 

[Randy88FJ62]

Great, thanks for the tips guys. I like the lockwire approach, too. I guess I'll give it a go with an original-size Helicoil and see what happens.

I remember looking for 12mm helicoil kits and they were really expensive compared to 1/2" kits. I ended up going 1/2" due to price but it depends if you want to keep the truck "original."

 

[Dynosoar]

I have used Timeserts inserts and they are stronger than taping the parent material. Expensive but very good.

Dyno

 

[Spike Strip]

Randy, did you use loctite on the helicoil?

 

[Blue77FJ40]

Time-serts are far stronger than helicoil. Expensive, but worth it. Time-serts won't come out by design. Good luck.

 

[Trapper50cal]

HeliCoiled my first 60's caliper mount bolts...never ever experienced any problems, and I went back to retighten them and they hadn't budged.

 

[Randy88FJ62]

Randy, did you use loctite on the helicoil?

Now that I think about it, yes I did. I used loctite red, whichever one it is that is for "permamnent."

 

[Spike Strip]

OK, thanks - I'm gonna have to do this eventually.

 

[Randy88FJ62]

OK, thanks - I'm gonna have to do this eventually.

Ross has the proper tap, drill, and reamer. All you would need is to buy a bag of extra helicoils for a couple of bucks from McMaster or other store.

 

[heydanno]

I finally got around to doing this job the day after Thanksgiving. I went the Helicoil route to keep the OEM thread size and the job was easier than I expected. The things I found helpful were to remove the shock and also the sway bar end link. This gave the clearance necessary to fit the right angle drill in there. Drilling was FAST--boy did that bit bite. I left the rotor on and installed and it was a non-issue. Tapping was also straightforward. The Helicoil tap is a tiny bit larger than your typical 1/4-1/2 T-handle tap wrench opening, so I had to pry the arms open a bit to get the tap to fit in the wrench.

Thanks for all the help. I feel much more confident in my brakes now.

 

[TobyB]

The only problem I have had with helicoils is that they occasionally come out with the bolt.

Timeserts have never done that to me.

Both are good repairs, as long as they go in straight.
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