Brake Caliper Bolts

Trapper50cal

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First off, I've done some searching and it appears as though the bolts that hold the caliper to the knuckle on my 83 60 (Nov.82 actually) are 12M1.25 50mm with a head size of 17mm.

Is this correct?

Furthermore, the boss in the knuckle is somewhat stripped (had to remove a brakeline bracket to get them to tighten)

So....

Heli-coil or Time Sert?

Kit number # ???
Source???
 

Cruiserdrew

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It kind of depends on what you want to do. I had a stripped boss and tapped it to 1/2 inch fine thread (drilled first with the proper sized bit) and it worked perfectly. You will also need to run a 1/2 bit through the hole in the caliper ear. The whole job took maybe 15 minutes. Use lots of "Tap-eze" to make the threads in the iron knuckle housing. Mine came out so clean, they looked factory. To secure the caliper, you run a fine thread 1/2 bolt.
 

Trapper50cal

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i assume...

It kind of depends on what you want to do. I had a stripped boss and tapped it to 1/2 inch fine thread (drilled first with the proper sized bit) and it worked perfectly. You will also need to run a 1/2 bit through the hole in the caliper ear. The whole job took maybe 15 minutes. Use lots of "Tap-eze" to make the threads in the iron knuckle housing. Mine came out so clean, they looked factory. To secure the caliper, you run a fine thread 1/2 bolt.

I assume length is important as the bolt protrudes into the inside of the knuckle doesn't it?

btw, thanks for the data!
 
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Post 290 page 10 in my build thread shows that I did the same thing but didn't have to clearance the caliper holes. I used 1/2" x 20 (fine).
 

Cruiserdrew

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You still have to tap the threads, he is saying he didn't need to clearence the hole in the caliper ear. I did, but not by much.
 

Trapper50cal

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thats...

That's what I thought....either that or it was pretty sloppy in there.

Thanks guys

I would still like the data on the bolt in case I end up doing the heli
 

2mbb

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I used a helicoil for the original sized bolt. It's probably more expensive than taping for 1/2", unless you already have the correct sized helicoils and tap. But I wanted to stay with the same sized hardware so there would be no confusion in the future. I've had no problem so far with the helicoil approach.
 

Trapper50cal

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now...

I used a helicoil for the original sized bolt. It's probably more expensive than taping for 1/2", unless you already have the correct sized helicoils and tap. But I wanted to stay with the same sized hardware so there would be no confusion in the future. I've had no problem so far with the helicoil approach.

now if only i could find out if the size I posited is the right one....:p
 

2mbb

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I checked what I have in the garage--I have three sizes of metric helicoils: 8x1.25, 10x1.25 and 12x1.25. So it must be one of those. The part number is 90101-12060, if that helps. If you want I guess, I would guess it's the 10mm diameter. I think the 12mm is too large diameter to require drilling for a 1/2" tap. A 1/2"x20 tap uses a 29/64" drill bit which is 11.5mm. This seems smaller than the 12mm bolt hole, but larger than the 10mm.
 
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Trapper50cal

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thanks

I checked what I have in the garage--I have three sizes of metric helicoils: 8x1.25, 10x1.25 and 12x1.25. So it must be one of those. The part number is 90101-12060, if that helps. If you want I guess, I would guess it's the 10mm diameter. I think the 12mm is too large diameter to require drilling for a 1/2" tap. A 1/2"x20 tap uses a 29/64" drill bit which is 11.5mm. This seems smaller than the 12mm bolt hole, but larger than the 10mm.

thanks for looking
 

Bodean

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Could this re tap be done while the knuckle is still on the vehicle? I am donen with the rebuild and don't want to take it all apart again.

Thanks!
 

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