Brake Caliper Bolts (1 Viewer)

[Trapper50cal]

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]

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]

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!

 

[boots4]

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).

 

[Trapper50cal]

wow

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).

Wow

Nice rig boots!!!

So, you didn't have to tap it out? it (the 1/2"er) just threaded in?

 

[Cruiserdrew]

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.

 

[boots4]

Thanks.

Cruiserdrew is right, I did have to tap in the threads.

 

[Trapper50cal]

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]

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]

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....

 

[2mbb]

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.

 

[Trapper50cal]

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

 

[Trapper50cal]

Does...

Does anyone have an opinion on which is better?

Time Sert vs Heli-coil

(Ninja bump)

 

[Bodean]

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!

 

[Trapper50cal]

I ended up....

I ended up heli-coiling, with knuckle still on vehicle. got a little sideways but has held strong and is fine.

 

[Bodean]

Tapped it with a 1/2-20 fine thread tap and used a 1/2 -20 bolt. Worked great!

Later