Stripped Brake Rotor Threads

[fiasco]

My brake rotors have threaded inserts in them that the lug bolts screw into to secure the wheel to the hub of the rotor. Several months ago one of those inserts stripped and would no longer hold the bolt, so I've been driving for a while with just three bolts in the rear-driver-side wheel.

Today, another insert stripped, and while I may be dumb enough to drive with three bolts in one wheel, I'm not dumb enough to drive with two, so now I have to do something about it. Here are the visuals.

#1 is the one that stripped a while back. #2 stripped this morning.


Here's a close-up of #1. The insert is gone. Originally it was just stripped, but over the months it backed itself most of the way out, so today I went ahead and pulled it out the rest of the way.


Here's a closeup of #2. The insert is still in there, but it doesn't look like it's in good shape - I'm assuming all the crud is the shavings that resulted from the stripping process.


Here are #3 and #4. The inserts are still in, and they look fine.



In this pic, there are three things. A is the lug bolts I currently have. B is one of a set of bolts I took off a parts car that was a more recent year than mine, but had the same wheels. I took them assuming they would be the same as what I already had, and would be good as backups/replacement, but obviously they are a different size, different length, and different thread. C is the insert I took from #1 above.


My rotors are in good shape and have plenty of thickness on them.

So now to the questions.
1. Am I going to have to replace the rotor with the damaged inserts, or could I just put in new inserts?
2. If I put in new inserts, am I going to have to rethread the hub to accept the inserts, or should the old threads work?
3. If I can't put in new inserts, and I have to buy new rear rotors, am I going to have to thread the new rotors to accept my lug bolts anyway?
4. If I have to replace the rotors, can I do that without opening up the brake system and having to bleed it when I put it all back together?

I've never done inserts like this myself and am not sure what is involved, especially if I have to cut new threads in the hub to accept new inserts. I've replaced brake pads, but never rotors, and don't know if there are tricks I should know or snags I should look out for. I'd appreciate any input, advice or help anyone has to offer.

Thanks,
-- se

[fiasco]

Ok - got into it a little farther. Clearly the threads are not on the rotor, they're on the hub behind the rotor. So I guess I need to get the rotor off and see if I can replace the inserts on the hub, or if I'll have to cut new threads, or replace the hub.

Still - any insights will be appreciated.

-- se

[fiasco]

Ok - still learning stuff.

Now that I'm down to the hub it looks like...

#1 originally had an insert which went bad and I removed today
#4 still has an insert in it, and it looks good.
#2 has no insert and the threads in the hub are stripped.
#3 has no insert and the threads in the hub do hold the bolt, but look pretty sketchy.


I have one of these

which I have never used, but I watched someone else use it to put inserts in the block of my '76 after we stripped the threads for the head bolts. So I have a general sense of how they are used. This one is obviously not the right size for my current need, but I think that, other than replacing the hub, this is where I'm headed.

So a couple questions.
What are my chances with #1 above? Should I try just putting in a new insert? Should I try to recut the threads without drilling it out again and then put in a new insert?

Thanks!
-- se

[spider2081]

You could post the need for a good used hub in the "parts wanted" section of this site.It would not surprise me if there are more than one available. That would be a much better fix.

[fiasco]

That's the downside of a daily driver. I need to fix it by Sunday night so I can get to work Monday morning.

[joelbert2k]

Looks like you don't have a lot of choices. There are enough Spider owners near you that you should be able to find a hub. Mark is not that far away from you and I'd bet he has one. If that doesn't pan out then the Helicoil is probably your only other option.

Joel

[fiasco]

What's involved in replacing a hub? Is that a job I'm going to be able to do, or will I be getting deep into the axle assembly?

-- se

[ORFORD2004]

More work for shure if you replace the hub.
Put a lot of WD40 when you use the helicoil kit and you should be ok.

[toyfiats]

What's involved in replacing a hub? Is that a job I'm going to be able to do, or will I be getting deep into the axle assembly?

-- se

The hub is integral to the axle, so if you want to replace it you'll have to replace the entire axle on that side (not the entire differential, but the axle assembly including bearing). Relatively easy to do if you have a spare axle, not so much if you don't. Better to repair in that case, but I will defer to a professional mechanic as to the wisdom of doing so on your specific issue.

[fiasco]

I can't find an M12 x 1.25 thread repair kit anywhere local. Plenty to order, but none to buy over the counter. I've checked all the hardware and auto parts stores I can find for Heli-Coil, Perma-Coil, Fix-A-Thred, Time-Sert, Coil-Sert and Big-Sert. Some places carry either Heli-Coil (Oreilly's and OSH) or Fix-A-Thred (AutoZone), but no one has 12X1.25.

If any SoCalers happen to have one that I could borrow, I'd really appreciate it, and I'll order inserts to replace whatever I use from your stock.

Not sure whether I'm more irritated by the possibility of spending Father's Day working on the #!$%!@ car, or not being able to find the stupid tool and spend Father's Day working on the #!$%!@ car, cause that means having to go begging for rides to and from work on Monday.

-- se

[So Cal Mark]

Tools R Us on Central has them. It's important to make sure the inserts are in straight, or the lug bolts will go in crooked. I've got lots of used axles if you decide to go that route. Sorry I didn't reply earlier, but we've been tied up with a funeral most of the day

[majicwrench]

A new-used axle from Mark would sure be the wise choice. If you do the insert, try NOT to drill and tap again, that will just remove metal. But then, unless you know what insert were used initially, they may be a diff external thread. I would use some locknut on the inserts as well, tis getting scary back there.
Get another axle.

OH and don't be getting things so tight. Lot of guys think tighter is better, that ain't the case. Got a torque wrench?? Use it and believe it when it clicks.
Keith