Internal thread repair help

[woody367]

Sorry if this is not in the correct section. I have several internal thread hole stripped in my aluminum transmission to mout the oil pan. I am looking for suggestion on how to repair them. I have had nothing but trouble with Heli Coils and will not use them. I was looking at TIME-SERTs while I like the design and the inserts are cheap the kit with the tools needed is like $80 just to use 1X. I need to repair like 8- 5/16" hole. Any sugestions without spending $100?

 

[vssjim]

Re: Internal tread repair help

The only inserts that don't require special tools and are very available are EZ Lock inserts.

 

[Copymutt]

Re: Internal tread repair help

If you can’t chase the existing threads w/ a tap to clean them up, step up a size. Redrill w/ the appropriate size bit and retap. Aluminum will clog the tap, so go slow & lots of fluid.

 

[SeisMec]

Re: Internal tread repair help

I have had nothing but trouble with Heli Coils and will not use them.

The few times I've used Heli Coils, things have gone well. All of them went into mild steel. Are they a problem in aluminum? What sorts of problems?

Not trying to start an argument. Just looking for info to avoid future problems for myself.

 

[Kevin54]

Re: Internal tread repair help

I don't know why you would have problems with Heli-coils unless you never busted the tang off after inserting them. And if that's the case, you'll always have a problem if the bolt bottoms out on the tang. Because when you go to back it out, you'll wreck the bolt and the Heli-coil. I've used Heli-coils for 40 years and had to fix the screw up of the line workers that messed up theirs.

 

[matt_i]

Re: Internal tread repair help

If you can’t chase the existing threads w/ a tap to clean them up, step up a size. Redrill w/ the appropriate size bit and retap. Aluminum will clog the tap, so go slow & lots of fluid.

That's what I would recommend, a 3/8-16 into parent metal for lowest cost -s imply get a larger sized fastener(s). The 5/16" dia tap drill will just core out the existing threads.

 

[kbuhagiar]

Re: Internal tread repair help

Sorry if this is not in the correct section. I have several internal thread hole stripped in my aluminum transmission to mout the oil pan. I am looking for suggestion on how to repair them. I have had nothing but trouble with Heli Coils and will not use them. I was looking at TIME-SERTs while I like the design and the inserts are cheap the kit with the tools needed is like $80 just to use 1X. I need to repair like 8- 5/16" hole. Any sugestions without spending $100?

What kind of vehicle & transmission are we talking about? Is the transmission in the vehicle, or out? Is it known to be in good operating condition? One or two stripped threads I can understand, but several? This may be indicative of other potential problems. If you are unfamiliar with the history of this unit I would be very wary, as the same person that caused these stripped bolt holes could have wreaked havoc on the internal components also.

Of course, if the transmission is known to be in good shape otherwise, then by all means proceed. If a 5/16"-18 thread chaser tap won't sufficiently clean thing up, tapping up to a 3/8"-16 sounds like a good plan.

In any case, good luck!

 

[chappys4life]

Re: Internal tread repair help

Have used heli coils over the years and always have had good luck.

 

[nadogail]

Re: Internal tread repair help

Years ago, I worked in an automotive machine shop and the shop routinely installed Heli-Coils for customers.

 

[Packard V8]

Re: Internal tread repair help

Sorry to pile on, but agree with the above. If you've had "nothing but trouble" with heli-coils, it's your technique, not the technology. Engine shops successfully use helicoils to repair your problem areas every day. Get someone who does it professionally to show you how.

jack vines

 

[Fialaja]

Re: Internal tread repair help

+1 for heli coils

 

[rlitman]

Re: Internal tread repair help

Timeserts, Keenserts and the like have their uses. Solid inserts are considered superior for sealing (as in spark plug holes), and many can have locks that prevent backing out. But the OP's use case screams helicoil to me. Cheap, simple, and reliable.

 

[DGersic]

Re: Internal tread repair help

I had three of four holes wallowed out for the inspection cover on a 709R4. Wood screws are not the right fastener here. I drilled out and helicoiled all four, with new bolts. Worked fine for me.

Two of four carbuerator bolt holes were stripped out because previous owner used too short bolts. Those also got drilled and helicoils.

Those are all in aluminum.

Then one of the bolts holding the intake manifold to the head stripped out on me. That also got a helicoil, though drilling and tapping that hole with the head on the engine is a bit more of a pucker job than the others were.



Sent from my iPad using The Garage Journal mobile app

 

[Indexmill]

Re: Internal tread repair help

Heli-coil inserts were designed for aluminum; to make the hole stand up to repeated screwings. Of course, they are also great for exectly the problem you have. But for an oil pan on a who cares transmission, just drill them out and tap to 3/8".

 

[MikeF2316]

Re: Internal tread repair help

I, too, have never had any problem with helicoils, but I've probably only done about a dozen in my life. I try to not need to do them...

 

[ChevyEFI]

Re: Internal tread repair help

Use a drill guide to get the tap hole straight. There are adhesives to help heli-coils stay, and that is what I would use for that repair.

 

[treeview]

Re: Internal tread repair help

Loc Tite makes a great repair

I've used it a few times with 100% success.

 

[ttpete]

Re: Internal tread repair help

With heli-coils, the end of the insert wire has to be within the first full thread of the hole. This anchors the insert and keeps it from backing out.