To tap or not

[Bob #32271]

I just replaced the transmission mount on my 69 4 speed. I messed up the threads on 1 of the holes going into the trans. Is tapping the hole the only way to fix this. The metal of the trans seems very soft, so I don't want to make things worse.

Thanks

[Dale Pearman]

Re: To tap or not

Get yourself a heli-coil kit at most parts stores. These repair kits work GREAT in aluminum.

Varooom!


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[Chuck S.]

Re: To tap or not

Bob,

Don't know how bad you "messed up" your threads, but I believe I would buy myself a tap and attempt to "chase" the threads first, i. e. run the tap in the original threads cutting off any galling or crossing threads. You will be surprised at what can be recovered. Just be sure your tap gets started square with the mounting surface (that's the hard part), and proceed gingerly. If it feels like you are getting enough resistance to cut new threads, better take a close look. If you're convinced the tap is square, proceed; if not perfectly square, back 'er out, and make another start. With a new tap, it won't take a lot of effort to cut new threads in aluminum.

If you find they are too far gone, or you mess'em up further, you can always default to the heli-coil.

Chuck Sangerhausen

[grr]

Re: To tap or not

Bob, Been there. First evaluate, can you retap. If so clean out the excess metal in the cross threaded bore. Vacuum or blow out with compressed air.Now if you do feel you can tap it out remember what type of tap do you need, a starter,finisher or what. You may need a set. Call a local cylcinder head shop and explain how much thread is left etc.And see what they tell you.they mess with threaded problems daily. The two previous posts gave excellent advice.Use your good judgement on this as it is easy to fix, just take you time.grr#33570