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View Full Version : How To: Repair a Stripped or Damaged Shift Knob Stud



Nicholas R
11-02-2012, 05:58 PM
The stud that my shifter know screws onto has had boogered threads as long as I have had it (I bought the shifter assembly for my auto->manual conversion). It had gotten to the point where the knob would become loose and wobble on the stud itself. Certainly not a desired effect while driving. I tried using a die to fix the threads but it was clear that the stud was beyond saving. Shown here is how I fixed this problem. You can too!

Here are the things you'll need:
M8x1.25 tap and tap handle
17/64" drill bit
several smaller drill bits to work your way up to the 17/64"
blue locktite
power drill
2 M8x1.25 nuts
2 13mm wrenches
a magnet (to catch filings and drill chips)
a hacksaw
a file
M8 stud, ( I believe mine is either 40 or 42mm. The 46mm stud had an unthreaded section in the middle which was undesirable)

Here is a picture of the basics:
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Here is my cross threaded and damaged shifter stud:
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First thing is to cut it off, and use the file to flatten the surface:
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Next drill a hole in the center with a small drill bit, went down about 3/4 of an inch; about half the length of the stud:
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Work the hole larger incrementally with larger bits:
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Finally the hole is 17/64" and ready for the tap:
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Start tapping the hole slowly with the tap:
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Jam the 2 nuts on the stud, put blue locktite on the stud, and thread it down into the shifter:
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Remove the nuts from the stud and the new stud is in! (actually you can still use one of the studs as the shift knob adjustment nut):
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Put the shift knob back on and you're good to go!:
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Bitsyncmaster
11-02-2012, 07:00 PM
Good Job.

Dangermouse
11-03-2012, 01:11 PM
Looks good

Did you have any method of ensuring that the drilled hole was centered and vertical, or did you just eyeball it from both sides?

Nicholas R
11-04-2012, 02:14 AM
Looks good

Did you have any method of ensuring that the drilled hole was centered and vertical, or did you just eyeball it from both sides?

Before I drilled the hole, I did mark the center by creating a dimple in the center of the shaft just using a hammer and a drillbit. That way I knew I'd be in the center when I started with the small bit.

As far as going straight, honestly, I just kept a close eye on it and did the best I could. Put the car in gear so that part of shifter was pretty much vertical, and drilled slowly.

Mark D
11-05-2012, 09:22 AM
Nice tutorial! I hope I never have to use it :wiggle:

Nicholas R
11-05-2012, 12:44 PM
Nice tutorial! I hope I never have to use it :wiggle:

Indeed I hope you do not.

Yes, just as a disclaimer, I recommend this being a very last resort. Like I said, my shift knob wobbled on the shaft so I had no choice. The picture of the original stud really doesn't show how bad it was. If you can save your original, do what ever you can to.

Truth be told it was kind of a leap of faith drilling down. I wasn't actually sure if it was solid or quickly became hollow. If this didn't work my plan was to (TIG) weld and blend a new stud into place but it wouldn't have been quite as neat. I was certainly glad to find that it was solid for the entire depth that I wanted to drill.

Timebender
12-27-2017, 12:37 PM
Good tutorial and looks like I might have to do the same, as my after market shift T handle (came with the car), is now not finding a happy place either.

Nicholas R
12-28-2017, 06:14 PM
Sure thing, at this point I'd say go for it. Luckily if for some reason you damage it or it is not repairable, the part is now available from DPI in stainless for $60: http://www.deloreanindustries.com/3-gear-change-lever-stainless/

When I took this on DPI had not yet reproduced this part; it was repair or nothing :wrenchin:

Josh
12-28-2017, 09:23 PM
Sure thing, at this point I'd say go for it. Luckily if for some reason you damage it or it is not repairable, the part is now available from DPI in stainless for $60: http://www.deloreanindustries.com/3-gear-change-lever-stainless/

When I took this on DPI had not yet reproduced this part; it was repair or nothing :wrenchin:

For that price its not worth doing this.
not saying Nick didnt do a great job on this tutorial!