Shift knob

[rdefabri]

The threads on my shift knob have been stripped, and essentially the knob just rolls around on the actual shift lever.

Is there any way to remove the threads from the knob itself? Do I need to rethread the metal or is there another (or better way)?

[Marty Rogan]

You might want to try wrapping the shift lever with some nylon plumber's tape. It might just give you enough additional mass to stop it from spinnig around.

Marty

[doradox]

You could use a heli-coil. It's a thread insert for repairing stripped threads. You drill out the old threads, tap the hole for the heli-coil, install the insert. Autozone or most other auto parts stores have kits. I think you'll need an 8M 1.25. Use some loctite on the insert so it doesn't come out.

Steve

[Arne]

If it's a factory knob, be careful in re-threading it. There is no metal in the original wood knobs. The base is plated plastic.

[rdefabri]

Arne,

Which in the picture is the factory knob? I am certain I have the factory original, and it looks like the knob in the left of your pic.

Steve - thanks for the suggestion, that's what I (think) am looking for. My threads are almost completely gone - it looks smooth in the hole, which supports Arne's comment that this is plastic.

I'd just have to install the insert from what I can see...

[Arne]

Arne,

Which in the picture is the factory knob? I am certain I have the factory original, and it looks like the knob in the left of your pic.

Left is the original. Details on that discussion are in the thread linked below, starting mostly with post #42.

http://classiczcars.com/forums/showthread.php?t=22039

[doradox]

Arne,

Which in the picture is the factory knob? I am certain I have the factory original, and it looks like the knob in the left of your pic.

Steve - thanks for the suggestion, that's what I (think) am looking for. My threads are almost completely gone - it looks smooth in the hole, which supports Arne's comment that this is plastic.

I'd just have to install the insert from what I can see...

If it's plastic loctite might not be compatible and could soften the plastic. You could fill it with JB weld and redrill the JB and tap to the original size. Be careful when drilling, the bit can sometimes really get hold of the plastic and instead of nice thin shavings it can dig in and split the workpiece (your knob).

Steve

[rdefabri]

Right - as I can be all thumbs, that's a worry. I liked the idea of the insert - there must be something that's plastic that could work.

What if I took the helicoil and secured it with something like putty? I have the mighty putty stuff, it works great for bonding materials...just a thought.

[DeesZ]

I had a similar problem with the nylon threads on my favorite knob. There is an easy fix, similar to the helicoil idea..... I simply took a nut that threads on to the shift lever (8MM I think, someone please verify), rounded the flats with a file, and mounted it into the bottom of the knob with a dab of JB Weld. Provided a great fit, and it will never strip again under normal use.

Hint on getting the nut "round" enough to fit in the bottom... after filing it 'close' to what I wanted, I mounted it on a threaded rod (the perfect piece here is the threaded slave cylinder push rod - same thread as the shift lever), then inserted the other end of the rod into a drill and spun it against the file and then abrasive paper.... Worked like a charm with cast away parts and a drop of adhesive.... not even a trip to the store!

Note: I tried several other attempts at reviving the nylon threads with things like JB Weld, etc. Nothing would 'stick' to it well enough for a fix. Also, if you do drill into that area, be very aware of how far in you go or you'll hit the pattern button at the top.

Pictures attached for your reference.

Comparison of the 'factory' set-up (front left) and my 'fix' (on the right)

Close up of the 'fix'

Three factory knobs ('72, '71, '73) virtually the same in construction

Edited September 25, 2008 by DeesZ

[doradox]

I had a similar problem with the nylon threads on my favorite knob. There is an easy fix, similar to the helicoil idea..... I simply took a nut that threads on to the shift lever (8MM I think, someone please verify), rounded the flats with a file, and mounted it into the bottom of the knob with a dab of JB Weld. Provided a great fit, and it will never strip again under normal use.

Hint on getting the nut "round" enough to fit in the bottom... after filing it 'close' to what I wanted, I mounted it on a threaded rod (the perfect piece here is the threaded slave cylinder push rod - same thread as the shift lever), then inserted the other end of the rod into a drill and spun it against the file and then abrasive paper.... Worked like a charm with cast away parts and a drop of adhesive.... not even a trip to the store!

Pictures attached for your reference.

Comparison of the 'factory' set-up (front left) and my 'fix' (on the right)

[ATTACH]25673[/ATTACH]

Close up of the 'fix'

[ATTACH]25674[/ATTACH]

Three factory knobs ('72, '71, '73) virtually the same in construction

[ATTACH]25675[/ATTACH]

That's an option too. McMaster-Carr has a variety of inserts for that very method. mcmaster.com and search for thread insert. Rivet nuts (page 3213) can be used for the same purpose too. You still may need to open up the hole in the knob a little depending on how worn yours is.

[rdefabri]

Well either I am crazy or it's not 8mm - that's a knock on me, not anyone else as I am frustrated at the moment (I cracked my dash panel that has the vent controls by being completely stupid....grrrrr).

Now, I have a 5-speed. I'd assume it was from a 280Z, but IIRC you can fit a BW T5 transmission pretty easily. Would that mean that the threads on the shift lever are English rather than metric? The 8MM hex nut (both in 1.0 and 1.25 thread pitch) did NOT fit.

To make things worse, I do own a Datsun/Nissan 4-speed tranny from a 1972 240Z that I planned to put into my car. The 8MM hex nut didn't fit on that either.

So - it's either 9MM (do they even make 9MM nuts? I couldn't find them at HD) or it's English. I am inclined to think it's 9MM, but again, I couldn't find that size at HD.

I am in an angered mood, so I am not thinking properly - my apologies in advance if I am posting something obvious, but my judgment is clouded at the moment

[doradox]

9 mm isn't a standard size. 8mm -1.25 is very close to the same as a 5/16-18 and a 10mm is a little bigger than a 3/8(9.53 mm).

Steve