I finally was able to source a new clamshell/steering column cover for my 1970 240z. Unfortunately, I can't seem to find the hardware for attaching the covers to each other and to the column. Can any of you tell me what thecorrect screw sizes and thread patterns are for this part? Also, if washers or lock nuts or used, can you please advise so that I can raid the local Ace hardware store tomorrow? As usual, thanks for all of your help.

Mike

I'll have to check one of my older "spares" for the quantity and sizes. But the main screws that hold the two halves together are standard plastic thread screws, kind of a sheet metal thread but with a blunt tip. Ace DOES have them as I've purchased some there.

However, there are TWO very important little screws which YOU'll have to dimension as they can be different from another set of Combination Switches.

There is a small threaded hole on the underside of the Ignition Key Switch housing as well as another on the underside of one of the Combination Switch halves. They're not BOTH the same size, but they're BOTH machine thread, small, short shank, and wide head. They're the ones that actually do the "locating" of the clamshell onto the steering column. The other screws above hold the two halves together.

Look on the underside of the clamshell and you'll note 5 or 6 of the larger holes, those are the plastic screw holes. (You'll probably need a long shank Phillips #2 screwdriver to access a couple of the screws.) You'll also see two smaller holes, one right in the center of the clamshell just about where the combination switch mount rides, and one in a recess below the opening for the Key Surround. Those are the smaller ones. When you get those, make sure you don't get them too long as they'll bottom out and not hold your clamshell firm.

If I get time later today, I need to clean a couple of electrical contacts on the Z's steering column, I'll take note of those screws. However, it may be as late as Sunday, the Roadster is in a show tomorrow and it needs a bath and polish today.

FWIW

E

Hmmm....sounds like this is going to be a bit more complicated than picking up a few screws at Ace and twisting a screwdriver. I really appreciate the fact that you took the time to provide such a detailed description. I think I'll print the thread and see if anyone at ACE can help locate the screws. However, if you do get a chance to actually identify the screw sizes and patterns it could help immensely. Thanks again E for your response and good luck at the show.

Mike

Okey-dokey. The front screw that goes into the combo sw. is a 12 mm thread length, counter-sunk #1 phillips head, with a 3 x .5 thread. The screw that goes into the ignition sw. is 11 mm thread length. pan head #2 philips head, with a 4 x .7 thread. It also uses an 11 mm dia flat washer and appropriate size lock washer.

George,

Thanks a million for the info...will see if Ace can provide the necessary screws tomorrow. Thanks again to Enrique as well.

Mike

George,

Do you happen to know the sizes and thread patterns of the hardware that connects the two halves together as well?

Mike

I have used #6 wood screws, 1 inch long as a good replacement. They are the correct diameter, ie they will not split the fragile plastic posts, but the thread pitch is more coarse than the stock screws. A sheet metal screw of the same size woukd be a better choice. Take the top half with you and find a screw size that seems to fit.

My 240 has been missing the locator screws as log as I've owned it, 13 years. I can't say the there has been any problems with them missing. They were gone when I bought the car.

Be sure not to over tighten - you will split the interior of the plastic screw holder. Get it snug and no more.

Thanks to all of you for the tips/info. Will take a kind and gentle approach to installing my clamshell.

Any pictures of the 6 screws? Will M4 X 0.7 work? Anyone?

On 15/7/2011 at 6:17 PM, george71z said:

Okey-dokey. The front screw that goes into the combo sw. is a 12 mm thread length, counter-sunk #1 phillips head, with a 3 x .5 thread. The screw that goes into the ignition sw. is 11 mm thread length. pan head #2 philips head, with a 4 x .7 thread. It also uses an 11 mm dia flat washer and appropriate size lock washer.

Whats the size of the screw that goes here? Im missing this one.