Tips on re-threading steering shaft?

[phenryiv1]

So this happened...



I took the car for an alignment after camber plates and an e36 rack swap install. I got it back and the turn signal cancel was malfunctioning worse now than before the alignment so I pulled the wheel to check the cancel nub. The nut (brand new) had compromised threads and the shaft itself was a mess. There were extra washers between the hub and the nut.

Upon examination of the old Momo hub versus the new one I can see that the hub has an issue with the casting of the cancel nub. I don't know if this caused the turn signal issues but my stalk will cancel from the right but not the left.



Alignment shop swears that they did not pull the wheel but I know damn well that when I installed the Momo wheel and the new steering nut that I used one washer- not 3. I found 2 washers in addition to the OEM one that I installed.

Looks like I will be re-threading the shaft from an M14x1.5 to an M12x1.5. Any tips before I undertake it?

Fun.

[LJ851]

Get another shaft. The steering column is not a place for less than 100% repairs.

[phenryiv1]

The shaft is cheap- $41. I will be replacing it. In the meantime I need the car to drive. Not my daily but it has to go to the body shop Wednesday. I had to wait 5 weeks for the appointment and if I miss it I don't have another month to wait for my punch list to be finished.

Several other manufacturers (MB, Porsche) use an M12x1.5 nut for the steering shaft so it isn't structurally unsound but I do want to properly repair it ASAP. In the meantime I need the car to move.

[LJ851]

Ok, how about rethreading to 1/2 inch (approx 13mm) instead of taking it down 2mm?

[phenryiv1]

Ok, how about rethreading to 1/2 inch (approx 13mm) instead of taking it down 2mm?

Good point...

I figured that the threading constituted ~1mm (.5 per side of the shaft itself) of the total diameter and I'd need another 1mm (again, .5 per side) to play with but I can always toss calipers on it before I just go cranking with the die.

If you look at the top picture the threading is GONE at the bottom end. That may already be a total diameter of 1/2" / 13mm so a 1/2" tap may be too large.

I'll just buy nuts in multiple sizes and see what fits.

[LJ851]

My 12X1.5 threading die measures 10mm ID so that would point to threads being 1mm tall radially so if your 14X1.5 threads are completely removed you could be around 12mm diameter currently. Either way, a quick measure of the shaft should point you towards the right die and nut.

[AndrewBird]

An M14x1.5 thread has a minor diameter of 12.344 mm.

You aren't going to be able to just thread an M12 die onto a shaft that isn't 12mm. It won't fit, and if you are able to force it, you will likely end up with fucked up threads in the end. If you don't have a lathe to turn it down, you might get away with spinning the shaft in a drill and using a grinder to get it close as a temporary solution.

[phenryiv1]

An M14x1.5 thread has a minor diameter of 12.344 mm.

You aren't going to be able to just thread an M12 die onto a shaft that isn't 12mm. It won't fit, and if you are able to force it, you will likely end up with fucked up threads in the end. If you don't have a lathe to turn it down, you might get away with spinning the shaft in a drill and using a grinder to get it close as a temporary solution.

Good point. I am not going to pull the shafts to put it in a lathe. If I pull the shafts I'll spend the $42 on a new one.

For now I was able to get the nuts secure enough to be hand tight with a socket wrench so it should be safe to drive to the body shop wednesday.

I will be ordering a new shafts and the securing parts.

[jeffnhiscars]

It's the splines that insure that the steering wheel turns the column whichis your major safety concern and they look ok. all the nut does is keep the wheel from being pulled off the spline (not a minor function) so if you are determined to drive it without replacing the shaft I'd drill a hole in the shaft and put a large cotter pin through it. Any gap between the top of the nut and the pin I'd fill with shims....until you get a new shaft.

I suspect this is more secure that a half ass re thread

[///M42 sport]

if you replace the shaft, mind posting some pics of the process? THanks.

[Northern]

I wouldn't be concerned with rethreading it to M12X* unless you tend to haul yourself forward via the wheel for some reason.

That said, "Better safe than sorry" is a good motto.

[SmokeE30]

if you replace the shaft, mind posting some pics of the process? THanks.

Only thing that's tricky is the snap ring at the top, I use a 18mm 1/2" deep socket and a hammer to get it, on an airbag car that is

[phenryiv1]

if you replace the shaft, mind posting some pics of the process? THanks.

Now or in the near future I will be replacing it and I will document the process.

[AndrewBird]

You could slice the threads off then drill and tap a hole down the center of the shaft and use a bolt instead of a nut. E34s are like this.

[phenryiv1]

You could slice the threads off then drill and tap a hole down the center of the shaft and use a bolt instead of a nut. E34s are like this.

I considered that but getting the hole drilled perfectly to allow for the tap to be square would be nearly impossible.