'33 Steering Box

[Stuart Giles]

One thing I found when working on A7 steering boxes is that replacing the felt bush at the top of the column with Bronze bush really improved the steering on the road.

I've also had the problem of the steering wheel going too far down the spline, I turned up a thin ring dimensioned on the inside to fit in the groove at the top of the column and dimensioned on the outside to be a snug fit in the steering wheel recess. When this ring  is cut in half, both bits can be inserted and you can tighten the wheel against this ring without it binding on the column.

Hi Stuart,
Two interesting suggestions there. I have a lathe, but am not an experienced turner. The wall thickness of a top bush would seem to be very thin, presumably it should also match the back of the steering column where the bush comes out of the outer column. Do you have more info on how you achieved this please?
Regarding the thin split ring, which sounds an excellent solution, any further suggestions as to method would be helpfulThanks you

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Yes, the bush is very thin, I just used an offcut of Bronze round bar, but you could probably use a bit of Aluminium alloy, there isn't a great deal of load on the bush; there will be a lot less friction on a metal bush than of a piece of felt. Basically drill out the piece of round in your lathe to near size, then use a boring tool to bore it to about 3 thou over the column diameter. Machine the outside of the bush to 1 thou oversize to the steering column tube bore. Warm the steering column tube with a heat gun, you should be able to drop in your bush. The steering column should be a nice running fit in the bush, if there's any stiffness, put a thin smear of blue on the column, rotate it in the bush and use a bearing scraper on the blued bits, Try the column again, if it still doesn't rotate really easily blue and scape it again. TBH, it's probably easier to do this job than write it up.

Re. the steering wheel issue, on all the columns I've seen there's a square section groove just below the spline on the steering column. I presume that the factory put it there to make the spline easier for them to broach. All I did was measure the diameter at the bottom of this groove, and then measure the width of the groove. Once you've done this, measure the diameter of the recess in your steering wheel. Put a piece of mild steel in your lathe chuck that's bigger than the diameter of the recess in your steering wheel. Machine the outside of the steel to a couple of thou smaller than the diameter of the steering wheel recess over a length of 3/8" or so. Now drill your piece of steel to just under the diameter of the steering column recess; a hole depth of about 7/16" would be good. With a boring tool, open out the hole to a few thou over the steering column recess diameter. Now using the boring tool again, bore a recess about 3/32" deep which ends up a few thou over the column diameter. It's important that the end of this recess is square as it needs to be a snug fit in the groove. You should now have a stepped hole in the steel. Now part off the piece of steel such that the length of the smaller diameter "step" is not less than the width of the steering column recess. It doesn't matter if it's a bit wider at this point because you can machine it back to size once parted it off, or even use a file if you're not confident of holding very short piece of material in the lathe. The whole piece of material should now be about 3/16" long or less. Now if you cut the ring in half with a hacksaw, such that you have 2 semi circles, the 2 halves can be slotted into the column groove. Hold these in place with one hand while you slide on the steering wheel down the spline and the two halves of the steel ring will be trapped by the steering wheel recess when you tighten the steering column nut. This should fix your problem permanently.