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View Full Version : TR2/3/3A Rebuilt steering has creative fix for NA worm bearing!



karls59tr
01-30-2017, 02:40 PM
I tore down two spare steering boxes to gain experience in the process before taking the one in my car out and tackling it. One of the boxes appears to have been rebuilt at some point. The worm gear looks in excellent shape and has the standard type caged bearing for the front. The bottom bearing was replaced with a tapered roller bearing(skf 10302 J2). This bearing is 1/2" long so a 1/8" thick aluminum plate,the same size as the cover plate,was fabricated to go between the cover plate and the box instead of shims! Actually there was one very thin bronze shim.
Also seeing as how the bearing was not a precise fit in the box opening a very thin shim was fitted around the outside of the bearing shell and then segments of this shim were folded over to keep it in place. The person who did this had to use his ingenuity seeing as how he did not have access to a new original bearing and kudos to him.
The rocker shaft looks in good shape as well as the peg so I should be able to reuse those.
The bushing appears newish and unscored so I might just leave that as well. If I clean up the rocker shaft and bushing and fit them together there should be no side to side movement ,correct? One other thing...the bushing seems to have been pressed in about 1/8' farther than it should have been. You can see the protrusion when looking into the hole between the worm and the rocker shaft. Is that an issue?
The bushing itself does not have that spiral oil passage on it that I believe the original has. Is this a concern?
CJD...I read your last thread on parts to buy for the rebuild. When you say "upper worm shaft seal" do you mean a bronze shim?

Any advice or comments most appreciated.:eagerness:

CJD
01-31-2017, 03:29 AM
Wow, that is quite the mod! Reading your explanation, I suppose the roller bearing set-up should work. The bearing itself is likely much more stout than the original little ball bearings. It does concern me when you say the bearing is held in by shims, though. If shimmed well over a large area of the race, it should hold. But, if it is just jammed in it could loosen with time. Remember the steering gear takes a lot of impacts from hitting pot holes and the like. Also make sure that the roller is perfectly centered, so it does not place a bending load on the worm gear and shaft.

It is important that the worm gear has no movement in any direction. In the stock configuration you want to adjust the shim pack under the end cover until there is just barely a preload on the 2 ball bearings. The bearings then hold the worm from side to side or up and down movement (in and out, depending on your perspective). Too much preload and you start to feel a bind. Too little and the worm will have play. The goal is zero play in any direction without binding. Setting the worm bearing preload is always your first step.

When working on steering it's important to remember that all play is cumulative. If the worm can move, then that play will be additive to the play at the peg in the worm...which will be additive to the play in the rocker shaft bushing. So, starting with the worm, adjust the 2 bearings to eliminate all play without binding the worm.

WHen happy with the worm bearing preload, next work on adjusting the peg clearance in the worm with the adjusting nut on the side cover. This is a balanciing act. The worm is machined to have a tighter clearance at dead center than elsewhere along the worm. So at dead center is where you make your peg adjustment. If the peg and worm are still serviceable, you want just a noticeable drag as the peg passes center, but the drag immediately reduces as you turn the worm away from the center steering position. The drag is no more than you can overcome by turning the shaft by hand through the center position with no leverage. Once you have the steering wheel installed that amount of drag will be barely noticeable because of the increased leverage of the wheel. If you cannot turn the shaft by hand without the wheel installed, then that is too much bind at center.

The bad news is that the steering box spends most of it's time in the center position as you drive...so the center position tends to wear the most. A sign of wear is when you get more bind in the peg just off center in each direction than you do at center. The center position feels like it sticks as it passes through center. Another explanation of the feel is that it seems there are 2 center spots instead of 1. If that is the case, then the worm is worn. Any attempt to adjust a worn worm gear just leads to frustration.

You are correct...the tighter the rocker shaft is in the bushing without binding the better for your steering. I would not worry about not having an oil groove. The oil will reach the entire bushing. To much play would be if you can feel enough movement in the bushing to cause a click when you move it back and forth. It should have no more than a barely detectable amount of movement.

I think the seal I must have mentioned is the one at the top of the split column boxes. It's less of a seal and more of a nylon bushing, if I remember right. It's been a while since I rebuilt the sp;it column box. You do have a real lip type seal where the rocker shaft exits the box. That one is important to keep the oil in the box without leaking. The one at the top doesn't see a lot of action...unless you can pull some "G's" on acceleration !?!

Anyway, I hope this addresses your concerns. If you are worried at all about the modified bearing, I am sure you can find an original bearing...so long as the end of the worm was not machined to accept the roller bearing.

karls59tr
01-31-2017, 01:51 PM
Wow, that is quite the mod! Reading your explanation, I suppose the roller bearing set-up should work. The bearing itself is likely much more stout than the original little ball bearings. It does concern me when you say the bearing is held in by shims, though. If shimmed well over a large area of the race, it should hold. But, if it is just jammed in it could loosen with time. Remember the steering gear takes a lot of impacts from hitting pot holes and the like. Also make sure that the roller is perfectly centered, so it does not place a bending load on the worm gear and shaft.

It is important that the worm gear has no movement in any direction. In the stock configuration you want to adjust the shim pack under the end cover until there is just barely a preload on the 2 ball bearings. The bearings then hold the worm from side to side or up and down movement (in and out, depending on your perspective). Too much preload and you start to feel a bind. Too little and the worm will have play. The goal is zero play in any direction without binding. Setting the worm bearing preload is always your first step.

When working on steering it's important to remember that all play is cumulative. If the worm can move, then that play will be additive to the play at the peg in the worm...which will be additive to the play in the rocker shaft bushing. So, starting with the worm, adjust the 2 bearings to eliminate all play without binding the worm.

WHen happy with the worm bearing preload, next work on adjusting the peg clearance in the worm with the adjusting nut on the side cover. This is a balanciing act. The worm is machined to have a tighter clearance at dead center than elsewhere along the worm. So at dead center is where you make your peg adjustment. If the peg and worm are still serviceable, you want just a noticeable drag as the peg passes center, but the drag immediately reduces as you turn the worm away from the center steering position. The drag is no more than you can overcome by turning the shaft by hand through the center position with no leverage. Once you have the steering wheel installed that amount of drag will be barely noticeable because of the increased leverage of the wheel. If you cannot turn the shaft by hand without the wheel installed, then that is too much bind at center.

The bad news is that the steering box spends most of it's time in the center position as you drive...so the center position tends to wear the most. A sign of wear is when you get more bind in the peg just off center in each direction than you do at center. The center position feels like it sticks as it passes through center. Another explanation of the feel is that it seems there are 2 center spots instead of 1. If that is the case, then the worm is worn. Any attempt to adjust a worn worm gear just leads to frustration.

You are correct...the tighter the rocker shaft is in the bushing without binding the better for your steering. I would not worry about not having an oil groove. The oil will reach the entire bushing. To much play would be if you can feel enough movement in the bushing to cause a click when you move it back and forth. It should have no more than a barely detectable amount of movement.

I think the seal I must have mentioned is the one at the top of the split column boxes. It's less of a seal and more of a nylon bushing, if I remember right. It's been a while since I rebuilt the sp;it column box. You do have a real lip type seal where the rocker shaft exits the box. That one is important to keep the oil in the box without leaking. The one at the top doesn't see a lot of action...unless you can pull some "G's" on acceleration !?!

Anyway, I hope this addresses your concerns. If you are worried at all about the modified bearing, I am sure you can find an original bearing...so long as the end of the worm was not machined to accept the roller bearing.

Thanks for all the info John. In regard to the bearing shim...it is about 5/16" high and goes completely around the bearing race. The machinist or McGuyver then folded portions of the shim top over to hold it in place.Looks like it will do the trick. I'm going to reassemble the unit and see if I can get the end play correct. I haven't pulled the steering box out of my car yet but I'm certain the worm in that one is shot. However there may be a useable bearing in there.
When it come to removing the worm gear from it's shaft I understand you fit a pipe over the shaft and hammer the the pipe so it drives thru the "swaged" or peened end then the worm gear can be removed. Then there is still enough metal to re-peen. Have I got that right? Also ...wouldn't banging the pipe end damage the bearing race on the worm gear??

CJD
01-31-2017, 03:20 PM
You got me on removing the worm from the shaft. I see there is an NOS worm for sale on Ebay at the moment, but the seller wants it's weight in gold for it.

I am like you in thinking that there is a high chance of damaging the shaft in removing the gear. It may be easier and cheaper to simply find a replacement shaft with a decent worm on it. But it sounds like there's a chance your's may still be good.

Geo Hahn
01-31-2017, 06:58 PM
That 'barn find, NOS' looks to simply be the replacement that Moss sells (still has the Moss packaging and p/n).

Some more info here - or perhaps you have seen it already:

https://www.mossmotors.com/graphics/products/PDF/667-375.pdf