Tompkins steering box upgrade

[JohnW]

Hello it's me asking dumb questions yet again,
The steering on my TC is very sloppy and is feels stiff to turn. I know these cars are known for heavy steering but this is more stiff than heavy. I have adjusted all the track rods, changed one wheel bearing and one king pin so there is no undue play anywhere in the front hubs however there is about 3" of play at the steering wheel.
So being used to adjusting steering boxes ( I also have an air cooled beetle) I though a quick twiddle and away I go .........wrong! When I turn the adjuster to take out the play all that happens is that the steering gets even tighter. So time to take off the steering box cover to have a look. What I can see looks very wrong to me, in the middle of the sector shaft is a sunken ball bearing which rubs against the middle of the adjuster stopping the thrust races even touching their mating surfaces. I have had a look Brown and Gammons site which has Tomkins fitting instructions and there is no mention of the ball bearing.
I think if I take out the ball and remove the burrs it has made I will be able to adjust the box as it should be.
Has anyone got any experience of this ?
Once again thank you for any help

[Steve Simmons]

Sounds like a previous owner bodge to me. All I can say is to be careful, as steering failures are not unheard of.

FTFU also has this info on additional things to check for safety:
https://fromtheframeup.com/uploads/TT_S ... _Alert.pdf

PS... there are no stupid questions.

[JohnW]

I will add this one to the list of poor repairs that have been done to this car in the past. To be fair to the previous owner he confessed that he didn't know one end of a spanner from the other and always employed a mobile mechanic (?) to do his repairs for him.
Thank you for the help again Steve

Just out of interest has anyone started a thread on things they have found have been repaired poorly or just wrong on their car?

[timberstone]

Agreed that this sounds like a really botched job previously, and thorough investigation needs to be done in order to be any safe for yourself and everyone else. The Bishop Cam is the "Achilles Heel" of the MGTA, TB and TC, which is one reason why it was eliminated for the MGTD, TF, A and B series.

In addition to the technical article by Doug Pelton about the Tompkins Kit Upgrade to the Bishop Cam steering box of the MGTC there are many websites and articles about our car's steering problems.

Please see the thread on this forum about your problem: Alternative Steering Box in TC's
viewtopic.php?f=2&t=311

A comprehensive discussion about steering for the MGTC:
http://www.mg-tabc.org/library/Buell-TC ... 3rd-ed.pdf

and again this forum:
viewtopic.php?t=787

viewtopic.php?f=2&t=608&p=2903&hilit=bishop#p2903

If this list is not comprehensive, then please search out the web.

Really liking the idea of starting a thread dedicated primarily to ".... thread on things they have found have been repaired poorly or just wrong on their car?" -- so starting one now !!

Octagonally yours
BOXLEY (Robert and MGTC0820)

[Duncan M]

The steering box was changed for the TD & TF because they wanted to go with rack and pinion. End of story.

A ball bearing on top of the sector shaft does not sound like a Tomkins kit. Got some pictures to share?

Everybody with a VW box thinks they are the best thing since sliced bread, but I have to wonder how many of those people have ever driven a TC with a properly set up front end and steering box?

My stock TC steering is set up perfectly and it is a joy to drive without a Tomkins kit. Nothing quite like the feel or quickness. BC box requires two adjustments. Top plate adjustment for straight ahead steering, and end plate adjustment to eliminate end play of the worm. Neglecting the end play adjustment will destroy the box fast.

[JohnW]

The steering box was changed for the TD & TF because they wanted to go with rack and pinion. End of story.

A ball bearing on top of the sector shaft does not sound like a Tomkins kit. Got some pictures to share?

Everybody with a VW box thinks they are the best thing since sliced bread, but I have to wonder how many of those people have ever driven a TC with a properly set up front end and steering box?

My stock TC steering is set up perfectly and it is a joy to drive without a Tomkins kit. Nothing quite like the feel or quickness. BC box requires two adjustments. Top plate adjustment for straight ahead steering, and end plate adjustment to eliminate end play of the worm. Neglecting the end play adjustment will destroy the box fast.

I would post pictures on here if I knew how.
If you are on facebook look on the Octagon car club page and you will see some pictures of said steering box. It definately has a Tomkins kit fitted to it and someone has drilled the end of the sector shaft and put a ball bearing in it (see my initial post). I have since removed the ball bearing so the thrust face is now in contact with the sector shaft top and adjusted the Tomkins adjuster as it should be and still have about 1.5" of play. The car drives much better but I still don't like it as it has very little feel, not much self centreing and too heavy. It makes my Beetle (air cooled) seem wonderful to drive and that is not set up for road use as it is a trials car.
I think the best way forward is to fit a VW steering box as has been said quite a few times.

Thank you all for the replies.

[Steve Simmons]

Hi John, below the reply box, click on "full editor". You can attach photos there. Just drag and drop them right into your post. Or you can also use the "attachments" tab and do it the old fashioned way.

Like most sites there is a size limit of course, so if you get an error then you will need to shrink them.

[Duncan M]

Have you inspected/replaced the sector shaft peg that engages the worm? Old one can easily be pressed out, and a new one pressed in. Also, the uniquely sized ball that goes on the end of the drop arm wears much faster than the other (different size) end link balls. You mentioned adjusting the link ends, but if any or all the balls and peg are worn out, they must be replaced. 1.5" play at the steering wheel sounds about right. Has your box housing been bushed where the sector shaft rotates? Most all have had this done, and it could need to be re-done. "Edit"-- I trust you have taken apart the box and removed the worm to inspect the ball bearings that the worm rotates on---

Have you adjusted the box for end play at the end plate? Do that first. Shims. Then do the straight ahead top plate adjustment. This is easy to do if you have a standard hard chrome flat top and shims. Toss the Tomkins kit, really. The steering, once properly set up does take some getting used to. You cannot tell if you like it or not by just taking a short drive. People tend to grip the wheel hard because of all the nonsense they have heard about the original steering. A light grip is the way to go.

[mgpsmith]

For what it's worth - since the end of Winter 2020, I have changed exu7617's steering from the modified top plate (pointed screw/nut-welded-onto-topplate bearing down on the center of the shaft) to a Tompkins kit (earlier style with the Torrington beearing) and most recently going back to the original top plate the car left the factory with. In all cases, adjustments were made according to the instructions accompanying the description of the method or hardware. I also owned 6165 for a while and that had been configured with a replacement box (VW I think).

Important to my findings are: All new rod ends/balls/kingpins/bushings/box bearings/peg 16k miles ago, and has been religiously kept lubed with clean grease and oil well in excess of the manual's recommendations. Toe-in is set at spec using the two-bob and masking tape method described by somebody in this group (what a slick way to set toe-in!). I've settled over the last couple of years on tire pressures of 28 front, 30 rear on Wayfarers....I liked 24/26 on the former B4s that I wore out.

My conclusion is that the factory did it best. The non-MG kit is too slow....go get an Auburn boat-tail speedster if you want that relatively numb sense in a sporty open car! The topplate alternates that use the standard box (e.g. Tompkins or the DYI Bolt) produce steering that is less predictable off-center. I set the stock box up by using feeler gages to determine an initial shim thickness, front end off the ground and oil out of the box. Then took shims in/out 0.002" at a time until just the least smidge of resistance across center. I then filled the box with natural base stock 80/140 gear oil (Yes it leaks a little but maybe that's good). The car tracks straight, does not wander, is predictable in its response to steering inputs and is a new pleasure to drive. I foresee that the only downside is that this exercise re: box setup will probably need to be repeated periodically, possibly as part of the annual service.