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MG MGB Technical - 'Argentina' steering rack disassembly.

Some good news, I think worthy of a separate thread for ease of reference, but following on from the recent "Rebuilding steering rack" discussion.
I have found that the inner ball joint on my "Argentina" aftermarket steering rack CAN be separated from the rack - it is a threaded joint ( 16mm x 1.5, apparently a "conduit thread"), threadsealed but able to be cracked open with the judicious use of a large stilson wrench. The balljoint housing proved to be solid, easily able to survive with just a little scarring, definitely able to be cleaned up and reused.
SO - to Willy and Paul, with thanks for your input, this means that I can withdraw the rack and look at making an inner and/or outer bush for the free end, as discussed in the other thread.
I hope this also means that (unlike me, as I bought a new rack!) others will be able to repair their aftermarket rack/bushes and re-use them, saving a fair few pennies.
A couple of photos to confirm the news.
John.





J P Hall

Ahh , very good, I had been wondering how they put it together in the first place
It'll be really funny if they assembled the bush and washers in the wrong order originally and you find the bush up along the shaft inside there when it's all apart
In the second pic. the shaft has a flat on it, was the end of the joint tapped down flat against there. That would have given a clue that it might screw out if it was tapped in there
willy
William Revit

Well done. A case don't give up, use a bigger hammer/wrench.

Locking the joint occurs to me as well as adjustment for the correct resistance to articulation. For the latter is that inside the part that has unscrewed? Or does a ball on the end of the track-rod bear against a recess in the threaded part on the end of the rack?
paulh4

Willy, the flats were only revealed when the balljoint housing moved apart from the tierod. It was a hidden feature.
Paul the balljoint is well hidden - all I can see is a plastic disc with a grease hole in the centre, deep down inside the threaded attachment of the balljoint housing. So it looks as though the threaded end of the rack becomes tighter against the plastic disc, and thus tightens the articulation. I did notice that the articulation loosened up when I first cracked the thread - a primitive version of the oem design!
HTH.
John.
J P Hall

Hmm
In the interests of safety, when you put it back together, even though I guess you'll be using plenty of thread locker, I'd be tempted to mark the location of the flat with a texta or something on the shaft so that after you have refitted the tie rod and adjusted the loading of the balljoint, you can locate the flat and then punch the end of that inner ball housing in against the flat for security--peace of mind
William Revit

Sealed for life. Duration of 'life' not specified :o)
paulh4

Hard to get good light down there, but you can see what I mean about the plastic disc.
Good point Willy - though as you can see, the outer wall of the balljoint housing where the rack locates is pretty solid. I had wondered about maybe a rollpin for good measure; then I remembered something stickier than either threadlocker or araldite - my wife's sourdough bread starter. Available from Supercheap auto soon! John.

J P Hall

Resurrecting this, has anyone used the one-piece inner joint and track rod from these people? https://www.ultimatepowersteering.com.au/mg-b/

If so how stiff was it to articulate?

I've had MOT advisories for both being worn on the roadster rack and an exchange rebuilt one just a few months later. I didn't test either the old or the first rebuilt rack until the second advisories, when the friction on the inner joint was barely able to hold up the weight of the still-fitted TRE.

The WSM says these must only articulate when a force of 32 to 52 pound inches is applied, which seems a lot, when so many including John Twist says they shouldn't be floppy but no tighter. 32 to 52 pound inches represents that force 1" from the joint, does it not? Reducing pro-rata as you move out from the joint - 2" halving it and so on?

A second rebuilt rack moved with a 2.3lb bottle of water at about 4" from the joint, which unless I have completely misunderstood what the WSM is saying represents about 10 pound inches. Is that right?

Adjusting one of the joints to resist 6lb at 7" made it very tight when in-line with the rack shaft, but it loosened up when moved to the side and up and down, tightening up when straight again. I felt this could affect self-centring on the road, so backed it off so it articulated equally all round.

Comments?

It's complicated by my only just discovering my MOT place uses shaker plates which look like they are going to tear the wheels off the car. But then they also test my V8 without that advisory so it must be picking up play in the roadster somewhere.



paulh4

Paul-
The replacement steering tie rod/track rod end Ultimate Power Steering of Australia has been designed to be a direct replacement for the Original Equipment end of the steering tie rod/track rod, but having a better design that allows an easy fitment to the Original Equipment Cam Gears steering rack of the MGB. This is a simple screw-on-and-lock design so that, unlike the Original Equipment design, there are no 'fiddly' adjustments required. Ultimate Power Steering has a website at: http://www.ultimatepowersteering.com.au/new-rack-end-to-fit-mgb-series-manual-steering-racks-1963-to-1980/.
Stephen Strange

That's what I assumed from the description, but what torque is needed to articulate the steering arm? And should the torque to move the factory joints really be as high as 32 to 52 pound inches?
paulh4

32-52 in/lb isn't much, that's only about 3-4 ft/lb roughly
10ft/lb is roughly what you can pull semi tight with something like a 6" adjustable wrench so 3-4 would be just a resistive smooth pull on something like a tie rod I'd say----As long as it's got some preload and can still move smoothly I'd say the 32-52 in/lb spec would be correct

willy
William Revit

Just to add---I found the following in a Holden Torana W/shop book-----similar rack- just to compare

Actual procedure from GMH manual:
"Adjust ball joint housing so that the tie rod will move when a load of 4 to 6.5lb (18-29Nm) is applied with a spring balance at a distance of 8in (203mm) from the centreline of the tie rod sphere, it is important that the load does not exceed 6.5lb (29Nm)."

It also says to re-check after tightening the lock nut, then stake etc.
William Revit

As said I did adjust it to 6lb at 7" but that made it very stiff when in line with the rack, easing off significantly when moved away from that. I was concerned that would affect self-centering so backed off to give the about the same force throughout its articulation.

When received one arm would only support 2.3lb at 4in i.e. 10 pound inches, about a quarter of the book value.

The V8 (130k in my ownership and the rack wasn't new when I got it) will barely support the weight of the TRE, but isn't getting these advisories. I weighed an old TRE at about half a pound and when fitted the bulk of that weight is about 9" from the joint which represents about 4.5 pound inches. So whatever wear the test is picking up seems to me to be coming from somewhere else. Waiting to take it back to be checked.

All Ultimate Power Steering have said so far is that it doesn't need adjusting (which I knew), not what the articulation force it is pre-set to.
paulh4

This thread was discussed between 06/12/2020 and 02/11/2023

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