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MG MGB Technical - Rebuilding steering rack

My 1974 B has play in the steering rack. Much over 45mph is not safe. I did check the inner tie rod adjustment on the passenger side. So I figure the rack is worn out. The rest of the steering Parts and suspension are good. Is there a rebuild kit for these or do I have to replace the entire rack? Thanks, George.
GH Higginson

Depends what is worn!
Check the UJ before condemning the rack.
The mesh between the rack and the pinion is adjustable..........up to a point.
The greater wear takes place around the straight ahead position.
Adjusting will improve free play there, but a badly worn rack will then just get way too tight on lock. If the rack is that worn you might as well invest in a new/re-built complete rack, but individual parts do seem to be available.

https://www.scparts.co.uk/sc_en/british-cars/mg/mgb-1962-1980/steering/steering-rack.html
.

Allan Reeling

Are you sure it's the rack, could it be yet another collapsable column gone sloppy
William Revit

Thanks Allan I will check out the up and the adjustment. I really appreciate your help! George
GH Higginson

Thanks William. When the shop showed me the wear, they moved the tire and we saw the play at the rack/ inner tie rod. Can a collapsed column cause that? George
GH Higginson

The track-rod _should_ move with the wheel. If not then the track-rod end is worn.

If you mean the steering wheel was clamped firmly and you could move the road wheel back and fore then the play could be anywhere i.e. track-rod to rack (adjustable), rack and pinion (adjustable up to a point as said), UJ (replace), UJ splines (loose bolts?) or steering column.

If the moving the passenger road wheel caused the track-rod at the rack end to go up and down rather than in and out then the rack bush that end is worn.

Other than that as in the other thread you need to clamp various points along the way between steering wheel and road wheel to see what has play and what doesn't, could be more than one component.
paulh4

George
To answer your question about the column----No-
Wear in the column shows up as excessive/loose radial play in the steering wheel and/or a rattle

With play on the inner end of the passengers side tie rod as your shop has shown you it could be either the inner ball itself or wear in the rack bush
The ball will show up as in/out movement while the bush will show as up/down

When you say it's not safe over 45mph, what happens then at that speed--

willy
William Revit

When I say over 45 mph it is unsafe is that the steering is so loose the car wanders and is hard to control. How do I know if the inner rod ball is worn and are there replacements? When the road tire/ wheel is grabbed and moved in and out, the inner rod moves in and out like a worn rack. The rack itself does not seem to move and I do not see any up or down movement.
GH Higginson

Hi George
It's a little bit difficult diagnosing without seeing/feeling but we'll have a go
First off , with the car sitting on the ground, if you lightly wiggle the steering wheel left right left right, does it have much movement , does it feel nice and connected or is there a loose spot in the middle --just wriggling it with one finger how far does the rim travel-
If you do have excessive free movement in the wheel you need someone to move it L/R while you check to see if it's in the column--worn U joint-- in the rack itself--or rack mountings broken off the cross member

Also in the attached pic. from left to right we have
tie rod
inner ball joint
rack
housing
Are you saying the tie rod moves in and out in the inner ball housing, or is it that the whole rack shaft is loose and moving freely in/out in the housing, the housing itself is bolted down and doesn't move unless the mountings have cracked off the crossmember which can happen but reasonably rare
If the boot is still in place you'd probably need to hold the ball housing through the boot so you can determine where the movement is or release the boot and slide it along the tie rod out of the way to see what's happening
willy



William Revit

While we're on steering racks, and with your permission, George: this is off the '73 BGT (see recent Telescoping Steering Column post) - am I right in thinking it's a non-original but good quality addition?(by my PO) - it looks very much like one advertised by B Hive in the UK; but where the balljoint housing locates into either end of the rack tube at full turn, there is just metal-on-metal - I would have expected some sort of bushing to be there. Does anyone have the same rack and wish to comment? I am emailing B Hive separately in case they can help.
Thanks again, John.






J P Hall

I may have misunderstood. The drivers end of the rack shaft is positioned by the pinion and its damper, and the passenger side by a bush 17H8664 in the rack tube which was originally felt or plastic but now seems to be phosphor bronze or similar. The ball joint housings just move back and fore inside the gaiters, and maybe the very end of the tube on full lock, but I wouldn't expect them to be touching the tube.

Current racks seem to have an adjuster screw and locknut in the cover that was previously over the shims, to set the damper. There's been several complaints about the quality of these racks, including the components under the cover being fitted in the wrong order which allows the drivers end of the rack and track-rod to move about all over the place



paulh4

Thanks Paul - I'll have a look in the rack tube passenger side and see if there is in fact a bush there. Have to remove all that lovely new molygrease I put in yesterday! I like your comment that in practise the balljoint housing shouldn't strike the rack housing - on the bench it's misleading, and I may well have been jumping at shadows.Regarding the pinion cover, yes mine has the adjuster screw and locknut; under the cover plate is the spring, the plastic yoke and the little disc which sits inside the spring, and gives the adjusting screw a surface to meet.
J P Hall

George, if it's ok with you I'll continue with my subsidiary question, under your OP heading of Rebuilding the Steering Rack.
I have re-examined my non-original rack to investigate what bush (if any) is hiding in the LHS ("free end") of the rack. At the pinion end of the rack tube, there seems to be only the damper/adjuster to stop the rack from flapping about.
I have a couple of questions:
(1) with the rack off the vehicle and with damper yolk and pinion shaft removed, the rack is so loose in the tube that there is daylight visible. There is literally 4mm of play between rack and tube/housing - is this normal?
(2) There is a circlip inside the rack tube at the free end, presumably keeping a bush and/or bearing in place. In my case, there is what looks like loose bearing shell - obviously not good: has anyone on this forum removed the circlip and can report what they found behind it?
(3) The balljoint housings in these aftermarket racks don't appear to provide for separation of the balljoint so that the rack can be withdrawn from the tube. So I may be prevented from fully disassembling and fixing anything! Can anyone confirm this?
Thanks all. John.
J P Hall

1. is to be expected at the pinion end, but not the free end.

2. On a Mini rack the free end bush was held in with a screw, and the Parts Catalogue implies that is the same for the MGB.

On these after-market racks I can't believe not having a supporting bush at the free and is the intention, but given the problems with damper assembly it wouldn't surprise me if it had been missed out. I can imagine that the bush was fitted to the rack before the ball joint was attached, then the two slid into the tube. It would need some kind of arrangement both ends of the bush to stop it sliding back and fore along the tube, such as the circlip on the outside, and a seat or another circlip on the inside.

3. Given the cheapness of the damper arrangement, having 'sealed for life' ball joints wouldn't surprise me.
paulh4

Thanks Paul.

Comparing the original balljoint casing (see Willy's excellent photo earlier) with my aftermarket version, it is widely written that the original design enabled either
(1) complete separation of the rack from the tie rod, by unscrewing the balljoint housing from the rack; or
(2) adjustment of the tension of the balljoint, per John Twist 's video.

The closeup of my aftermarket version below gives me the tiniest bit of hope that it might also be screwed together - see the little ridge where the rack and balljoint housing join, the width of a fingernail, in the photo. My understanding is that separation of rack from balljoint is the only way to remove the rack, examine the bushes, replace and reassemble.

Has anyone tried (successfully or not!) to unscrew the Argentinian-made version? I don't have the gear at home to safely (nervously) attempt this, but have an engineer who can have a go for me on Monday.

Thanks always. John.



J P Hall

The original certainly did allow for complete removal and adjustment of the pressure at the ball joint to control articulation, I've done both in the past. The threads were very fine and horribly easy to cross.

The crucial aspect for doing those, that doesn't seem to be part of this ball-joint, is the threaded sleeve that locks into recesses in the ball-joint housing and the rack shaft to prevent the housing rotating relative to the shaft, as in the attached. Without a similar visible locking method I would suspect that it has been locked in some other way that won't allow non-destructive unlocking. The worst part of that would be if the rack was fitted to the tube before the ball joint housings were fitted, making it impossible to remove the rack shaft from the tube.

But out of interest why do you need to disassemble the ball-joints?



paulh4

Paul (and I hope this is of interest to someone else somewhere!) - there is what looks like a loose or broken bearing or bush (not sure which yet) hiding behind the circlip on the passenger end of the tube. My understanding is that after I (hopefully tomorrow) remove the circlip, it might be possible to remove any remnants of bush or bearing; BUT that I will need to withdraw the rack, minus the balljoint assembly from one end, in order to install a new bush or bearing to stop the "free" end of the rack from flapping about in the tube, That is why I want to separate the balljoint from the rack at one end - so that I can withdraw the rack from the tube. Without a bush at least, there is nothing centreing the rack inside its tube at the passenger side, and only the damper adjustment at the opposite end.
There is one other possibility - it might be feasible, without taking apart a balljoint, to persuade some sort of split/spiral bush to squeeze into the rack tube, located again behind the circlip. Because there is at least 4mm daylight between the circumference of the rack and the inner wall of the tube, I hadn't thought of a split bush until you asked the question,
Make sense?
John.
J P Hall

Yes it does make sense. And as I have doubts that you will be able to dismantle the ball joint it may well be the only way.

What material are you thinking of using? Hard may not open up enough if split lengthwise, but soft may unwind itself if the spiral is too 'fine'.
paulh4

Something like polypropylene stock, drilled and reamed and then diagonal cut to fit; maybe a polybush, similarly modified - that sort of material could offer good wear characteristics, while being flexible enough to open up to slip over the rack.
I don't want to damage the balljoint housing, as its function is perfect - all of the trouble with this rack is inside the tube.
One other question - If I'm up for a new rack, I wonder whether any of the UK or US suppliers offer a rack assembly where the balljoints CAN be separated, so that in future, the rack can be repaired instead of the current "throw away" design? I would hate the next owner of this B to suffer the same fate.
Thanks for your interest Paul - I'll report again after we've tried to remove the balljoint.
John.
J P Hall

I wonder too. But if the pinion adjustment is the same as I posted on 10th then I doubt it as the usual suspects I have looked at all show the same. Another problem someone had with this type is the steering shaft wasn't true so as the rack was pushed from side to side the UJ end described a circle, and when attached to the column with the UJ left the steering stiff-free-stiff-free as the wheel was turned no matter how he positioned either rack or column. I just hope I never have to replace either of mine.
paulh4

That's one reason why I've actually been keen to salvage my current aftermarket rack - in spite of the problem I've found internally - because even with apparently no centreing of the rack inside the tube, and no effective bushing at either end (but see below!), the bloody thing has been working well in terms of free and easy steering - albeit with a loud clunk on initial takeup of the wheel.
SO - today I decided to remove the circlip inside the free end of the rack tube, and see what the moving part was, lurking behind the circlip. It is best described as TWO washers or shims, the innermost one smaller than the outer; absolutely no evidence of other bushing material - just two shims which I guess were originally a tight fit against the inner wall, but which by now are floating loosely! The inner rack wall appears to be slightly conical, hence the smaller innermost shim. But as far as I can see, these shims achieve nothing, nada, nix - their internal diameters are about 28.5mm and 30.5mm respectively, while the shaft (round section) is only 25mm. I can't understand why these shims were put in, unless I'm missing something.
Thought others might be interested in this mysterious bit of engineering, especially if anyone has an "Argentina" rack on their car. I'm certainly going to follow up the possibility of inserting some properly functioning bushing at each end of the rack tube.
John.






J P Hall

I'm wondering if there should be some felt-like material between the two shims. Was the circlip in a slot? A cylindrical poly bush in a tapered tube is going to experience all the wear at the inner end, and may go loose fairly quickly.

You shouldn't need a bush at the pinion end, the rack should be sandwiched between the pinion shaft and the damper, with the damper adjusted to give no play but freedom of movement from lock to lock. On a worn rack if the damper engagement is too tight it can be free in the middle but tight at the ends.
paulh4

You're right Paul, no need for a bush at the pinion end - I partially reassembled and proved that today. At the free end yes, the circlip sits in a groove, so appears original to this brand of rack. As well as trying to salvage this rack (even if only as a spare), I am currently canvassing the UK suppliers to see who is offering the best price. Freight of course adds a lot. Not sure whether US suppliers are competitive.
John.
J P Hall

John
trying to get my head around this- So, working from the outside inwards there was a circlip,larger washer, smaller washer all going into the tapered housing---Was/is there another circlip or step up in the housing at the other end of the taper, or do you mean a straight bore in the housing with a tapered/chamfered end
From what can be seen in the pic here it looks straight with a tapered end but what's further up in the housing from there another circlip or step or is it straight
Have you had a look from the other end to see if there are any remains of a bush up in there riding along the shaft
Any chance of a close up pic up in the hole where that circlip goes
willy

It'll be interesting-
If you make up a bush there
ll have to be an air bleed somewhere like a slot in the bush or a flat along the shaft otherwise the gator is going to explode
William Revit

Thanks Willy - I'm going to double check where the tapered bit starts and finishes - I think it's as you describe - parallel walls at the opening, then circlip groove, then a couple of cms tapered slightly, then most of the bore parallel. Very relevant in figuring out whether rebushing is feasible at the free end. Expect an update in the morning.
When I sprayed air-fed degreaser (kero) down the tube in each direction, no other bushing (felt, plastic,anything) emerged. Just grease.
I'd love to get my colostomy camera down the bore, but there's not enough clearance - but even the probe at the entrance might be helpful, so I'll try.
I had seen your comments about pressure buildup in the bellows - if I do try a neoprene bush it will have to have a diagonal slice to enable it to go over the rack, so that should relieve pressure. Good point though.
Man ... the things we do, in the pursuit of our hobby (at least it's a hobby in my case, I rather think you're very much a professional)!
John.
J P Hall

John
Maybe it just had an 'o' ring in there for a bush and the oil/grease has eaten it
I think i might have come up with an idea (bit of a worry) for a bush--
If that smaller washer is placed into the housing as far in as it will go, roughly how far is it from the visible face of the washer to the start of the circlip groove--and same with the larger washer, if that is pushed in as far as it can go, how big would the gap be to the back of the circlip
William Revit

Sorry Willy, I missed your message yesterday. In the morning I'll take those measurements and update on here.
Thanks for your interest - I've kept it on the BBS because by now there must be other people with the Argentinian racks starting to (or about to) play up, and given how they are designed, it would be nice to be able to effect a repair. Against the wishes of the designers, it seems!
John.
J P Hall

OK - doing my best, here are some measurements, Willy:

The outside wall of the end section of the tube (some 87.5mm) tapers from 46.75mm down to 43.8mm, so we might assume that the inner wall of that section of tube reduces by the same amount. The visible part of the inner wall, immediately inboard of the circlip, measures pretty close to 35mm, so the most inward part of the taper is probably about 32mm - BUT the smaller washer only sits about 13-15mm down the tube; the outer (larger) washer is thus 13-15mm nearer the circlip, and the circlip sits in its groove.
Follow??
A photo is attached, but it's b##### hard to get a good shot.
I don't know whether this helps you to wrap your head around it, Willy! What a shame no suppliers seem to want to make a steering rack that we can open up and repair. Just sayin'.
John.
PS In the photo, what you can see right down the tube, is the smaller washer, poked down as far as it will go.



J P Hall

Ah, very good, Your Townsville son will sort that out for you quick smart
A polly bush shaft clearance size id and housing size od and 15-?mm thick to be a nice tight circlip fit
Cut it in half and fit them in there between the two washers
You could even make it say 25mm long with a step for the extra length to protrude into the tube through the smaller washer to give it some more surface area
In the pic that smaller washer looks like it's sitting on a little shelf, do you think the bore in the housing is straight back to that point, it would be really good if it was but not the end of the world if not just a hands on measuring job, your man will fixit,
I was going to ask for more measurements like washer od etc but if you've got the Son on the job it's a bit pointless
Let us know how you get on though please, it's all very interesting, I haven't had anything to do with one of these racks before so all good learning stuff
Cheers
willy
William Revit

Slightly better lighting - the first internal "step" is part of the housing, 20mm down the tube; this is where the larger shim and the circlip go. What looks like a second "step" is in fact the smaller of the 2 washers/shims, sitting in place 20mm further down the tube. So it looks like a bush to interference fit from the lower washer up to the top washer, secured by the circlip. Measurements as near as I can get for the bush would be:
o/d 35mm, maybe tapering to 32mm.
i/d 25mm.
Width 20mm.

I could also put a second bush in the outer section of tubing, but it would need to be secured somehow.
John.



J P Hall

Yep
Just looking at it the bore in the area between the two washers appears parallel
I reckon you're on the right track ,but just the one bush----If you were to fit a bush to the outside of the circlip it will limit the travel of the rack and reduce the available steering lock on that side
You could step the outside of the bush to the id size of the washer and the thickness of the washer and circlip so that it pokes out flush with the circlip and the same on the inside end but have it poking through a bit further in there---A total bush length of around 30mm would be plenty
Just my 10 cents worth--
I'd drill the hole through the polly first to just undersize, then cut it in half horizontally then back in the lathe butted up and clamped and bore to size, then clamp the halves onto a dowel and then machine the outside---Doing it like this will make it possible to make the outside a nice tight fit in the housing--
I don't know if polly rod is colour coded or not, don't think it is but making bushes up i've found the black rod seems to machine up better--don't really know,might just be in my head, but the black HDPE (engineering plastic)rod would be the go for the job
William Revit

Drew a roughy up for you--something like this would work


William Revit

Fantastic help and advice thanks Willy - and your drawing will go with me to Townsville next week. My eldest son, whose real name is Ben Hall (and he looks the part, too) will have a look and we'll talk to a rack-building guy as well. Not his usual job, as he's with the V8 Supercars.
It will be interesting to report whether we have a win in a week or so.
As said before, I hope this is of interest to others - I find it fascinating!
John.
J P Hall

Ben Hall-!!, not working for the Kelly gang I hope
William Revit

Quick update for Willy and anyone interested: as luck would have it, my new (aftermarket/reproduction) rack arrived from MGOC on the very day I was in Townsville showing the "old" one to a steering/cv joint specialist. The specialist reckoned it would be a few hours work to strip, create and fit a bush at the free end, and reassemble - at $160 an hour plus at least $200 for materials. It was a short conversation, as he was not interested in helping me by just making a bush and letting me worry about prepping, fitting and reassembly.
So my mechanic son looked at my early thinking, plus Willy's drawing - while at the same time examining the bush arrangement in the brand new item supplied very promptly by MGOC. Conclusion: the new rack has a white neoprene(?) bush at the free end in almost exactly the position I had first considered (ie the outermost section of the rack housing), BUT held in place by a grub-screw. I think this type is mentioned in Paul Hunt's Steering section. We can try to fabricate a slightly tapered bush in HDPE, with a split in it, to slip over the shaft and push down inside rack housing - held in place by the original retainer and circlip; OR we can make a simpler bush, akin to the new MGOC example, not tapered, and add a rollpin or grub screw to help retain it. Theoretically, we could do both.
The first photo just shows the look of the new rack, with the rhs boot pulled back to reveal the "sealed for life" balljoint housing.
The second photo is a closer look at the balljoint housing and the grubscrew. Again, the new replacement rack does not appear to allow separation of inner balljoint for withdrawal of the rack - so not helping maintenance or repair.
I plan to buy some black HDPE stock and get a mate to practise making bushes. Cost - a few beers. Will report more soon.
Yours, John.






J P Hall

Thanks for the update John--
The 'specialist' is a bit of a rip off
$5 would cover materials
Shame you're so far away, it'd be an interesting little project, but the need for dead acurate measurements between the washers prevents doing the distance thing

good luck with it
willy
William Revit

Too true, Willy - but hey, when we do our next motorhome amble to Victoria, I just might sneak the rack into the Winnie and detour to Tasmania! Last Christmas we Winnied down to Port Fairy and I came back to Qld with a TC bulkhead and doors stowed in the bath!
Thanks for your interest - I will post what I end up doing.
John.
J P Hall

Willy and others - see today's post " Argentina steering rack disassembly".
J P Hall

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

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