How to check a steering rack - or just a new one?

[AndyPen]

Picking up on, but avoiding hijacking Gary's thread, before refitting a steering rack what checks can you do on a bench?

(viewtopic.php?f=3&t=29043)

In my case, one that was refurbed by a professional who I'd normally just trust... but as it is such a pain to get too... should I just fit a new one and be done with it?


Thoughts folks?

[InnoCooperExport]

MokeSpider (or just Spider on here?) wrote a good rebuild guide over on TMF.

http://www.theminiforum.co.uk/forums/to ... type-mkii/

[AndyPen]

I really need an idiots guide how to check it when assembled / in situ possibly - consider me an idiot as I’ve no facilities to copy such great work

[Daz1968]

I gripped the main body in a vice and pulled, pushed and tried for sideways movement on the track rods, even small play can be felt easily, mine was fine on the rack itself but I had to change the bush on passenger side as that had some play which is a common wear point.

[docka]

can the passenger side bush be changed on the car?

[woodypup59]

can the passenger side bush be changed on the car?

Yes - with difficulty.

You have to remove the stake/pin in the inner ball joint to get the ball joint off. Turn the steering to the drivers side and wedge the bush onto the rack with a self tapper or such like. Remove the tiny self tapper holding the bush in and wind the bush out using the steering wheel.

[Andrew1967]

Depends if you want a Mk1 rack I suppose Andy ?

Mk2 racks are available new, but beware 'reconditioned' racks because they can and do overlook the real problem with them ... the bush !! Remember, you need to fit Mk2 arms if using a Mk2 rack.

Changing the bush is not that difficult on the bench, fiddly on the car. Once the old bush and housing are out it's not too bad to reassemble on the car.

Best to check it before fitting it though. Stick the rack in a vice and with the L/H steering gaiter pulled back try and rock the rack side to side in the housing. Any movement will mean the bush is worn or non-existent.

[docka]

can the passenger side bush be changed on the car?

Yes - with difficulty.

You have to remove the stake/pin in the inner ball joint to get the ball joint off. Turn the steering to the drivers side and wedge the bush onto the rack with a self tapper or such like. Remove the tiny self tapper holding the bush in and wind the bush out using the steering wheel.

Which is more difficult, renewing the bush on the car or replacing the entire rack with the engine in?

[Gary Schulz]

I can say I tried the self tapper screw method where you wedge screws between the inner rack and the bushing and I think all it did was scuff up the finish on the inner rack. I am debating which path to move forward with (rebush the old rack or just drop in a brand new rack). I am going to be removing the rack by dropping the rear of the subframe a couple inches. It will be a much more accurate and quality job for me to be rebushing it once it is out.

Brand new racks are very inexpensive so that is why I am also struggling with this...

[Fanfaniracing]

I always rebuild the old Steering Rack.

I had once massive troubles with a new one...

If you rebuild it the proper way, it works fine and you know what you get!

[Spider]

There's a couple of checks you can do on a used rack before fitting to assess it's condition, at least as far as wear goes.

Generally, if the Gaiters are torn, and it was used that way for any length of time, you can be sure that the rack is worn and possibly kaput.

First up is the Bush in the non-business end and more often than not, these will have worn or flattened depending on what type is fitted. If you wind the rack over all the way so that you have all the length poking out the non-business end, then check as Andrew has suggested, you'll usually find any play here. I'd suggest here as well, removing the gaiter on this end and having a look to see if the bush fitted is a felt type. If it is, I'd suggest you replace it, but with something other than felt.

Then check the Pinion, Rack Teeth and Yoke for wear. While you have the rack wound over on the non-business way, move it back off the stop a little, then rock the Pinion back and forth a few degrees while looking at the Inner of the Rack, You'll notice as well as it moving back and forth, it will also rotate a little, it needs to be less than about 5 degrees here. Then do this same check when wound over the to the other end, then, in the middle, where it will have the most wear. Ideally, the amount of this rotation we'd like the same at all parts of the rack travel, but you'll find in this central area, it will rotate a bit more. This indicates the amount of wear in the teeth of the main inner rack. Also feel for any free play in the pinion in this central travel area, against the rack itself. If you find the Pinion is easy to turn here, compared to the effort needed at the ends of it's travel, you can take a shim or two from the Yoke and try again. Here's where it gets in to a balancing act. You can get it shimmed to feel nice in the central travel area, but you may find it will want to lock up of=r get quite tight on the ends of the travel. The more time you spend on this, the nicer the steering will feel as probably around 70% of the feedback the driver gets from driving a car is via the steering wheel.

This is by no means fool proof and really, the best thing to do is to strip and rebuild it. They are not difficult and usually only take a few hours to do. The bearings are a bit difficult to get a hold of, I don't know of any suppliers in the UK, however, w have a couple here, though, usually, the bearings will be fine, it's normally only when it's been run dry or water has been allowed to get in to it.

The other thing is that the original design of these racks was to run them with 90 weight Gearbox Oil (200 ml for the UK Racks) and at some point, to get around oil leaks from them, they switch to grease, which was in my opinion, a disaster. I would suggest if the rack has grease in it, filling it with Oil. The Oil not only lubricates the inner parts but also has a small cushioning effect between many of the inner parts. The Rack is an interference design, meaning, many of the inner parts must run with no clearance (and infact a small preloading) so it has no free play at all. Oil here is not displaced, where as Grease will be and it won't flow back in to these parts, leaving them to operate dry.

I'd suggest using the rack you have or overhauling it. The new racks don't come within a bull's roar of the original racks.

MokeSpider (or just Spider on here?) wrote a good rebuild guide over on TMF.

http://www.theminiforum.co.uk/forums/to ... type-mkii/

Cheers for the mention here. When I signed up, 'Spider' over there was already taken, though, we never see them

[AndyPen]

Depends if you want a Mk1 rack I suppose Andy ?

Mk2 racks are available new, but beware 'reconditioned' racks because they can and do overlook the real problem with them ... the bush !! Remember, you need to fit Mk2 arms if using a Mk2 rack.

Changing the bush is not that difficult on the bench, fiddly on the car. Once the old bush and housing are out it's not too bad to reassemble on the car.

Best to check it before fitting it though. Stick the rack in a vice and with the L/H steering gaiter pulled back try and rock the rack side to side in the housing. Any movement will mean the bush is worn or non-existent.

Thanks that is really helpful - it is actually a Mk2 rack anyway, off a 22K car many moons ago, so got the arms off it too - plus spares on a spare set of S disc set ups from the 970. I shall pull and tug as you suggest

[AndyPen]

There's a couple of checks you can do on a used rack before fitting to assess it's condition, at least as far as wear goes.

Generally, if the Gaiters are torn, and it was used that way for any length of time, you can be sure that the rack is worn and possibly kaput.

First up is the Bush in the non-business end and more often than not, these will have worn or flattened depending on what type is fitted. If you wind the rack over all the way so that you have all the length poking out the non-business end, then check as Andrew has suggested, you'll usually find any play here. I'd suggest here as well, removing the gaiter on this end and having a look to see if the bush fitted is a felt type. If it is, I'd suggest you replace it, but with something other than felt.

Then check the Pinion, Rack Teeth and Yoke for wear. While you have the rack wound over on the non-business way, move it back off the stop a little, then rock the Pinion back and forth a few degrees while looking at the Inner of the Rack, You'll notice as well as it moving back and forth, it will also rotate a little, it needs to be less than about 5 degrees here. Then do this same check when wound over the to the other end, then, in the middle, where it will have the most wear. Ideally, the amount of this rotation we'd like the same at all parts of the rack travel, but you'll find in this central area, it will rotate a bit more. This indicates the amount of wear in the teeth of the main inner rack. Also feel for any free play in the pinion in this central travel area, against the rack itself. If you find the Pinion is easy to turn here, compared to the effort needed at the ends of it's travel, you can take a shim or two from the Yoke and try again. Here's where it gets in to a balancing act. You can get it shimmed to feel nice in the central travel area, but you may find it will want to lock up of=r get quite tight on the ends of the travel. The more time you spend on this, the nicer the steering will feel as probably around 70% of the feedback the driver gets from driving a car is via the steering wheel.

This is by no means fool proof and really, the best thing to do is to strip and rebuild it. They are not difficult and usually only take a few hours to do. The bearings are a bit difficult to get a hold of, I don't know of any suppliers in the UK, however, w have a couple here, though, usually, the bearings will be fine, it's normally only when it's been run dry or water has been allowed to get in to it.

The other thing is that the original design of these racks was to run them with 90 weight Gearbox Oil (200 ml for the UK Racks) and at some point, to get around oil leaks from them, they switch to grease, which was in my opinion, a disaster. I would suggest if the rack has grease in it, filling it with Oil. The Oil not only lubricates the inner parts but also has a small cushioning effect between many of the inner parts. The Rack is an interference design, meaning, many of the inner parts must run with no clearance (and infact a small preloading) so it has no free play at all. Oil here is not displaced, where as Grease will be and it won't flow back in to these parts, leaving them to operate dry.

I'd suggest using the rack you have or overhauling it. The new racks don't come within a bull's roar of the original racks.

MokeSpider (or just Spider on here?) wrote a good rebuild guide over on TMF.

http://www.theminiforum.co.uk/forums/to ... type-mkii/

Cheers for the mention here. When I signed up, 'Spider' over there was already taken, though, we never see them

Another helpful post - cheers Spider.

This one is supposedly reconditioned by a firm who does a lot for the rally fraternity... including minis back in the day. I don't actually doubt their workmanship but better safe than sorry when so much work is needed to get the rack out again once the car is assembled. It is already oil filled by them btw.

They also spotted right away that it was a Mk2 for example, and double checked that I had the correct arms. As it was off a low mileage car he also commented on the condition when I brought it in, saying how good it was and was I sure I wanted the work done.

So all sounds good, but my nerves jangled a little after the chats on here... so I want to double check.

Now I can thanks to the contributors on here

[Gary Schulz]

I got the rack out of the car yesterday evening. Finally got it apart and here is what's left of the bushing-

20200620_081636.jpg

The felt wasted away a long time ago and was found inside the rack housing as hardened debris. The bearings for the pinion are perfect and everything else looked very good except for the surface finish of the rack where I tried that stupid self tapping screw trick. DO NOT USE THE SELF TAPPER SCREW TRICK! I spent a long time deburring the rack where those screws mauled the surface. Not a good idea!

20200620_081729.jpg

I will be ordering some bronze and most likely Acetal to machine up my own bushings. I will probably try both to see what I like. Most likely I will machine the bushing a bit on the narrower side so any angular misalignment in the rack will not cause binding at the bushing.

The saga continues...

[jay weinstein]

I think those parts go with the plastic bushing setup not the felt one.

[Gary Schulz]

Maybe. It is pretty hard to tell what the material is. Some pieces look like they may have been porous originally but overall what's left is just petrified at this point...

[Spider]

If you look at the later plastic type bushes, they don't make a 360 degree contact with the rack, put have 3 fat points. Best I can determine, they are made that way to allow for misalignment and also to reduce friction.

I have been doing the bushes in Bronze going back to the early 80's. I bore them undersize, press them in, then ream them once fitted up. Then I align the bush end of the rack to the other end. It is easy to do, the rack will lock up if you don't. These days, I do this by fitting the inner so it comes up flush-ish to the pinion end then between V Blocks in the press and a block of shaped timber to press against, straighten it up using the inner as a gauge until it lands central in the pinion end, I just do it by eye. They don't need much force at all to bend them. For many years, I was just fitting the OD of the Bushed End in a length of heavy pipe and just push it around by hand to do this.

The rack in my wife's Moke I rebuilt using a Bronze Bush around 1984 or 85 and it's done over 300 000 km since then. I have had to replace the gaiters a couple of times in that period, but otherwise, I've not touched it.

[Gary Schulz]

I need to buy a reamer to fit the OD of the rack and it is 2X the cost of a brand new Mini Spares rack! Of course the OD of the rack couldn't be the same as the rear swing arm pivot pins. What I love about old cars is they hadn't yet discovered economies in tooling...

I need an adjustable reamer to hit 0.840". I am sure there are cheaper places to buy reamers but this is becoming illogical on many levels.

[AndyPen]

Stick with it, patience can be pushed to the limit with these things eh?

Took both boots off my recon rack and set it to one side on cardboard when my phone went, but forgot how far the oil could run once it reached my painted concrete floor!!!! What a mess as hadn't broomed it for a week or so!!

Did the tests though, and thankfully all looks good - so left it upright for the night to let the new oil settle in a bit.

So if nothing else, your misfortune has helped me to avoid the same problem - so thank you all

[Gary Schulz]

Just to finish off the saga of the bad steering rack from a couple of previous threads- I wound up purchasing some bronze bushing stock close to the desired size and machined it to the correct dimensions on my lathe. I guess I didn't snap any pictures of the machining/reaming process but it isn't anything amazing to look at anyway. I pressed in the new bronze bushing into the passenger side of the rack and rechecked the size once pressed in to see if it needed a final reaming. The press fit is fairly light so the sizing on the ID remained good. Note- the bushing is also partially drilled to accept the set screw that comes in from the side. Here is a shot of the new bushing in situ-

20200626_122353.jpg

Once this was squared away I took at look at the fit of the rack inside the housing. As pointed out, the cast ends of the rack outer housing really are not machined in-line with each other. This is completely unimportant with the felt bushing because it just conforms to allow the inside rack to shift around as necessary as you turn the steering wheel from left to right. It is basically a pretty sloppy assembly as it comes from the factory. Sloppy but good enough. Once you replace the felt with a precision machined bushing that has much tighter clearance you find out that as you insert the inner rack through the bushing toward the pinion end of the housing the inside rack actually hits the outer housing before it gets to the pinion! The next picture shows what I mean. This view is looking through the end of the rack outer housing at the pinion side toward the bushing side (passenger side). You can see the inner rack hitting the wall of the housing before it gets through to the pinion. It is touching the housing where you see the red mark-

20200626_145951.jpg

In order to fix this situation you need to press on the middle part of the housing (the steel part only!) at the correctlocation to allow the aluminum ends to come into alignment. The next photo shows this process with the rack housing setup in a small press. It is best to creep up on this slowly since you don't want to over do it...

20200627_115713.jpg

When this is done carefully you will find the inner rack moves very smoothly inside the housing with everything lined up nicely.

After that process it was an easy task to shim the pinion and the tensioner (if the is the correct word). I had several racks that I stole shims from to make sure I had the right combination to get this one just right.

20200628_144812.jpg

The only tricky part here was coming up with a way to measure the proper pre-load for the pinion. The manual calls for having the pinion begin rotation with an applied torque of something like 15 in-lbs if I remember correctly. I made up a little test rig by gently clamping a vice-grip horizontally to the pinion and adding a 7.5 lb weight two inches from the pinion centerline. My description is poor and I am not sure if I took any pictures of this setup but you just hang that weight 2 inches out on the handle of the vice-grip and keep playing with the shims/preload until this applied weight just causes the pinion to rotate.

I am sure most don't bother with this step and just adjust to "feel" but this way I know things are correct. I really don't want to be dropping this subframe again to fix anything else on this rack!