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Steering Rack Bushing Replacement And Upgrade

suspension

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#1 Mini_Fox

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Posted 23 December 2013 - 05:28 AM

I developed a clicking thunk at the passenger footwell recently, I think it had always been there but it was getting worse.  My steering wheel was also growing a bad shake.  I checked the previous usual suspects, ball joints are brand new, tires are new, tie rod ends are tight, q5000 axle joints are still running true (finally!).  In my searching around I found similar symptoms which lead to concluding the passenger side rack bushing was toast.  I bought a replacement nylon bushing and to say it was disappointing would be an understatement.  Can't really blame the parts suppliers, they usually have very little control over the parts they receive, and we just have to take what we can get.  I have found I have no faith in reproduction/replacement parts for minis, so I have gotten used to having to modify or simply make my own parts from scratch, just to have parts that will actually function.  This project was no exception, so I set out with the intention of making a bronze oilite replacement bushing, or a hard bearing plastic if bronze wouldn't work.

 

This is my first post, so I tried putting the pictures in the post, but i guess they just attach in a lump.  Ok, background:  I have a modern replacement rack, i suppose it would be a mk2 style since mk1 racks don't really exist anymore.  Just run of the mill nothing fancy.  This was done with the rack still on the car.  I looked through the Haynes and Leyland shop manual and the internet before breaking into the car, and the process seemed to be "just take it apart" so I went ahead.  After removing the tie rod from the steering arm and sliding back the boot i gripped the inner ball joint housing with a large pair of vise grips and cracked it loose.  Note:  normally i would use the correct wrench, however this joint has only 2 thin milled flats on a smooth ball, and the flats were at an inaccessible angle against the body, so there was no choice.  On this rack these ball joints are also non-serviceable.  The housings seem to have been simply rolled over into a ball at the factory, not threaded together like the suspension ball joints.  The joint simply threads onto the end of the rack, no locks or keepers or anything, so it may be worth checking these on occasion for looseness.  The rack can be turned out fully several inches, and you can give it a good wiggle to see how worn or sloppy your bushing is, mine had at least 1/16" wobble all around.  The first picture is what greets you as you lay on your stomach or grind your knees on hard ground.  the rack shaft projects from the center, the plastic bushing around it, and it is held in place with a snap ring.  There is no screw retaining the bushing like the manuals state.  In the infinite wisdom of china or whoever else cheaps these steering racks together, if you look closely, you will see in the picture that the snap ring in fact has no eyes, only flat square ends.  This is fine for putting the thing together, but you have essentially made the thing impossible to disassemble!  Im not sure if this is a scheme to sell steering racks by making the unserviceable or what, but we'll move on.  I tried everything to remove this darn stubborn ring and finally succeeded by using a small, (1/16"-ish) cylindrical diamond dremel bit and carefully grinding across from the split in the snap ring.  Fortunately the same cheapos who decided on a blind snap ring didnt think to harden them.  After about 10 minutes of careful grinding the ring was in 2 pieces and came free after a fair amount of picking and prying.  In the picture directly across from the snap ring opening you can see where the grinding was started.

 

When fully turned the rack recedes past the bushing, allowing you to use a pair of snap ring pliers or some other tool to go inside the bushing, squeeze open and extract it.  My bushing was not particularly tight and came out easily.  The bushing did not look particularly warn, but i was still not impressed with its quality.  The replacement resembled my removed bushing but was even worse.  The bore is a nicely machined round bore, no mystery triangles or locking lugs.  The strange shape of these bushings I can only attribute to: a) for oil flow (if/when you put oil in these things, i suppose that was when the rubber boots were made to last longer than 3 months) b)it allows alot of sloppiness so you can pound them in with a hammer and all the little ribs will compress and grip the bore without needing to be too precise.  The bushing I machined was from standard oilite bronze that was kicking around my shop,    

 

Important dimensions: The rack diameter is .827", the rack bore is 1.170"/1.171", (it was difficult to measure).  The bushing dimensions I machined were: .829" inside, 1.168" outside and .750" long.  The snap ring I used was a 1 1/8" from ace hardware.  I can't guarantee these dimensions from one rack to the next, but i would imagine theyre pretty close.  There were no triangular lobes or fingers, i was considering adding them, but i was going to grease my rack not oil it, and with the round bore there was no serious reason for the extra work.  I had a picture of the bushing but I deleted it, imagine a bronze tube on a table.  These dimensions allowed the bushing to easily slide into the bore over the rack shaft and to my surprise (i was worried I was too sloppy with my lathe work) there was no discernible play in the rack arm when fully extended!  You can adjust your dimensions to suit your personal fitting tastes.  I did not want the bushing to fit too tightly in the rack in case i would need to remove it later.

 

The second picture is the bushing assembled with the snap ring in place.  Before inserting the bushing I pumped some grease around the rack shaft so the bushing would squish it down when inserted.  Slid in the bushing, snapped in the snap ring (what a relief after fighting that pieces of junk earlier) and smeared more grease on the outside of the bushing, after I took the picture.  With the oil impregnated oilite bushing and the slow motion the steering rack does, the extra smears of grease should be more than enough, and definitely more than the rack has when it first came apart!  Screw the inner ball joint back on, i squished and smeared some more grease on the exposed part of the ball.  I didn't know if the grease would work down into the ball, but seeing that it was going to be trash someday anyways, I figured it couldn't hurt.  I gave the vise grips a bump with a hammer to make sure it was tight and re-zip tied the boot and attached the tie rod end to the steering arm.

 

NEW: I added a picture of the 2 plastic bushings. the top part is the new replacement, the lower is the original.  You can see in the new part the thinner walls and that the center bore is not even on center with the outside diameter.

 

Impressions: Just after putting the bushing in and the car still on the jack it was a huge difference.  It had been a fight to turn the wheel for moving the rack shaft in and out, and now it was like the car was sitting on jackstands, i could turn the wheel with one finger!  I took it for a drive on the freeway and it was amazing.  Absolutely zero shake vibration, anythign from the steering, even over rough construction areas and road splits of the freeway.  It tracked so smooth it was like driving my power steering subaru!  I was considering threading a grease fitting into the rack, into the bushing with oil grooves so grease could occasionally be pumped in, and doubling as a retaining screw for the bushing, but I decided to just let it be.  I was also intending to use iron based heavy duty super-oilite, but the standard bronze was free in the scrap bucket, the piece required for chucking in the lathe would also be large and slightly expensive.

 

I have done lots of little upgrades and projects like this on my mini and I always wonder which have been done before and when.  Its usually extremely simple shop practice or machinery standards applied to parts on the mini to make up for whatever they were lazy on.  But something like this I wonder if there was ever a racer or driver that wanted solid steering and did this, or did it never come up?  Im considering making these bushings and snap rings as a kit, do you think there would be any interest?  I can;t believe while researching this simple thing how many times the answer was "just buy a new rack, they're so cheap its not worth the trouble."  A new rack for me is approximately $150, which is not cheap, and does not solve the problem of junk parts causing problems.      

 

 

 

         

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Edited by Mini_Fox, 27 December 2013 - 11:52 PM.


#2 Island Mini

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Posted 26 August 2014 - 03:50 PM

Hi Mini_Fox

 

Crazy awesome work mate! Very detailed and well executed! Can't believe it didn't get more recognition, but I guess some things just slip through the system.

 

I have been searching high and low for someone else who dared try to service the rack. I too am in a position where I have a worn bush on one side and one missing on the other and see no reason to throw my perfectly good rack away. (Thanks previous owner!)

 

If the replacement bushings are indeed as shocking as you mention then I would be very interested if you put together a kit or even could just make me up a couple?  :shy:  It really sounds like an upgrade worth doing!

 

Let me know if you're interested

 

Thanks

Toby



#3 Ska car

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Posted 27 October 2020 - 02:31 PM

Interesting reading for me as I now have to get the steering fixed for the second time, and have needed it done twice before on another mini.
Steering a car is important!
Thank you for posting.

#4 Spider

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Posted 27 October 2020 - 07:54 PM

There's since been a reasonable complete guide posted up in FAQ;-

 

http://www.theminifo...l-uk-type-mkii/

 







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