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| Rack teeth count https://www.ausmini.com/forums/viewtopic.php?f=2&t=101884 |
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| Author: | TartanRed [ Fri Jun 23, 2023 7:41 pm ] |
| Post subject: | Re: Rack teeth count |
I've read this thread with interest. Now I'm a bit worried though. I have a late 6001A type rack fitted in my 850. The rack is 11/75 date and has the straight notch cutout for the pinch bolt. Should this rack be fitted with spacers under the U bolts. Pretty sure mine is not. What do the spacers look like? |
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| Author: | timmy201 [ Fri Jun 23, 2023 7:58 pm ] |
| Post subject: | Re: Rack teeth count |
I’ve confirmed the pinion for mine is 6001A, no undercut and it’s 0.010 oversize Attachment: IMG_6972.jpeg Here’s a photo of the spacers for you Tartan, with extra info in the link below viewtopic.php?f=2&t=101850 |
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| Author: | eightfifty [ Sat Jun 24, 2023 8:07 am ] |
| Post subject: | Re: Rack teeth count |
It's good to know what you've got. Most of these things look the same superficially. On an 850, the standard rack is UK made and is part number 21A715, although the number 2942 is actually stamped into the housing. The workshop manual incorrectly states the diameter of the rack shaft, but it is smaller than the 7/8" rack in AYA racks. Also, the UK rack has six pinion teeth compared to five on the Australian racks. However, an Australian rack is an acceptable replacement for the earlier UK rack if replaced as a whole unit. Individual parts, including the tie rods, are not interchangeable. For ausdino's (sorry, Tartan red's) rack, it would seem (if you have AYA6001A) you need those spacers. As we all know, the issigonis offset driver position also means that as a cheap way of putting the wheel in front of the driver is to angle the steering axis over towards the driver's side of the car which makes the steering wheel on your left (for RHD) closer to you than on your right. If the spacers are not fitted, it is possible that the steering column is not sitting in its unstrained natural sideways position and undoing the parcel shelf bracket (and supporting the weight) might reveal if there is any strain in the sideways direction (as distinct from the up/down position which of course has to be adjusted with the U bolts loosened). |
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| Author: | TartanRed [ Sat Jun 24, 2023 11:20 am ] |
| Post subject: | Re: Rack teeth count |
Thanks Timmy, now I need to confirm that my rack needs these, and then locate a set! Not looking forward to trying to fit the spacers now, without dropping the subframe... |
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| Author: | winabbey [ Sat Jun 24, 2023 4:05 pm ] |
| Post subject: | Re: Rack teeth count |
Out of interest I see the rack lock rings have been remade. https://m.facebook.com/groups/751056448 ... 042222284/ For those not using Facebook this is the post. I believe available from Link Automotive in Mitcham. Brand new steering-rack lock rings manufactured in Melbourne from 1045 mild steel to better-than-factory tolerances. No more grief trying to save the old rings when replacing rack-bush or assembling a reco rack. $43 for a pair - collect Viewbank or Mitcham or add $10 for postage. Attachment: Steering Lock Rings.jpg
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| Author: | eightfifty [ Sat Jun 24, 2023 5:56 pm ] |
| Post subject: | Re: Rack teeth count |
Doug, it doesn't say which rack these suit, but I presume the Australian rack AYA6001(/A). The Australian rack is 7/8" dia (0.875") and the inside thread is 20 TPI - it's fairly easy to get a tap of this size. However, a UK rack is 0.840" dia and also has 20 TPI thread and one has to cut the thread manually in a lathe. The Australian lock ring can't be used on a UK rack, as in an original Morris 850 rack. Later model racks for Enfield Mini also have the smaller rack dia. The above product looks well made and offered at a reasonable price. I'm not sure what is meant by better than factory tolerances but they certainly look OK in the picture. |
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| Author: | winabbey [ Sat Jun 24, 2023 10:35 pm ] |
| Post subject: | Re: Rack teeth count |
eightfifty wrote: Doug, it doesn't say which rack these suit, but I presume the Australian rack AYA6001(/A). Yes the seller says, in answer to a question in that FB thread. |
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| Author: | Bill B [ Sun Jun 25, 2023 9:55 am ] |
| Post subject: | Re: Rack teeth count |
I still don't understand the purpose of these 'spacer brackets'. Most of my experience on minis has been on my own 3 cars and none of them had these brackets - accepting that is a small sample. How do you decide whether a car needs these brackets? As a reinforcement for the rack housing, the rack still ends up being attached to the toeboard, which is not a rigid panel in itself. Even the alignment purpose seems a bit odd when there is wriggle-room at the parcel shelf bracket bolt holes to allow some adjustment. Maybe the steering rack unit should have been attached to the subframe rather than the body in the first place. |
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| Author: | cooperess [ Sun Jun 25, 2023 10:33 am ] |
| Post subject: | Re: Rack teeth count |
I am with you Bill B, I am trying to understand the need for the brackets. |
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| Author: | eightfifty [ Sun Jun 25, 2023 10:51 am ] |
| Post subject: | Re: Rack teeth count |
Bill, the official word is "When fitting the reworked or later type rack to the toe board, spacers Part Number AYA 6007 must be fitted under the 'U' bolts between the rack housing and the toe board, to ensure the correct positioning of the pinion to the steering column. Spacers are only applicable to the Mini Range of vehicles." In practice, it is seen (hopefully in pictures posted previously) that the pinion alloy housing for 6001A iss 1/4 taller compared to 6001 although both racks are marked AYA6001. As you know, there is a sponge rubber dust seal fitted over the pinion that seals the top of the housing to the toeboard. If spacers are not used, then one is effectively squashing this sponge rubber seal an extra 1/4" which it may not accommodate before being squashed "solid" and putting undesirable strain on the pinion housing, and possibly causing the rack to be crooked and the axis of the pinion not perpendicular to the toeboard. Thus, the rack has to be spaced back a bit to maintain clearance between top of pinion housing and toeboard. |
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| Author: | eightfifty [ Tue Jun 27, 2023 7:10 am ] |
| Post subject: | Re: Rack teeth count |
I've found a drawing which shows the installed position of an 850 rack - this has the same dimensions as AYA6001 (shorter pinion housing). You can see that even if the dust seal were to be removed, the lengthened housing of AYA6001 would be hard up against the toeboard. What's a bit worrying is that so far I've seen no mention of any need for longer U bolts, but I will investigate. Edit: I've changed t he picture to show relative positions of AYA6001 and AYA6001A in relation to the toeboard. As can be seen, with no spacer, and 6001A fitted, the boss of the pinion housing is hard up against the toeboard - no room at all for the sponge seal. So if the sponge seal is fitted, it is almost certain that the rack is being bent or unduly stressed with the U bolts tight. Note, these assembly drawings do not correspond with a specific part number so they are hard to find. There's probably one showing 6001A with spacers, but no luck yet. For the new picture below, I snipped an outline of 6001A from it's drawing and scaled and rotated it to match. Blue is 6001A, orange is 6001. |
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| Author: | Bill B [ Tue Jun 27, 2023 1:03 pm ] |
| Post subject: | Re: Rack teeth count |
Thanks, Tony. The light is slowly dawning on me. I must admit the sponge dust seal was compressed a lot when I fitted the rack. Another clue I noticed was there were more than 2 threads showing past the nyloc nuts, suggesting something might be missing. Will make up a set of spacers for it. Only Drmini here has quoted a thickness for the spacers as 1/8" but included a question mark. |
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| Author: | eightfifty [ Tue Jun 27, 2023 1:11 pm ] |
| Post subject: | Re: Rack teeth count |
There's a drawing of these spaces in any of my Engineering Series books - although the thickess of the strip is not shown. The strip is 0.099" thick material. I've redone the picture above to show the significance of the space available. |
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| Author: | Bill B [ Tue Jun 27, 2023 5:13 pm ] |
| Post subject: | Re: Rack teeth count |
eightfifty wrote: There's a drawing of these spaces in any of my Engineering Series books - although the thickess of the strip is not shown. The strip is 0.099" thick material. I've redone the picture above to show the significance of the space available. Have found the drawing in your book. As the spacer wasn't mentioned in the text, I had no idea what its purpose was. Thanks again. |
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| Author: | eightfifty [ Tue Jun 27, 2023 5:53 pm ] |
| Post subject: | Re: Rack teeth count |
Yes you're right. But there is mention of them in the Cooper S second edition which has been available for a while. I add to these books all the time as a result of the interesting questions raised here and produce a new edition when there's enough changes to make it worthwhile. If there is something missing that I feel should have been mentioned, I often provide information and a drawing on this forum. The first pass on these books just used a parts book for reference, but of course many details not mentioned are of interest some of which I don't know about until someone asks the question. |
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