I was sold a reconditioned Australian steering rack to replace my Rover one, I remember reading there is a difference with the arms. Will this cause any issues?

I installed the rod ends 12 turns each but I am not sure how much I reduced the thread engagement during the alignment, it was 1-2° out. The toe out on turns is correct or at least within 1°

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

You won't have as much lock, the Oz racks have less travel, only 2.3 turns lock to lock.
But it should steer OK, people here have been mixing up racks and arms for years.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I am yet to check but apparently it needs spacers between the rack and body which would explain one of the issues I am having.

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

I have now looked at it and the rack is very close to the floor so I believe it does need spacers. When I installed the column I knew something was wrong but I wasn't sure what it could be.

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

Oz rack were fitted with a 1/8"? Thick spacer each side.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I sourced some spacers to fit, apparently they are only to reinforce how the rack is secured but I don't believe it.

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

The reason for these spacers and a comprehensive review of the different racks and arms fitted to the Australian Mini range (not Rover Mini) can be found in my BMC Engineering Companion book. The spacers are a result of the change of height in the casting of the rack housing which came about due to the inclusion of a ring spacer on the pinion, which in turn was the product of a change in the way the pinion was machined so as to reduce fatigue at the bearing shoulder. Some Australian racks have the spacers (with associated rack housing) and some don't. The use of the correct steering arms is a safety issue and one that should not be lightly dismissed. Some tie rods have a longer threaded length than others. As well, early tie rods have a smaller diameter and if used with a later seat will result in a dangerous condition of reduced contact at the inner end. The reduced turning circle found on some racks, particularly Moke, was achieved by welding a spacer on each end of the rack, most likely to reduce chafing of the sunraysia wheels and tyres at full lock. regards, Tony

Tony the late racks with the pinion spacer use the same aya6001 casting as the previous one without spacer did.
The casting is just machined deeper to move the bearing outwards.
I have rebuilt over 100 of these racks.

Spacers were used on all aya6001 racks.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I am definitely going to change the arms to the Australian ones from my van. When I mentioned the arms to the mini business who sold the rack and spacers he tried to say the arms only change the Ackerman angle (which is clearly not the only thing), there was no mention of the thread engagement which is concerning.

He is also who questioned why I would want to use the spacers and that they are only there for reinforcement.

I don't want to go around saying he doesn't know what he is talking about etc. but this is very concerning that he doesn't know these things. There is some clear information from BMC on another forum regarding the thread engagement issues when mixing rack and arm types.

Less critical but to question the quality of their work, the rack boots are secured with cable ties which are not suitable when doing an alignment without twisting the boot. It has also been suggested to me that this may mean the rack has been filled with grease not oil.

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis

Kevin, I am sure what you say is right, but 21A715 and AYA6001 have no pinion spacer. In late 66, a new rack was introduced which has a longer casting to accommodate a pinion spacer. Picture below. The problem was that the new rack was not officially given a new part number, just a revision note on the revised drawing. To avoid confusion, P&A gave it a number 6001A to identify it. The actual racks are both stamped 6001 but 6001A has an obvious extension to the housing where the pinion spline is. There is a service bulletin which covers this C31/69.

UK rack FAM7306 appears not to have a pinion spacer but for Moke, this rack was renumbered AYA6002 with spacers welded on each end of the rack to reduce turning circle. If AYA6001A is used without spacers, the rack will be crooked and the steering column will strain the pinion at the spline. The rack spacers are to accommodate the increased length of the casting boss so that the rack mounts square to the body.

There are six different steering arms`with angles either 23 or 27 degrees and with varying casting dimensions (thick or thin, some with tabs for a ball joint tool). Minimum thread engagement at the tie rod is specified as 12 mm. Some tie rods have more thread than others. I would recommend matching all these parts up correctly. In the 1800 range, there is a similar mix of parts, and on my (previous) car, some kind former owner had fitted arms with different angles on each side!

If I might add, if you are rebuilding a steering rack, it is essential that the pinion spacer be installed the right way up, with the inside chamfer pointing down towards the gear teeth.

Are there really 6 different kinds of steering arms?? AIUI there are 2 kinds of Oz arms (thick and thin (allegedly?? S and non S). (An old and bold (and very successful) racer I once chatted to said they always used the thin arms. If they hit something hard enough to bend them the damage was a lot more obvious (and easier to fix) than other damage that might caused by the shock transmitted by the stronger arms). The UK had 4 - thick and thin versions of the type 1 and type 2 (my labels) racks. Maybe the Sportspack Rover racks could be considered as a type 3 when they added the lock limiters to allow the use of 13" wheels???.

The ball joint tabs 850 refers to are probably the "ears" added to identify the type 2 steering arms (they are certainly don't play any part when using any of the ball joint breakers I have).

The advantage of the type 2 rack is the 3 odd feet it takes out of the turning circle. Type 2 setup (rack and arms) drop straight into a Mk I.

While the mixing of type 1 (and Oz) arms with type 2 racks does alter the Ackermann angles this has not been an issue with mates who have done so. (Some professed complete ignorance of the problem). Similarly, the ball joint engagement with the tie rods of mixnmatch setups may or may not be an issue. If there is an issue (insufficient engagement - which is easily checked when installing bits) then the usual solution was non Mini (Triumph I think was preferred) ball joints. UK Mini specialists (used to??) provide these.

Cheers, Ian

Yes indeed, six different arms (that is, 6 pairs) for the MIni and Moke range from ADO15 to YDO23, all pictured in the book. I will refrain putting a picture of the book in my post. The part numbers are 21A73, 21A1464, AYA4030, BTA894, AYG4094, BTA896. Angles are either 27 or 23. Some are thick, some are thin. All differ in some other detail.

Out of interest, I've looked into the issue of the tabs added to the side of some arms and the drawing refers to them as "extractor lugs" as shown below.

Regards
Tony

So there wasn't as much difference as I was expecting, I guess about 1/4" but relative to the amount of thread engagement it is a lot. Most importantly the spacers are now installed so the rack is sitting properly.

Thread engagement with incorrect arms.


Arm comparison. Notice the ears/tabs, it would allow for a larger range of ball joint separator sizes to be used.


Alignment done at 11pm outside.


Just have to bleed the brakes tomorrow as I had to disconnect them to lower the subframe. I would've done it tonight but it isn't legal to make noise after 7pm

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1986 Mayfair (998 auto), 1974 S, 1974 Van, 1972 PMG Van

Too many minis