Steering Rack Overhaul- Peter and Spider

[Kiwi Craig]

This one for Peter and Spider Chris,
I posed the question on Monday, but it ended up in the How to.. section
Could you please explain in detail exactly what is required to fit the 1622 bearing to a Mk 1 rack?
Please explain where and by how much machining is required.
Would Peters idea to use a 1622-2RS sealed bearing be a better idea, particularly for the top bearing that would get minimal/no lubrication.
Thanks in advance.

[Spider]

Cheers Craig.

I haven't fitted them to a UK MKI Rack, but recently fitted a set to the UK MKII.

In that case, it was a later type that had the spacer in the Pinion, I was able to leave the spacer out, fit the bearings and then shim as normal. It did take a few more shims that usual. I had done them previously by machining a recess in to the bearing cover cap and thinning the spacer.

Off the top of my head, I don't think there's enough 'height' in an early UK MKI Housing to fit these bearings, you'd need to shorten up the teeth on the lower side of the pinion - maybe. You'd need to do some measurements first. The later UK MKI racks have a bit more room here, though the 'intermediate' MKI Rack, you'd need to shorten both ends if the teeth on the pinion. There was a late MKI Rack that had a separate spacer, you'd leave that out.

The bearings I used were the RS types. I left the seals in for the upper bearing, but removed them from the lower, though, leaving both as sealed bearings would be fine.

[Peter Laidler]

Spider has really hit the nail on the head. The trouble I found, after rebuilding a batch of 8 or 10 for some pocket money was that there are several variants. Chris describes these mid to late Mk1's as 'intermediates', using a separate spacer and some original parts and later parts until they eventually become standard..... and then they become 'centralised' Mk2 spec.

I have had to machine spacers too, to get the pre-load right. Having a few to play with really opened my eyes to the variables. Ironically, I've still got a Mk1 type casing tube and bits here that I couldn't assemble. Clearly I'd used the original parts elsewhere and..........

Using spacers to set the pinion teeth centrally on the rack teeth to cater for the height/thickness of the new bearing is perfectly acceptable providing the pinion cover is sealed and exerts the correct loading onto the pinion with no slack (just been told that what I should have said was 'end float'. Sorry!). The yoke keeps them in perfect mesh.

Added a bit later..... Interestingly, if you ordered a new rack and pinion, always a matched set, after Mk2 production commenced, you'd only get a Mk2 type, regardless of what you ordered! So I can imaging Mk1 rack rebuilders in the late 70's onwards facing the same conundrum

[Kiwi Craig]

Thank you very much for your info Peter and Chris. Much appreciated.
I will look into it further.

[Kiwi Craig]

Well a Bit of News here....
I dismantled my rack , the top pinion bearing is shagged, the steel cage has broken.
The bottom bearing looks just fine.
The number on the bearings is N 7975 which ARE available from Bearing Revolution in the UK.
Price is a hefty GBP33 for such a small bearing, scarcity value...
When they then quoted a ridiculous GBP60 to send to New Zealand I thought I might give it a swerve !!!
However.... the 1622 deep groove bearing, either sealed or not, is quoted as the same ID and OD but 13/32" wide
compared to the N 7975 which is 3/8".
I can't see that 1/32" wider can make that much difference to the position of the pinion on the rack, and certainly not enough to bind with the rack.
With 2 new bearings the width would increase by 1/16" which may require making up a thicker shim to get the pre-load right.
The 1622-2RS bearing is available here in NZ for $10 (GBP5) which is a far better proposition.
I have since contacted a fellow Cooper S owner here in NZ who may have a source of used original bearings.
If he can find some in good condition I may fit one of them.

Peter and Chris, and others, what are your views ???

[Spider]

The 1622 is wider and hence why I've made suggestions of either leaving out spacers or machining various parts.

If you can get the real deal, then that makes life much simpler. I've reused many Rack Bearings, of course, we all like to replace with new all the 'wear' parts in any assembly, but when they aren't available, then alternatives, including good used bearings, need to be considered.

As you, Peter and myself have found, often the upper bearings are no longer serviceable, however, 5 times out of 10, the lower is fine.

Just be sure to clean it up and then have a good look at it in the sunlight with a magnifying glass. Because of the motion (limited movement) and loads (often impact), to the naked eye, they can appear OK but the balls can have flat spots and the rings uneven wear. You can sometimes feel them too.

Having said that, I've found with the 'other' 5 out of 10 bearings, if the rack has been assembled with grease, or the boots have torn and it's run without oil, then there's usually very little of the internal parts that can be saved.

I've long felt that these really should have had tapered roller bearings rather than balls, mainly as they cope better with impact loads.