OK brains trust. I have a conundrum to air. (Apologies for the long post, too)

Firstly the background. Maurice is a 1967 1100S with only 90,000 miles under the belt and nearly all original in the mechanical department. As he was beginning to dribble a little more than his owner, I decided it was time for replacing driveshaft, timing cover and primary gear seals, so out came the whirly bits. All the evidence suggested these were in fact the originals!

As I have an extreme dislike of the rubber cross joints I also have sourced over time a set of Hardy-spicer inner joints and the associated bits such as diff output shafts etc. While the mechanicals were on the bench I figured that sine I had to dismantle the diff assembly to change the shafts, I'd also go the extra mile and fit the 3.444 crown wheel and pinion I had standing by as well.

Maurice is a 12Y engine so had a 3.765 crownwheel/pinion assembly. My calculations indicate this should drop the revs at a 100kmh cruise by about 400rpm. Easier on the ears, but still in the power band. All fine in theory. I am given to understand that the joint assemblies are an easy interchange. Hmm, but are they?

Diff installed, gearbox and engine gaskets and seals all buttoned up, in went the motive lump. H/S joints bolted up at the diff fine. Then I proceeded to re-install the hubs, only find that the top of the hub simply wont go far enough in for the ball joint to drop in. Empirically it seems that the actual drive shaft must be a few mm longer than required, or, conversely, that the H/S assembly is a tad longer internally than the rubber bizzos and their associated drive flanges.

A search of the parts book isn't very helpful. It shows the drive shafts for both manual and automatic boxes (auto fitted with H/S joints) are the same part numbers (RH 17H8598 & LH 17H8599) This says to me that the bloody thing should fit?

Am I missing something here? Is it a rookie error that I'm making? Having never dabbled with H/S joints or rubber cross thingies before I accept that if there's a mistake to be made, I will make it. My first thought is to perhaps grind off a couple of mm from each drive shaft spline, but that does seem a bit butcherous.

I treasure your thoughts and advice people!

Cheer, Pottsy

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Smile Up at The Trucks!

OK, I've just sussed out that there is about 15mm difference in the length of the joint assemblies (see below). That explains my issue I guess.

I see only three possible solutions.
1. Pull it all out again and revert to the rubber jiggers. (I REALLY don't want to do this)
2. Perhaps fit a longer lower arm, although it's already a 1.5 degree arm, and that would not address the problem in the centre of the wheel arc.
3. Cut/grind/linish the inner end of each shaft by 15mm at least. Smacks of butchery, but should work.

I've yet to measure the depth inside the shaft side of the trunnions. Perhaps the H/S one is shallower? We'll see.

Opinions?

Cheers, Pottsy

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Smile Up at The Trucks!

I swapped my mini from the rubber cross joints to the Hardy Spicer ones and the driveshafts worked fine

Your Hardy Spicer uni joints appear to be a bit longer than the common mini ones (I don’t know if they are compatible with Morris 1100S but I would think so?). If you compare the length from the flange to the universal cup there’s a fair difference to yours. I don’t know if these would solve your problem but worth a try if you can find or borrow one

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OK, been doing a bit more investigation.

The output flanges for Cooper S are listed on a couple of Mini parts sites as part number 22A1152. The same part number is listed for the M1100 auto H/S coupling.

The Diff assembly for Cooper S is listed as BTA145. The same number as that listed for M1100 auto.

The sliding joint assembly complete for Cooper S is 27H7880. The same part number listed for M1100 auto.

The drive shafts obviously are longer than the Mini ones, but the same for auto and manual M1100.

I am now seriously buggered if I can see where the problem lies, unless the sliding joints I have are not, in fact, for a Cooper S.

Research and measurement will be ongoing. Incidentally, I'm using the M1100 parts catalogue PUB1013M for reference.

Cheers, Pottsy

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Smile Up at The Trucks!

The Cooper S units appear to be shorter at the diff end than the ones in your picture.

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Cheers Dave.

Have to agree Dave. Here's a pic of mine with a ruler. Overall length is 150mm. (Looks wrong because of parallax)

If anyone can measure a Cooper S one we will have a definitive answer I suspect.

I'm also curious about the casting number F1880R. May be a red herring of course.

Cheers, Pottsy

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Smile Up at The Trucks!

Those joints are off a Morris 1300 auto, I have a set exactly the same, and that is what I removed them from. And as you have discovered, not the same as Cooper S.

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Steve

Gradually the mystery is resolving! Thanks Steve.

However, given that the 1300 auto was still an ADO16 I can't help feeling they should fit. However, I think I've cracked it.

Somewhat amazingly, a Mini driveshaft is shorter than the 1100 one, but this still fits the splines. Given I need to have a shaft shorter by 15 to 20mm with these H/S joints, I tried a Mini shaft in comparison. Blow me down if it doesn't look like they will fit!

In the picture the difference is only 30mm. The splines in the slip joint are fully in the yoke, and the shafts as shown are at what would be their normal operating position, ie, roughly horizontal. There's not enough extension at the extremes of suspension travel for the splines to come out of the yoke by more than a few mm.

I reckon this will work. What do we all think?

Cheers, Pottsy.

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Smile Up at The Trucks!

This picture from the 1300 Auto manual shows the UJ to be smaller at the diff end. I real8se it is a drawing but the size and shape can clearly be seen. Yours appear to have a larger gap between the flange and the bearing.


That being said if the Mini shafts work then problem solved.

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Cheers Dave.

We Have a Winner!

While the solution using the Mini shafts might have worked, I was uncomfortable with about 1/3 of the inner spline being out of the yoke in the normal drive position.

Thanks to a Good Mate (He knows who he is!) I was able to not only do a comparison with "real" Cooper S H/S joints, but also obtain a pair of the right ones for Maurice.

In the pic below the Cooper S unit is the bottom one.

I guess it's possible the dodgy ones are Morris 1300, but I don't understand why, if the track was wider, they didn't just use longer shafts and stick with the existing joints? Surely a re-designed drive shaft would be cheaper that a whole new joint, unless of course they already had the longer joints readily available. We may never know!

In any case, Maurice is now going to get put together again and will terrorise the streets of Melbourne some more!

Thanks for all the help people. It's what fora like these are all about.

Cheers, Pottsy

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Smile Up at The Trucks!