mk1-forum.net

Hi guys!

Have a mk1 Cooper S here wich has the rubber type couplings on the driveshafts/diffoutputs...

Two years ago someone changed to the Minispares plastic QH-Type couplings and now they've broken again.

I suspect that the mecanic who changed them just tighten the U-Bolts & Nuts to much so they broke.

On the side they don't broke they are more Oval than round...

Is this a common problem?

Till now i never saw one broken...

Best regards

I’ve seen the plastic drive couplings broken a number of times in competition Minis. For me the rule of thumb is any engine putting out more than 80 BHP it is Hardy Spicer couplings without a second thought.

Alan

Those U bolts are stupidly tight.

They should be tightened so that 1/16" of thread protrudes beyond the lock nut.

As above. An avoidable failure caused by not following the fitting instructions.

TAKEN FROM MINISPARES SITE:
The rubber coupling alternative made by Mini Spares has superior nylon cups with needle bearings. U bolts should be tightened to 8-10lbf.ft-do not over tighten.

What i suspected was now confirmed by you guys!

Thanks for the help!

The first time these came on to the market I bought a pair straight away and they had a Steel adaptor cups instead of Nylon , never seen another pair since .
Too harsh or too expensive wouldn’t know but they were boxed Hardy Spicer .

Not sure if it is an illusion carried by the picture but in the last picture with the complete coupling, the flange on the gearbox looks bent

roymck wrote:The first time these came on to the market I bought a pair straight away and they had a Steel adaptor cups instead of Nylon , never seen another pair since .
Too harsh or too expensive wouldn’t know but they were boxed Hardy Spicer .

I have part of a set of those in a box in the shed! Never seen another set either

Some discussion about the metal type here: viewtopic.php?f=3&t=21194

Available [at a price...] from Heritage Garage in the USA.
http://www.heritagegarage.com/parts_hg5 ... g_set.html

I have tried both the rubber and plastic joints. The rubber seem much more reliable and study. They saw over 90bhp ATW.

swindrum wrote:

roymck wrote:The first time these came on to the market I bought a pair straight away and they had a Steel adaptor cups instead of Nylon , never seen another pair since .
Too harsh or too expensive wouldn’t know but they were boxed Hardy Spicer .

I have part of a set of those in a box in the shed! Never seen another set either

Interesting! I have a few sets of the steel versions here.....used them back in the day on my 1071 race car....were very reliable....
Glad I held onto them.....

After some issues with the Carb and Corvid19 pause. I could go for a 10 km testdrive and after that i found this:

This time the couplings where by sure not overtighted!
I tightened them with 10 lbf.ft as described on the Minispares site.

Any ideas?

The ones on my car are white plastic , wonder if they have altered the plastic specification?

Don't think it tells us anything we don't already know but stumbled across the original fitting instructions for QL5000 couplings (From 1991) earlier when looking for something else in a pile of paperwork....

If it is the same side that broke again I would immediately guess that one of your yokes is bent. Depending on where you are at I have a box of parts from those. If you cover shipping I'll send you another cap. I also have some yokes if one of yours turns out to be bent.I am in California.

Brian

Just a thought .. i am fortunate to have a 4 post lift & with the front of car jacked up i spun the wheels while looking upward & was very surprised to see one drive shaft was "Bent" this slight but actual bend along the length of the shaft was very apparent when the drive shaft was removed & changed. How it became bent i have no idea probably from past Rally Days .. suggest to just check your drive shafts>

When I built the Orangebox to go rallying I used MiniSpares QL5000 but had trouble with them breaking up, went through two sets in very little time, unusual for their stuff is usually pretty good. I then used a set of original ' white ' QH ones and they did three years rallying with 1293cc with no issues at all.

A few years back I found a new set of steel QH QL5000 at Bingley Minifair and now have theses fitted, brilliant things.

I allready checked the driveshafts on a late.

The coupling on the right side was bent and changed. Now the left side has gone, but the couplings and shafts are straight.

Hope its good now or i change to rubber couplings...

Rather than buy MS repros don't forget you can refurb the old white QH couplings with new GU102 Triumph Stag UJ's - see:-

viewtopic.php?f=3&t=24206&p=207415&hili ... ag#p207415