Talk Morgan Forums Morgan Sports Cars Morgan Plus Four, Supersport & Plus Six (CX & CXV Generation Vehicles) new cx member with odd noise

Welcome to the clonking drive shaft club!!

Yes, I have been back to the factory three times with this issue. It is a very common, not to mention irritating' issue. I have spent time with Mark Baldwin talking about this and spoken to MWS about it. The noise is emitted due to take up of the clearance between the male (drive shaft) and female (wheel hub) splined surfaces.
There is a very specific wheel installation process required to deal with it and even then, it will need to be repeated at least twice a year if the 'clonk' is to be avoided.

In summary:
Only grease the internal splines of the hub with graphite grease. Greasing the drive shaft only pushes the grease towards the inside of the shaft assembly, achieving little. Don't overgraze anything as all it does is spin out under centrifugal force and goes all over the palce (including the brake calipers!).
Using the octagonal spanner (I changed to spinners to ease wheel removal, that and they look better) tighten the nut approximately 3.5 full turns until hand tight. Give three decent blows with the mallet whilst wheel is off the ground.
Drop wheel to ground and give three more reasonable mallet blows. The wheel nuit self-tighten so overuse of force is not required although I must admit to giving mine four of five mallet blows when at ground level.

And that, apparently, is that.

On my last factory visit I drove away 'clonk free' but by the time I got home, the drive shafts were clonking again.

Frankly, I have stopped worrying about it, as irritating as it is. That and the squealing brakes!

The longer I have lived with my Morgan the more I have learnt that every car has it's own idiosyncrasies and if you love em, you learn to live with em!

We put up with a lot from Morgan but there is no way I would accept a clicking noise from wherever. remove the grease and start from fresh if it still persists ask them to change the complete set up for alloys as its not fit for purpose they should spring into action as its quite a big job. Em

^ I agree with Aerotaff,

A clonk is a clear indication of too much tolerance / clearance on the splines, it won't improve with age ! In fact the clonk will accelerate wear on the tiny face of each spline on the load side, suggesting additional grease packing...is er boll**ks, as a permanent cure

Trads don't clunk with the same wheel manufacturer, MWS

The cx unlike the trad wasn't designed for wires. There is a bolt on adaptor plate. In early cars the holes in the plate for the studs alloys bolt onto were to big causing wear. I am with Cooperman this needs fixing. If you live near Slough I would ask MWS to look at it.

Also are you sure it isn't slop in other parts of the transmission?

The oversize conversion plate theory which has raised its ugly head several times before is a more plausible reason for the clonking noise. It should be easy to check the splines interface though by removing all grease from wheel and hub and testing the fit by feel. On trads this only caused issues if the spinner or hex nut was not tightened sufficiently against the hub taper.

No doubt the recommended grease "cure" is a short term botch.

If it is the conversion plate oversize holes causing the issue I would be tempted to suggest taper nuts with matching machining of plate.

Be careful the splines can get v sharp.

Here's one I prepared earlier. April 2022.

It ought to be noted that the clonk is evident on CX P4's with auto transmission. I have yet to hear of a manual version suffering the same issue. However, that's no guarantee, as the original post states ...

Many thanks for the info The wire wheels are defiantly form over function. A bit like the rest of the car really