Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Rear universal joint touches transmission tunnel

Hi, I have a 4/4 2 seater 4 years old, when I have a passenger and let’s say drive enthusiastically, i occasionally get a noise coming from the rear axle, yesterday I checked under the car and evidence of the rear uni joint coming into contact with cast alloy tunnel casing. It has accured a number of times over a few years. Any thoughts ?

No. 1 fix contain my drive I g habits! Never happens when the misses is the passenger.

I had this happen occasionally on my Plus 4 before I fitted the 5 link rear suspension, particularly on hard right hairpins. This continued to occur even after I had a panhard rod and the more rigid 5 leaf rear springs fitted.

There may a couple of reasons why this occurs on your car.

1. At about the time your car was built Morgan were being supplied with rather poor quality springs. Our 2012 car had only 9cm (or less) of unloaded ground clearance under the centre crossmember when we got it home from the factory.

2. Under hard acceleration the front of the diff twists upwards. Anti tramp bars are not normally fitted to a 4/4.

To resolve points 1 and 2 a new set of 4 leaf asymmetrical leaf springs would help. I'm not sure if these are still available from SSL.

3. Under hard cornering the axle will move to one side slightly. A panhard rod will resolve that problem.

The combination of hard cornering and acceleration will combine the above two effects as the rear suspension is compressed and flexs due to the two forces being applied.

My solution has been to fit the 5 link rear suspension. Not cheap but it has transformed the car from a jolting cart to a comfortable sporty tourer. The 5 link suspension completely controls the movement of the rear axle.

By the way; the rear transmission tunnel is a panel of sheet aluminium, not cast.

If the noise is occurring mainly during cornering then I'm sure its caused by lateral movement of the rear axle. The remedy is to fit a 'Panhard' rod, Tim Ayres at New Elms supply the Rutherford Panhard and other fittings, not too expensive and quite easy to fit.

David, 2001 4/4 4 seater.

Sorry Peter that's not correct.
The rear most section of the transmission tunnel where it joins the back board is an aluminium casting.

It's unfortunately quite common for the propshaft to catch on it. It normally catches on about the 10 o'clock position viewed from the perspective of the axle. A panhard rod will normally restrict the sideways movement enough to stop the rubbing, and is a relatively cheap fix.

Simon @ SiFab.co.uk

I stand corrected Simon. I have even had the front part of the tunnel off. I must admit I thought it was flanged and welded sheet but I had other things on my mind at the time. This is mine in construction.



I'm glad you said "a panhard rod will normally restrict the sideways movement enough to stop the rubbing". On mine it did not

Hi Guys,
Thanks for your replies.
I will initially remove the cast alloy cover and use a rotary burr to remove material from the contact area. It seems they all do that Sir.

Thanks again.

That will be a job and a half in itself. Seats out, peel bach the leather trim, etc.

My recommendation would be to try fitting a panhard rod first. It will help the handling too.

Thats option 1, option 2: drive round corners like a grandad with poor sight.

You should be able to get in and clearance the casting with a small die grinder and a carbide burr from underneath
It won't be pretty but it will work
Use wd40 or candle wax on the burr to prevent clogging
And wear eye protection
Take it from someone who knows, having metal drilled out of your eye is not fun

Simon @ SiFab.co.uk

Your car is a similar vintage to mine. The rubbing you describe was one of the symptoms of the weak rear springs that I replaced last weekend. I went for 4 seater 4 leaf springs from Mulfab as we often tour with a lot of luggage on the rack. Very pleased with the result.