Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Clanking Sound

Hi there
New M3W owner. I keep hearing a clanking sound from the back, particularly when I downshift. I’ve read a few posts about bevel box and control arm issues but looking for a little more detail and perhaps confirmation. It sounds like someone dropping metal pipes from a truck. One of the posts said it’s normal but hard to believe given how loud it is. I read one post about tightening the belt but not sure how to do that. Any thoughts?

The belt can jump if it is not tight enough more usual on hard acceleration in lower gears when you will get a loud bang bang from the rear, not a metallic sound.

The belt tension should be such that you can this the belt approximately 45 degrees in the centre between the two sprockets.

To tighten the belt you need to remove the split pin in the rear wheel spindle undo the nut, 36mm spanner you may also need a 24mm spanner to hold the other end of the spindle. You can then adjust the tension using the tensioning screws, 17mm spanner, on the rear of the swing arm, undo the lock nuts first. Tighten the locknuts and then the rear wheel spindle and replace the split pin.

I am also a new M3W-owner. I had the clancking sound when shifting. The sound increased, and I started to experience vibrations from behind. After a while I couldn’t drive more than 50 km/h due to the vibrations. I brought it to the dealer. The problem was a loose joint where the bolts/nuts were loose. Apparently this happened rather often. They tightened it and used locktite to fix it. It was fine after this, but now I can hear a faint clanck when downshifting. I have asked the dealer to check it.

If you have a M3W with the NVH kit on (post 2014- the big steel beam between the bevel box and the gearbox) the rubber mountings can allow the bevel box to move under acceleration and deceleration. It nods and the front input flange can hit the chassis, there will probably be some witness marks. Some cars are more prone to this than others and the drive belt has to be a bit tighter on NVH equipped cars. Phil Bleazey has produced a BB mount that fixes the flexing in the BB mount. Info here: http://www.bleazey.co.uk/M3WBBinstallationmanual.html. I have this fitted to my car and it works well.

Do you know where the "loose joint" that happens happens rather often is RHBigSmile? It would be good to know but your description is a bit vague.

I don’t know where it is, only that it is related to the BB-box.

I had a clanking on deceleration. Seems the dealer left WAY too much slack in the belt

From recent experience it is possible for the belt to come into intermittant contact with the small stub mudguard as fitted when new.
Mine was a very specific circumstance due to bevel box re mounting so may not be relevant.
It made itself known as a series of 'ding' sounds or 'clanks' on hard acceleration.
Check for contact marks on the mudguard.

that is exactly what mine was doing

Loose belt, 90% sure.....