Morris Minor Owners Club

Check the angle of the pinion shaft versus the gearbox output shaft, they should be parallel, both horizontally and longitudinally.
If they're out you have some adjusting to do.

Wish I'd never sold the orig diff now... If it ever stops raining I will check out this angles between gbox and shaft. I'm sure they looked ok before. I will try this week and replace the prop or the diff. These seem to be worst suspects, although lots say bad diff would be v noisy. And it's not.

Hey ho.....!!! Updates to follow....

PB

bmcecosse wrote:Always go back a step when you hit problems. I believe it's highly unlikey to be a problem with the prop shaft - provided the U joints are not badly worn. So yes -try another final drive. But also check in case the half-shafts are bent....

If they are bent, the Mmc Birmingham must have sold them to me bent... Will check for sure!!!

PB

It's possible they are standard shafts that have been heat treated - if so - they may have bent in the process......

bmcecosse wrote:It's possible they are standard shafts that have been heat treated - if so - they may have bent in the process......

bmcecosse wrote:It's possible they are standard shafts that have been heat treated - if so - they may have bent in the process......

They are newly manufactured chunky ones but possible that they are bent I suppose. But they were not a problem to fit and I guess if they were bent they'd be a bugger to get into the diff???

Just a point to check since the vibes only came along after you fitted them. Easy enough to swap back to standard I guess..

These vibrations can drive you absolutely crazy. On my Series II it was propshaft and uni joints. Once straightened and balanced with new joints the difference was astonishing - it felt like a modern car!

On my EJ Holden (Kind of like a PB Cresta) I had a very bad shake at 40 mph plus, got intolerable at 50 mph. No matter what I tried it would not go away. In the end it was a combination of

1: Bent Propshaft *PLUS*
2: Bent Half Shaft *PLUS*
3: Loose Pinion bearing in diff.

If the vibration is no different coasting downhill in neutral at 40 mph its got to be one of the above or a combination.

Good luck!

Hummmmmm

Ok. I tried a borrowed prop shaft today. No difference.

Think issue is worsening. Any chances it could be the flywheel??

Well, I think that if it were the flywheel, it would produce the vibes even when stationary, no? Going back to your original post, and the things you changed, the diff seems to be the only thing that could account for your present misery.

Bazzalucas wrote:Well, I think that if it were the flywheel, it would produce the vibes even when stationary, no? Going back to your original post, and the things you changed, the diff seems to be the only thing that could account for your present misery.

Good point. Well made.

Misery?? Spot on...!!!

Have you swopped the half shafts out yet??

No. They are next on the list...

Reading back to the start of this thread - I notice it's just had a 1275 Marina engine... How was this connected to the gearbox - is it a standard 4 speed Minor box? What flywheel is on the engine? Is the bearing in the crank tail good?

bmcecosse wrote:Reading back to the start of this thread - I notice it's just had a 1275 Marina engine... How was this connected to the gearbox - is it a standard 4 speed Minor box? What flywheel is on the engine? Is the bearing in the crank tail good?

It's a recon engine fresh from the engineers. Standard Morris box. Backplate and modified flywheel from Mmc. Engine and flywheel etc were allegedly balanced. ....

Find a longish hill with not much traffic and coast down with engine switched off. If the vibration is still present it won't be your flywheel/clutch etc.

I think I'm going to have to go along with the consensus here and say that it must be in that new diff you had fitted.

David53 wrote:Find a longish hill with not much traffic and coast down with engine switched off. If the vibration is still present it won't be your flywheel/clutch etc.

I think I'm going to have to go along with the consensus here and say that it must be in that new diff you had fitted.

Hope so. It's the easier remedy!! Will find a hill but prob not be til Friday.

Ok. Down hill. Engine off briefly. 50 mph. Vibrations.

Think the prop MAY have made small difference at 40mph.

Will try half shafts and diff

Gearbox seems to be popping out of third on few occasions now- could this be linked??

No - just a worn gearbox.

IT IS FIXED!!!!


It was caused by.......



THE GEARBOX!!

Thanks for the help guys n gals!!!

Care to elaborate?