Excietment tinged by bad vibes.............

Post by **muggwump** » Sat Jun 28, 2008 9:12 pm

Hi All, just picked up my new (to me) Minor convertible. She's in lovelly condition with lots of sensible upgrades for reliable safe motoring. I'll list them all when I have more time.
Problem is that there is a very bad vibration from some where between the propshaft and the rear axel. It comes in at about 40mph and doesn't really quieten down until you hit over 60!! and this vibration is really bad. It's like the car is going to shake itself to bits

It is worse if you ease of the accelerator or dip the clutch.
Any ideas?? I'm not that mechanically minded so any help is very much apprieciated.
Also there seems to be oil leaking from the diff drain plug and the bottom of the gearbox. The car has been standing for a while and the blast back from North Yorks to Lincs is the first long journey it's done in a year. Could it just be that the drain plugs need tightening (he says hopefully.
Again any suggestions welcome.
These 'Minor' troubles are a real shame because the car really is a beauty, clipper blue with a navy hood. I will post pics soon

Post by **d_harris** » Sat Jun 28, 2008 9:52 pm

Definatly worth tightening up the drain plugs as they are likely to be the cause of the leak - make sure that theres enough oil in there as well.

With the vibration, I'm not too sure, is is soley related to road speed or does it depend on which gear you are in?

Post by **muggwump** » Sat Jun 28, 2008 10:33 pm

It comes in at around 42mph just as your changing up from 3rd to 4th gear, and is really bad when you dip the clutch to change gear so as though it's worse when there is no engine load.

Post by **Welung666** » Sat Jun 28, 2008 10:37 pm

Could be a worn universal joint or the flange is loose or worn.

Post by **ASL642** » Sat Jun 28, 2008 10:38 pm

Check the universal joints on the propshaft. This sounds like a problem we had recently with one of ours - ended changing the propshaft. You can change just the u j's and dont have to change the complete propshaft. We had a spare which made it easier.

There was a decided clonk when in gear and moving forward, then slowing down about level with under your back seat.

Post by **rayofleamington** » Sat Jun 28, 2008 10:54 pm

As well as the UJ's, check that there is no play where the prop fits in to the back of the gearbox (it fits in a plain bush that wears over time and wears quickly if the gearbox oil is very low).
Also check that the diff flange runs true.

Post by **Kevin** » Sun Jun 29, 2008 8:28 am

Also make sure that the gearbox steady cable is not done up too tight as this can give vibrations it should only just have the slack taken out of it.

Post by **dalebrignall** » Sun Jun 29, 2008 9:28 am

have the ujs been greased recently,propshaft could be out of balance

Post by **muggwump** » Sun Jun 29, 2008 9:56 am

Just been and tightend the gearbox drain plug and the engine drain plug. The diff drain plug is leaking as well but don't have a tool forthat.
I have noticed a small hole in the bottom of the gear box. It's about 3 inches back from the front of the box and directly at the bottom. It has a split pin dangelling out of it???? any ideas, it certainly doesn't look correct.
I have checked the front of the propshaft infront of the UJ for play and it seems fine but the front uj has a couple of mm play, is that normal or should there be no play at all?
The rear UJ dosen't seem to have any play in it.
I'll jack up the rear of the car later and see if the flange thingy that the rear UJ bolts to is running true.

Post by **paulk** » Sun Jun 29, 2008 10:53 am

The hole at the front with the split pin in is perfectly alright. Its in the bell housing around the clutch and is standard.

Post by **callyspoy** » Sun Jun 29, 2008 11:31 am

i had a vibration just like that when i had the supra, scariest thing in the world, did a little check and it was the prop nut and bolt were loose, tightened them up and it was great! but i guess you would have noticed that when you checked for play in the UJ.

Post by **muggwump** » Sun Jun 29, 2008 4:32 pm

Ok so should there be any play at all in the UJ's?
Also is changing the UJ's a difficult job? I can't see where they come apart.
If its the flange thing that attaches to the rear UJ, does anybody know where I can get just that bit. Ilooked on the ESM site but didn't see it listed.

Post by **Stig** » Mon Jun 30, 2008 1:33 pm

I had very similar symptoms from a loose nut on the nose of the diff - as they're supposed to be tightened to something like 140 ftlb it wasn't what I was looking for! This gave a little vibration under power and a lot of vibration when lifting off or coasting. Tightening the nut cured it but I replaced the UJ as well as it had probably suffered from the experience.

UJ's aren't too difficult to change yourself. I thought there was a 'tech tips' article on the MMOC site but can't find it now. It should be on the Tech Tips CDROM though and in workshop manuals.

Post by **beechford** » Tue Jul 01, 2008 8:40 am

would nt be a bent wheel by any chance or just out of balance. Or may be a flat spotin the tyres after standing for a while,try jacking up 1 wheel at a time and spin by hand to see if theres any wobble there. just for fun and its cheap too,ceeyas

Post by **d_harris** » Tue Jul 01, 2008 12:43 pm

A 3/4" (I think, but sure someone will correct me if I am wrong) ratchet will normally fit nice and snug in the diff drain plug and you should be able to do it up with it.

Post by **rayofleamington** » Wed Jul 02, 2008 12:14 pm

the front uj has a couple of mm play, is that normal or should there be no play at all?

There should definately not be that much play in the front UJ!
If it's left like that too long, it will either self destruct or at least damage the output bush in the back of the box:(