Can tyre 'flats' be shown on a balancing machine?

Swap wheels front to back, if the vibration doesnt change then its something else. My moneys on propshaft.

Thats a good point, I bought a cortina once that felt like it had square tyres, I changed the wheels for a different set, no different. Went for the prop next, it was bent!

I do use him and someone else . On the machine nothing seemed untoward on the wheel at all. I may just jack up each corner and give them another spin mind you.

I also thought prop, except it looks brand new complete with weights on it. I have turned it 180 degrees at the axle end tonight (as my MOT man suggested). Either my dad and I are going nuts, or the vibrations have calmed down a touch.

Bar the prop being balanced incorrectly, it does have a toothed disc on the front of it (mounted between the gearbox output shaft flange and propshaft flange. That was put there so as to make an electric speedo drive. I cannot see it being that though considering people use much thicker ally spacers on their props.

Sorry, 90. It is still there though are the vibrations, just a little less.

Has it got IRS ? If so worn drive shaft CV / UJ joints could be another cause. Might not even be worn - just seized.

Paul H

I had a Mk3 cortina in last year that i chased a vibration on, i had the wheels balence 4 or 5 times and after 3 hours of after hours work in the tyre shop it was a combination of squared off tyres (from being parked for months on one spot) and buckled wheels, when i put the 2 worst tyres on the 2 worst wheels the car was undrivable over 40 MPH.
The machine would show a perfect balence BUT the balencing machine only span up to 50 odd MPH any speed over that and thing shook like Elvis having a fit, this was on new wheels and tyres that although they had done under 200 miles had sat for 3 years and only driven to shows a couple of times a year.
All the above was compounded cos the owner had fully polybushed the entier car, on rubber bushes it would have been way less noticable.
The way i found the problem was to get a pointer on the tyre and rim and spin it on the balencer with the cover off and watch the run out, eventually after hours of moving tyres round the rims i got the weights down from 135G to 25gramms and the car was way more drivable.

Not sure what type U/J are on the rear but if they are anything like the mini ? when you undo the Uclamps the rubber cross may well just fall appart like prop doughnuts do on a lot of fords? Age can harden them in a certain postion and although they look OK when free of the clamping forces they look bent ?
Output shaft bearings in the box is another vibration point but usually they can be felt through the gearstick?
keep at it i'm intreaged as to what it is now