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propshaft or not

Posted: Sun Apr 12, 2015 2:29 pm
by twin40dave
Hi guys I've had my V8 humber on the road for about six weeks now and ever since its first motor way journey it's had a vibration from the backend but IT'S not always there there first I went and got my wheels balanced. Still vibration but I can't narrow it down to what it is a rand the company who made my prop hj chard from Bristol and they said it was balanced but I could take it off and they would re-balance it which I will have to do just to eliminate it but it's just weird that it's an intermittent vibration I was wondering if you guys could shed some light on this
Cheers Dave

Posted: Sun Apr 12, 2015 3:07 pm
by JSF55
I've had tyres flat spot after sitting too long in one place in the garage, could it be this ?

Posted: Sun Apr 12, 2015 3:43 pm
by ChrisJC
You need the centreline of the diff pinion to be in the same plane as the gearbox output shaft, so for example if the gearbox was dead horizontal, the diff pinion would also need to be dead horizontal.

If the pinion was pointing skyward by 5degrees, so would the gearbox.

And the joints on the propshaft have to be correctly aligned.

If you can't meet those requirements, you can always get a CV joint propshaft as was fitted to the SD1.

Chris.

Posted: Sun Apr 12, 2015 4:15 pm
by kiwicar
Also while the gearbox O/P and diff I/P need to be parallel (in the same plane) they need to be off set from each other so that they and the prop-shaft do not form a straight line.
best regards
Mike

Posted: Sun Apr 12, 2015 4:18 pm
by twin40dave
Thanks guys I will check them out this week they both make sense

Posted: Sun Apr 12, 2015 5:31 pm
by Ian Anderson
One or more tyres delaminating

Almost you can hear the vibration more than feel it but it will get worse and then the tyre will eventually let go

Jack wheel up and spin it attack surface with a piece of chalk to check if the tyre is actually round

Ian

Re: propshaft or not

Posted: Sun Apr 12, 2015 11:49 pm
by stevieturbo
twin40dave wrote:Hi guys I've had my V8 humber on the road for about six weeks now and ever since its first motor way journey it's had a vibration from the backend but IT'S not always there there first I went and got my wheels balanced. Still vibration but I can't narrow it down to what it is a rand the company who made my prop hj chard from Bristol and they said it was balanced but I could take it off and they would re-balance it which I will have to do just to eliminate it but it's just weird that it's an intermittent vibration I was wondering if you guys could shed some light on this
Cheers Dave
Change wheels/tyres front to rear.

Check wheels are correct fitment and spigot aligns correctly.

What is the design/construction of the propshaft ?

Posted: Mon Apr 13, 2015 6:33 am
by unstable load
Like ChrisJC said, along with the flanges needing to be parrallel to each other AND slightly off centre, so the crosses of the joints need to be correctly set along the shaft. The yokes need to be in the same plane at each end and not angled with regard to each other. Look at the main picture on this site for what I mean.
http://www.pruftechnik.com/solutions/ap ... nment.html