Balance your Propshaft!

[David53]

Well, I have fitted the propshaft after fitting new joints and having it balanced. My God! It's a different car! As you know the new Uni joints had made the shaft terribly out of balance giving me nasty vibrations. But it is now clear that the shaft had always been just a little out of true, and was sapping energy from the transmission to the wheels. The car is now so incredibly smooth, and feels like it has about 20% more power. Little parts on the dash that used to rattle at speed no longer do so and it is just so much more pleasurable to drive.

So if you've never had it done it might be worth shelling out the money for a professional balance!

[kennatt]

if its only slightly out,and not due to worn ujs ,two large jubilee clips put on the prop work, by driving then slowly moving them round the prop driving again and moving them a bit and so on and so on untill the vibration smooths out.Done it several times on mgbs which were a bit prone to the fault.dosent work if the prop is wildly out though.Cheaper than a pro job and certainly worth a try before resorting to it.

[David53]

Not sure how much in the UK - here in Australia it was $120 (about 80 pounds). This included getting dents and dings out of it and balancing. Absolutely worth the money in my opinion!

[MarkyB]

Nice job!
20% more power and no rattles! It must feel like a new car.

[bmcecosse]

I don't see how fitting UJs made the prop go out of balance - were the parts refitted in exactly the same orientation with the new joints?

[David53]

I'm not sure either Roy. It's possible I didn't fit them correctly as I know the propshaft place checked them over when they got the shaft. All I know is the car runs much smoother than ever before and has more energy than it used to have. You notice the difference in an 803!

[bmcecosse]

Well -I did have 3 X 918cc Morris 8Es at one time, and they were truly pathetic. And then an 848 Mini......soon greatly improved by fitting a 1098 ! So yes - I do vaguely remember low powered cars....

[chrisryder]

in a similar vein i replaced my prop uj's a few months ago and then found it to be awfully bad, barely happy going over 50 without fear of everything falling apart.

i fear i may have got a flange the wrong way around, which would indeed hinder the balancing, but after taking the prop off and turning the one flange around (the one i wasn't sure i'd got right) it made it no better, or worse really!

i succumbed and found a place to balance it for me. i left it with him and when i went back to collect it he told me that the new circlips that came with the UJ's were too thin, so didn't centralise the UJ fully. he fitted some thick ones he had in stock, and balanced it for me, and painted over the weights.

£15. Bargain of the century! Was a place called 'Proptech' based in Kidderminster, if anybody's interested!

[bmcecosse]

£15 sounds reasonable - but the £80 mentioned earlier..........

[mike.perry]

It depends on how much you have done. I had new yolks fitted to my propshaft

[Alec]

Hello Kenatt,

you have a lot more patience than I, how do you know which end to start on, surely it takes too much trial and error?

Alec

[kennatt]

I was instructed be an ancient mechanic about 40 years ago to put two together in the centre of the prop and progressively turn them round the prop untill an improvement was felt. the last one I did about 20 years ago took about five goes before I got it right.The old guy said that most prop wobble,as he called, it was at the centre of the prop.Worked for me. But yes at 15 or 20£ probably not worth the effort nowadays,I've not seen how the pros do it but would think they have a similar device to put weight onto the prop to find out where its needed before they weld that little block on same principal as wheel balancing I suppose.

[Alec]

Hello kenatt,

most imbalance is at the end, unless the shaft is bent, I don't remember ever seeing a shaft with balance waights in the middle? Professional outfits put the shaft on a machine that spin sthe shaft and identifies the imbalance.

Alec

[kennatt]

yes come to think of it ,it might of been the back its about 40 years ago,and the mind dulls a bit especially after all those gallons of scotch I've had since then,think I might have one now or two