Prop shafts

[Tony Gamble]

Hi

Does anyone have details of the various lengths of prop shaft for the various vehicles.

I have just parted with two at 34.5 inches , and have one at 33.125 inches [ 33 1/8 " ] but not sure which vehicles they were off.

Anyone know ? [ I have a feeling that I shouldn't have parted with the 34.5 " ones ! Anyone got one ? ]

Tony G

[Ian Grace]

Hi Tony.

34.5" is the standard length for the 3-speed boxes. The shorter one is for the later 4-speed box. When I bought my first Minor, it has a 4-speed box and a 3-speed prop shaft - there was NO coupling at the back end - the two spiders being bolted together! Saves money on couplings, I suppose!

I think your 33.125 might be from a '34 synchro box.

It would be helpful if owners of various cars measured their shafts - 3-speed, 4-speed crash and 4-speed synchro.

[ashford]

I presume that there must be also be two different lengths of propshaft for the long chassis models as they also used the three speed and the four speed boxes. These propshafts may be the same as a pre series morris 8. They still have the spider joints but a much larger diameter hollow shaft.

I have also heard that there may a difference in the length of the four speed synchomesh and the four speed crash as it not always easy to swap them. Does this affect the propshaft lengths as well?

[prharris25]

These prop shaft lengths are very confusing. I have a 2" diameter one 45 7/8" overall spider to spider. This I believe came from either the '34 lwb Family Minor I broke some years back or a pre-series 8. Not sure. Whatever, it is available free for anybody who has a use for it and can collect from Liss in Hampshire. Comes complete with one centralising spider and a fabric coupling (this has seen better days).
Paul.

[DF9053]

Following on from some of the comments in the crownwheel and pinion thread, should we be trying to shorten the propshafts if we use the later slightly longer pinions. I had thought that DF had an original ratio but noticed yesterday that there is a spacer in between the pinion housing and the front housing on the axle, so presumably this indicated one of the later larger pinions is in there. I recall Ian and others saying how difficult is it to get the propshafts on, well this was true on DF I guess this extra 3/16 does not help and also puts added pressure on the couplings. These were new 18 months ago but show signs of fatigue already, perhaps the prop length is causing this.

Any thoughts?

cheers
Jeremy

[Ronald]

I for one am a firm believer in making the propshaft 'fit' where you are using it, regardless of where it originally came from, if you use the right prop for your car, but with lets say the thicker drive couplings, then that in itself is adding to the pressure on the pinion in the diff, i would suggest that in order to do away with any adverse pressures, that you should 'ideally' bolt one end of the prop with it's coupling to eother diff or 'box, and try the coupling in the other end, if it's too tight, then i would be tempted to shorten the sahft so the the coupling fits with almost no pressure, as even sitting in the car will add to this, let alone loading the car with potentially two adults and maybe 2 children etc....... we all know what effect loading the minors up has on the rear brakes eh/...... so it stands to reason it has a similar effect on the pressure on the drive couplings...... maybe to much pressure is why they quite often appear to break up so soon......

Just my ramblings...... i might be talking rubbish..LOL!!!

[Tony Gamble]

I think both Jeremy and Ronald are perfectly correct in their thinking , and I agree that for several reasons it would be a good idea to slightly shorten the prop shaft.

It can certainly be the devil's own job trying to fit a propshaft in between diff and gearbox with new couplings.

How many of us can say we've been there !

Tony G

[chris lambert]

I spent an afternoon trying to fit the prop shaft to the Semi-Sports. It also had new flexible couplings. My next door neighbour told me the following day that she thought I was having a fight with a rabid dog, and had I been an East End docker before I moved to Suffolk?
I had course to ring Brian Ellams, the car's previous owner, shortly after I had got the car mobile last year. His first question to me was "How did you get the prop shaft to fit"? Apparently, it was after failing to achieve this that Brian decided to sell his car!
Chris

[Toby]

I remember Dad renewing PJs couplings, despite the fact all was well before renewal it didn't fit with new couplings. At the risk of teaching an old dog new tricks, after a thought of slackening u bolts or shackle pins and the use of jacks, I think it was Geoff Beech who recommended jacking up the chassis to allow the axle to hang lower thus lengthening the gap between the couplings. Or at least thats what I seem to remeber the solution being!

[cammy]

I think there may be a potential problem in jacking up the chassis to let the axle hang. I have NG jacked up like this at the moment and if I attach the propshaft to the CWP it will sit on the chassis cross member at an angle of about 30degrees to the horizontal I guess. Of course I may have got the bits in the wrong place but I don't think so. However, possibly releasing the front shackle pin (of the rear springs) could well allow the axle to travel back as the rear shackle swings rearward (with a little help).

Don't know if this will assist as I sit at the feet of the more learned members. Perhaps worth a try though.
Clive.

[Ronald]

It's one thing actually getting the propshaft to get bolted on, but if you have too must end to end pressure, it could easily lead to early diff failure...... due to too much load on the pinion.........

[halbe]

Hello,

What are the thoughts on the forum for a change to a more modern prop shaft?
What about a circular distance piece between the spider and a modern u joint?

It would certainly be better for both the back axle and gearbox

Halbe

[chris lambert]

Halbe,
My brother fitted a Hardy Spicer 'type' unit to his M Type after he had ruined a couple of cw&p due to his competition work. After that he had no further problems. At Thorpe Abbotts Halbe you will have noticed the difference when driving our cars, between Trevor's 34 model more modern arrangement and say, my saloon. Far fewer vibrations from the transmission. Once again the purists will say balance out the propshaft correctly and use 'decent' fabric couplings and you should be OK.
Chris

[1936morriseight]

Hi Halbe,

In the UK and presumably in Holland there are companies in a number of major cities that will manufacture new Hardy Spicer U/J prop shafts complete with sliding joint to your specification - all I believe they need is the precise distance between the flange faces of the gearbox and differential unit. Obviously you would need to replace the (fabric disc) spiders on both the box and diff unit with 4 bolt flanges. It's possible that the Morris Eight Ser. I / II / E diff flange will fit the Minor, not sure about the gearbox flange though. I believe the going rate for Austin Seven / Morris Eight size shafts start at around £95. The U/J's used on the Morris Eight are the same as those on post war Minors / frog-eye Sprites etc. so are readily available.

Jeff
1936morriseight

[Trevor Wilkinson]

The propshaft on my '34 minor is the standard set up with fabric couplings. Care was taken to set it up to run true.