Some points when working with the drive shafts

M

mikecoombs

Active Member
Just a couple of pointers for those whohaven't been through it...
The Bolts that secure the drive shafts to the stub axles in the diff are a very particular length. Their length is curtailed by the closeness of the flange to the bearing seal. They are designed to take the tab washer, the thick loading washer and the brake disc but not extend beyond the rear of the mounting flange. In practice this means that if your tab washers have lost their tabs and you don't have spares, you still need to fit them or the bolts can rub the bearing seal.

Ever wonder why when you took the axles off everything stayed in place but when you try to get them back on there isn't enough contraction in the De Dion tube to get the bolts in? That happens because as the De dion drops down they arc downward till the tubes shorten to their stops. However, at the same time the lower main links move inward. When you disconnect one shaft they spring back out to their neutral position taking the De dion with it which also allows it to drop further down, when you go to put the axles back they are not long enough to fit the wider De Dion, hence the gap. Solution is to move the jack stands from under the body to under the wheel end of the lower main arms or jack up the wheels or hubs. Be very aware that when you lower the jack, the stands will have a lateral load on them so you may well need to do it in steps and tap the stands across as you go. Jack stands on wheels would help but ensure the wheels can hold at least 500Kg per stand and you are on flat ground with the front tied well down.
 
Another thing to remember is never be tempted to lay the disconnected shafts up on the de dion tube to gain more space while working under there, because you'll nudge the wheel, or the shaft, and it will come crashing down, smashing you on the head/nose/teeth..... (Delete where applicable).

And before you ask, no I've never done it, but I know those who have.
 
Hi, greetings from tassie, have 73 p6 2000 converted to 4.4 running 320 hp at back wheels, have spent lots of time underneath fixing UJs and replacing gear box. Car is import from hong kong as 2000TC and i soon realised it is a crossbreed. Matches the v8 in body dimensions at front frame, and suspension is same as v8 but 2000 springs. I removed the original engine mounts and replaced them with 3500 mounts. Also still have the 11 inch steering wheel from hk and has original fitted ps. Only needed to change the aircon as was originally mounted under parcel shelf and was dead with hoses missing and compressor in boot. Also came with slippery diff, great for burnouts, 2.89 ratio.
Have heaps of parts here for sc, tc and v8s. Also some door glass from NZ car if anyone interested.
Fitted 14 inch alloys from sd1 and no rubbing even with 5 people in car and boot full of building gear and boot rack loaded with gear too.
 
any idea where the Slippery diff came from? Been after one to fit for years but they are a very unusual combination. Is the 4.4 an ex P76 engine?
 
Yup, fitted in lovely. SD1 bw66 auto (blow them too easy) though looking for good 6 speed, have all p76 clutch components and olds clutch components and adapter/ bellhouse. Slippery came from hong kong original to car. Have been told they were also available in california.
Have plenty of spare parts for 2000/3500 i have wrecked over the years.
 
Diff looks like a rover one, same as others i have. Have you heard of anyone else twisting one of those short axles off before? Not a half shaft but the stubby axle itself, i have done 2. I use ford ujs on halfshafts and holden on tailshaft.
 
Yes it is not uncommon to break those drive shafts. It is a combination of too wide a tolerance in manufacture and the spline design. I'm making enquiries next week about getting some bespoke units made up.
 
The actual axles don't normally break though the universals go on them. You can get the genuine ones still. the
P76 has considerably more torque than the rover engine so I'd expect some drivetrain issues.
 
The stub axles don't fail because of tolerances, they just fail because the spline design. A solution much cheaper than a bespoke unit would be to take 3500 stub axles (which received factory shot peening and/or different heat treat) and have the spline ground down so the axle's splines are entirely contained in the mating diff side gear.

Yours
Vern
 
Vern Klukas said:
The stub axles don't fail because of tolerances, they just fail because the spline design. A solution much cheaper than a bespoke unit would be to take 3500 stub axles (which received factory shot peening and/or different heat treat) and have the spline ground down so the axle's splines are entirely contained in the mating diff side gear.

Yours
Vern
Click to expand...
So are people managing to break the 3500 stub axles as well or are these holding up better with bigger than standard power and torque ?
 
Your quite right Vern, I'm looking into that very thing tomorrow! When the diff goes in for its gear change.
yes we break the diff stub axles
 
Righto thank you for that. I guess it might be worth looking at getting some made from a better material.
 
Just fix the flaw with the splines sticking out and a crack developing at that spot and the material would be plenty strong enough. That's my opinion anyway.

Yours
Vern
 
Having not fumbled around with these things yet is anyone in a position to put up a pic of one with some indicators of the problem area ?
 
Hi
I have never kept the shafts i have broken to show break point,taking out spare shaft tonight and will try to take picture of area.
Regards,
Clive.
 
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