Differential

[Guest]

Hi,
I have the diff on the bench to change the seals, all is well apart from the drive shafts bearings, they have a lot of discolouration and appear to have run very hot. One side the bearing is rough, this may and only may have happened when trying to extract the flange off the stub? shaft. My main concern is why the bearings have run so hot as to blue them.
Car has only 33,000 miles on it and apart from this every thing is in great condition, the crown wheel, pinion and planetary gears all look just great, although it is difficult to assess the tapper rollers supporting the crown wheel they seem smooth running.
John

[Stagsongas]

John,

My car had rough output bearings at just 23,000 miles but no sign of overheating like yours. I just wonder if someone had the hot spanner out but gave up before you got there? It would be most unusual for those bearings to go overtemp. unless the diff were short of oil, but if so there would be damage elsewhere too.

I'd replace the bearings (you need a 20T press at least) anyway, and you have to remove them to replace the seals. I'd also recommend a good look at the quill housing whilst you're at it, mine was just about to fail and if not for the useful info. posted by people on this site I may not have examined it so carefully.

Regards

Steve

[wilf]

You can get reconditioned output shaft assemblies from the likes of Paddocks, with a service exchange deposit on yours.

That way you don't need to worry about 20tonne presses...........

Also, while you are about it, you can fit an uprated extension housing, got mine from LD parts (also they have/had the good quality bearings to go in them).

[Guest]

I'd replace the bearings (you need a 20T press at least) anyway, and you have to remove them to replace the seals. I'd also recommend a good look at the quill housing whilst you're at it, mine was just about to fail and if not for the useful info. posted by people on this site I may not have examined it so carefully.

Hi thanks Steve,
Tried 20Ton press, no go would have needed heat as well we took the bearing off backwards, a light machining to remove the lip on the shaft and slid it off without disturbing the key.
We decided? that it looked worse than what it was, as the oil does not have detergent there is a tendency for it to look a little burned. Also the bearings hopefully were contaminated which will explain their earlyish demise. Replaced with very expensive sealed bearings, not sure whether to remove the inner seal and leave the outer seal plus the original seal??
Although the quill housing seamed just fine I'll double check.
John

[Stagsongas]

John,

I'll post a pic. of my faulty quill housing tomorrow which might help. Even so, after seeing some of the horrors shown on this site (I recommend you search on 'quill housing reinforcement) I would not run a car without this modification.

I too was given the more expensive option of shielded bearings just because they didn't have the non-shielded ones on the shelf - but! To ensure continuous lubrication from the diff. oil I'd have had to pull at least one shield out anyway, so I elected to wait for the original type, and for £20 less. Imperial bearings (there is nothing special about their construction other than that) are certainly becoming expensive nowadays.

Regards

Steve

[Stagsongas]

John,

As promised, here are a couple of pic.s of my Quill housing after paint removal. You can see the significant undercutting of the weld (over 180 degrees in circumference) has produced the perfect conditions for stress fracturing to occur. Frankly, I'm amazed it lasted for 23,000 miles.

Stag_Quill2.jpg

Stag_Quill1.jpg

The undercut weld was dealt with by more welding and the housing was then strengthened using 4 tabs as shown elsewhere on this forum.

The effects of a failed Quill housing are quite severe - when it breaks, the axle twists downward, pulling both handbrakes on by pulling the cables tight. You are not going anywhere then. When repairing things, you may find the the diff. has been damaged too. This is a risk I wasn't prepared to run, and even if I had not found the undercutting I would have strengthened the Quill housing as the steel tube is very thin, a weak link carrying the significant amount of stress placed upon it.

Regards

Steve

[Guest]

[QUOTE=Stagsongas;277789]John,

As promised, here are a couple of pic.s of my Quill housing after paint removal. You can see the significant undercutting of the weld (over 180 degrees in circumference) has produced the perfect conditions for stress fracturing to occur. Frankly, I'm amazed it lasted for 23,000 miles.

Stag_Quill2.jpg

Stag_Quill1.jpg

The undercut weld was dealt with by more welding and the housing was then strengthened using 4 tabs as shown elsewhere on this forum.

The effects of a failed Quill housing are quite severe - when it breaks, the axle twists downward, pulling both handbrakes on by pulling the cables tight. You are not going anywhere then. When repairing things, you may find the the diff. has been damaged too. This is a risk I wasn't prepared to run, and even if I had not found the undercutting I would have strengthened the Quill housing as the steel tube is very thin, a weak link carrying the significant amount of stress placed upon it.




Thanks will take a look to check, succumbed to the sealed bearing still debating on removal of the inside seal?.

[Stagsongas]

John,

Like anyone else, it has to be 'best guess'. The original bearings didn't have seals, but both yours and my originals didn't last so well. They might last longer with seals, or not, who knows? I doubt the diff. oil has corrosive properties and EP90 can certainly withstand the high pressures as it does OK for diff. teeth. It just might be that the modern grease in a sealed bearing has much higher spec. than EP90 can offer.

All in all, guess away, the first of us who suffers a replacement bearing failure tells, the other, OK?

And we'll call it Science....

Regards

Steve

[Guest]

Thanks for your help Steve,
For some reason all the bearings and seals needed replacing, input output wheel etc. Removed the inner seal on the pumpkin output shafts. Took 35tons to press off one of the wheel hubs, needless to say it ended up in the scrap bin waiting for a replacement, and blew the pipe to the pressure gauge on the press. Oh my what a difficult car to work on.
John