I've found this discussion Extremely interesting and informative!
On the farm we used the Gusher criteria that Grant (Correction, Doug) mentions , and if a diff reached that state the whole unit was changed, not messing with seals.

In fact, only when I came to this part of the world did I discover people actually worried about a few drops of 90 weight gear grease around the pinion seal and an occasional drop on the floor. I've never seen a dry one except nearly new, and with a few tens of thousands of miles on, every one has been "damp." I was told this was a good thing, that kept the seal from eating into the shaft.

Nix also has a less-than-dusty-dry pinion area, which I didn't think was too bad for a 40 year old car and I wasn't going to worry about it anyway, but after reading this thread, I'm going to leave completely alone except for brushing off the breather.

Thanks, Guys.
(';')

 

Rainy day wonderment: The original IRS cage was developed for racing.
Parking brake not needed and not included. All went very well.


In olden thinking, race development goes to regular car design and production. The caged IRs goes in tot he E car. Racing heritage. Oh, we need a parking brake. Task assigned to one or more engineers as a team. result, the smallish pads and mechanical application see til the 87 production ended.


Oh, exhaust. Out the side won't work. Under, going to get scrapped.
another task assigned. result, "adequately sized pipes, through the cage.


Hillside parking: I've done my share in nearby San Francisco in several critters, including my 83. Proper curbing of the curbside front wheel essential. Can't rely on P or hand brake alone or both.


Off topic, a bit. A recent downtown disaster happened. Brake failure on a tour bus. Air braked. Clearly failed. No back up on these ???
As I understand them, they are basically a combination of mechanical and air cans. At one time, I thought the defaullt sans air was brake lock. In that bus, seems not! Oh, it was rebuilt from a discarded Washington DC metro bus. common failures lead to selling off the whole fleet.


SF's MUNI just bought a new fleet of ultra long and supra expensive hybrid buses!!! Oh, oh, they can't manage some of the steeper hills!!! I wonder if the brakes are up to it anyway???


The fabled cable cars use manually applied wood shoes on a steel rail.
work fine, most of the time, but once in while, oh, oh!!!


Carl

 

I agree on the airflow situation as you've described; I'm sure you're correct



The outboard brake design was decided on long before Ford came along....and I'll wager a week's pay that is was entirely a cost-cutting provision. The inboard brake IRS, though lauded for many years, must've been very expensive to produce. A conventional outboard brake IRS would be much easier build and with virtually no down-side. The increased unsprung weight just isn't that much of an issue in the real world.


Then they're not working correctly !




That's what I was taught as well. Use the parking brake to hold the weight of the car! The parking pawl then becomes the backup.

Try explaining this the most people and they look at you like you just came down from Mars



I never had to rely on the parking pawl as I found the Jag parking brake held the car perfectly well anywhere, anytime. But your experience obviously is different so I won't beat it into the ground


Cheers
DD

 

So Doug, your advice is to leave well enough alone! I appreciate the feedback as I am really struggling with the decision and today, I pretty much concluded that I should leave the pinion shaft seal as is, and just check the breather. As for the output shaft seals, I have now read the service manual many times, and I continue to be concerned about the bearing preload issue; I suppose one compromise would be to replace the O-rings, which does not require disassembly of the shaft bearings i.e. no need to tamper with the bearing preloads. I am not sure if new O-rings will do anything for me.
FYI, my leaks are not yet "gushers"; rather, the differential is wet, but not "dripping wet" so I would say there are slow leaks on the output shaft seals, perhaps driven by excessive temp given the condition of my rear brakes. Maybe with new brakes, things will stabilize a bit?

 

From what you've described, yes





An alternative is to buy rebuilt stub axles. Coventry West and others sell 'em. New bearings and seals, with the bearings properly set-up. Ten minutes per side to install 'em with the brake calipers and rotors already removed. About $150/each last time I bought 'em, years ago



Hard to say. How's your crystal ball these days?

The leak I had on my old Series III never got worse even after many years and many tens of thousands of miles. Shrug

Cheers
DD

 

Good morning Doug,

Haven't posted for a while. Just thought I'd mention that on my 74 XJ6 the rear end leak was solved with a new Pinnon seal. It is dry now for prox 10K miles. I recently purchased a 1989 KJ-S HE. It is dry as I would expect it to be. The XJ-S has 70K onit at this time. It is winter so it is put away and I switch between my Grand Cherokee and the XJ 6 depending on conditions. I did have some issues with limited RPM on the V12. It would to out at 4500, a little low for that engine. After a lot of digging around, the info came from the Jag Lovers manualon the XJ wherin they mention the secondary coil located in front of the radiator. ONLY THE PRIMARY IS used. I found an appropriate coil and all is well.
Just though I would mention that because I came to the forum with the rpm issue and no one could help. A lot of good suggestion but no solution. She will now run to red line with no issues.

Thanks for all your help.

jack

 

I was greasing Nix's rear end today, in preparation for a longish road trip this weekend, and decided to track down once and for all what is leaking back there.

The pinion area is virtually dry, but some years ago (long before my ownership), one of the laminated rotors was changed out for a solid one (professionally done I'm sure), and THAT'S where the leak is! It's the side bearing seal!

It's not leaking enough to cause alarm, YET, just enough to keep that side of the case below the shaft wet and drip on the floor once in a while. (>WHEW< I thought one of my new calipers gave it up already!)

In compliance with suggestions in this thread from those with Way more experience than I have, I'll keep an eye on it, but until it reaches Gusher status, I'll basically leave it alone except for occasional cleaning.

When it gets too bad, we'll put the Rhonda S3 junkyard diff in, changing it straight across.
(';')

 

LnrB:


I'd not fret. A bit of a weep is not an issue. Three seals there.
One pinion input. Nothing around to get an excess. Safe, merely
keep the pumpkin lube level up.


Two outputs. A tad more critical. Lube on the rotors not good. but, I suspect more than a mere weep would be an issue. Rotational speed being an excellent wiper.


Way back when, in army days, I was a platoon leader. (looey )! in an AAA SP unit. Old half tracks. We prepared for an Inspector General inspection!! My tracks flunked!!! We did check the levels in the motor pool . OK. But driving them to the inspection point deposited
90W on the "box" walls and we flunked.


My argument fell on deaf ears....


He.., I had checked dozens of diff's by the finger method just fine!!!


l


Carl