MGB Pinion Oil Seal Replacement - MGB Tube Type Axel

[fleshy1]

I just finished replacing both U-joints and while I was spending quality time under the car I noticed a lot oil of leaking from the pinion oil seal. Since the replacement of the u-joints I can now hear differential whine while at speed. I'm assuming that I'm losing oil through the seal and this may be the source of this loudness. I recently changed the oil and topped up the unit so I was also noticing that gear oil smell.

I understand that leaking seal could be an indication of a worn pinion bearing but since the diff wasn't dry the last time I changed out the oil and the worn rear u-joint was probably causing stress on the system I'm willing to risk just replacing the seal to see if I get some results.

The factory manual I have indicates that one needs to measure the amount of torque required to loosen the flange bolt during disassembly so that one does not crush the collapsible spacer behind the outer pinion bearing during reassembly. Is this possible with a modern click-type torque wrench? Can I just keep setting the torque higher and higher until it comes loose then shoot for that when I put it back together? It also says to use a special tool to hold the flange while removing the nut. Can I just work against the parking brake and weight of the car and a wheel chock (I'm thin enough to fit under it without jacking it up)

Thanks to all.

 

[Scott_Hower]

Might want to do a search, we beat this horse pretty good a couple of weeks ago.

I'd be really surprised if you can get it off without impact tools. Can't recall the torque spec, but I'd imagine it's at least 150lbft.

 

[jlaird]

140 if I remember correctly but whats 10 lbs amoung friends. That without a power wrench, impact type is a real pain of a job even with it out of the car.

 

[fleshy1]

Found the thread back at the end of November. Looks like using an impact driver will work. Can't make it any worse than it was....

Should have done my homework before I bugged you guy, sorry.

 

[Steve_S]

I wish you were a little farther south, Eric. I'm about to do this very job as I finish up a complete rear end rebuild. Anyway, glad you found the info you need!

 

[fleshy1]

Steve,

I'm next door to Pasadena and I commute to Calabasas on a daily basis. Send me a PM if I'm anywhere near you, it'd be nice not to do this alone.

 

[Grantura_MKI]

You should never use a torque wrench for loosening any fastener. Most banjo diffs do make a little noise, even after a rebuild. Just the nature of the beast.
Cheers, David.

 

[Steve_S]

I guess I had the wrong Sierra Madre! I live right next to Calabasas. I'll send a PM with my contact info.

 

[fleshy1]

Just as a follow-up...

I can say that this replacement is pretty straight forward with the right tools.

With Steve's help (and car lift) we were able to knock this out in an hour (shooting the breeze aside).

Tools:
1/2" wrenches
1-1/8" socket and breaker
gear puller slide hammer
pre-drilled angle steel from hardware store
paint
bicycle bottom bracket tool
mallet

1. Remove the drive shaft flange (mark it first with paint!)
2. Paint the nut and pinion as reference
3. Line up the angle steel holes with pinion flange holes and use a hacksaw to cut a space for the 1-1/8" socket.
4. Bolt the angle steel to the flange.
5. Remove the nut using a breaker and the angle steel. Count the exact turns required and remember the orientation the nut came off in.
6. Remove the pinion flange.
7. Use the gear puller to remove the old seal.
8. Grease the new seal and use the bottom bracket tool and mallet to drive it home. This tool has the perfect size hole to allow the pinion shaft to pass through and apply even force to the seal.
9. Install the flange and count the number of turns back to the mark. You'll need the angle steel to get it snugged back.
10. Install drive shaft.
11. DRIVE!

Again, many thanks to Steve for his help!