Banjo Bearing Lubrication Question

[19Fordy]

I am installing the red Torque Tube Seal to prevent rear gear oil from draining into the torque tube as my 40 is "raked". It fits between the banjo and the end of torque tube and has a neoprene oil seal that rides on the drive shaft coupler. I have a few questions as I notice that the RED T T Seal blocks off the hole you see in the banjo and the matching "cut out" in the torque tube.
1. What is the purpose of the afore mentioned hole and cut out?
2. Is it a form of vent for the rear end?
3. How does the big bearing (shown) get lubrication?
4. Will blocking the "hole" and cut out do any damage to that bearing or anything else?
I am thinking that the rotation of the ring and pinion forces gear oil from inside the banjo through the big bearing. That oil is then returned to the banjo by the matching of the "hole" and the "cut out". Otherwise it would just build up inside the red torque tube seal.
Therefore, wouldn't it be wise to modify the red torque tube seal with a little external tube that permits the gear oil to return to the banjo via the hole?
I appreciate any and all ideas and info. that you may provide. Jim

[Terry,OH]

1. The hole and groove allowed oil in the torque tube to drain back into the differential. The oil came through the pinion bearings.
2 yes the hole does act to allow any pressure in the differential to pass into the torque tube. I do not believe that is the primary purpose. It was to return oil. If it was a vent then the hole and groove would be on the top or there would be two sets of holes. The early Ford banjo did not have a vent.
3 The pinion bearings get their lube from the differential through splashing of the ring gear through the oil. There is going to be very little oil on the bearing side of the seal (very little room) and it can drain back through the bearing if it builds up. There will also be a very small amount of oil going into the pinion spline & drive shaft spline coupling area, this is minor and not a problem.
You should have no problem installing the seal. One area to check is make sure none of the rotating pinion bearing cage touches the stationary seal holder. If there is any interference make sure the seal holder is ground down for clearance. Do not grind any of the bearing cage!

[JSeery]

With that seal added I would install a vent in the axle housing. I had to install a vent when I went to an open driveshaft with a V8 QC center section. All axles really need a vent, on the banjo Ford the torque tube allowed enough additional expansion area that they didn't consider it an issue. If you do some research you will see may fails when attempting to add an axle vent to a banjo axle! There were hollow bolts that could be added to the center section to provide a vent, these do not work. The ring and pinion throw the lube around when turning and will force lube out of just about any vent near the center section. The best location, IMO, is the upper surface of the axle housings out a little distance from the center section. The housing material is thick enough to drill, tap and install a vent fitting. I think it is best to use a vent with a length of hose looped up over and secured to the frame (similar to most modern axles) to prevent water for entering the vent hole.

[19Fordy]

Thank You Terry,OH and JSeery for your logical and clear explanation of how that bearing is lubed, your venting info. as well as your incite. You have been a BIG help as I tend to "over think" these situations. When it comes to drilling the hole in the axle housing for the vent tube I would like NOT to let any metal chips drop into the axle tube. I was thinking of magnetizing the drill bits, starting with the smallest drill first and finish with the correct tap drill. I would also put grease on the drill bit point. Then I was going to use a tiny magnet and drop it thru the drilled hole (on a string) so as to pick up any metal chips that may have fallen in. Then I was going to pour some gasolene into the axle tube and let it run down and drain out of the banjo center section drain plug so as to 'wash out" any metal residue. Is that OK to do? Below is the axle housing vent I made using some brass fittings and .005 filter material. The top part can rock back and forth. The threaded piece is hollow end to end. Thanks for your feedback in advance.

[topchop]

19Fordy, nice homemade vent, should work well. Have used the grease on drill bits in the past successfully to avoid chips in tubes.

Found these to work well as vents too.


http://www.ebay.com/itm/10pc-Air-Bre...8AAOSwiDFYNakk

[JSeery]

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All sounds good to me except the gas into the axle housing part. I would stop with the grease and magnet.

[19Fordy]

topchop: Thanks. Your idea looks pretty good too. Would they keep out water?

JSeery: OK. I will follow your suggestion. Many thanks again. JIM

[Terry,OH]

It is probably a good idea to vent but IMO I would not drill and tap after assembly. I have had mine unvented for two years now without any leaks.