FLYER15015 Posted May 23, 2019 Share Posted May 23, 2019 O.K. guys, here is a question for you. While installing my new drive shaft, I noticed a bit of diff oil dripping from the right side rear backing plate. The dreaded axle seal issue. So I ordered 2 new inner seals from "Hagens" @ about $12.00 each and plan to make my own felt outer seals. However, I noticed that the differential does not have a vent, and I am wondering if when things get hot the oil is expanding (like all hot things do ) and pushing thru the seals ? Oil level is "just" below the fill hole threads, when the car is on level ground, and under load. Therefore my question is, should I drill and tap the top of the diff and install a vent ? Sure would like to know if anyone else has done this and if so where is the best location ? For Spinny, certainly not right over the crown gear, but maybe off to the pinion gear side. I await your collective advice. Mike in Colorado Link to comment Share on other sites More sharing options...
Spinneyhill Posted May 23, 2019 Share Posted May 23, 2019 If your new inner seals, both sides, are modern rubber lip seals, it seems it would be beneficial to install a vent. Best place would be about half way between diff. and hub. The brake pipe splitter mounting bolt might be a good one to use. Remember the diff. is in a fog of oil and foam (hopefully not too much foam with the oils of today) when the car is in motion. Link to comment Share on other sites More sharing options...
FLYER15015 Posted June 5, 2019 Author Share Posted June 5, 2019 Spinney, O.K. I received the inner lip type seals, from Hagen's and I will pick up tomorrow the new lip type outer seals (national # 473475 or SKF # 23666) from O'Reillys Auto parts. I found that the outers had been converted to lip type some time ago, but the inners were the original felt type, and are leaking badly. My question is when I replace the axles do I "pack' the 2 rear wheel bearings with wheel bearing grease ? There is a zerk just behind the axle flange, but you cannot inject "wheel bearing grease". I do have some high moly waterproof chassis lube that is meant for boat trailer wheels, that often get submerged in water. I await your valued opinion. Mike in Colorado Link to comment Share on other sites More sharing options...
Carsnz123 Posted June 5, 2019 Share Posted June 5, 2019 Having recently rebuilt the diff in my 1929 Plymouth i have the following words of wisdom: Yes vent the diff. I added a fitting on the main pumpkin on the opposite side of the crownwheel and put a pipe up into the car as it goes through fords at least once a year. Yes grease the wheel bearings when you install them. I've seen people shagg a new set of axle bearings as the oil does take its time getting to the axle bearings. More so with the inner seal setup Chrysler employ The fittings by the axle bearings are designed for lube to be added (cant remember if grease or thick oil. need to dig out manual.) The inner seal isn't 100% important. I omitted to fitting it due to damage in the housing from an axle breaking in the distant past. no oil gets on the bakes but it does make its way down the keyway and out the hubcap. fitting a modern lip seal to the inner will mean you have lube the axle bearings on a regular basis. The Plymouth and Chrysler Diffs use a similar setup. I've got 75W-90 in it due to there was a full bottle on the shelf in the garage. 1 Link to comment Share on other sites More sharing options...
Spinneyhill Posted June 5, 2019 Share Posted June 5, 2019 What he said. Except I have had diff. oil in the drum when the inner seal didn't work. While you are in there, note were the grease nipple puts the grease, between the bearings. You need to add a reasonable amount of grease to do much good. Too much and it comes out the seal. I just use NLGI 2 grease - most of it now has "molypoly" or molybdenum disulphide anyway. Based on what I read on these fora, the old felt and leather seals allowed some "breathing" as the air inside the diff. heated and cooled, expanded and contracted. Lip seals don't allow that very much at all. I would tend to put the vent on the axle housing rather than the diff. housing. During operation, the diff. will have so much oil flying around some will get into the vent. I would hide it in the brake pipe union bolt if I could, but then I don't ford many rivers. 1 Link to comment Share on other sites More sharing options...
FLYER15015 Posted June 5, 2019 Author Share Posted June 5, 2019 Thanks mates. Odd that I get 2 valuable responses from N.Z. (half a world away), but it is much appreciated !!! You fellows know each other ? Cars, funny you should mention diff oil leaking out the keyway as mine was doing that too. There are threads on the brake drum O.D. where the axle sticks out but no cap. Guess I need to find / make a cap to cover and seal the axle nut. I'll be sure to add a bit of silicone behind the axle nut washer too. You both get a trophy. Mike in Colorado 1 Link to comment Share on other sites More sharing options...
FLYER15015 Posted June 7, 2019 Author Share Posted June 7, 2019 (edited) Some continuing information for those who follow regarding the differential and brake work on my '31 CG, Chrysler imperial . I found the 2 outer seals (National Oil Seal # 473475) are readily available @ O'Reily's Auto parts for about 12 bucks a piece. The 2 inners (P/N LYO 37002 ) I got from Hagen"s @ thirty bucks, with eleven of that being shipping. The master cylinder was from "mopar direct" / ebay @ $125.00 with free shipping, and was a direct fit. The wheel cylinders were from "moparpro" / ebay @ $225.00 for 4, and required opening up the locating bolt holes in the backing plate, just a little bit. I did notice that though the split bore cylinders work, they are about 1/2" longer than the originals, and the brake shoe adjusters need to be backed off ALL THE WAY,. I can still hear 2 of the drums dragging just a bit. Need to take some short drives to wear in the brand new shoes, or go back in and dremmel the adjuster cams so the shoes can retract a bit more. If the drums heat up, that will be the fix. The diff vent is in up top of the pumpkin and opposite the crown wheel. Lots of clearance here and with a right angle drill and hand tapping the 1/2" pipe thread it went well. I took "Cars" advice and RTV'd the square key slot on the axle and behind the washer on the axle nut. I see that the drum is threaded on the outside for a cap, Wonder what those look like ? Need to improvise a set for now, just to play it safe, as I'm tired of cleaning oil off the rear wheels. Thanks to all for their help. Hope this little blurb helps someone with the same issues later on. That's what I think the forums are for. Mike in Colorado Edited June 7, 2019 by FLYER15015 (see edit history) 1 Link to comment Share on other sites More sharing options...
Gunsmoke Posted June 7, 2019 Share Posted June 7, 2019 I have the rearend out of my CD8 Roadster project at this very moment and have been pondering carrying out all these same rebuilds, seals, wheel cylinders, vent etc. So this post is timely and helpful, also provides sources for the bits. Thanks for posting. Link to comment Share on other sites More sharing options...
FLYER15015 Posted June 8, 2019 Author Share Posted June 8, 2019 4 hours ago, Gunsmoke said: I have the rearend out of my CD8 Roadster project at this very moment and have been pondering carrying out all these same rebuilds, seals, wheel cylinders, vent etc. So this post is timely and helpful, also provides sources for the bits. Thanks for posting. So, is it worth a "like" ? 1 Link to comment Share on other sites More sharing options...
Gunsmoke Posted June 8, 2019 Share Posted June 8, 2019 Definately worth 2 if I could do so! Link to comment Share on other sites More sharing options...
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