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Replacing Simplicity 725 rear axle seal


dextyr

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I have my Model 725 Simplicity tractor apart for painting and other repairs.  Has anyone ever replaced the rear axle seals without splitting the transmission case?

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1 hour ago, dextyr said:

Has anyone ever replaced the rear axle seals without splitting the transmission case?

Yes, you can use (2) sheet metal screws. Drill (2) holes the same size or a little bit bigger than the minor diameter of the sheet metal screw 180 degrees apart in the oil seal. thread the screws in and pry out the seal. I clean the axle tube with lacquer thinner and put masking tape over the keyways and ring groove to protect the lip seal during installation. You may have to get a length of tubing such as pvc or steel to drive the seal into the counterbore. The axle tube seals are P/N 2154269SM or Timken/National 473157.

FYI, the original 725 transaxle uses bronze bushing as bearings between the axle tube and the transaxle case. They are prone to wear and cause the seal to leak. If worn they will need to be replaced. In order to replace, the transaxle case needs to be split. If you have to split the case you may want to consider having a machine shop bore the case for needle bearings and shifter shaft seals to put the issue to bed. I have done my 725 and helped @ShaunEwith his 101. You can search for his post. Original bronze bushing P/N is 2154260SM. Needle bearings are P/N 2157519SM/Koyo B-2816 LH & P/N 2157520SM/Koyo B-2824 RH.

Or you can replace transxale with a 2210 3-speed transaxle which has the axle tube needle bearings, which I used for the other (2) of my FDTs, 2012s

You will also want to check all the keys and keyways between the axle tube drive gear and axle tube, axle tube and differential, and differential gear and axle shaft. The original 725 axle tube stopped on the LH side just past the axle tube seal. The new axle tube will be longer to hel support the axle shaft.

Another weak link of the 725 is the roll pins between the RH wheel hub and differential gear. I would check them also.

I have converted all (3) of my FDTs to the newer style spring loaded limited slip differential, newer axle shaft with welded LH wheel hub and newer RH 1-piece wheel hub.

Any questions, just ask.

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Thank you both very much.  This is exactly what I needed.  I have to do left and right sides.  I have the complete transmission up on my work bench.  Hope it goes smoothly.

Dick

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Bill -

I've got my axle out and one seal out (non differential side).  The axle tube is worn where the seal was but the tube is full diameter where the seal wasn't wearing.   Will the axle tube plus a speedy sleeve fit back in if I take the alxe tube out to put the sleeve on?  Same question on the differential side if it is grooved too.  The side I pulled the seal from was leaking.  The other side doesn't seem to have leaked so I'm hoping that end of the axle tube isn't grooved.

Thanks - Dick

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This Bill can't help you with the speedy sleeve idea.  It sounds like a lot of work.

I seem to remember someone having success not driving the seal all the way in so the seal rubs on a "good" part of the tube.  (I don't remember if they bought a seal with a longer "side" dimension so it could be driven all the way in and have the seal contact area be further out.)  

For the cost of a couple of seals, that's what I'd try first before tearing apart the tranny.  

 

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Axle tube moves vetically on the differential side 1/32".  No horizontal movement.  No discernable leakage on this side.  Leave alone or is that amount of movement a problem down the road?  No movement at all on the other side.  I have new seals that I think I can seat in farther and get behind the current groove.

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1 hour ago, dextyr said:

Axle tube moves vetically on the differential side 1/32".  No horizontal movement.  No discernable leakage on this side.  Leave alone or is that amount of movement a problem down the road?  No movement at all on the other side.  I have new seals that I think I can seat in farther and get behind the current groove.

Not that you want to do this much work, but here is an option since you have the transmission out on a bench.  If you have vertical movement, the original bronze bearings in the transmission housings have wear.  New axle seals will potentially stop the leaking for a long time or they may leak again relatively soon based on lubricant level.  

This is an option since you have it removed currently.  Since the original bronze bushings lasted 50 years or so, replacing them with new will suffice.  I chose this option based on @Bill725's success.  Please disregard the provoked snide remarks.  I'm very happy with the results.

https://simpletractors.com/forums/topic/64413-landlord-101-transmission-bgb-overhaul/

 

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