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1986 CAT 416 rear axle seal leak

mike ens · 2020-05-29 10:04

I have a 1986 CAT 416. The rear axle will start to drip at the end against the rim once the outside air temp reaches 70°F or higher (with the equipment not moving). The drip is not bad at 70°F, however, at 85°F, the drip is steady to the tune of 1/2 quart in 24 hours. I only use the equipment on the farm, primarily the backhoe, so there's not much "travel", only on the farm. I'm trying to avoid tearing down the rear end to most likely put new seals in. I will be changing the final drive axle oil with the heaviest oil recommended by CAT is SAE50(went with Sunoco TO-4 Transfluid p/n 511305). I'm not optimistic that this will solve the leak. The backhoe gets very little use, so my question is, is there any additive i can put in the rear end that will "thicken/stop/slow leaking" that will not damage the seals/brakes/etc? A slow drip is acceptable to me, but a 1/2 quart a day is not. I welcome/appreciate any thoughts anyone might have for a "quick fix".....thanks in advance!

Replies11
  1. #1Nige2020-05-29 20:37

    There is no “magic additive” unfortunately for you. The only fix is to tear it down and replace the leaking seal(s). I personally wouldn’t waste time changing the oil. If you want help with parts you’ll need to post a Serial Number.

  2. #2mike ens2020-05-30 08:35

    Nige, Thank you for responding to my question. I really was hoping for something like an STP or Lucas stop leak, or as you say, "a Magic Additive". I have a stretch of 4 cooler days coming, and i need to finish a project before i tackle the repair. I noticed in some threads, people have thanked you for supplying them with possible step-by-step instructions, parts diagrams/ Part#'s. I would greatly appreciate and information/help you can offer. One question i have is, do you think it would be prudent to change the axle seals on both sides while things are apart, or do i only have to take one side apart to get at the leaking seal? Are there any tricks to how to handle the rear end assembly when removing, i will be working on a gravel floor, not concrete. Lastly, the brakes are little to none, no grinding, just bad. While i have things apart, any advice or what to look for for the brake issue? The serial # is 5PC03141 Thanks again Nige!

  3. #3Nige2020-05-30 11:46

    So you're happy to run a machine will "little to none" brakes but you're worried about an external oil leak..? Hmmm, time for a priority re-evaluation methinks, but that's just my opinion. And as well all know, opinions are like a$$holes, everybody has his own. I'll send you some info.

  4. #4Bls repair2020-05-30 11:54

    To get by you could use the out rigger to pick up the leaking side when not in use.

  5. #5Nige2020-05-30 11:59

    I sent the OP the parts breakdown and the R&I/D&A instructions for the rear axle assembly. If anyone wants to chime in with tips to make the job go easier for him, then now would be a good time.

  6. #6mike ens2020-05-31 11:39

    BLS, Thanks for the suggestion. I now park the back hoe on a slightly slanted slope for the same effect. thanks again for your suggestion.

  7. #7Nige2020-05-31 11:45

    Offroad Equipment might well be a good source of parts supply for a machine of that age. www.offroadeq.com/

  8. #8mike ens2020-06-01 07:30

    Nige, Thanks for the link.

  9. #9mike ens2020-09-06 09:35

    Hi Nige, You have helped me out in the past, so i thought i'd reach out with another subject. To refresh your memory, i have a 1986 CAT416 s/n:5PC03141 I believe the bearing(s) in the fan pulley are beginning to fail. I found a water pump kit (7w6223)on off road equip, which i think contains the bearings. Any chance you have the diagrams/instructions for the removal/replacement for the bearing(s)? or the bearing p/n's? I hope it can be done without removing the radiator....so i thought i'd ask you if you can offer any help on this subject. Thanks in advance Nige, _mike Thanks in advance Nige, _mike

  10. #10Nige2020-09-06 10:19

    The procedure says nothing about having to remove the radiator before removing the water pump, only the fan. The bearings don't have a separate part number. All they are shown as is being part of the water pump repair kit.

  11. #11mike ens2020-09-07 08:54

    Nige, Thanks again for the info.....much appreciated. Have a great day! -Mike