520 HC hydro leak

[Brockport Bill 1,715]

i suppose this info is somewhere on a thread but this is a new adventure for me - just got 520 HC 1988 year - model C1-20OE01 --  has hydro oil all over underneath -- actually combined with grass, dust, debris etc its caked on like super glue -- I have no idea where to start -- I began by starting to wipe black glue all off - its everywhere underframe -- plus around entire rear end and sides of hydro housing case -- most of fins covered- plus rear hitch, axles, under seat pan, etc . Why the prior owner drove it I have no idea - abuse of a good horse !!!  Seemed to make sense to clean it, run it, to then see new leak location -- I put one quart oil in hydro and it literally poured out somewhere underneath rear end of tractor - fortunately I had cardboard down. I am guessing this model has likely few suspects of what this leak is - Can someone suggest what the likely villain is from prior history of this model? Do I clean it, put it back together,  then run it and locate leak on clean surfaces - or is there a smarter strategy? I have seat, seat fender pan off and about to remove fuel tank and wheel to continue removing stuck on oil. If possible, I want to avoid trip to a shop and many hundreds of $$$$.... thanks!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[lynnmor 7,353]

Go just a bit farther by removing the seat support and cleaning things completely.  Did you check the drain plug?  The bolts that hold the seat support go into the transmission and should have some sealant on the threads.  The axle seals are a common problem and usually cause oil to run onto the tire.  The dipstick tube may be loose or cracked, so check that.  Hydraulic connections may be leaking.  Until you completely clean up the entire area, you can't be sure where the leak is.  I would suggest using Purple Power, a paint brush and a garden hose for the cleaning, make take several applications.

[EricF 589]

If the oil/muck mess is all over the top of the transaxle and pump, it's possible that it's left over from when someone refilled hydro with fresh oil, but never cleaned up afterwards. Filling the transaxle (as you'll eventually find out  ) is a messy exercise in patience -- the proper grade of oil is thick and filling it through the dipstick while allowing air to escape results in a little to a whole lot of spillage depending on how fast (or lucky) you are. It may "burp" air bubbles out which will spatter oil everywhere on top of the axle, the pump, under the fender pan. If it's not cleaned up, it will attract dirt and grass clippings like nobody's business.

The whole area under the fender pan, over the hydro pump, and on top of the transaxle on my 520H was packed and caked with muck and spilled oil because the shop that had been servicing it apparently never bothered to clean it up properly after filling the axle. To get it all, you have to take off the seat, and then the fender pan so that everything can be cleaned up -- the shop never took that kind of time. Over several service intervals, the layers of oil and crud and oil and more crud built up.

 

Taking everything off to clean also ensures that you can inspect the bolts and put never-seize on them. The previous owner's shop never did... and I found several of them seized-up and in need of drilling out.  

With the area cleaned up and degreased, the hydro pump will run cooler with its fins all clear of debris. Keep an eye out for any further leaks -- but a lot of times it's just a mess left over from service that was never cleaned up. At least with everything clean, it's a whole lot easier to spot and trace back any leaks.

[Brockport Bill 1,715]

one challenge i noticed to remove fuel tank to be able to clean tranny area is the one wire connection to fuel gauge unit on top of tank is " clip on clip off " but the other is "permanent" connection -- so i have to find somewhere the wire leads under console to disconnect -- why would someone design it that way? Am I missing some easy solution - thanks for all the insights !!!!!!!!! Otherwise I have to remove set of screws and remove entire gauge unit from tank???? Huh??

[Charbs152 254]

de-greaser and a pressure washer work wonders

[EricF 589]

Careful with the pressure, though. The spray can drive past seals or into fittings where it doesn't belong.

[lynnmor 7,353]

The wires had 1/4” disconnects from new, so someone knackered it.

[Brockport Bill 1,715]

actually i just had that conversation this morning with my son about the pressure washer and possible damage to wiring and especially to seals or water bearings intrusion - thanks for heads up to be cautious  -- was thinking degreaser as pre-soak then wash it off low pressure.................my larger question is what is likely historical  520 hc pattern of where oil is coming from and likely source of oil leak and possible fixes? 

[lynnmor 7,353]

2 hours ago, Brockport Bill said:

actually i just had that conversation this morning with my son about the pressure washer and possible damage to wiring and especially to seals or water bearings intrusion - thanks for heads up to be cautious  -- was thinking degreaser as pre-soak then wash it off low pressure.................my larger question is what is likely historical  520 hc pattern of where oil is coming from and likely source of oil leak and possible fixes? 

 

There are only two things that have any significant number of oil leak problems.  One; they will spill oil from the dipstick when stored for some time where the temperature fluctuates considerably, the cause is not clear but my guess is that air in the far reaches of the system is expanding and contracting and acts as a pump.  You might go years, and maybe never, with no spill.  Secondly, the axle grease seals fail after a number of years, how often is a matter of usage and luck.  If you are getting leakage from other areas it is probably related to the abuse suffered by the previous owner, for example running the hydro over-heated from all that debris.  Yes, those hydro's need to be clean and the fan running well.  I had the fan bolt just loosen and the transmission got hot, re-installing the bolt with thread locker solved the problem.  I can give you no definitive answer as to where you have a leak, the previous owner didn't care about the tractor and there is no telling what these types might damage.

[Brockport Bill 1,715]

yes. lynnmor  -- its amazing how people can abuse a piece of equipment - some people's attitude just as long as it keeps running.... until it doesn't !!!!! SAD !!! However, like many likely on this forum,  my dad taught me a tool will take care of you as well as you take care of it - trying to pass along the same lessons to my children and grandchildren by example and words

[Tuneup 1,433]

Old iron is really forgiving - can take so much abuse. I had a tech friend back in the early HP days - Paramus NJ - that never changed his oil in his Ford wagon. When the red light came on, he added a quart. I don't know how that thing moved but it lasted forever.