some general questions about a leaky bush hog

   / some general questions about a leaky bush hog #1  

jojo200517

New member
Joined
Jun 2, 2011
Messages
7
Location
gaffney sc
Tractor
Tafe 35DI
I have an old bush hog that is at least 20 years old, not even sure the brand or original color as its kinda rusty and weathered. Its kinda beat up but it does cut pretty well and no bad shaking or anything. I don't use it much at all but the between working 6 days a week and rain off and on I had missed getting some of the back property mowed with the zero turn until it was knee high. I figured that was good enough excuse to hook up this old girl and mow it down then run over it with the mower to give it a better look.

All went well with the mowing considering it was in the mid 90's with no breeze. It is when I got off the tractor that I seen the front seal on the gearbox of the bush hog was leaking. It only looked like a little bit so I kinda wrote it off in my mind as it just got hot from mowing and that I'd check the oil level next time I went out. Well a couple days later I needed to do some plowing and when unhooking the cutter I realized that in fact a decent amount of fluid had leaked out this front seal. I'm pretty confident I can fix it by replacing the seal and get some more usage out of it however I am not sure exactly where I'll be able to get a seal not having any type of part or model numbers. I have read that this is standard 90 wt gear oil is pretty universal for these gear boxes so that won't be an issue however I have no clue as to how much(and have learned the hard way what too much can do) I haven't tried to take it apart yet but I was wondering if anything is pressed in or what not.

I guess my next step is to flip it over get the blades and stump jumper off and get the gear box unmounted and in the shop where I can work on it. I'm assuming there is some type of bottom seal? Should I go ahead and replace it while i'm tearing stuff down?

Sorry if my first post here is long and rambling, just looking for someone to steer me in the right direction.
 
   / some general questions about a leaky bush hog #2  
Most gearboxes have a plug on the side that's the fill/ level plug. Fill with oil until it's level with the bottom of the hole, and it's full.

The seal is probably a standard size. When you get it out, you should be able to take it to a good tractor parts place and they can find one to match it. You might even find a factory part number on it when you get it out.
 
   / some general questions about a leaky bush hog #3  
Many a 20+ year old rotary mower gear box is filled with grease for the reasons you describe. Some of them have been running that way for years.

MarkV
 
   / some general questions about a leaky bush hog #4  
If just the input shaft seal leaking and gear box is not over filled. remove the pto input shaft by removing the shear bolt. and clean the area. Then with a small punch or old screw driver pull the seal out and take to any parts store Tractor or Automotive and they can order or have in stock the seal.There is stamped into the metal part of seal a replacement number. These seals get damaged when wire or some grass or dirt around pto shaft gets into the seal area.
Heavier weight oil or grease helps slow the leak.
If the lower gear box seal is leaking it is going to take considerable work to get to.
ken
 
   / some general questions about a leaky bush hog
  • Thread Starter
#5  
Hey guys, I got a chance to look at it a little more and found the plugs. I don't know really if it was overfilled before but i'm guessing it would have came out before now if it had been because it has been run much harder and for longer periods of time before with no leaks. For the record I don't ever recall the plugs being removed by my dad and I ceartinly have never took them out. The stuff that is in there is gosh awful nasty looking and kinda runny (didn't seem near as thick as 90 wt gear lube to me)

Without flipping it over and looking for evidence of a leak on the bottom side I wouldn't know if its leaked out that one or not.

My next task will be getting the shaft off and the front plate. Got the shear bolt out but the stubborn thing is on the shaft pretty good. All the yanking I could put on it by hand didn't budge it. It got a good soaking with pb blaster and hopefully some gentle taps of the hammer can get it started sliding off.

Thanks for the info on finding a seal. When I get it out I'll head down to the local NAPA and see if they have something and if not i'll make a nice long drive down to the tractor place.

I'm thinking about grease instead of oil to make the leaks less when I put it back together. Maybe something half way inbetween like 00 grease? or just plain jane red grease from the local tractor supply?
 
   / some general questions about a leaky bush hog #6  
If the seal lasted this long without leaks. and the pto shaft never broke the shear bolt it has had a easy life. Using a brass drift punch or soft type metal so as not damage the coupling put behind the coupling and just keep working it off. If as most shafts it is designed to spin with out the pin in place so would not twist the pto.
Type of oil it held the probally 90 weight gear oil why go to a thicker type. some and I have used grease but the gear box was wore out and lots of slack in gear meshing.
Good luck in the repairs. Just think of all the experance your gaining.
I might add there is sometimes a spring clip to keep shaft from coming off when the shear pin is broken.
ken
 
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   / some general questions about a leaky bush hog #7  
Make certain there is a vent on the gearbox. Usually that's in the form of the top "fill plug". As mentioned, don't over fill. Your seal is in all likelyhood, a "standard" seal, almost always available at bearing supply houses, and most GOOD auto parts stores. Better than not chance if the input seal blew, it saved the output seal, IF it was in fact, pressure that caused the failure. It COULD be early signs of bearing failures coming soon though.... Best to take a close look NOW. Long story short, I'd change BOTH seals if you go to the trouble of removing the gearbox.

"Corn head grease" (available @ John Deere dealers) is a good alternative to 90wt gear oil. All else fails, use standard "gun grease"......Seen 'em run for YEARS with grease in the gearbox.
 
 
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