Replacing seal in gearbox

[AlbertC]

Thanks Dave M7040

I had already found the site in your posting that showed the exploded view. I have the Bushog 286.

I am assuming the seal I need to replace is Ref # 14, part # 88860. In order to replace the seal am I right to assume that you can access this seal and pull it off the shaft without taking any parts off the gearbox (after removing the pto driveline) or is there more to it than that. I would have assumed that there was some type of metal o-ring to keep the seal in place but I don't see any part like this on the exploded view.

Some previously mentioned that they would be concerned about what caused the seal to leak in the first place and suggested looking at the bearings. Taking the thing apart to look at the bearings is beyond my competence level. I did look at the pto shaft and confirmed that it is not too long. As I stated above this hog is only about 5 years old and has seen very light use. Have no idea what could have caused it to leak.

 

[Dave M7040]

Thanks Dave M7040

I had already found the site in your posting that showed the exploded view. I have the Bushog 286.

I am assuming the seal I need to replace is Ref # 14, part # 88860. In order to replace the seal am I right to assume that you can access this seal and pull it off the shaft without taking any parts off the gearbox (after removing the pto driveline) or is there more to it than that. I would have assumed that there was some type of metal o-ring to keep the seal in place but I don't see any part like this on the exploded view.

Some previously mentioned that they would be concerned about what caused the seal to leak in the first place and suggested looking at the bearings. Taking the thing apart to look at the bearings is beyond my competence level. I did look at the pto shaft and confirmed that it is not too long. As I stated above this hog is only about 5 years old and has seen very light use. Have no idea what could have caused it to leak.

The important aspect that many who think disassembly is the easy way, is the critical job of the correct thickness gasket.

The seal is held in by friction alone as there is little pressure inside.

The seal is held in place by friction around the outer circumference of the seal and the housing.

Small flat screw driver and a hammer.

Find the tiny line separating the seal from the housing and tap the screw driver into this gap. Work around the seal with the hammer and screwdriver.

The seal body is thin metal and what you are doing is bending it to loosen the friction in its hole in the casting.

Invest in the new seal. If the problem turns out to be more serious and leaking resumes, often for those without particular skills, buying a new gear box, not from bush hog buy from the company who makes the gear box for them, is the most cost effective way to get back in business,

This video by COMER an international ag gearbox manufacturer gives you an idea of the importance of the correct skim/gasket and I suggest you watch it just to broaden your knowledge

When changing bearings on Model HP gearboxes up to 12", always double check the bearing looseness. - YouTube

This video is on the screw method of seal removal another member mentioned
How to replace a leaking oil seal - YouTube

Dave m7040

 

[BHD]

this may have been already said, but if the seal is gone, one should check the bearing for play, one may need to reset the clearance on the bearing, most likely it is removal of a shim, to tighten it up ,

some shims are different thickness, so it may take some trail and error, to get the correct one,

 

[Texasmark]

Put in Lubriplate 105, in the white tube, turquoise top, most auto parts stores. Thick enough to stay put and thin enough to get around the gearbox.

While you are at the AP store get a vented fill plug too so that when the machine is working, you won't get pressure buildup which forces your lube out of the leaking shaft seal.

Have done it many times and never had to look back. Only time I ever had to go into a gearbox was with a Mohawk twin blade 8 footer whereby I high centered on a terrace with a 100 hp PTO and 45 hp gearbox......as is usually the case, even with proper maintenance, the slip clutch on the mower didn't protect the gearboxes.

 

[mike48130]

If your PTO side seal is bad I would check the bottom seal. The bottom one is where I have had the most issues.

 

[MESSMAKER]

It is most likely the bottom seal. Hay twine or a bit of wire will damage it if it gets wound around the blade shaft. If you are just leaking a bit, use Corn Head grease. It solves the problem. It has an added benefit of not pouring out and leaving your gearbox dry. I have used Corn Head grease in a half a dozen units and never lost a gearbox. I have lost 2 gearboxes. One was a shaft breakage and the other was from a damaged seal that allowed the box to run dry.