Finish mower gearbox repair help.

[Bluest]

The gearbox on my finish mower is leaking a lot of oil and I'd like to replace the input shaft seal to see if that improves matters. It also throws some oil out through the vent hole in the filler cap, whywould that be?

I know nothing about the gearbox, not even the maker.

If I take the bolts out of the plate around the input shaft, will that give me access to the seal? Are there any nasty surprises awaiting when I open it up? I don't want a load of bearings or shims or some such to come flying out then I can't figure how it all goes back! All tips and warnings appreciated.

 

[brown40]

I see you already have it off, but a heavier oil or light grease might hold. I'd try that, and watch overfilling it--sounds like pressures building when it heats up and there's too much oil being slung around.

 

[prs]

There is usually a pressure/vacuum bleed on the gear box. That yellow colored cap at the top may be fitted with it. The side bung plug you show in first photo sets the correct lube level. An assembly diagram always helps, but seals, keys, and even bearings are "usually" available parts in general supply. They don't go "spring" when you open them, but parts do stick and cling and stink a bit. Mine has been rebuilt twice in its 34 years of hard use. I use the standard grade gear oil and change each season.

prs

 

[Bluest]

I'm pretty careful with the oil level, I always fill it half way up the sight the glass, so I don't think I've over filled it. Been using regular 80w90 gear oil in it.

 

[brown40]

I have been using 85/140 in the tiller and bushhog--had 5 gallons of it, and it's been fine. its stickier and thicker and sling/foam less than lighter oil. '00' grease is something I've heard about a bunch on here as a solution to leaky seals. If you do decide to take it apart, sketch out the order of removal. There's nothing advanced about them: bearings and seals. Biggest thing is getting new parts right where they should rest, and having unscored shaft and spindle. I'd try the shortcut first, and if it's still an issue tear it down. Tear down and rebuild sometimes ends up being more expense/time than full replacement--depends on the manufacturer/seller.

 

[GManBart]

Tear down and rebuild sometimes ends up being more expense/time than full replacement--depends on the manufacturer/seller.

That's what I was thinking, but I'm not sure if that would be the same with U.K. prices. The last time (only time) I looked at the price of parts to rebuild an Omni RC-30 it was cheaper to just buy a new one (around $125).

 

[Bluest]

I'm not sure what the replacement cost would be here. I don't even see any for sale on line. Then again am I searching for the right thing? What are these gearboxes called? I've been searching "pto gearbox".

Assuming they are standard items, the cost of seals and bearings etc. is very low here. I already have a load of 80w90 so it might be cheaper to fix a seal than change to a thicker oil.

As for hassle, I actually enjoy this stuff. Tractor is just a hobby for me.

 

[EddieWalker]

Is it leaking oil out the bottom of the gear box? I have a landpride mower that was doing the same thing. For year I just pumped grease into it to keep it going, but when I needed to replace my blades a few years ago, I decided to fix the leak at the same time. You will have to take off the pully to get to the bottom of it. On mine, it was a rubber seal that went around the shaft. It was just a couple bucks to buy a new one.

Do you have gear shops in your area? Where does the dealer go for parts?

Eddie

 

[Bluest]

I think it's leaking round the input shaft. It's dry underneath, but can get the pulley off if necessary.

I bought the mower second hand off a trader in all sorts of used machinery. He didn't do any repair work. Agriculture is not such a big lifestyle here, certainly not where I live, so don't know any dealers in this type of stuff.

Once I've identified them, getting seals, bearings etc is easy.

 

[Bluest]

Went and had another look with fresh eyes tonight. It is definitely weeping oil past the input shaft seal. So two probably unrelated problems.

1) oil being pushed out the breather. Maybe due to being used on steep hills upsetting the oil level. Need to reassemble and experiment with this.

2) Leaky input shaft seal. Opened up the gearbox, removed old seal, ordered new one. It's now sat there looking like this...

Any thought as to whether this fine score mark, furthest in, might prevent the new seal from doing its job?

And this is what the seal looks like. £3.50 for replacement, about $5 I'd guess.