Gearbox for RCB60-I mower - disassembly trick?

[lloydd]

Hi all,

Now that mowing season is over, I am taking the time to work over the RCB60-I belly mower on my new-to-me B8200DT. Primary task is to repair the gearbox powered by the front PTO shaft. The manuals call for 90W gear oil for lube, but the seal is gone - just leaks out in a puddle.

I have the gearbox pulled and separated from the lower jack shaft. Just need to get the pulley off to reach the lower seal. My three jaw pulley fits this job pretty well. I've tapped on the shaft and applied lots of PB Blaster. I sure don't want to bend the pulley, as Messicks is pretty proud of their new ones (Part #70712-99750, $102.88)

It's not rusty and I'm not wild about heating it with 'the gas wrench' unless I have to. What is the secret handshake to getting this thing to pop loose?

thanks,
Doug
Kingston, TN

 

[Dave_eng]

I do not remember if this is possible but at least consider trying to get the box apart with the pulley still on the shaft.

Once apart, then you have a better chance of getting the pulley off with something supporting the hub behind the pulley while trying to press the shaft through the pulley.

The pulley will bend easily.

Dave

 

[Big Kahuna]

Take #4 off then remove circlip and drop shaft thru gearbox, then support pulley and press shaft off.

Big Kahuna

 

[lloydd]

OK - thanks for the new strategy. Mine is sure not working, that's for sure.

I even hung the dang thing right side up from the rafters. More PB Blaster dripped right down the shaft, more tapping, more puller tightening. Won't budge.

thanks,
Doug

 

[lloydd]

Re: Gearbox for RCB60-I mower - rebuild

Well, I managed to get the pulley off the shaft finally, and did not bend anything. But the vertical shaft assembly does not want to drop out the bottom. I've removed both oil seals, all 3 circlips and can see the ball bearings, but it it still wants to stay put.

So I cleaned things out with a kerosene dip and scrub. Once the grit came off the shaft tines started looking more promising and the gears spun a lot more smoothly.

One problem so far - one of the PO's must have tried to replace one of the side stay bolts with a longer one - and managed to break through the inner wall of the gearbox casting. So there is likely a chip of cast rattling around inside the gearbox. Or was, and has already been chewed up by the bevel gears - this is 34 years old.

But the hole might be where my lube leak was coming from. I'd like to put some kind of short plug down the bolt hole to close this off before putting the *correct* stay bolt back in. Or might a rubber washer be enough? Thoughts?

Given that the lube filler and drain holes are much lower than these bolt holes, this may not have been a problem. OTOH this belt driven gearbox runs at engine speed and there is probably lots of splash lubrication keeping the bevel gears lubed.

I've got new Kubota oil seals from Messicks and am ready to put this back together. Your input is welcome before I lose the chance to fix something else while I'm this far in.

Merry Christmas all!
Doug

 

[Cglaza]

IMO, you would not be able to get a new case. I think the best way to go at this point is jb weld the hole after degreasing the hell out of it. You would have to put a bolt in after the jb weld to hold it up in there and you may need a couple applications to get it done. I wouldn't try silicone because you wouldn't be able to get jb weld to stick. Or better yet, I think there is a putty that would work in this situation better but for the life of me can't remember what it is called.

Sent from my moto z4 using Tapatalk

 

[GreensvilleJay]

hmm, once 100% of the guts are removed , super clean the casting, power wash,use TSP, wash again, and OK, another time
If, IF, there's enough space ,use JB Weld to glue a thin, tin plate on the inside to cover the hole. Make as big as possible so LOTS of JBWeld will bond the tin to the cast. You could then pour some JBW into the hole , just be careful...not too much.... the other holes are a good guage though.
The other choice is to braze the opening shut, old school, but it's the best way.

I've done #1 with oil sump area of cracked B&S engines, some went 13-15 years before failing....
Did #2 on a Willys xfr case....

 

[sheepfarmer]

And if all else fails, or even if it doesn't, consider using 00 grease instead of oil. Less likely to leak out past a seal and trashing the gears before you notice it. Kubota tech put in my deck because any leak is virtually undetectable if you don't take the whole deck off the tractor.

 

[jmngray]

Hi all,

Now that mowing season is over, I am taking the time to work over the RCB60-I belly mower on my new-to-me B8200DT. Primary task is to repair the gearbox powered by the front PTO shaft. The manuals call for 90W gear oil for lube, but the seal is gone - just leaks out in a puddle.

I have the gearbox pulled and separated from the lower jack shaft. Just need to get the pulley off to reach the lower seal. My three jaw pulley fits this job pretty well. I've tapped on the shaft and applied lots of PB Blaster. I sure don't want to bend the pulley, as Messicks is pretty proud of their new ones (Part #70712-99750, $102.88)

It's not rusty and I'm not wild about heating it with 'the gas wrench' unless I have to. What is the secret handshake to getting this thing to pop loose?

thanks,
Doug
Kingston, TN

How in the world did you get the gearbox off the deck?! I've tried for an hour and can't figure it out.
Took off blade, little cover with the tabs and the Cclip. On the top the entire gear box is loose. Shouldn't it just pull straight up? In the parts diagram there is another C clip about half way up the shaft but I can't figure out how to get the other pieces off to get to it.

 

[BruceP]

But the hole might be where my lube leak was coming from. I'd like to put some kind of short plug down the bolt hole to close this off before putting the *correct* stay bolt back in. Or might a rubber washer be enough? Thoughts?

Brazing (bronze based) is the accepted way to repair cast-iron. Perhaps a blob of brazing material will re-seal that broken area. (after light grinding to prep)

Exhaust manifolds are repaired by brazing all the time.

This is a 5 minute job for experienced person. (always PREHEAT cast material before brazing... then wrap with insulation so it cools slowly and evenly)