Had a breakdown!

[284 International]

I finally had something fail due to wear and not abuse or improper assembly. My YM240 has a separate hydraulic pump to power the loader. I had left the tractor at my dad's house so he could do some cleanup. After only a few minutes he called me and said the loader wouldn't work.

A quick trip back to check things out revealed that the hydraulics for the loader weren't working at all, but the system was full of fluid. Stuck working on it away from the shop and my tools (such as they are) I tore down what I could easily access after failing to be able to drag the thing out of the spot it's in.

The problem was pretty obvious quickly: The intermediate shaft between the crankshaft and the forward mounted pump (It sits just underneath the battery) would spin, but the pump's shaft would not. A couple bolts later, I had the shaft out:

It's a really weird setup (to me) called a chain coupler. It's about 5 inches long, and is a spool shaped piece of steel with gears on the spool ends. Then, a double thickness of chain attaches one side to a sprocket on the crankshaft, and the other side to a sprocket that fits onto a keyed shaft:

The Woodruff key was quite mangled, and was the proximate cause of the pump's failure to operate.

The crankshaft side of the shaft has obviously been broken (breaking?) for awhile, and originally was captive to the crankshaft sprocket by the double-linked chain, but that is mostly destroyed. The sprocket teeth on two of the three sprockets on the shaft are SEVERELY undercut and worn (semi-visible in a couple of the photographs) beyond serviceable life.

A chain coupler gives a little bit of misalignment allowance for flex, but in this case it wore itself out. I'm not sure if it's due to excessive misalignment, inadequate lubrication (I've never lubricated it, but have under 50 hours on the machine since I've bought it) or a combination of them. I haven't pulled the pump out yet, or the crankshaft pulley, to examine them, but will take pictures as I go if people are interested in the repair.

 

[Neat 1500]

they do have some elaborate drive systems on some of these yanmars. my 14MkII has a double uni jointed shaft about 8" long thats on a slight offset but its worn out and wobbles badly that drives the electric PTO. very hard to get something made to replace it let alone the cost. even the drive shaft is similar and also it too is worn out and makes a h#ll of a racket when driving.

 

[winston1]

You have probably already browsed some of the sprocket vendors. Don't know the shaft size or chain size of yours but here is an idea of sprocket and chain cost. Chain Couplings - Couplings, Collars, and Adapters - Grainger Industrial Supply

 

[YannyMan]

Neat, new shafts are avaliable... They cost as much as the tractor (almost) though!

 

[Car Doc]

Ouch!

The shaft on the pump could be re-keyed rather than replacing the pump by a careful person with a small cut off wheel like a dremel tool and a jig built (edit: short piece of 1/2" angle iron clamped to shaft comes to mind) to help make straight cuts that could be clamped to the shaft. The set screw in the new gear could be put down into the old worn keyway for extra holding power that would also dictate where the new keyway would be. (I know this mental pic is hard to visualize but I see it clear as a bell)

It would take some doing but with a new key handy it could be fitted pretty easily I think may take some fine tuning with a good 1/8" square file also, the gears and chain should be no big deal and get a can of motorcycle chain lube the good sticky stuff! :thumbsup: good luck

 

[California]

... or just plumb the loader to the tractor's hydraulics, via the divider block under the front of the seat.

 

[clemsonfor]

Or cut and splice into the high pressure line like all the VN recons have.

 

[California]

Or cut and splice into the high pressure line like all the VN recons have.

The US Yanmars already have a factory-installed diverter block for this. To use this you remove (install?) an allen-head plug inside one of its ports to send the fluid out/back for the new application, in series ahead of the 3-point lift. The loader on my YM240 is plumbed this way.

 

[284 International]

I don't have much time to work on things at the moment, but will spend some time pulling it apart and seeing what I'm actually faced with. My strategy is first to get it out of the yard and back to my garage, so I'm not working in dirt and weeds.

I'm hoping the pump's shaft is ok. I couldn't see it, but could feel the groove for the key, and it seemed to be in usable condition.

I wonder how many thousands of hours this thing has on it to wear the chain out like this. It's going to be a fairly simple fix, but it's a nuisance to have my loader go down like this. I've come to take it for granted!

 

[winston1]

The US Yanmars already have a factory-installed diverter block for this. To use this you remove (install?) an allen-head plug inside one of its ports to send the fluid out/back for the new application, in series ahead of the 3-point lift. The loader on my YM240 is plumbed this way.

My YM2002D has those ports also.