YM240D front axle leak repair progress post

oksanaut · Jul 2, 2018

I recorded my attempt with 1.5mm:
google video

oksanaut · Jul 2, 2018

normde2001 said:
Anything other than "snug but free" is serious overkill, when considering a maximum speed of 7-8 mph. Backlash is mostly concerning "whine" at speed.

Well, and what whine would I hear sitting atop a 2-cyl diesel with exhaust at my ear level?

winston1 · Jul 3, 2018

Looking good. :thumbsup:

oksanaut · Jul 3, 2018

rScotty said:
I think that 2 mm is reasonable. As Winston say, you may have to assemble it many times. Shims don't have any upper limit, they just gradually become known as "parallel face ground washers" as they get thicker. But I've seen them considered as "shims" all the way up to about a quarter inch (6mm) thickness. Basically I would shim to whatever it takes for the engagement backlash to be loose ... but small.

I like to think of the thickness (width) of the ball bearing shell itself as being part of the shim thickness - and it's a pretty thick shim itself, often being in the 15 to 20 mm range. Designers use bearing width as part of the shim calculation since bearing width is very, very flat & consistent.

Don't forget any paper gasket thinkness. Thin paper gaskets can be as thin as .1mm thickness (.004") and the thick black fiber gaskets with the punched out holes can easily be .5mm (.020"). Hmm... Are there any paper gaskets in there? I've forgotten just what combination of gaskets and seals Yanmar used.
Maybe it's time to think about gasket goo, though.

It would be interesting to track how the sealing of that bevel gear front axle has evolved from the time that Yanmar first brought it out as a Yanmar exclusive - until today when it is the type of front steering axle used by most every 4wd tractor on the market.
luck, rScotty

There are no paper gaskets in this stack. There is one from knuckle housing to cover, but it does not add up to this stack.

normde2001 · Jul 3, 2018

oksanaut said:
Well, and what whine would I hear sitting atop a 2-cyl diesel with exhaust at my ear level?

Precisely why you don't need to be concerned with backlash.

rScotty · Jul 4, 2018

normde2001 said:
Precisely why you don't need to be concerned with backlash.

Norm, I'm not understanding why you are so unconcerned with backlash. As I see it, backlash is primarily used as a way to make sure that the mating surfaces of the bevel gears is on the center of the tooth and not out as the edge.
rScotty

normde2001 · Jul 4, 2018

rScotty said:
Norm, I'm not understanding why you are so unconcerned with backlash. As I see it, backlash is primarily used as a way to make sure that the mating surfaces of the bevel gears is on the center of the tooth and not out as the edge.
rScotty

If the teeth are "out at the edge" there is a LOT of play and they are NOT snug but free. I would lube with 90 wt and assemble/shim so that it just turns freely with no slop, forget measuring backlash.

oksanaut · Jul 24, 2018

Hello, I am back with updates!

Cleaned, painted, and assembled with about ~1.5mm of new shims, filled with new oil on Sunday and left it for another 2 weeks (until we are back). So far so good. Below are photos I snapped during the process.

Some things I noted: as it has been mentioned before, I&T guide is not exact and it is better to have parts list to check against diagrams. Still operating without a proper YM240D manual, so... by the seat of pants in some cases.