YM276D Brakes

[richriddle]

I have been out of town and will try to pry as close as possible to the pin and cam pins.....there isn't much room to pry though. The torque will be the last resort.

 

[rScotty]

I have been out of town and will try to pry as close as possible to the pin and cam pins.....there isn't much room to pry though. The torque will be the last resort.

Well, not quite the last resort. The last resort would be something even more extreme. Maybe filling the brake drum reservoir with penetrating oil followed by lots of hammering on that cam.... and ultimtely followed by using a metal cutting tool to take the cover off in pieces until you can get enough space to get to those brake shoes and make some clearance between them and the brake drum. I've never had to go there, but it's possible that others have.

The problem is that the brake cover is not only a dust and water cover, it is also used for mounting the brake shoe actuating mechanism and the pivots for the brake shoes. So if the shoes have worn grooves into the brake drum and gotten stuck into that expanded position, then there isn't any way to un-expand them. Especially if the springs have rotted away.

And brake service becomes a problem too often because that that cover is not well vented. All in all, that whole brake system design is not well thought out. And that is being generous. Yanmar didn't think through the details of how brakes are used and what happens to them when they get wet. So back in the day when these were under warranty, we always did see a lot of un-necessary rust in the Yanmar springs, brake cam, and drums. It's a problem for gray market machines used in rice paddys too.

Those of us who have had to deal with rusty Yanmar brakes are careful not to let it happen again.
It may cost a cover, but you will get it off, and nice brakes are almost worth the effort.

To avoid another "too soon brake job", lathe the rust pits out of the inside face of the drum, replace the shoes with new bonded ones, use new springs, and make sure water can't enter via the brake cam shaft. Oh, and while you have it off, make up a proper vent for the brake cover. You might want to check if the vent on the axle housing behind the seat needs improving as well.
rScotty

 

[CoyPatton]

I have been out of town and will try to pry as close as possible to the pin and cam pins.....there isn't much room to pry though. The torque will be the last resort.

How true that there is very little room to pry. True is there is very little room anywhere—seat, floorboard, you name it and these yanmars are just tight on space. With that it mind to pry on the brake cover—a couple of wonder bars (mini crowbars) may be in order. It looks like you have a bit of separation between the cover plate and the tractor body. If the springs are still connecting the shoes, you should get that natural tendency of the shoes wanting to fold if you can get any movement with prying the cover away. Then that force should push the plate further out.
Again good luck and be patient as you try to get it apart

 

[California]

The last resort would be something even more extreme. Maybe filling the brake drum reservoir with [non flammable!] penetrating oil followed by lots of hammering on that cam.... and ultimately followed by using a metal cutting tool to take the cover off in pieces

Just a suggestion ...



It never occurred to me to cut that cover to pieces, now that's extreme! rScotty it sounds like you've nearly had to do this.

I wonder if it would be sufficient to just cut out some material around the cam then pry the cam toward the center of the drum to disengage it from the shoes.

 

[rScotty]

Just a suggestion ...
It never occurred to me to cut that cover to pieces, now that's extreme! rScotty it sounds like you've nearly had to do this.

I wonder if it would be sufficient to just cut out some material around the cam then pry the cam toward the center of the drum to disengage it from the shoes.

Well, it's easier on the smaller Yanmars where the cover isn't so thick. The YM155/165 brake cover is only stamped steel with some welded parts supporting the cam and spindles. The YM276 brake cover looks more formidable. It may even be an an unrepairable casting. On those smaller machines you can sometimes get a very slim tool slid between the cover and case and pry around until something good happens. The case cover will bend a slight amount without breaking. Not so sure about the 276 though...

The trick I've never tried is running the tractor and using engine torque to separate the drum and shoes. I wish I had thought of doing that - but the problem I always seemed to see was rust-related wear in the drum trapping the shoes behind a wear lip and so unable to pull the cover off. You can't fold the shoes inside the drum, but with enough constant straight pull horizontally out away from the tractor....maybe using some sort of puller or studs & nuts ..... and keeping outward force on the cover while rotating the transmission countershaft rather than running the engine.... I think you might get it off.
rScotty

 

[California]

I have been out of town and will try to pry as close as possible to the pin and cam pins.....there isn't much room to pry though.

Is there a substantial wear lip in the left side drum that you exposed? This might give a clue of what to expect in the troublesome right side.

I haven't found much of a wear lip in any of the three I've had apart. Brake problems were limited to the shaft cemented into its bore.

 

[richriddle]

I am currently sidelined for a large blood clot in the left leg......apparently the wife doesn't want it to dislodge, move to the lungs, and kill me. That means no working on the farm or tractor until competent medical authority allows.........old age sucks.

 

[California]

I am currently sidelined for a large blood clot in the left leg......apparently the wife doesn't want it to dislodge, move to the lungs, and kill me. That means no working on the farm or tractor until competent medical authority allows.........old age sucks.

Wow! Take care of yourself. That project can wait.

Hope you're better soon.

 

[CoyPatton]

I am currently sidelined for a large blood clot in the left leg......apparently the wife doesn't want it to dislodge, move to the lungs, and kill me. That means no working on the farm or tractor until competent medical authority allows.........old age sucks.

Sorry to hear about the blood clout! Listen to your wife, the brakes will be there when you get better.
And yes getting older is not for the faint at heart.

 

[Jtullis13]

Hope you heal soon, be careful we don't want anything bad to happen to you. Keep us posted on your health and your tractor once you are up and doing better.