YM276D Brakes

[richriddle]

The right rear brake on the old YM276D is frozen. I watched the video and ordered the new brakes from Hoye Tractor. The brakes should arrive on Monday. How difficult a job is it to remove the brakes when they are frozen? The video mentioned the cover plate is cast and to be cautious.

 

[California]

The Hoye video is great. He takes the wheel off, I didn't, on the three Yanmars I've done. I think working there is safer with the wheel on. I suppose total job time is the same either way.

Usually the problem is the shaft stuck in the cover, not the shoes stuck, so it's a simple project. Note there's an o-ring at the exterior end of the shaft so you can't free up a stuck shaft by oiling it there.

The examples I've worked on had everything stuck worse than Aaron's example. I took a thin flexible putty knife and drove it in at several points around the perimeter of the cover to get it loose. There's a paper gasket, so there's a little slack to drive the putty knife into. Take it easy driving the shaft out of the cover, don't bend or break it! Penetrating oil, time, twisting the lever instead of a direct push, will eventually loosen it. Don't overlook the snap ring!

You can swap old front and rear shoes on each side to even out the wear. Also on some models the 'dead' anchor at the far end of the shoes can be rotated a quarter turn to bring half-worn shoes closer to the drum. I used non-runny silicon lube on the o-rings and shaft, so it wouldn't seep onto the shoes.

This is an easy project, NBD. The stuck brakes I freed up in 2004 still move freely, and the original shoes still seem ok. I like the way old Yanmars were designed to be owner maintained.

And a comical picture to imagine: When I test-drove the YM240 I tested the brakes with a hard push at full speed and darn near looped around in a circle. Seller said 'I forgot to tell you don't use the left brake. It doesn't release. Just drop the loader bucket to stop'. I wished he had told me sooner.

 

[richriddle]

California,

Thanks for the reply; you're a fountain of knoledge and quite the gentleman. I plan to go to the farm tomorrow and look at the tractor and possible work off the shoes. The brakes on it have left a lot to be desired for some time......to say the least. The 276D is in a garage so it's a great spot for working on it, but it's a bit tight toward the wall. I am also considering updating the seat on it because it's cloth. Apparently it didn't rain where the previous owner lived.

 

[richriddle]

I started on the brakes today. Took off the tire and removed the cotter key/pin to disengage the brake rod. The shaft isn't budging even a fraction. With the shaft not moving, is it safe to attempt to remove the cover? I don't want to break the cover or any other parts. Here is a picture of what is visible with the tire removed. You folks who do this job with the tire on must be contortionists.

 

[California]

I started on the brakes today. Took off the tire and removed the cotter key/pin to disengage the brake rod. The shaft isn't budging even a fraction. With the shaft not moving, is it safe to attempt to remove the cover? I don't want to break the cover or any other parts. Here is a picture of what is visible with the tire removed. You folks who do this job with the tire on must be contortionists.

View attachment 654125

That's more elaborate than my old-school YM240. After taking out the cotter pin I was able to put a big Crescent wrench on the naked lever, to force it to 'disengage' position. Here's a photo (from my recent axle housing replacement project) showing its simplicity. Can you get a Crescent wrench or pipe wrench in there to rotate the lever?

I think putting the brake pedal at its highest position then rotating the lever until the cotter pin can slip in, might indicate where the lever should be when disengaged. Or the sweet spot where the shoes are fully released, may be a little beyond that position. Good luck with this!

 

[richriddle]

That's more elaborate than my old-school YM240. After taking out the cotter pin I was able to put a big Crescent wrench on the naked lever, to force it to 'disengage' position. Here's a photo (from my recent axle housing replacement project) showing its simplicity. Can you get a Crescent wrench or pipe wrench in there to rotate the lever?

I think putting the brake pedal at its highest position then rotating the lever until the cotter pin can slip in, might indicate where the lever should be when disengaged. Or the sweet spot where the shoes are fully released, may be a little beyond that position. Good luck with this!

The cotter pin has been removed and the lever is "naked." A pipe wrench or Crescent wrench will most likely work....a pipe wrench more than Cresent most likely. Your advice on placing the brake pedal at the highest point seems spot on and offers a good approach.

If I am looking at the photo you provided, you have the axle off but the brake is still in place. I need to watch the Hoye video again.

 

[HoyeTractor]

That top nut is also part of an adjuster cam for the other end of the shoes (link below to a similar part for reference but not the exact one for your tractor). If you are lucky and that top cam has been adjusted out and it is not froze also- you might be able to loosen the shoes off a little bit that way also. Sort of a long shot but a pretty easy thing to try.

Brake Cam Pin: Yanmar Tractor Parts

 

[richriddle]

Will it be better to try moving the arm with a rubber mallet, hammer, or some wrench? I am guessing this will take some time to remove.

 

[California]

If I am looking at the photo you provided, you have the axle off but the brake is still in place.

Yes. The brake drum inside that cover is driven by a smaller countershaft that is forward from the bullgear. (The big gear at the inner end of the axle).

Will it be better to try moving the arm with a rubber mallet, hammer, or some wrench? I am guessing this will take some time to remove.

Whatever works! Start gentle, increase force as needed. I expect a big pipe wrench could move it, worst case, but its likely not stuck that severely.


Aaron - Wow you guys have Everything!

 

[richriddle]

I completed the following steps:
1. Removed the brake linkage.
2. Tapped the brake lever back and forth so it's now able to move with a small pipe wrench.
3. Removed the 7 bolts holding the brake cover in place.
4. Wedged a flexible putty knife around the entire perimeter of the brake cover which sliced the gasket.
5. In the area near the upper back, placed an extremely thin bladed straight slot screwdriver in place (can't load pictures for some reason).

After doing those things:
1. When moving the brake lever, the brake cover rotates about five degrees back and forth. The brake cover won't rotate more because it contacts parts of the frame.
2. The cover remains extremely tight.

Moving forward:
1. I don't want to break anything.
2. Would you recommend hitting the lever like in the Hoye video? It looks like a dead-blow hammer was used.

Other duties at the farm came into play including burning off a large pile of debris and performing mechanical work on the wife's 1965 Mustang getting it ready for the season. I didn't mind that because her car now isn't taking space in the Yanmar garage.

 

[California]

It sounds like the cover is free of the housing, so that has to be the shoes too expanded to come out of the drum. Is it certain that the brake lever is in brakes-released position?

If i were doing that project I might lay the removed wheel under the tractor for safety, then run the tractor in gear, forward and reverse, to make the brake drum move relative to the shoes and hopefully break them free. Think safety!

 

[Jtullis13]

It sounds like the cover is free of the housing, so that has to be the shoes too expanded to come out of the drum. Is it certain that the brake lever is in brakes-released position?

If i were doing that project I might lay the removed wheel under the tractor for safety, then run the tractor in gear, forward and reverse, to make the brake drum move relative to the shoes and hopefully break them free. Think safety!

California you have the right idea on both parts of this! Great suggestions

 

[richriddle]

I have been away a few days but decided to take off the left rear brakes to determine approximatly what position the lever should be located; after all, both sides need to be replaced.

 

[richriddle]

It sounds like the cover is free of the housing, so that has to be the shoes too expanded to come out of the drum. Is it certain that the brake lever is in brakes-released position?

If i were doing that project I might lay the removed wheel under the tractor for safety, then run the tractor in gear, forward and reverse, to make the brake drum move relative to the shoes and hopefully break them free. Think safety!

I removed the left brake in about two minutes doing exactly the same thing done to the right that remains frozen (for lack of a better word). The rear tires are reinstalled in place for safety if the YM276D fell, it would land on the tire. As you suggested, when the tractor runs, the left wheel spins free and the right wheel is locked in place. The right wheel rotates just a hair. When the tractor is turned off, you can move the entire assembly by hand about five degrees, but it wont' budge after that. The five degrees is the approximate distance it can travel before the cover contacts another part. Prior to today, one needed a tool to move the assembly the five degrees. Since the YM276D is up on jacks in the rear, it might be possible to throttle more power than the simple low idle to see what happens. Here are a few of the pictures of the left side brake.

 

[richriddle]

I increased the throttle today and it didn't change anything. The left wheel spins with the throttle but the right wheel is frozen. When moving the wheel by hand, it looks like the slight movement of 5 degrees on the right wheel isn't moving inside the drum, but has the entire drum moving as well, in other words frozen to the walls of the drum. I am guessing that because when the right tire moves the 5 degrees, the left tire also moves five degrees.

 

[CoyPatton]

Trying to grasp the issue from your pictures and descriptions and am somewhat confused. I admit I have not ventured into my yannie’s brakes (perhaps I should before an issue). Since you have the one side loose and shoes removed, could you reinstall the plate, and compare the movement of the brake camshaft lever from the disassembled side to the ‘frozen’ side. This would give you a reference to travel and then perhaps a reference to the cam position on the stuck side.
Another though is to unbolt the cam shaft and upper pin to remove the outer plate. That way you can at least see where the shoes are stuck at and perhaps disassemble from there.
Again I have not been into mine, but your upper pin appears to have a nut, Hoye’s diagrams show nuts. With an O-ring in the camshaft for movement and a replacement available from Hoye, it comes out some how.
If like vehicle drum brakes, the shoes have cut a groove into the drum and are locked behind it. Either the camshaft is stuck/frozen or the spring(s) have broken and have the shoes jammed.
Good luck!

 

[richriddle]

Trying to grasp the issue from your pictures and descriptions and am somewhat confused. I admit I have not ventured into my yannieç—´ brakes (perhaps I should before an issue). Since you have the one side loose and shoes removed, could you reinstall the plate, and compare the movement of the brake camshaft lever from the disassembled side to the ç´*rozen side. This would give you a reference to travel and then perhaps a reference to the cam position on the stuck side.

You are correct. I did just that and have the lever and the cam position of the opposing plate in the position that would not be forcing the shoes apart.

Another though is to unbolt the cam shaft and upper pin to remove the outer plate. That way you can at least see where the shoes are stuck at and perhaps disassemble from there.
Again I have not been into mine, but your upper pin appears to have a nut, Hoyeç—´ diagrams show nuts. With an O-ring in the camshaft for movement and a replacement available from Hoye, it comes out some how.
If like vehicle drum brakes, the shoes have cut a groove into the drum and are locked behind it. Either the camshaft is stuck/frozen or the spring(s) have broken and have the shoes jammed.

I will attempt to remove the upper pin from the left side that is already out. My guess is that it will need to be pressed out, but that's just a guess. If it requires a press, it won't happen in the tractor. You might be right about the shoes cutting a groove in the drum. The camshaft now moves and isn't frozen. There is no room to see if springs broke. I might get a larger dead blow hammer to see if it can jar something loose.

Good luck!

Thanks

I appreciate your response.

 

[rScotty]

Rich, have you unscrewed the studs to see if that gains you anything?

Later...editing.... Well, I thought that they were studs, and I thought you said you had removed cover nuts.
But I just looked at the YM276D parts manual and it shows the cover held on by bolts. Odd.....
rScotty

 

[California]

The left wheel spins with the throttle but the right wheel is frozen. When moving the wheel by hand, it looks like the slight movement of 5 degrees on the right wheel isn't moving inside the drum, but has the entire drum moving as well, in other words frozen to the walls of the drum.

Pressing the left brake should apply all the engine torque to the right side. In the lowest gear, this would be substantial force, perhaps enough to break something. I would try that, reverse first then forward, but think safety!!! Reverse first, because I assume forward motion jammed the shoes somehow. Maybe a lining came loose and climbed over the other lining?

 

[CoyPatton]

Before I tried to apply a low gear torque to one wheel (lots of force with a low range low gear) lots of things to potentially damage other break loose a jammed/stuck/frozen brake shoe, I would try prying as near as possible to the pin and cam pin. Do not get real carried away at prying, but the effect I am suggesting you try to recreate is the tendency of the shoes to want to spring to the middle. I watched Hoye’s brake video again and with little apparent pressure in the video, the shoes ‘folded’ toward center away from the outer plate. I suggest to attempt to pry equally near each pin at the same time. Also realize that if the shoes spring loose any pressure released will push outward, so be prepared for possible flying pieces.
Again Good Luck!