B7200 rear wheel lock up

[tim0477]

Hi,

Was mowing in 4WD (yard is a wet mess this time of year) and the left rear wheel just locked up. Ground speed increased, and I ended up going at about a 30 degree angle. Left wheel would not go forward, tried reverse and it freed up. Tried forward again and it was perfectly fine for the rest of the hour and I half I mowed with it. I jacked the back end up when I was done and both wheels turn freely, the differential lock engages and disengages properly. I did notice that the left brake is more "grabby" than the right brake. I have had bonded brake pads separate and lock up automotive wheels before. Only other thing I can think of is there were a few extra links of tire chain I had wired up that came loose. This was what I thought it was at first, but nothing around the fender is broken, scraped up, or otherwise damaged. I would think that if the chain caught something, I would have been able to find something bent or broken. Anybody have any ideas on this one?

Thanks,
Tim

 

[DsBota]

One of the chains get tangled on a brake rod and then loosened off when you put it in reverse? How many loose links?

 

[Bulldog]

I have seen one rear slide like you said and speed increase but I have always been in 2wd when this happened. I would say you can rule out a break issue. If the break for some reason had been applied it would have transfered the break power to the front wheel on that side as well. Is your 4wd working properly? Everything you're describing sounds like it was in 2wd to me.

 

[tim0477]

DsBota,

3 links. Enough to reach the lift bracket arm for the MMM on the 3PH. It could also reach the height adjuster for the MMM. When I had it jacked up I tried to see what I could get the loose chain to catch on. I could get it to catch on the lift bracket, but applying any good amount of pressure would pop it off. If I angled it just right, it could also catch the height adjuster for the mower deck and hold tight. I kind of doubt this though because the height adjuster bracket is only a small piece of angle iron and the adjuster is maybe a quarter inch thick rod. I would think if it caught either of these, they would have surely bent. Whenever I wash all the mud off of it, I will have to look for scraped off paint.

Bulldog,

I am sure it was in 4WD. I would not have made it through that particular part of my yard in 2WD. This has turfs on it and doesn't take much of anything to make it slide around in slick conditions. The 4WD worked fine the whole time I was using it.

I still want to check the brakes. The left side grabs hard with very little pressure on the pedal while the right side takes hard pressure to give the same amount of braking. Any tricks to accessing the brakes? Looks as thought the fenders have to come off and there appears to be a plate covering where they would be.

Thanks,
Tim

 

[asbug]

Could be a detached brake shoe pad?
Just a thought.
KC

 

[Bulldog]

I have never done brakes on one of those but I have heard they are about like doing the drum brakes on a truck. Let us know what you find.

 

[tim0477]

Hi again,

I did look at the brakes for the left wheel that locked up and didn't find anything out of order. Plenty of life left in them though. They are very much like a automotive drum brake. Odd that there wasn't a slack adjuster in there like a car or truck would have though. Not too much trouble to get at. Remove fender, slack off the brake rod, remove the 4 bolts and tap the blue cover out away from the differential case. Drum stays with the case and the shoes come out with the plate.

Cleaned the mud off of things and found the height adjuster for the MMM was scraped up on both sides and tweaked ever so slightly towards the rear. Loose end of the tire chain must have caught it. Strange things happen I guess.

Will still check the right brake to see why it doesn't grab as well as the left.

Thanks,
Tim