Allis 720 rear brakes

[Bird76Mojo 44]

Hey all.. I recently acquired another 720 and the left rear wheel is locked. It'll rotate back and forth about 1 degree of rotation, which makes me think the brake is seized. The left brake pedal has less movement than the right as well. I took the rear pto cover off and both brake rods have movement fore and aft when you actuate the brake pedal. The parking brake was apparently left engaged for several years. I now have it in the off position. We drug the tractor around in both directions, in a gravel driveway to see if it would release but we had no luck. Are there any tips or tricks to these brakes? I've never tore into one yet.

GB

[Rigger9020 13]

I would suggest removing drop axle housing. That way you can access the brake shoes. Also when the housing is off check to be sure it rotates freely. I suspect you might have a issue with it (because of the slight movement).

Good luck Mike

[720nut 4,225]

If it didn't work loose you probably have no choice but to tear apart. Just my .02

[Bird76Mojo 44]

Thanks guys. I was looking in the manual last night and it definitely looks like I'll be tearing the drop housing off, etc..

GB

[JP 0]

Do you have the 'parking brake' off? Rhetorical, I know. That will sometimes lock one wheel 'more' than the other. I have also seen those levers broken off (easy to do).

[Bird76Mojo 44]

That was the first thing I looked at. It's fully in the off position.

GB

[isetta 50]

Birdman, I had to power mine up and try to drive it forward and back before it broke free. Seems like I thought a lot about whether to go forward or reverse because of the way the brake actuators are ramped and whether that even made any difference. I was concerned about breaking something doing that but took a chance and lucked out. Like they say in the fine print: "your mileage may vary"

[Bird76Mojo 44]

Isetta, you know, that was my next idea. I thought of trying to pull it on pavement too. I do have two other tractors as possible donors though, in the case that I broke something or made the situation worse. I'm down with a pulled muscle in my back right now, otherwise I would've already had it torn down.

Do your brakes work good after getting everything freed up?

GB

[isetta 50]

I think it makes a difference if you power it vs pull it because of the leverage from gearing. I could be wrong but when you pull or push the mechanical leverage is not favorable. Kinda like trying to push start a car in first gear vs fourth. The brakes on the Powermax series are weak. The good thing is you don't need to use them much, if at all. I just rock the hydro lever fwd and back to slow and stop. Others will chime in here but the general concensus is that even after an overhaul the brakes are crap

[Bird76Mojo 44]

I won't have a very good understanding of the rear end and its weak points until I tear it apart to see what makes it tick. I've looked over the manual, read through that section twice, and stared at the pictures forever. lol I'M SOO PREPARED! haha

What I wouldn't give for a nice, covered concrete shop to work in..

GB

[isetta 50]

Yup, those brakes are hard to understand by looking at the manual. Good luck and hope the weather holds out

[Bird76Mojo 44]

I think I "get it" on how they work. Two outer stationary discs are bolted/pinned, but still float some, to the differential. In between those are two rotating discs that must be splined to the differential output shaft. Those two inner rotating discs have a set of balls between them and some sort of mechanism that when rotated, the balls spread those discs apart and apply pressure from them to the stationary discs..

At least that's how I'm seeing it in the manual.

GB

[Gcabinet1 16]

I just got done freeing mine up.

I picked up a 4041 that had been sitting for quite some time. Both were almost welded together with rust.

Took a while to get it apart, I put new seals in while I was at it. Good luck

Gary

The guys here were a great help