Help, 09 JD 4720 cab tractor "brake/rear axle locked"?

[Ramairfreak98ss]

In the last few hours using the tractor, several times it seems like while digging in dirt/mud, that the tractor parking brake was on.

I tried to back out of a hole digging dirt, and the machine would bog hard like it clouldn't move, then suddently its like it broke free, like its attached to a chain and it busted lose suddenly.

No odd noises or anything though.

ONE time while reversing in the driveway at about 3mph, the rear axle suddenly locked up, like the parking brake engaged and i didn't have my foot anywhere near the pedals.

We later dumped a bucket of stone and the machine couldnt roll backwards away.. it now moves forward/backwards about 6" and the rear axle locks.

I went under the machine, verified the brake cable is working correctly, all free "assumed dirt or something was stuck up there".... the lines are moving, the rod assemblies are both moving both left and right levers on the back axle and its dead stuck.

I disconnected both rods, tried moving both levers forward and both backwards 'and while i know dangerous', had someone roll the machine backwards and forward inches to see if it was still stuck.. yep.

Called the dealer.. not much help, they wanted to tow it. I know this will end up turning into a huge repair bill. Tractor had 400hrs on it last summer, in July, when the parking brake got jammed, pedals stuck way down couldnt come up, so i disconnected them and we just had no parking brake.

$600 later, dealer updated it to the 2011+ model 4000 series rod lever parking brake design instead of the cable that came with it.

Before i'm forced to get into removing an axle at 475hrs, what should i try?

 

[jenkinsph]

I haven't had any problems with the cable release on my 2009 4520 tractor so far. I would say that the brakes on these 4000 series are cheap compared to the other Deeres I have had in the past. I much prefer hydraulic actuation over the mechanical crap on these units. It is a good thing I don't need them very much.

 

[dusty3030]

Something about the brake might have caused it but it has been my experience that the parking brake ain't got the grip to stop it in my tracks. As many of us do I have taken off with the brake engaged on my 4120 and the tractor easily overpowers the brakes. The brakes hold it firm from rolling when parked on a hill and seem to be adjusted correctly, but they aren't holding so well to stop it in its tracks if I drive it with them engaged.

If I am reading your posts right the dealer upgraded them only 75 hours ago, I would push back on them a little if I were you and hold their feet to the fire a little that they might have been throwing parts at something else and to stand behind their repair here. At least a free transport and diagnosis or a free mobile visit checking it out at your place.

 

[dusty3030]

To add to this my gut feeling is that if the axle is completely locking up it is something other than the parking brake, FWIW.

 

[sunnyside360]

I had similar problems. Turned out to be the brake shaft going into rear housing was rusted badly. I put penetrating oil in around the shaft while working the shaft back and forth and it finally loosened up. In my case, I use a 3ph broadcast spreader for spreading fertilizer and the dust gets all around the rear housing. The fertilizer dust is very corrosive on metal causing problems. I now pressure wash after using the spreader and haven't had any more trouble.

 

[Ramairfreak98ss]

Dusty... yeah the tractor can usually overpower the parking brake... and this isn't just the parking brake.. it rolls forward in lowest range and stops the rear tires dead in their tracks.

Sunnyside360.. what is the brake shaft part? where does it go into the housing? i'll try to check that area tomorrow. I recently had this thing stuck in mud up to the bottom, which im sure doesn't help, but i pressure washed it that same afternoon when i pulled it out, and again the next day just to blow off any extra mud underneath. Keep in mind, the locking started long before getting it stuck, and then this about 5 days after i had gotten stuck.

 

[Red Horse]

In the last few hours using the tractor, several times it seems like while digging in dirt/mud, that the tractor parking brake was on.

I tried to back out of a hole digging dirt, and the machine would bog hard like it clouldn't move, then suddently its like it broke free, like its attached to a chain and it busted lose suddenly.

No odd noises or anything though.

ONE time while reversing in the driveway at about 3mph, the rear axle suddenly locked up, like the parking brake engaged and i didn't have my foot anywhere near the pedals.

We later dumped a bucket of stone and the machine couldnt roll backwards away.. it now moves forward/backwards about 6" and the rear axle locks.

I went under the machine, verified the brake cable is working correctly, all free "assumed dirt or something was stuck up there".... the lines are moving, the rod assemblies are both moving both left and right levers on the back axle and its dead stuck.

I disconnected both rods, tried moving both levers forward and both backwards 'and while i know dangerous', had someone roll the machine backwards and forward inches to see if it was still stuck.. yep.

Called the dealer.. not much help, they wanted to tow it. I know this will end up turning into a huge repair bill. Tractor had 400hrs on it last summer, in July, when the parking brake got jammed, pedals stuck way down couldnt come up, so i disconnected them and we just had no parking brake.

$600 later, dealer updated it to the 2011+ model 4000 series rod lever parking brake design instead of the cable that came with it.

Before i'm forced to get into removing an axle at 475hrs, what should i try?

I would be inclined to agree with Dusty 330-find it hard to believe that the brakes would cause this thing to lock as you describe-unless something (Disc?) nhas broken and is jamed somehow. My 07 4720 cab had the same issues with the lousy cable brake system. Should have been a free upgrade to the rod system-itself "no prize" but not surprisingly, we owners had to pay for a JD design error- I bought the kit and did it myself- a very frustrating two or three hours. In that 600 buck charge did they itemize?

 

[SwLWildcat]

I would drain the oil from the diff and look for metal. If the oil comes out with chunks it's going to be expensive. When our skidder diffs fail we drop the oil. If there is metal in the diff oil we pull it and rebuild. If the oil comes out clean I would look for other possible scenarios like seized brake cables, etc.