deere 544G locked up

[25skinner]

we have a544G that we used behind our shop,we shut it off and came back later to put it away and it will not move at all . the park brake is not locked and it shifts into gear.. it must be the brakes in the rearends.that are locked..is their anyway to unlock them so it can be pulled to the shop, its getting cold and to far away to plug it in..any one with a idea as to whats wrong your feed back will be much appreciated

 

[Keith_B]

If you found out how to resolve this, please post it. I have a 544G with the same problem. Thank you.

 

[ts360]

Im having this same problem now with my 544g and would just like to see by chance if anyone has had it and gotten it fixed. Thank you.

 

[heymccall]

Im having this same problem now with my 544g and would just like to see by chance if anyone has had it and gotten it fixed. Thank you.

Describe your specifics?
Engine runs?
Can you see the shaft turning between the engine and transmission?
Does parking brake release?

 

[ts360]

Yes the engine runs and I just discovered that the transmission operates by removing the drive shafts. I originally thought that it was just my rear differential but it turns out that it is both of them. The parking brake switch does seem to operate normally. There must be something electronic that is holding pressure on the brakes? Im not very familiar with this brake system, thanks for the reply.

 

[Bigbert]

The TCU usually never got any impact on service brakes, only parking brake. So I doubt there is something electrically/electronically.
Maybe a silly question: You are sure the mat on cabin floor does not put pressure to brake pedal? I'm asking this question because I experienced this a few times with brakes (hot brakes) and gaspedal (low power).

 

[Nige]

There must be something electronic that is holding pressure on the brakes?

Try (carefully) cracking a brake line at one or all of the wheels. Do you get oil out under pressure.? If yes then look at the brake pedal in the cab first as Bert suggested above.

 

[heymccall]

It's a 544G. It has bleeder screws. Crack a bleeder on the stuck axle with engine off.

 

[ts360]

I did check my pedals and while there is plenty of dirt around them, they both seem to function properly and successfully hit their stops. I cleaned the dirt away from them and checked for any debris interfering with them and everything seems good there. I did crack the two bleeders loose on the front diff today without the engine running and I got a steady stream of oil for a split second then I tightened them to prevent letting air in. I'm thinking now about a possible malfunction in the brake valve under the pedals, maybe they are stuck open? I think I will try cracking the brake lines without the brake applied and see what kind of pressure I get out. Thanks again guys for the assistance.

 

[ts360]

It's a 544G. It has bleeder screws. Crack a bleeder on the stuck axle with engine off.

I was trying to prevent letting air in when I did this before but now I realize there probably shouldn't be any pressure there without the engine running or the brakes applied, thanks for the suggestion.

 

[Nige]

.....but now I realize there probably shouldn't be any pressure there without the engine running or the brakes applied, thanks for the suggestion.

Correct. Any pressure in that line and the brakes will be applied. You can open the bleeder valve on any wheel slowly and let the oil run until it stops. That should let the pressure out from all 4 wheels unless it has a split braking system with separate lines for front & rear axles. In the latter case you'll have to open a bleed valve on the front axle then one on the rear to achieve the same thing. No air will get in while oil is coming out.

EDIT: Make sure you have chocks under the wheels while you are messing with the brakes. If they do release while you are underneath you don’t want the machine to move.

 

[heymccall]

As far as "air" in the brakes, A) the hydraulic tank is higher, and 2) to bleed them, set a brick on the pedal, engine running, drain hose on bleeder, and open bleeder until air free.

 

[ts360]

Ok so I just opened the bleeders on the front and let the pressure out and my front wheels now turn. Thank you very much guys, I now have a direction to go in and can now push the machine with my backhoe to a better spot to work on it(its in the middle of a parking lot). I'm thinking its probably something with my brake valve but should be able to narrow it down now. Thanks again.

 

[Nige]

I'm thinking its probably something with my brake valve but should be able to narrow it down now.

I think you're right - likely the spool inside the brake valve is stuck in the ON position.

 

[br1474]

So in the G loader I do believe there are to brake pedal valves. But the one on the left has a declutch switch hooked to it. Or it is possible both pedals hook to one valve under the cab. But that left one has the declutch. If it has the 2 valve setup. The lines are all tied together. But you’ll have pressure available even with engine off because of the accumulators. Mounted to the bottom of the cab. For when engine dies while moving. It would take about 20-30 pumps to get accumulators discharged. You can confirm discharge with key on and pump the pedal until the brake pressure alarm comes on similar to semi tractor air brakes. Also for what it’s worth in the 50 or more Deere axles I have rebuilt. The brakes in the axles never needed bleeding, you can do it but not necessary.

 

[ts360]

So in the G loader I do believe there are to brake pedal valves. But the one on the left has a declutch switch hooked to it. Or it is possible both pedals hook to one valve under the cab. But that left one has the declutch. If it has the 2 valve setup. The lines are all tied together. But you’ll have pressure available even with engine off because of the accumulators. Mounted to the bottom of the cab. For when engine dies while moving. It would take about 20-30 pumps to get accumulators discharged. You can confirm discharge with key on and pump the pedal until the brake pressure alarm comes on similar to semi tractor air brakes. Also for what it’s worth in the 50 or more Deere axles I have rebuilt. The brakes in the axles never needed bleeding, you can do it but not necessary.

Thank you for the info, it is much appreciated. Yeah I've never had to bleed a high pressure hydraulic system before, I don't know why this would be any different. In the service book, it says to utilize the brake pressure warning like you said for testing, but I am unable to do this because nothing on the dash on my machine works.

 

[Nige]

Pump both brake pedals until they go hard which will be your indication that the accumulators are discharged. Use wheel chocks to prevent unwanted machine movement and always take care when disconnecting any brake line.

 

[br1474]

Find the pressure switch then you can use a voltmeter on continuity test

 

[Nige]

Find the pressure switch then you can use a voltmeter on continuity test

But will that pressure switch close at any brake system pressure above 0psi.? Not having any specs for it I have no idea.
If that is not the case the switch could be open according to a DMM and there still could be 50, 100, or whatever psi (albeit relatively low) pressure in the lines. My 2c.

 

[br1474]

True, the more I think about it. The accumulator test was to, pump till the light came on then until brake’s were hard.