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Ooohhh Deere
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Discussion Starter · #1 · (Edited)
Does anyone know a limp mode or emergency bypass for the park brake. I have had this machine down for 4 days now with a disabled prodrive due to a parkbrake pressure problem. Local dealer is struggling with the problem. Installed a new release valve after a mega journey to get a new valve, it didn't fix the problem. It's not an electrical problem. I think it's a problem in the valve body.

There must be some way to bypass this situation because if this happened on a train line crossing or in a town street, what then????? Can't move it.
 

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One would assume pressure is supplied to disengage park brake, one would assume loss of pressure activates park brake, is there anyway of supplying pressure to the park brake via another source? Even a power pack hand pump? Then try and move machine? Is the sensor detecting pressure or does it work of actual brake position, park brake may have packed up inside etc...can you loop sensor and try and drive....is there any restriction in dump return line? can you undo and dump to a bucket when switching park on and off...if new valve body fitted one would assume if electrics and pressures checked out ok the park brake itself is shagged...sure you've tried most just thinking out load...

Good luck!

Ant...
 

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Since it is detecting park brake pressure, this should be harmless, because by the wording of the message it's pressure that disengages the brake, maybe it's a brake pressure sensor problem.

The trouble may not be electrical, but it is an electrical signal that's shutting you down. Maybe a new pressure sensor is required. Or if there is a pressure problem, get rid of the signal from that sensor or create the signal that it should be producing as the case may be.

I have a mower with a similar system that will act up this way on occasion because the foot brake never gets used. A whole bunch of fast and hard foot brake applications with the engine running and the electronics on seems to make the sensor recover and the processor recognize its signal range again. On this machine the variable signal from the brake pressure will process a signal to lower or stop the ground speed setting of the drive system.
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Ooohhh Deere
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Discussion Starter · #10 · (Edited)
Can you not disengage the park brake manually with the supplied bolts? This could get you going to combine but you would not have a park brake when the combine is shut off.
Tell me more please. I don't think this is possible as its a fully sealed brake chamber with hyd pressure needed to release the brakes which I assume are also wet brakes. Our dealer knows nothing of this trick.

All sensors checked out okay. I do t gave much time to muck with this thing but I now think the pressure supply solenoid might be the problem.

I have called in the BIG GUN to assist:D:D
 

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Ooohhh Deere
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Discussion Starter · #12 ·
Thanks for the replies people. Turns out it was the pressure valve and the dump solenoid both failed together. Or one broke the other. Who knows. Disappointing how long that diagnose took and no parts in stock. But to be fair the machine broke on a Friday so I was never going to get the parts till Monday. Thanks Drew from JD dealer.

I recommend anyone with a prodrive with 5500hrs:eek: might wanna buy these parts or you might be stuck on a frieght train crossing somewhere.:mad:
 

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Ooohhh Deere
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Discussion Starter · #13 ·
Where are you located? I've never seen a 70 series combine with decals like that before. Looks like a 60.
Well spotted. Good eyes.:D
It's actually one of them test headers from mother Deere. Badged as a 60 but with all the 70 features. AUS. Been a good machine.
 

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I dont have my computer with me to read up on it. Your dealer should be able to look it up on service advisor. I havent played with one for a year or two but i know we used to disengage the park brake manually to remove the driveshaft to set shoe auger gear backlash. I believe there are four bolts that need to be installed on the right hand side of the trans. They are extras on the shielding around the trans. They have nits on them but are not holding anything. Hopes this helps
 
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