B7500 HST differential lock

[grsabourin]

Hi,

I have an issue with the differential lock pedal of my B7500 HST. The pedal is locked in upright position (not lock). As I seen on video and on other tractor it is normally easy to use just push to lock. Is someone my confirm that? The under the seat seems rusty. This is the next place where I will go investigate. The system to adjust the height of the rear attachment seems also suck. Is some one as seen this kind of issues previously

Thank you

 

[MikeyA]

As long as everything is lined up in differential, it should push down easily...only resistance would be the return spring. It sounds like yours has frozen in position....you might try some penetrating oil on the linkage where it goes into transmission.

 

[85Hokie]

Hi,

I have an issue with the differential lock pedal of my B7500 HST. The pedal is locked in upright position (not lock). As I seen on video and on other tractor it is normally easy to use just push to lock. Is someone my confirm that? The under the seat seems rusty. This is the next place where I will go investigate. The system to adjust the height of the rear attachment seems also suck. Is some one as seen this kind of issues previously

Thank you

Take Mikeys advice - grease everything and check everything - to engage, you might need to move the tractor forward of backwards a foot or so, it should drop in after that.

IF not in long time - it might be bound and the lube make take a bit to free, allow some time for the lube to "work"

 

[grsabourin]

It was what I was thinking. I will remove the seat and grease all the moving pieces. And see if I can get it move. Thank you for your advice

 

[grsabourin]

I have dismantled pedal assembly under the seat. The problem is clearly not coming from there. The small shaft going in the casing is really hard to turn. I was able to turn is with gentle hammer hit. What is next dismantle the side of the casing in axel seal etc? Is someone have any recommandation?

 

[D2Cat]

I have dismantled pedal assembly under the seat. The problem is clearly not coming from there. The small shaft going in the casing is really hard to turn. I was able to turn is with gentle hammer hit. What is next dismantle the side of the casing in axel seal etc? Is someone have any recommandation?

It sounds like you are NOT working on the differential lock because it us usually a round bar about 3" long laying in a flat position down by your heel as you set in the seat.

The round knob that ought to turn is an adjustment to regulate how fast the 3pt goes down. If this makes sense to you, don't force the round know too much. Spray it with some PB Blaster or similar "rust buster". Not WD40, that's designed to keep things from rusting, but does not loosen the formed rust.

 

[grsabourin]

I'm pretty sure I have the right thing. I have dismantle the seat and now I have access directly to all levers under the seat. The differential lock pedal is linked to differential by a lever going over the differential/transmission from the left to the right after a small metal piece goes to the back of the transmission.

I do not understand how it can not be the differential lock because it was connected to the pedal on the left side.

 

[MikeyA]

I would continue to gently work the shaft to see if it loosens, if not, you may have to take that side of the axle housing loose to access the diff lock mechanism. It sounds like it hasn't received any lubrication from transmission and has corroded to shaft.

 

[mendonsy]

Just for laughs I tried pushing the diff lock pedal on my B7500 by hand today. It took a bit of force to move the first time I tried it but got easier after that. I very seldom use it so it has probably been a couple years since the last time it was used.

 

[grsabourin]

I was finally at the point to start dismantle the differential casing to see what happen. Before that I have used large quantity of rust stuff. The good news is the stuff did a great job and now the differential lock pedal move freely. I just bought this tractor few months ago a probably previous owner never used it. Still have similar issue with attachment height controller under the seat but it is not a big deal I will probably never use this. Thank you for all your advices