Case 450B Dozer

jking7489 · Apr 8, 2019

I have recently acquired a case dozer and working through some issue mostly due to it setting for a couple years. One thing that has struck me as odd and didn’t happen until a few hours of running is the left track always has power unless the FNR lever is in neutral. My first thought was seals gone in the control valve underneath the seat but after looking at a diagram there doesn’t appear to be o rings there. Am I looking in the correct direction or anybody else ever had this issue?

MossRoad · Apr 8, 2019

Welcome to TBN. :thumbsup:

DJ54 · Apr 9, 2019

Not sure I understand your meaning. Are you saying the left track continues to drive while the left track lever is in the neutral position, between high & low..?? Will it power the track, when the left track lever is put in high, and right in low, so as to make a power turn..??

If it's still driving, when the left selector is in neutral between low & high, then I'd have to say something happened internally, but without looking at the transmission breakdown (which I don't have time to look right now) to see what may be causing that. We had a 450C at work, that had over 10,000 hours on it, and never experienced something like that.

Is the right side driving OK..?? Easy way to tell is to tram it a ways,with the blade up of course. If it makes a slow gradual turn, the direction it turns, is the side lacking drive.

Both sides should drive, once the selection is made for direction, either F or R. The only way to kill a track, is to put the high low lever for a track in neutral, between high & low, or, use a brake, which will disengage that track, before applying the brake. You can also test the right side, by putting the left track in neutral, and right track in low. If it doesn't move, the right track isn't driving. If that is the case, it may just be the linkage that disengages the right track, before engaging the brake, is frozen up.

If you've never operated one, and the brakes are grabby, that is the nature of those dry disc brakes. Especially if they have been ran in water, like when we did a lot of creek channel work. Sediment, and moisture will get in the brake chambers after some time. The steel expansion ball bearings will get rusty and rough, plus sediment in the grooves they ride in will make them grab, and go to full braking. If you take them apart, and clean them up, braking action will be much smoother. You'll also want to check the fluid level in the master cylinders, and properly bleed them for some decent pedal, and adjust the brake as it should be.

jking7489 · Apr 9, 2019

Yes the left track has power even when in neutral position. Right track seems to function properly.

DJ54 · Apr 10, 2019

Does the left track work in both high & low..?? Like you, I looked at the parts diagram, and don't see any seals that could be leaking. That being said, if the track only works in low, is possible that the left track control spool is broken, stuck in the low position..?? If it works in both high & low, then that wouldn't be the problem.

Have you tried killing the track, using the brake? If that does not stop the track, or it seems it's trying, I'd be looking at the left brake spool, and spool spring.

Never had one apart, and not real sure how it works, just looking at this assembly, and trying to figure out why the left side is still being fed oil pressure, to engage that side of the transmission clutch pack. I've attached the exploded view of the valve assy., for quick reference.

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