Serial # n5m406088 Got a couple of skid steers on my to do list with similar drive problems. This one and a Deere 260, but I will open a separate thread for that one. This one, the customer said that it made a loud noise and then the machine wouldn't move. He thought maybe a broken chain.
When I got to look at it, I could get it to rock a little back and forth and by trying different positions on the drive handles was able to get it out of the road. Both sides would move, and both tires on each side moved, so no broken chain. Trying to get it into a better position to work on it; I was able to get it to move about twenty yards before it stopped again. The right wheels move a bit more reliably than the left, but when everything stops, the right side does also. Also, it seems that revving it all the way up has a helping effect. Shutting it off for a bit seems to get it to start moving again. So I suspect when the oil heats up that it is bypassing. Another strange thing (and the thing that makes it similar to the Deere that I need to look at) is that the left side wheels will start by not moving when you pull the lever. Then suddenly move very fast for about half a rotation and stop dead. I cut open the hydraulic filter and found nothing interesting. I did find that the machine was 7 or 8 gallons low on hydraulic oil. I thought that it may have been a drive coupler problem (because the client heard a noise) but the pump for the implements is mounted to the end of the dual hydro stats and the bucket lift and curl work fine even when the drive stops. So... I am hoping to hear some theories. I sort of think that the hydro stat pumps are bad. I also hope to get a little service info. I need to know how to test the pumps and maybe what to look for in case drain tests for the drive motors.
Loud popping noises aren’t good. How are the implement hydraulics working? Almost sounds like a pump shaft or coupler break.
Naw, bucket lift and tilt work fine.
By the way, vetech63, I am a fan of the content you post here.
You should run a charge pressure test.
LOL….I’m just a lowly minion amongst the greats.
Any idea how. I could ask at my case dealer, the techs there are pretty helpful. But, to be honest... It is the lowest tier dealership that I deal with.
Don't sell yourself short. I tend to lurk on this sight . I can't remember any of your posts not making sense. Wish I could say the same for myself. I tend to only hit this message board with a glass of bourbon. It has embarrassing results.
Do you have a service manual. If not, would your dealer copy info out of theirs for you?
I concur, check charge pressure. This pdf is a little blurry but still ok to read
If you snap a chain and I have in 440 before. One side will work and the other will be locked up. All other hyd functions will work, but the best you can do is spin in a circle. If you lost both sides of the machine. It is likely something else.
Disregard, I see you have ruled out a snapped chain. It wouldn't let me edit for some reason.
Thanks for the info, I can read it just fine. But I can't seem to find what the correct relief pressure is.
Charge pressure should be at 360 PSI and I would guess wide open throttle.
It was the relief pressure I was asking for, but thanks. I rounded up a service manual for a 420. But it had the info for this machine also My charge pressure is only at 140 psi. Shimming the relief did nothing. So I'm thinking my next step is going to be pulling the pump and tearing it apart unless someone has an idea of what else it could be. I am sort of thinking about the charge pump. Perhaps the keyway on the gear sheared. Or some sort of internal leakage. But since the customer said it made a noise when it stopped working I leaning toward a broken hard part.
It's worth noting the brakes on the 430 are spring-apply, hydraulic-release type. They depend on having at least 200 PSI of charge pressure from the tandem drive pump in order to release. You could try operating with the springs replaced with similar sized flat washers to rule out other problems.
Are you thinking that my charge pressure is being lost through the brake valve? I tried isolating the brake valve by calling it and re ran the test. Charge pressure was still 140 psi.
Capping not calling
Not necessarily. Pulling the brake springs is just to eliminate them as a symptom of the low charge pressure problem. I can attest that accidentally applying the brake in a 430 will result in a loud noise and the machine not moving. Also jerky, hesitant movement while cold and no movement when warm could be related to the charge pressure being just below the brake release pressure.