I have a cat d3g serial number BYR01324. Operator was using it yesterday pushing a small pile of dirt, and then the machine came to a halting stop. I search this website yesterday and found the same issue numerous times while with different results. First thing I did was get the codes, I had two six one which I knew was left pedal fault and 244 which was parking brake switch. I cleared the codes and I got back 222 which tells me there's no active codes. The machine won't start with their parking brake off, with the parking brake on the machine will start and when I go to turn the parking brake off the light stays on and no movement from the left joystick. The horn and the speed buttons work, no change with throttle. I don't have any access to testing hydraulic pressures, anybody have any advice.
Change the park brake switch.
Agreed. That's where I would start. I forget how much the switch is but it's not expensive.
Pump coupling probably stripped.
Changed the switch, no different. Is the light on the switch supposed to light up? I still have hydraulics to the blade.
Go looking at the condition of the coupling for the hystat pump would be the next step.
Yes, it lights up. Check fuses and breakers first, then wiring harness. There is another known problem with them, and that is a black box on the firewall in front of the decelerator. Seems like you can take the engine enclosure off and it's right there but I've slept since then. I can't remember what it is called but they caused a brake problem too. I only had brake problems while stationary, never while moving. Seeing that yours suddenly stopped while working makes me tend to agree about that pump coupling. Have you felt a pulsing vibration while running it?
Do you have any way of seeing whether the machine will move at all with the engine running, blade up, and park brake switched to the OFF position..? That would definitely confirm if the nylon coupling between the flywheel and the hystat pump item #1 in the diagram below) has failed.
I will check in the morning, is there anyway to check besides removing engine? I can start the machine and put blade up and park brake off. It doesn't move, I could try and push it and see if it rolls at all. I have plenty of other equipment to help work on this.
If the park brake light on the dash never goes out then the coupling is likely stripped. That light works off a pressure switch on the brake. If you have a pressure gauge that fits the fittings on that machine my the implement valve crank or up and go through connecting the gauge to them. If they're all dead the pumps aren't turning.
Good point about the brake pressure switch and back to the OP the park brake light stays on when the switch is thrown. A pressure gauge on the parking brake test point would confirm it. The way to get at the coupling is to remove the belly guard. The pumps are then lowered down through the hole. Here's the procedure, also the hydraulic schemtaic for the machine.
Don't pull the pumps. Pull the engine. Much easier. Rear engine mounts are on the pump mounting plate. You don't want to wrestle that plate down and have to support the rear of the engine if it will even fit. The worst part is trying to crawl under the radiator guard to drain the coolant and get the bolts loose. You can get it done in a day with all the parts at hand. Change the pump shaft seal while it's apart.
Ok, I'll check the brake switch pressure and also see if I can see any sign of the coupling. Thanks for the help. I'll post again after testing.
So I checked the brake solenoid under the floor access panel, with the parking brake switch on or off, the solenoid is magnetized accordingly. I checked for any access the the bell housing to see if the coupling is gone but there is no way to see anything. The speed sensor hole showed me the smaller metal gear turning... Where is the parking brake pressure switch? The diagram says near the left drive motor but I see nothing. If I don't have pressure with the brake off does that mean the coupling is broke?
Through the speed sensor hole you're seeing the flywheel ring gear, not the pump coupling. The brake pressure sensor is on one of the brakes. I think on the front side of the right one but I'm not sure. Yes if you have no oil there the coupling is almost surely stripped.
Do the diagrams below help..?
Yes, thanks for everyone's help. Checked pressure at PB switch, zero pressure anywhere on pumps. Almost positive it's the coupling. Gonna put it on the trailer and send to the shop. Thanks for the tips.
Hello dshequip .. how did you go with d3g ? I have the same issue . cheers Sam
Sam, try starting a new thread. Be sure to post your machine Serial Number. When you do that include as much information as possible, such as how the problem developed, etc, etc. From what i can see from the above it was 99% certain the splines on the pump coupling of the OP's machine were stripped.