On my 1845C the back up alarm is intermittent. I've metered out both of the pressure switches that close to initiate the alarm and they are both on the fritz. One of these is open constantly, the other closes intermittently. Never have went further than lifting wires and terminating meter leads onto the spades; then from the operator seat, stroking the hydrostat units for operation. Again, no response or state change from the one switch, and intermittent operation from the other. Tractor is either a 1995, or 1996 build and these are "Nason" branded pressure switches. I don't know if they can be calibrated, or are just a make/break type affair. I've been told they were kind of a high failure item and am wondering if a substitute is available, or known about as I'd like to have this alarm operational again, as it should be. Thanks,
They are just on or off switches. I think some closed at 2000 psi and some at 600 psi. Part number 87370805 might work on your machine. There were several part number changes through the years. Just think about how many times pressure has hit them over the years, it's no wonder they go bad.
Thank you for the part number to research. I'll like having this operational again. I need to pull the spool which controls the booms up and down also as the "float" position is no long attainable. I pulled the spring cap from the rear of the valve and the "trough" the steel ball rides in is really worn out. Hoping this can be welded up and recut as the spool itself is not available separately without the complete valve.
We always unhook those annoying things.
Someone installed a on-off switch on one of mine and I unhooked the other machine and wired in two led lights strobe lights instead to let people know I am in reverse.
They are pretty well useless since everyone ignores them. Just pisses off homeowners when plowing a parking lot at 0300
I guess I might be tempted to do a simple experiment and install say a 3,000 psi gauge into those ports and see the maximum pressure the senders will be seeing. Then you could shop around for switches rated for something a little higher. Maybe also note the pressure needed to actually start the machine moving and make sure the replacement switches will close at that pressure. At the quarry when we had to run after sundown we were allowed by MSHA to use back-up strobe lights during the night. Just a simple switch to direct the output from the beeper to the light. Then again some people would bitch about that I'm sure!
My skid steer just uses spring loaded electrical switches on the vertical lever attached to the pump shafts on each side. Short pieces of coiled wire like the outer cover of a choke cable connect to the switches. The coiled wire flexes from min. to max. linkage travel in reverse. I think there's some adjustment so the reverse alarm isn't going off with just slight movement or if the linkage needs adjusting as well. Maybe something like this could be adapted so you don't have to bother with pressure switches??