Above and to the right of the screw on hydraulic cartridge filter and drip tray is a Male/Female electrical connection to (I think) the pressure switch. Had my son shut down in the middle of Running the Machine for roof / shingle repairs in our "Man Cage", when we moved down for another course of shingles, was enough of a puddle on the ground to notice. When inspecting/tracing found the small but constant bead/leak coming from the electrical connection. Unscrewed the assembly; blew out with air, and removed the top of the "sensor" via 2 small phillips head screws; turned a 1/2" plastic allen head (flow regulator?) all the way in; reassembled; no more leak. Q1. What is this thigamajig I'm describing. Took a cell phone pic to bring the 30 miles north to parts dept. Q2. What's the amount of trouble I'm getting into if running the machine without replacing the thigamajig? (10-20hrs work planned this w.e.). Regardless, I'm going to replace, since when the allen head was kept at it's original position, even after cleaning,maintains the slight stream. Only in fully closed was I able to stop from leaking. Late 90's 753 (BICS no BOSS). and thanx in advance.
Sounds like a hyd temp sensor. If your machine doesn't have full BICS control, you could probably remove it and plug the hole, if the hole is pipe thread, then put in a new sensor when you have a better opportunity.
:iagree
I think I am having a similiar issue with the 743B that I am running. If I flip the cab up there is a sensor on top of the pump with two wires coming out of it. It starts squirting fluid in a fine stream as soon as the bobcat is started. I know it should be changed, but is it safe to run until tuesday when the holiday weekend is over and I can get the right part?
Welcome to the forum jtwthaxj. :usa I'm not aware of a sensor on top of the pump as you described it, so can't say for certain. But if it's a simple pressure sensor, as long as you've verified the machine has no operation problems or noises, would probably be fine to remove the fitting and plug the hole until new sensor is obtained.
Thanks! I may not be describing it accurately, but it looks like a temp or pressure sensor, but everything is working properly. I just wanted a little moral support, so I would feel comfortable putting this thing back to work.
Hi, Not exactly sure but what I believe you are describing is a switch that will close (or open depending on pressure differential) when the filter becomes plugged and oil is bypassing the oil filter. When the switch indicates (or senses) the filter is plugged or becoming plugged it will operate a light or buzzer in the cab. These switches can leak externally if the sealing inside the switch becomes damaged. I reccommend you replace it and do not just put a plug in the hole. This little switch will save you alot of grief when operating properly. Hope this helps, Z
I'm thinking he's talking about the filter pressure sensor as well Z2898, just not for certain. jtwthaxj mentioned in another thread that he has already changed engine oil and all filters, including hyd filter. I'd say he'd be ok running it over this weekend if he's performed these services and the machine is operating without any issues.
Yes I have replaced the hydraulic filter, and the machine is operating properly but I worry running it more than an couple of minutes with that little red light on, given my limited knowledge thus far. I can post a pic in a few for further deliberation. Where would be the best place to obtain a service manual for my 743B?
Sorry the first pic is kinda crap but it gives you a general idea of where the sensor is. The second pic is a little better, maybe you guys can tell me what exactly it is. I figured that I may pull it just to get a better look at it and put it back on before I run with it. Sorry the blackberry pics work but they definitely are not the best in the world.
Man, it's been years since I've looked in the belly of a 743, but that looks like the case drain line from the drive pumps going back to the hyd filter and oil cooler. That would be the pressure switch that monitors return line pressure to indicate clogged filter. If you've changed the hyd filter, you should be ok for the weekend.
Haha! I would dare to admit how many times during the past month or so I have looked into this thing. I borrowed it from a friend with the intention of fixing a couple of small things.... yeah about that. I run it for a few hours and then spend the next entire weekend repairing something else. Figure most of the repairs are cheaper than paying rent considering the amount of time I have had it. Here is a pic of the sensor I have pulled it out cleaned it off, there is a allen head screw under the rubber cap on the end. I pulled the cap and gave it a couple turns like the guys earlier in the thread. Maybe the leak will go away... Sounds like I'm safe to run it until I find a store open to replace it. Thanks, JT
That's a Hobbs pressure switch. If it's leaking, it's because the diaphram inside is busted, ain't nothing gonna stop it leaking except replace it. The set screw under the rubber cap is what adjusts the pressure value of the switch. You could replace it with a Hobbs switch from NAPA store, but you don't know what pressure value it's set at, could be anywhere from 15 to 45 psi, no way of knowing. Just going to have to get a new switch from Bobcat.
I got a new switch I haven't had an opportunity to install it yet to be sure this was causing my light issue, but its now made by honeywell and thankfully is only about 30 bucks!