hello all. Been running my bobcat 742b gasser round my property. Recently blew put a hydralic pressure switch located under the cab seat right on top of the hydraulic pump. Bobcat part #Hydraulic Oil Pressure Switch 6671062. Now I was pretty sure to mark both electrical connections so that I put them back on just the way I found it but sure enough, running it the other day and noticed that it has popped again and leaking fluid all over. My question is do you think the electrical connections were put on backwards or is there something else wrong with it. If so any help would be greatly appreciated. just want to add that hydro filter and fluid have not been changed in a while but other maintenance has been done to engine and such. Thanks Joe
742B Bobcat Hydraulic Pressure Switch (keeps blowing) help!
- Thread starter beatbox82
- Start date
the electrical connections have zero to do with the threads. If the switch is blowing out you likely have a bad thread in the back of that funky tee on top of the pump. That line is charge pressure and well lower pressure than drive pressure, so you have a mechanical problem with the threads
No way would the wires be the issue.
This is a switch to turn a light on the dash when the charge pressure gets low, it has a diaphragm that moves to do this and they fail over time, i guess it's possible that the new one you installed was faulty. I'd install a 150PSI gauge to see whatyour charge pressure is, it shoudl be 90-120PSI from memory, if it's too high, i guess it could have blown it out on you.
flyerdan
Well-known member
- Joined
- Mar 7, 2009
- Messages
- 983
Gotta agree with the bad threads. Did you use the same sender or a new one? If the threads are rolled, (like using a BSP sender in a 1/8" NPT fitting) they can distort, and the softer metal is usually on the sender. Get the old magnifying visor and a thread gauge and check both threads for damage.
I can't see a Bobcat developing enough pressure to punch out a good pipe thread, even a failed relief valve should cause a drive coupler to fail because the rotating group was too hard to turn before blowing fittings out.
