+I HAVE A CAT 257B2 SERIAL 0257BKSLK07584, HAD BEEN USING IT WITH GRAPPLE AND EVERY THING WORKED GREAT. changed over to forks finished job. went week later to do some clearing, installed grapple now everything but grapple won,open or close, following this form was able to track down to bad rocker switch. replaced now i can hear solinoid click but still no grapple function, checked all fuses and relays all ok. read that pressure release switch could be bad, but don,t know how to check it out. any help would be thankful
Hi Ronnie, need some more info about the grapple you're using. Is it purely hydraulic? Or does it use an electrical connection? Also, without any attachment attached, hitting the auxiliary buttons or thumbwheel on the RHS joystick, does it sound like it's loading/stroking the pump with engine bogging down slightly?
it works from the hydro lines from the skid steer
not getting any pressure and it doesn't i change the sound of the unit when I operate the switch
Check that the quick couplers are fully attached and hooked up properly.
If you can't hear it loading up the hydraulics even slightly without an attachment it this is most likely electrical. Start engine, run for 1 minute to build up pressure in the pilot accumulator, shut engine off. Then, sitting in cab, key on, arm bar down, press switch to release park brake, hit the auxiliary buttons (or work the thumbwheel) on your RHS joystick. You should hear some clicking or hear at least something happening from these solenoids... If you don't it's time to check these buttons (or thumbwheel) on the RHS joystick. Do you have an electrical schematic?
tried to pull schematic online but could not get a good one, I hear clicking at the solenoid but it does not put flow or pressure to the aux. line. I have a good connection and also loosened line at the grapple and cannot get any leaks. its like the pressure release is not allowing buildup
I'll send you one. Keep an eye on your messages.
The Auxiliary Pressure Release button on these releases pressure simply by actuating the A1 and A2 solenoids I pictured earlier. There is an additional relief on the line to the male coupler (on the machine) circled below. These are usually integrated into the quick disconnect coupler valve on the load frame. When these fail you will still get pressure build up and work tool function on the female line... From here I think we need to test these A1 and A2 solenoids. They're proportional solenoids so easiest way to test without a laptop is to test inline for current (amps). Should have 0 amps when not commanding work tool functions. This means your pressure release switch in the cab is working properly. Should have 1.8 amps when comanding work tool functions. This means all the wiring to the ECM including the buttons or thumbwheel on the RHS joystick is working perfectly. If everything's ok there time to pull the A1 and A2 solenoid valves out and check for damaged o-rings. The thought of both these solenoids failing at the same time is unlikely. Are there any other symptoms we need to know about? If everything checks out ok we're into checking hydraulic pressures.
The product consist listing on SIS tells us little about how this machine was shipped. Tell me, does it have high flow? Problem occurs in high flow AND standard flow? It's the lowest rocker switch next the key switch. If you don't have it this will be blanked. Earlier models had two sets of lines running down the LHS of the load frame, one set for standard flow and the other for high flow... just making sure you're connected to the correct quick disconnects.