Terex PT30 hydraulic schematic needed

[2traxs]

Would anyone happen to have a hydraulic schematic in a PDF file that they will share, for a PT30, trying to diag a No hyd pressure to drive system and lift and tilt

 

[Arny L]

You might want to check, lap bar switch, seat occupant switch, door switch, all of those can shutdown hydraulics.

 

[2traxs]

Thank you for the reply, I did check all of those and the tested good, I also jumped the pigtails to each of them just double sure, but I'm not getting any pressure at the control valve test port, any other suggestions would be greatly appreciated

 

[Arny L]

Any blown fuses? Non operating safety relay. Damaged wiring or inoperable solenoids in pilot block. Poor ground connection, near bottom of hydraulic tank. Check hydraulic filter for metal. Stripped drive coupler between Eng and pumps. That’s all I can think of.

 

[2traxs]

Thank you very much for your help and guidance it is much appreciated, I will check each one of those, I thought if the pump was turning then it would have pressure at least at the test port, can the pump be spinning and good and any of those items keep the test port from having any pressure, TIA

 

[Arny L]

I believe so, not positive. To verify all safety interlocks, you should be able to hear pilot block solenoids clicking, when raising or lowering lap bar, seat switch, door switch. Key on Eng off. Block is located under your feet. Access by removing floor plate, or removing belly cover. This will give you a better visual of wiring.

 

[2traxs]

Hey Arny I checked the solenoid coils at the control valve block under the foot area, and I am only getting 12v at the soleniod on the far right side, the other doubled stack soleniod coils I am not getting any voltage at them, should all 3 of these be getting 12v at the same time do you know ?

 

[Arny L]

Your safety switches are all in series, to provided a ground for safety relay. Can you hear safety relay clicking when key is on, eng off, and operating lap, seat, or door switches. Relay should be with fuses I think. I can see that someone has changed the pilot block, by the coloured tie raps on hoses. Also your wiring doesn’t look very good, some open copper showing. If you’re hearing relay clicking then your switches are working, but you have to be seated, door closed, lap bar up and down. All three have to function.

 

[Arny L]

I would brake clean that whole area, and clean up some of the wiring. The single solenoid has an extra ground wire scabbed onto the original ground, that is wrong. Someone was obviously having an issue. See where it is grounded. The 12v is there when key is on, the saftey system completes ground, if that makes sense.

 

[Arny L]

The double solenoid is for your auxiliary oil flow.

 

[Arny L]

 

[2traxs]

I have a feeling the safety soleniod is bad, I am getting 12v to it but I can't hear or feel it clicking when the 12v gets applied to it, and it gets very hot when 12v is left powered to it after a short time

 

[Arny L]

It’s the ground side that matters. Back probe the black terminal of that solenoid with a pin. Attach test light ground clip to pin. Probe 12v side with other end of test light. With all safety switches engaged, it should light up. Don’t guess. But your on the right track.

 

[2traxs]

Thank you Arny I'm trying that now

 

[Arny L]

I forgot to add, the ground wire that is added onto the safety solenoid ground wire should be disconnected. If it is doing all the grounding then all your safety’s are by passed. At least that’s what it looks like from your picture.

 

[2traxs]

I wanted to say thanks to you Arny for helping me diagnose my problem with no hyd pressure, it turned out the person I bought it from had the plastic coupler flywheel replaced awhile back and they installed it backwards and the tandem pump coupler gear teeth were only catching about 3/16" of the plastic flywheel teeth and they wore them smooth

 

[Arny L]

Well that’s not the outcome you wanted, but glad you found it. Good luck