Cat 320B LL Forestry Swing Machine Hyd Lockout

r20d12 · Sep 22, 2018

TVA said:
Yes! I miss understood you earlier. OP has no stand by pressure on either mains, so it’s either both unloaders just fully opened up at the same time ( which is highly unlikely), or we don’t have any flow from pumps. Since i don’t know CATs I’m wondering if the pumps can be fully destrock by PRV valve at least ( maybe ) when arm rest is s down, and there’s pressure switch somewhere on pilot line which sends the signal to an ECM which in turn adjusts the PRV signal pressure to “stand by” flow. Otherwise I don’t see purpose for thes unloaders!

I like how you used "WHICH IS HIGHLY UNLIKELY". That's a joke with my CAT friends cuz the old guys blamed the ECM for everything back in the day. Cat had so many good ecms returned for warranty they started putting that in the troubleshooting section. They go down the list of possible causes then at the end it says failed ECM "WHICH IS HIGHLY UNLIKELY" LOL everytime one of us truly suspects an ECM. The others will say which is highly unlikely. Goodtimes!

r20d12 · Sep 22, 2018

TVA said:
I just looked at manual and I didn’t see the pressure switch, there’s travel, implement, attachment pressure switches but no “ pilot on” pressure switch. So for now not having stand by pressure is a problem, unless someone can convince me otherwise!

Its just a mechanical micro switch

rmllarue91 · Sep 22, 2018

Soo did op ever check suction screen and return filters? I had a 235b with bad pump drive coupler that but would build few hundred psi off pressure due to friction drive... I've never seen any excavator without some standby pressure but I've not seen everything.

TVA · Sep 22, 2018

rmllarue91 said:
Soo did op ever check suction screen and return filters? I had a 235b with bad pump drive coupler that but would build few hundred psi off pressure due to friction drive... I've never seen any excavator without some standby pressure but I've not seen everything.

Friction drive is somewhere on the back of my mind, but I didn’t even want to announce it. We are having problems getting OP do things to find out what is going on. I think right now he is going electrical route.
I’m in a suction restriction theory phase, I haven’t ripened up to friction drive theory yet!

One thing I don’t get is what all of this got to do with starter replacement?

rmllarue91 · Sep 22, 2018

I'm guessing starter is unrelated unless it's simple hyd. Lock in pilot. I'm thinking coupler drive broke on start up. Had one like this years ago that was ice in suction...

TVA · Sep 22, 2018

TVA said:
Friction drive is somewhere on the back of my mind, but I didn’t even want to announce it. We are having problems getting OP do things to find out what is going on. I think right now he is going electrical route.
I’m in a suction restriction theory phase, I haven’t ripened up to friction drive theory yet!

One thing I don’t get is what all of this got to do with starter replacement?

rmllarue91 said:
Soo did op ever check suction screen and return filters? I had a 235b with bad pump drive coupler that but would build few hundred psi off pressure due to friction drive... I've never seen any excavator without some standby pressure but I've not seen everything.

I think the only time You probably not gonna see stand by pressure on delta P load sensing system with integrated ( inside pumps discharge ) metering orifice systems. I think if I’m not mistaken that’s what OP has on his harvester pump ( at least that pump has that options ) even then it should have two gauge port on each side of orifice - for diagnostic purposes. The delta P that use directional control valve as a metering orifice there’s should be back pressure because system needs to see that pressure drop out of something!

TVA · Sep 22, 2018

rmllarue91 said:
I'm guessing starter is unrelated unless it's simple hyd. Lock in pilot. I'm thinking coupler drive broke on start up. Had one like this years ago that was ice in suction...

The thing is that everything drives off of gear which also lower pumps main shaft and also pistons holder, for that to happen that gear must be intact and everything else in pieces, ( look up A8VO ). I think OP would have heard something like that!

TVA · Sep 22, 2018

TVA said:
The thing is that everything drives off of gear which also lower pumps main shaft and also pistons holder, for that to happen that gear must be intact and everything else in pieces, ( look up A8VO ). I think OP would have heard something like that!

I’m not sure if I’ve ice possible in Willow Alaska at this time of year!

TVA · Sep 22, 2018

TVA said:
I think the only time You probably not gonna see stand by pressure on delta P load sensing system with integrated ( inside pumps discharge ) metering orifice systems. I think if I’m not mistaken that’s what OP has on his harvester pump ( at least that pump has that options ) even then it should have two gauge port on each side of orifice - for diagnostic purposes. The delta P that use directional control valve as a metering orifice there’s should be back pressure because system needs to see that pressure drop out of something!

I’m sorry, I was wrong - posicon will not show any stand by pressure, except maybe slight return filter and cooler back pressure.

BrianGrenier · Sep 22, 2018

When the computer wouldn't boot (again) it seemed that spending the afternoon working on new starter connections would be productive.
There are 4 fat terminals going to a starter terminal and the new starter terminal is a bit shorter and the nut supplied had few threads to the face of the terminal, not so great connection.
I used a lot of noalox and got good tight connections, aluminum to aluminum lugs and a copper crimped lug fitting on the copper starter terminal.
Picture shows the new connection and the starter, but there is no computer and no hyd pressure. I will read through previous postings and see what is suggested.

Thanks for the help!

Bluox · Sep 22, 2018

Where did your starter switch go? Have you checked your pump controller fuses? Check the wiring harness under the cab especially where the cab hinges .
Good luck
Bob

TVA · Sep 22, 2018

BrianGrenier said:
When the computer wouldn't boot (again) it seemed that spending the afternoon working on new starter connections would be productive.
There are 4 fat terminals going to a starter terminal and the new starter terminal is a bit shorter and the nut supplied had few threads to the face of the terminal, not so great connection.
I used a lot of noalox and got good tight connections, aluminum to aluminum lugs and a copper crimped lug fitting on the copper starter terminal.
Picture shows the new connection and the starter, but there is no computer and no hyd pressure. I will read through previous postings and see what is suggested.
View attachment 186435
Thanks for the help!

I hope you insulated that pretty good !

rmllarue91 · Sep 22, 2018

Man would I like to work on this....

r20d12 · Sep 23, 2018

rmllarue91 said:
Man would I like to work on this....

I said that earlier. It would be a fun one no doubt!

BrianGrenier · Sep 23, 2018

It's a fall day with lots of color in the trees, a moose grazing nearby, no snow yet! Come over if you want.

So if one checks the pilot pressure on the port that cat provided which was 400 PSI some of you guys are saying I need to T-in before that one and check pressure. If so, at that main pump or near the solenoid under the cab.

Ohmed the solenoids at the pump compartment in the diagram sent on the first page with
Solenoids ohms right to left
1 1.1
2 2.2
3 7.8
4 17.8 or o.l now 1.1 now 5
Computer stopped again

There's another test port at the Fram filter visible in an earlier picture and that port is a different size than the fitting from CAT.

Anyway, just been chatting with this post to keep in the loop and obviously I have to check out the electrical first for the computer.

TVA · Sep 23, 2018

Those four solenoids is PRV, high travel, leveling mode and trenching mode - got little to do with your problems. The one you need check sits separate on hydraulic manifold, and even if it works there’s no guarantee that the lock out valve that it supposed to shift is doing that. That’s everybody is telling you that you need to check pressure after or down stream of that valve.

TVA · Sep 23, 2018

BrianGrenier said:
It's a fall day with lots of color in the trees, a moose grazing nearby, no snow yet! Come over if you want.

So if one checks the pilot pressure on the port that cat provided which was 400 PSI some of you guys are saying I need to T-in before that one and check pressure. If so, at that main pump or near the solenoid under the cab.

Ohmed the solenoids at the pump compartment in the diagram sent on the first page with
Solenoids ohms right to left
1 1.1
2 2.2
3 7.8
4 17.8 or o.l now 1.1 now 5
Computer stopped again

There's another test port at the Fram filter visible in an earlier picture and that port is a different size than the fitting from CAT.

Anyway, just been chatting with this post to keep in the loop and obviously I have to check out the electrical first for the computer.

That test port by FRAM filter is looking like the standard PD style quick connect ( or snap ) used by CAT, Case, Etc. it’s on right circuit (pilot ) but in wrong location - it is BEFORE or upstream of lock out valve. If you will find similar test connector on manifold with single solenoid ( BTW you posted picture of it before and even recording of sound ) then it is what you need.

TVA · Sep 23, 2018

TVA said:
That test port by FRAM filter is looking like the standard PD style quick connect ( or snap ) used by CAT, Case, Etc. it’s on right circuit (pilot ) but in wrong location - it is BEFORE or upstream of lock out valve. If you will find similar test connector on manifold with single solenoid ( BTW you posted picture of it before and even recording of sound ) then it is what you need.

BTW I wouldn’t recommend using FRAM filters!

BrianGrenier · Sep 23, 2018

Just because the filter was orange I assumed it was Fram, this filter was Donaldson.
The update is the computer's running again. Computer lead in wire to connector on side of ac heater box, was stretched there or on the other end of the same cable, looks like the ground wire was stretched, but since the computer is running I'm leaving it for now, it looks stable.
The priority then is the Hydraulics.
I pulled the solenoid, 121 - 1491 underneath the cab. Ohms were high, I lowered it and when reinstalled it the controls didn't work at all with no thunk sound. I adjusted it higher and controls will thunk but no main pressure.

Thanks again for the help, I think I'll take the solenoid to the dealer, the service guy Derek is pretty friendly and helpful.

B

TVA · Sep 24, 2018

Another thing kinda slipped out of everybody’s mind: we treat this machine as excavator! But that’s a forestry machine! The third pump/system also affects torque limiting, with PRV in the “picture” it’s easy to assume that how it’s done, but no one knows for sure because we have no pumps full code or even diagram or pictures of all controll hoses connected to the pump. There’s few different hydraulic options when it comes to hydraulic coupling with PTO pump. PRV is one of them and would be natural choice because it requires no changes to machine, but you never know!

Cat 320B LL Forestry Swing Machine Hyd Lockout

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