Does anyone know the trick to hooking up the hydraulic couplers on a 420eIT with multi purpose bucket. I change from bucket to forks once in awhile and getting the hoses hooked back up on bucket is a real pain. Is there a trick to relieving the pressure and working with the Cat couplers?
Good question Imm and I don't have an answer.. We have a 420D IT I bought new in 2003 with the aux hydros and have never hooked up any hydro's to it. Now the QC to go from forks to bucket is handy as a shirt pocket.
A "flat face coupler" works well. With machine off, work the bucket controles to relieve pressure first. Works for me.
Do you have op manual or serial#? Not sure if those have the relief switch in the cab to dump aux pressure. This is not the tool I was looking for but I did find this that may help. There was one posted on this site several years ago that had a big over center handle and was built a lot heavier but you may want to give this a try https://xboomcoupler.com/QCMate.asp
This machine is electro hydraulic so by moving lever or switch (in this case) nothing happens, when machine isn't running. Thats why I'm wondering if there isn't some other trick or something to relieve pressure. With a lever , even if running , a guy can feather the valve some but with the switch its all or nothing. Bumping switch is still to much. Ser # cat0420EVDAN00428
On a lot of Cat equipment there is a solenoid operated valve that dumps aux pressure to tank. They are usually just a rocker switch.
The hydraulic system pressure release procedure that should be carried out before connecting or disconnecting the couplers is as follows. I've only included the important parts of it: - Lower all attachments to the ground. Stop the engine. The engine start switch key must remain in the OFF position for at least 4 seconds. Turn the engine start switch key back to the ON position. Press the hydraulic system shutoff switch to the ON position. Operate all the implement hydraulic controls through all positions in order to relieve hydraulic pressure. Repeat this step until all hydraulic pressure is released. Return all the hydraulic control levers to the HOLD position. Turn the engine key start switch to the OFF position. The procedure is actually in the Operation & Maintenance Manual for your machine. I assume you don't have one, they are actually quite useful and not expensive. Around $50.
I've read that statement in book many times and have literally put my thumb on that paragraph and then turned back to the console section where it identifies switches. No where does Cat say there is a hydraulic shut off switch. I think I know what they are speaking of but nothing happens when I go through sequence. The switch I'm thinking of is on right side below start switch but its always on. Maybe I'm being dense....
How do you mean, "always on".? If it's a switch surely it has an ON position and an OFF position.? I'd say it is #42 on the illustration, titled "hydraulic lockout". It means the same as "hydraulic shutoff switch" in my experience. On the electrical schematic it is referred to as the "Implement Lockout Switch". It also appears to have an LED inside it, so one would assume that when the switch is in the ON (unlocked) position the light would illuminate to indicate that fact. It might pay you to check continuity and make sure that switch is actually working.
Thats the one. I'll have to check it to make sure it actually works. Its definitely the switch I have experimented with a few times.
I guess the first question ought to be - does it have an LED inside and does said LED go on and off as you move the switch..? - with the machine key switch in the on position obviously.
The wire marked R912-OR on the switch output side is what pulls in the "implement system enable" relay. If the switch is found to be working correctly there is the possibility that the relay contacts could be stuck in the closed position.
Does not have an led. Has small tab that supposedly keeps it locked in one position, but that doesn't work
If that locking tab isn't working there is every chance that the switch is foobarbed. Not the end of the world if it is, a new one is $31. Part Number 300-4994.
thanks , hopefully I'll get to check it soon.
The easy test for operation of relieving the system is to raise the boom 8 inches from the ground, then follow the above sequence but use the boom down lever. If the boom lowers, the accumulator and switch are working correctly. And, remember, it's an accumulator that supplies the override, so it'll only work once or twice before the accumulator is empty. The engine will need to run again to charge the accumulator again.
Accumulator discharged.?