Hi I have a 2002 cat 301.5 i was moving it and had to lift the main boom, the boom started to lift then just stopped also the bucket will not work or the dipper arm and it will not track. It will swing and the blade will work so nothing on the right joystick works and only the swing on the left hand joy stick oil level is just above the low mark on the sight gauge the blade will lift the digger off the ground no problem i am at a loss any help would be appresiated
Good day & welcome I suggest you begin check out the servo pressure. Kind regards Uffex
Good day Does not add up but if have a pattern change valve be sure it has been fully selected. Kind regards Uffex
Hi Thankyou for you reply I will check out the servo pressure as you suggest i dont think there is a pattern change valve, but I am not sure? Regards Peter
Post a Serial Number, then someone can look at the machine hydraulic system for said valve. The pattern change could even be electronic controlled from the monitor panel.
ok here is the serial number 5DW04680 year 2002
That's the engine S/N (there is an ISO engine icon to the left of it), but the machine one is right there above - the last 8 of the PIN - 3YW03104. For service and parts information the Serial Number is the only thing you need, year means nothing. See the attachment for the location of the pattern change valve but I get the impression your machine does not have one. It is an option that was not fitted to all machines.
Hi Nige thank you for the attachment I have the day off tommrow so will have alook I really appreciate everones help, will let you know if there is a pattern change valve Kind Regards Peter
There is no pattern valve, but I have found that If disconnect this solenoid valve picture attached everthing works if I plug it back in then the issue returns no boom lift etc. I think it is the boom lowering valve but not 100% sure. would anyone be able to confirm if thsi si the boom lowering valve?
It is indeed. I can’t remember where it gets its feed from. Do you have an electrical schematic to go chasing power.?
Good day Its not so easy to follow with the snapshot have you the complete hydraulic schematic? Kind regards Uffex
Yes I have the electrical schematic I will check it out to see where it get its supply from.
I have the complete hydraulic schematic still studying it, ist easy enough to follow but not so easy to see what is what in the small space that all the hydraulics have been shoe horned into Kind Regards Peter
Check your mail.
Good day From what I can see my first port of call would be to the relay, see attached. Kind regards Uffex
Hi Uffex Thank you for the attched diagram I found the relay it is energized when the engine is running bringing in the boom lowering valve solenoid, I removed the realy and have checked it out it is ok, it switches ok when 12 volt is is applied. it looks like the relay is tied up with the oil pressure switch I assume that with the engine running the oil pressure switch is open stopping the relay from energizing this is my next port of call, with the relay unplugged and the engine running everthing is working plug it back in and it all stops Kind Regards Peter
Good day Peter I guess it must be as you say a pressure switch, there is one on the left side of the schematic, following the cables it appears to go in that direction(405-F76-GY 18) if that is it will be connected into the boom lower pilot line. I cannot find the engine oil pressure switch which is a little confusing. Kind regards Uffex
That one in Grid D-9 is the engine oil pressure switch. Follow wire 405-E18 which morphs to 405-A27 at CONN 4. Follow that to Grid B-5 and you'll find a splice. One wire continues as 405-A42 and goes to the warning lights & alarm system. The third wire in the splice is 405-A28. That wire backtracks and morphs into 405-F76 at CONN 2. Follow 405-F76 and it takes you to the boom lowering relay where it functions to complete the ground circuit for the relay coil. Wire 125-F52 at the boom lowering relay is switched power from the key. So I would say you have a short to ground somewhere in that 405 Grey wire, or a failed engine oil pressure switch. EDIT: An easy diagnosis would be to disconnect the 405 Grey wire at the engine oil pressure switch with the engine running. If the problem goes away it’s the switch, if it doesn’t there is a fault in the wiring somewhere.
If you find the oil pressure switch is indeed defective then the 153-6617 Part Number shown on the schematic is updated to 544-4080.
I disconected the wire from the oil pressure switch and the oil pressure light obviously didnt light up but the relay still energized, so as you say it looks like a short to ground but what i dont get is if there is a short to ground on that circuit then why is the oil pressure light going out with the engine running as it is linked to the same circuit? there is a Transister block that is also part of the system could it be faulty not sure what it is there for?
The oil pressure switch contacts opening (as the oil pressure rises on startup) cuts the circuit to ground. The idea is that LOW oil pressure (switch contacts closed) with the engine running causes a short to ground and pulls in the relay coil, thus opening the boom lowering valve and putting the implements on the ground for safety. If you have a wiring fault on another part of the circuit that is causing a short to ground I don't think that is going to stop the oil pressure switch from working (and indicating via the warning light) correctly. However what it is going to do is cause the boom lowering relay to pull in permanently and cause the symptoms you currently have. See below. With the engine stopped the switch is closed and you have a circuit to ground. As soon as the oil pressure rises far enough to open the contacts the relay coil should no longer be powered and the boom lowering valve stays closed.
It was the Relay itself, It has voltage on both terminals supplying voltage to the Boom lowering solenoid now just to fined where to buy one? does anyone know of a good place other than finnings. Thank you all for you help and in put it is very much appreciated Kind regards Peter
To prove the relay is faulty, why not switch it for one of the others on the machine.? There are 4 or 5 relays all the same 115-1615 Part Number. The one for the lights would be a good candidate to use for for a test.
Hi I will try that out thank you for the suggestion didnt think of that, at least it will prove if it is the relay or not i will let you know how i get on Kind Regards Peter
Search the schematic for 115-1615 it will show you all the possibilities. Some, such as the start disable relay, will obviously be unfeasible but you should be able to find something.
Hi Just an update for you I got a new relay from amazon fitted it and all back working Thank you all for you input and help, hope this tread helps others that might have the same problem cheers peter