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Les Wilkinson
Les Wilkinson,
Category: Heavy Equipment
Satisfied Customers: 6
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O & K RH6 hydraulic safty cut out valve, where is it?

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O & K RH6 hydraulic safty cut out valve, where is it?
JA: Sometimes things that you think will be really complicated end up being easy to fix. The Heavy Equipment Mechanic I'm going to connect you with knows all the tricks and shortcuts.
Customer: Thankyou
JA: Are you fixing this yourself? What have you tried so far?
Customer: Yes I am a diesel fitter by trade, the excavator has been parked up for 5 years, I have started it but there is no drive to the tracks or any movement on any rams, just like when the arm rest is lifted to get in, it cuts out all the hydraulics. I have bypassed the switch, but would like to know which solenoid valve needs to have power to power up the servo circuit.
JA: Is there anything else the Equipment Mechanic should know before I connect you? Rest assured that they'll be able to help you.
Customer: I think that is all.
Hi Its les here.
Do you have the serial number of the unit , will then be able to get the info from my database.
You may also check the negative control pressure on the hydraulic pumps as the pumps may be de swashed resulting in negative flow.
Customer: replied 16 days ago.
Oh dear, this has gone from complicated to very complicated, I will get serial number off the machine & get back to you, it was built in 1999, I do not know how to check the negative pressure on the pumps, I have also found another solenoid valve under the seat so will try energising this when I get the serial number, Thank you for your help, one more unrelated question, have you any idea, where I could purchase a workshop manual for this O & K? many thanks, Pete.
Hi Pete,Don’t panic we can get through this together , we just need to identify the problem.
We can go step by step, you will need at least a digital multi meter to check voltage.
I have an idea where you can purchase a manual i will check for availability.
Lets just get the serial number first so i can review the systen.
Do you have the number yet, i have a contact in Europe who can possibly assist with info.
Hi I have some info for you but i need to ask some questions to ensure i have the correct unit.
Please contact me.
Thanks Les
Customer: replied 16 days ago.
Sorry, just got in, machine is in a field on a farm a couple of miles away & I had to do some other work this afternoon & try a few more things while I was there.
on the id plate it is year of manufacture 1998.
next line is RH6 COMPACT
next line id no' is 117723
I hope this helps
The only place I seem to have high pressure is on a solenoid valve block with an accumulator at one end, when the end valve is energized the engine revs drop a little, when the other valves are energized the engine note does not change, a pipe goes to another single solenoid from a valve block on top of the solenoid nearest the accumulator that if it is pressurized it is much lower pressure than the end solenoid valve.
The single solenoid valve was not clicking so I removed it & dismantled & reassembled, it does make a slight sound but not as loud as the others. with the solenoid on top it is marked
A on the side that I think is the feed from the solenoid block with the accumulator on the side.
B that is at the bottom inline with the solenoid that I think go to the servo valves operating leavers.
C oposit A but slightly further down the valve away from the solenoid that I think goes to the tank as oil poors out continuously & a pipe full but can be stopped with a piece of paper pushed in the pipe.
I can not blow through A with or without the solenoid energized, these solenoids are all connected with small hoses nothing over 3/8", not like the 3/4" + on the rams & motor drives, Thanks, Pete.
Hi Pete,I will review this tomorrow, the agents for this brand are Cat, they are very strict on tech data release.
However i do have acsess to a very large data base.
Now i have the serial number i can narrow this down to the correct model.
In respect to the info you have supplied i have an idea that the pilot pressure is not active or has been dumped to tank.
You mentioned the stepping down of pressure on the valve with the accumulator, this would be correct as the average pilot pressure is between 20 to 30 bar.
The accumulator is in a healthy system supposed to hold residual pressure to allow a hydraulic function to be activated with a non operational engine.
Most excavators incorporate a small gear pump driven remotely to supply pilot pressure.
Once i have the correct schematic for the electro / hydraulic system we can create a test procedure on the relative system.
Are you able to chat tomorrow?
Customer: replied 16 days ago.
I am self employed so every day is the same to me & it is my Excavator, I would very much like to purchase a workshop manual or even a manual or cd or downloadable file if you could help on that? many thanks, Pete.
I am sure we can get you sorted out Pete.
I will contact you tomorrow.
Have a good evening.
Regards Les
Customer: replied 16 days ago.
Thank you & you, Pete.
Customer: replied 16 days ago.
The solenoid valve under the floor beneath the seat has the following numbers on it I think they are
When I google LT30A31 the first picture is of the single valve under the seat, I was thinking to block of C pipe that I think is return going to the tank & connect the pipes together that go to A & B so connecting what I think is the feed from the valve bank with the accumulator to what I think is the feed to the pilot control valves?
Also if I knew what the pilot control operating pressure should be I could check this.
I have disconnected a pilot pipe to the main spool block but only a small trickle comes out that momentarily stops when I open what I think is that control valve.
Sory to keep bothering you but something I do not think important that I have done may mean something to you.
Once we have the schematics we will be in a better position.
Tell me is the engine a Deutz air cooled?
Would you be able to send some pictures of the main control valve, and the accumulator valve.
As i noted before pilot pressure usually runs at 30 to 25 bar.
Customer: replied 16 days ago.
it is a 6 cylinder Deutz air cooled, no pictures personally, but I may be able to get someone to take pictures for me.
Customer: replied 16 days ago.
Could you send me a copy of the schematics, I could then tell you of any oil flow or pressure between the valves marked on the plan?
Now i have the info ican barrow it down and send it via the app peter
Customer: replied 16 days ago.
I am not very good on computers, I don't have any apps, do you want my email address or do you already have it from the site?
Customer: replied 16 days ago.
That would be great if you can get it to me, then we are sure we are talking about the same part, Thanks, Pete.
You email us fine for the schematics, i can also attach to these conversations , i will leave that up-to you.
Customer: replied 16 days ago.
Could you email me please. thanks.
thats no problem, just send your mail address.
Customer: replied 15 days ago.
Thank you we can chat in the morning
Hi Peter
I have only been able to locate a parts manual in the interim.
My contacts are searching fo a service and ops manual for this unit. I will mail the parts book to you a little later as it is a large scan and i need to compress it.
If this book is correct it contains a rudimentary schematic set which may assist.
I will contact you when the manual has been mailed.
Customer: replied 15 days ago.
That's a good start, if it is the right book, at least I can confirm the part I suspect, thanks, Pete.
Good plan i will be in touch later after i have send the book.
Hi Peter i cannot load the file.
I recommend you request the file via mail from***@******.*** request file cvfgcv1294.
This will release the file for the parts book to you.
We can then carry on the diagnosis over the week end.
Here is the schematic so long
Hi Peter did you review the schematic yet???

ll good

Customer: replied 15 days ago.
Sorry not long got in, yes I have had a look at the schematic you sent me, but it does not mean anything to me, I can guess what some of the things are, but does not seam to match my excavator, I have emailed the email address you sent me so hopefully with the full parts book I can explain to you exactly what I am trying, is there still a chance you may be able to source a workshop manual for this excavator? all the best, Pete.
Pete we can try and get this sorted

Hi Peter did you receive your parts file.

Les Wilkinson and other Heavy Equipment Specialists are ready to help you
Customer: replied 14 days ago.
Thank you, ***** ***** have, I think it is for the previous machine to mine as it is non servo.
I bypassed the valve I mentioned & it is all up & running, thanks for your help I am all sorted now, but would still like to purchase, parts book & workshop manual for future use, all the best, Pete.
Many thanks Peter call again if you need help