JCB 212S Hydraulic issue

[Hydraulic1]

Hello everyone. I have a hydraulic problem on a JCB 212 S back hoe. When using hydraulic levers hydraulics initially work then stop completely. If operator slowly opens hydraulic levers it works but when opened fully it completely stops. Original thought was maybe pressure relief problem but I see all spools in there respective control valves have their own relief valves and since all functions have the problem I ruled that out. I want to check pump pressure. Can anyone tell me where to check pump pressure? Pump has pressure line going to what appears to be a priority valve. This valve feeds all the control valves and the steering circuit which is separate and works fine. Do I check main pump pressure there? Suction hose from reservoir is about 3" wide and I am assuming it has a suction screen? I will check the hose and screen as well. I have no hydraulic schematic or repair manual so I am digging a little blindly. Wondering If anyone can offer any advice or help or if anyone has had this problem. Thanks!!

 

[jcb jeff]

the control valves you are referring to are ARV aux relief valves protects each circuit you need to put a pressure gauge on the machine to see what you have it might be pump as a good way to test this put boom down on the back and say 3/4 revs lift boom up and half way whilst keeping lever in the same position drop the revs back and see if the boom stops if so you will need to do a flow test the main pump to determine for sure.could be mrv o rings blown i you need need more help just shout

 

[greg9504]

I sent you a message with links to the manual, let me know if you didn't get it. There is a test port right near the pump, may have a rubber cap on it. There is another test port on the loader valve, the loader valve has a main relief valve on it as well.

 

[Hydraulic1]

the control valves you are referring to are ARV aux relief valves protects each circuit you need to put a pressure gauge on the machine to see what you have it might be pump as a good way to test this put boom down on the back and say 3/4 revs lift boom up and half way whilst keeping lever in the same position drop the revs back and see if the boom stops if so you will need to do a flow test the main pump to determine for sure.could be mrv o rings blown i you need need more help just shout

ok Jeff thanks for the reply. I will take your advice and try it.

 

[Hydraulic1]

I sent you a message with links to the manual, let me know if you didn't get it. There is a test port right near the pump, may have a rubber cap on it. There is another test port on the loader valve, the loader valve has a main relief valve on it as well.

Greg, Thanks so much for the manuals!! I got them no problem and I can't tell how much I appreciate it! I should be able to get back to troubleshooting today or tomorrow and I'm confident this manual will help. I'll let you know how I make out. Thanks again!!

 

[maddog]

I'm wondering if it's an electric problem? My JD was doing the same type thing, found a small connection hidden way up under that likes to come lose.

 

[Hydraulic1]

I'm wondering if it's an electric problem? My JD was doing the same type thing, found a small connection hidden way up under that likes to come lose.

Maddog just wondering why you think electrical? where a bouts did you find the loose wire?

 

[greg9504]

There isn't much electrical in the 212S hydraulic circuits. It's pretty much all hydraulic/mechanical. The only case where there is a solenoid involved is if you have the "smooth ride" option.

 

[maddog]

Okay Greg9504 wasn't sure.

Hydraulic1; My excavator has a funky connector underneath the floor panel. It gets lose which causes most of the hydraulics to stop working or makes them jumpy.

 

[jcb jeff]

been thinking about your troubles i think yours being an American model wont be to dissimilar to the uk but from memory depending on year of machine and it is basically 2cx in the uk .The hyd pump is on the engine and may or may not have a priority valve on the back of the pump which will supply oil on priority to steering and brakes over hydraulics even if yours dont have priority on back of pump i would look at the steering /brake circuit as you have supply oil to steering and brakes.Does your machine have a brake pressure switch which measures low pressure so if you pump the brakes when running you should here charge the brake circuit after the charge valve the oil then travels to loader valve block and if brakes need oil you will loose flow to hyd loader circuit so if your brakes keep charging and you can here the engine noise change as it keeps dropping in and out you can also test that by setting machine at tick over and keep pumping the brakes and you should here it.
if it is constant doing this on its own you may have a faulty brake valve /accumulator basically pinching flow from your loader side i guess if you whilst lift a loader service you pump the brakes and see what happens.

 

[greg9504]

JCB Jeff, I don't think that will be his problem. On the 212s/2CX the brakes use a master cylinder and are not part of the overall hydraulic system. Well at least on the ones I'm familiar with, which is the ones from about 2002 on (serial number 930000 onward). There is a priority valve for the steering.

 

[jcb jeff]

There are some machines around s/no 760001 upwards i think which had power brakes /charge valve not sure if it is different as we are over the pond from you ,going back to hyd 1 fault need to put some gauges on to see whats what, but if not priority valve sticking possibly try turning the steering whilst operating boom and see if that makes it stop if not possible flow test to confirm.In the uk we used to have problems with 3cx machines front loader valve block having internal crack inside causing poor performance and a hissing noise inside.

 

[Okielite]

Any chance I could get you guys to send me a copy of that 212 manual? I have a 212SU coming in tomorrow and I want to get some oil and filters ordered. Thanks in advance.

 

[djkeev]

Good Morning!
I have a 2000 JCB 212S 4x4x4
I had the same problem as the OP had with very weak hydraulic action on the excavator and the front dump bucket.
Sadly the OP never posted a resolution to his problem.....
Anyway, The attachments would stop any movement if I pushed the control lever into full position.
If I just "nursed" the lever moving it a fraction of an inch I would get very slow and very weak motion.
I changed the hydraulic fluid using AW32,
I pulled the screen in the fluid tank and cleaned that,
I installed a new hydraulic filter in the tank,
and still, I had very weak activity.

It turns out that the system was only running 300-400 psi of operating pressure.
The steering worked fine, the brakes worked fine, getting preferential hydraulics as it is designed to do.
The MAIN RELIEF VALVE for the Hydraulic system ended up being the problem.

It is located to the rear of the front bucket controls below the heater control valve (remove the plastic side cover by the control levers, 3 bolts...... WHICH ARE RUSTED IN!! it took some doing but I got the bolts out using long needle nose vice grips on the rivet nuts accessed by coming in from the side between the cab floor and the frame )
NOTE: BE VERY CLEAN when you remove that valve, used a cleaner on the gunky mess and compressed air to clean the area. DO NOT DROP ANY DIRT INTO THE HOLE FOR THE RELIEF VALVE!!!! You will regret it if you do so.

I didn't have a new Relief Valve, nor did my JCB dealer. There were two 1/2" and smaller orings that were torn.
replaced those O rings and all is well!
I think that I may order a new Valve for peace of mind. I am told to NOT rebuild them if you don't have the gauges to set the pressure. (3200 psi) They are preset at the factory.

Hope this helps future readers.....

Dave

 

[greg9504]

Thanks for the update. If you buy the replacement valve please post what you paid, I'm curious what the dealer would charge.

 

[djkeev]

The Main Relief Valve is JCB part # 25 / 607233 and sells for $386 US
I was going to get one to have on hand but my parts guy says that they are stocked by JCB USA and are readily available if the need arises.

They also make a repair kit for the valve.

 

[cherokee101]

I'm trying to locate a pump for a 1994 model US JCB 210S. The old one will not seal up. I've put it in five times and it still leaks. I can't see any cracks but feel like it has one somewher that opens up under pressure. The oil comes out one of the bolt holes.

JCB will sell a retrofit kit apparently but I don't have that kind of coin for the pump, the kit and all the retrofitting that seems to go along with that.

Do you know of a replacement pump option or a reason this pump may be leaking. I replaced the seal kit with a new on and it still leaks.

Hope you are able to respond with some alternative. Right now I have a lovely 13,000 lb yard ornament that I wish was a lovely little working 210S.

 

[Dsiss3]

Who can tell me what the transmission pressure should be? Thanks

 

[greg9504]

Dsiss3, All of that is in the service manual. Do you have it? I have one for Mrk3, serial number 930000 on wards. PM me your email and I can send it to you.