Pump regulator adjustment

[Ratmotorhead]

Hello gentlemen I am wondering if any of you have any thoughts on how to set the pressure on the regulators on a 4300c linkbelt I am getting an engine bog issue when I pull in the dipper in. I have good fuel pressure new filters and no junk in the fitting at lift pump. I have 4000 psi at both pumps ,dipper will relieve at 4500 psi on in and out . My pilot is 580psi. How is best way to tell if pump is at full swash,and are the regulators something to consider. Kinda a grey area for me. Any tips

 

[Tones]

Check the flow of the pilot pump. I have been told that machines of this era the pump wears, still pumps pressure but the flow drops off and valves don't open properly. Has it got a flow valve on that circuit? It maybe mounted on the boom.

 

[Ratmotorhead]

Thanks for the response Tones. I will check my pilot pressure again today,it seems right on ,although I haven't checked flow on it, also I will check pressure going right into regulator. I do get signal drop at both valves when a function is used,I believe that's how it works at regulator ,I may be wrong about that

 

[Coy Lancaster]

Have you checked your fuel supply as of yet? I know on the Case models of the same era if there was a fuel restriction the engine would bog down. Check the banjo bolt at the fuel settlement bowl, they have a bad habit of clogging up with trash.

 

[John C.]

Those regulators were based on main pressure and the problem that came up over time was that the regulators would leak internally which would cause the pumps to put more load on the engine. I haven't look at a C model pump in years but as I recall there was a single allen head screw with a lock nut at the pump. It adjusted total machine load when both tracks were in operation and at full flow under pressure. Basically while you were climbing a hill. As I recall turning the screw in reduced the load on the engine. A photo of the pumps might jog my memory.

I have a video of adjusting the CII pumps if you are interested. I would have to put it up on YouTube and send you the link as doing this stuff can be hazardous.

 

[Ratmotorhead]

Thanks for the response guys any input helps me out a lot. I have taken care of any fuel issues with engine,new sediment filters ,cleaned banjo filter, 18 lbs fuel pressure to pump, 17 lbs boost at turbo. I did blow a hose on the dipper in side and I am hoping I had a internal flaw inside since it had been ran with the wires all rotted off and showing. I got it replaced this weekend but haven't ran it yet. I have three set screws on regulator but no info on what does what. I will try to get some pics early this week of the reg and pump. It also has three hoses going to regulator, one comes from left main valve one from right. And the the third from my pilot pressure adjustment valve.

 

[John C.]

The two hoses from the main control valve are called negative control. When you operate a function the pressure on those get lower which signals the pump to stroke up. The hose from the pilot system is a reference pressure which is part of making the regulators work.

Let us know what you find.

 

[Ratmotorhead]

Hi guys here's a few photos of the pump and regulator in my Linkbelt 4300C excavator.
Hey, John C., thanks for your input. Is the set screw with the locknut in the regulator photo the one you referenced?
The photo of my pilot pressure adjustment valve shows one line going to the regulator. I am going to check this line for pressure. The other two lines I have checked. They have 580 pounds of pilot pressure. When I move a function that pressure does drop like it should. Any comments or suggestions?

 

[Ratmotorhead]

More photos regarding the Linkbelt 4300C excavator.

 

[John C.]

Top photo showing the big cartridge with the allen allen head screw and lock nut. Turning that in is supposed to reduce the load on the engine. You have to be careful when trying to turn the screw as a lot of the time they would get locked up with rust and snap off.

That was the odd thing about those pumps. The older they got the more they loaded up the engine. We had a heck of a time as a pump would break and a new one be installed. The operators would complain like crazy that the machine performance was ruined.

 

[Ratmotorhead]

Anyone know what the solnoid with the two black wires in the first photo controls. My wiring diagrams just show it as solnoid. I am wondering if it controls which mode pump is in

 

[John C.]

You are correct. You can put a multi-meter in series with the wires and read the milliamps that are going through the coil as you change the mode setting in the cab. I don't recall the specifications anymore of what they should be but you should be able to read a difference when you shift the modes.

 

[Ratmotorhead]

Hi guys on the earlier post one of the hoses from my regulator is said to be reference pressure, is it to have pilot pressure also. It seems that if the other hoses drop in pressure when a function is used,which they do by the way,another pressure should be there to shift it ,or move it. Am I thinking about that right. Finding pump specs on an old machine like this is like needle in haystack. Any thoughts are appreciated

 

[rmllarue91]

I never seen this style pump but I second the pumps are not destroking fast enough. Seems all case excavators I've been around needed pump cut back cx290 and a 9020 for sure. Parts break down might make the swash angle control easier to picture. Adjust both at the same time 1/4 turn or less at a time. If you don't see steady progress you have another issue.

 

[John C.]

I'll see what I have in info. It will be on the CII pump though and not the original C. They worked about the same I think.

The hose you are talking about is pilot pressure. That is the steady reference pressure. As I said earlier main pressure is used to control the output.

 

[Ratmotorhead]

Thanks for the info John C . I hope to get some time this weekend to do more tests on my machine . I got the impression that the high and low track speed has a lot to do with my bogging problem. The control panel has no high low for tracks or button on joystick and haven't looked into how that is controlled by pump, any ideas. Thanks rmllarue91 also.

 

[John C.]

I don't recall if the C model machines had two speed travel. On the CII models the high low was moving the swash plates inside the travel motors with pilot pressure. The cook book entries should point you in the right direction for troubleshooting your problem.

 

[Ratmotorhead]

Did some testing on linkbelt today. My first test was to see if I had pilot pressure to the pump regulator. I already knew that I had negative control ,it did drop in pressure when a function was used. I teed into my remaining line with a slightly lower pressure guage this time for a more accurate reading . Imade the mistake of having my pilot pressure at 570 at idle instead of wot,it probably had over 1000psi which would not let regulator move. At full throttle I set it at 570 psi and no more bog . It actually ran pretty nice. I was trying to get a change in reaction by powering the solnoid on regulator at half throttle, but had no change ,I am not sure if it has 24 volts in power mode and less for the economy mode. Now I need to set all reliefs again and continue on, maybe I'll get to use this machine yet

 

[John C.]

The solenoid will stay at 24 volts all the time. What changes are the milliamps going through the coil. You need a digital multimeter to read the amp flow. Good work on the pilot pressure. Do all the functions work OK at low idle as well?

 

[Ratmotorhead]

Thanks for the response. I left 24 volts to the solenoid I just have it on a switch in the cab,I was hoping the three position switch controlled the current to solenoid but it doesnt it must have had other components that are gone. All functions seem to operate at a lower rpm but my pilot pressure drops to 200lbs I am not sure if that is normal since none of my books show pressures at idle. I am one happy guy in Ohio.