Hydraulics Mystery:loader:Can you solve?

   / Hydraulics Mystery:loader:Can you solve? #1  

Wayne Weaver

New member
Joined
Nov 28, 2009
Messages
7
Location
Florida
Tractor
mahindra 3525 w/ Loader
Here's the challenge:
My front-end loader has 2 functions:
1. Lift the bucket (big pistons)
2. Tilt the bucket (smaller pistons)

To begin, the 'lift' function works just fine.
The 3PH system works just fine.

The 'Tilt' function does NOT work just fine!The bucket will only tilt in the downward motion, but will not tilt back up.
This is the problem of the challenge.
The tractor is a Mahindra 3525...but this shouldn't matter to the mystery.


Clues -
1. The hydraulics control arm (back at your hands) for control of the 'lift' and 'tilt' was greased around the 'needle pistons' with general grease.
I thought this was a good idea at the time to ensure smooth, non-rust future action. I've since recognized that I placed grease in a poor location...should have just used WD40.

2. The 'tilt' function was getting slower and slower before it stopped lifting.

3. Remember I said, the tilt downward action still works, but the upward action does not? Well, the needle pistons (back at the control) has a needle piston that pushes inward for the tilt to lift. That needle piston will not go inward at all....whereas, it should by operation.
It is hydraulically locked is my guess.

4. The hydraulic pump works...cause the 3PH and the 'lift' function on the front-end loader work fine.

5. There are no leaks at any of the pistons. Valves....etc.

6. The hydraulic fluid level is fine....remember, the other hydraulics all work.



My thoughts:
I think grease got on the other side of the needle piston and hydraulically locked the one valve line. Grease and fluid most likely make a nice clot...but I don't know this.

Last request:
1. If you know what the problem might be, tell me how you would fix it.

2. If you know what the problem might be and you know of websites that will educate me...please direct me.

3. I have never unhooked my hydraulics, don't know too much about them, and if you are willing to talk me thru the overhaul replacement of lines and fluid, I would greatly appreciate....please respond.
 
   / Hydraulics Mystery:loader:Can you solve? #2  
If you are POSITIVE something at the valve is not working properly, I would take it appart and clean it out. I cant really picture what you are describing, but to verify it is the valve, if you have quick disconnects, swap a couple of them around. If the problem goes elswherer, it is the valve. If the problem remains with the curl up cylinders, the problem is somewhere after the valve.
 
   / Hydraulics Mystery:loader:Can you solve? #3  
No familiarity with your equipment but check all your quick connects to make sure they are on properly. Also check the joystick connections. :)

Do you have freezing weather? If so a heat gun directed at the valve may melt some ice if that is a problem.:)
 
   / Hydraulics Mystery:loader:Can you solve? #4  
needle piston= valve spool???
definatly locked up...probably mechanically...there is spring assembly on opposite side of spool...take cap off,and inspect/fix..2 allen screws I believe..
 
   / Hydraulics Mystery:loader:Can you solve? #5  
Lets call the action of the smaller tilt cylinders bucket curl meaning if the bucket was flat on the ground and you wanted to raise the cutting edge up to stop material from falling out you would curl it back. That means you put oil on side of the piston and the oil on the other side of the piston is returned to sump. Check the connection path of the lines on the loader. If you do not mind loosing a bit of oil and using a clean bucket the oil that would go to sump can be discharged into a clean bucket. If you have torn a hydraulic packing on the cylinder then oil will continue to pore to the bucket aslong as you are shifting the spool valve. You can put those lines back on and cross check the down action of the bucket.
Craig Clayton
 
   / Hydraulics Mystery:loader:Can you solve? #6  
needle piston= valve spool???
definatly locked up...probably mechanically...there is spring assembly on opposite side of spool...take cap off,and inspect/fix..2 allen screws I believe..

Not a Mahindra ... On my Branson I was having sticky joystick function and sometimes it didn't want to function the up down or the curl... dealer told me on the control valve (where all your hoses plug in) there are two boots held on by allen screws, under them is the spring assembly, remove the boot ... the spring assembly will stay, clean the springs, apply grease, intall the boots. Worked great for me. The boots have small air holes and moisture can build up causing corrision.

I guess the spring assembly has something to do with the valve action ??
 
   / Hydraulics Mystery:loader:Can you solve? #7  
Check those QD's, and swap them around.
 
   / Hydraulics Mystery:loader:Can you solve?
  • Thread Starter
#8  
When I disconnect the QD at the control, what will happen?
1. Will fluid squirt out for a second?
2. Will fluid squirt out for a quart, gallon, a teardrop...nothing?

I will have hydraulic fluid on hand, but if the tractor is off (the pump not going), then I would guess that only a small amount of fluid would come out.

How would I keep air out of the line while I swap around the QD's?
 
   / Hydraulics Mystery:loader:Can you solve? #9  
When I disconnect the QD at the control, what will happen?
1. Will fluid squirt out for a second?
2. Will fluid squirt out for a quart, gallon, a teardrop...nothing?

I will have hydraulic fluid on hand, but if the tractor is off (the pump not going), then I would guess that only a small amount of fluid would come out.

How would I keep air out of the line while I swap around the QD's?

No it will not squirt ... Did you try the Covers and clean the spring assembly?
 
   / Hydraulics Mystery:loader:Can you solve?
  • Thread Starter
#10  
No...not yet on cleaning the spring assembly.
Will get to it as soon as possible.
Will continue this thread for resolution after I disconnect, switch the connections, and double-check the spring assembly.

Thanks for the help and advice for now.
 

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