hydraulic pump shimming to increase/restore pump

   / hydraulic pump shimming to increase/restore pump #1  

kellytheaker

New member
Joined
Mar 5, 2006
Messages
21
Location
Rockwood Ontario
Tractor
110 TLB
i was hoping to entice a discussion on the shimming of these hydraulic pumps , and is this a common shop item that should be dealt with - if so i would appreciate an education in the process . I notice in a prior post the third manifold in the pump is the work zone to be shimmed . I currently would like to know if the pump on the 4600 is a standard JD item and do they all pretty much all operate on the same principal . Thanks in advance .
 
   / hydraulic pump shimming to increase/restore pump #2  
It seems to be very common.

I think that if you want to go down this road, you really should have a good hydraulic guage to test your work. There was a spell where all the Blue guys were doing this. One of them made up a quick connect guage set, and it was a real help. They then made it available to the TBN community and shipped it all around. Maybe it is still available. Even if it isn't, it would not be a bad idea to spend a bit and have it.

It is also a good idea to make sure you have agood handle on hydraulics. i got a link to an online course, let me know if you want it, it escapes me at the moment...
 
   / hydraulic pump shimming to increase/restore pump
  • Thread Starter
#3  
certainly , i would like to understand hydraulics better . So if you have info please , when you have the time. I have another small tractor i am selling and the fel seems a little sluggish, a grey K. As i stated earlier , this does seem to be an area i should understand.
 
   / hydraulic pump shimming to increase/restore pump #4  
Here it is:

Hydraulics Course thread

Also, you should search the forums, there should be lots of info. Look both in the specific brand and in Customization.

Finally, as I understand it, there are several possibilites. You could have a factory detuned setup, where shimming is the solution. Unless it is detuned by use of inline orifices ( I have seen those specified for the economy deere tractors - the 990 - I wonder if any 990 owners have removed this?) If the problem is due to failing componants like worn seals - well - shimming will likely help you 'find' those!
 
   / hydraulic pump shimming to increase/restore pump #5  
I think the only inline orifice associated with the 990 is a flow restrictor to reduce the free-fall rate of the loader and help prevent cavitation. It has no effect on lift capacity since it doesn't reduce pressure, just flow rate.

The 990 does, however, have a lower relief setting than most other similar sized Deere tractors (this is unrelated to the flow restrictor orifice). It is set to 2250psi rather than 2500psi. A loader on a 990 will therefore have a correspondingly lower lift/breakout capacity than if mounted on a 4000 Ten series or similar tractor.

I expect shims could be added to the relief valve to bump it up the ~10% to match the fancy tractor models without damaging anything. I may try this sometime, but haven't bothered yet ...
 
   / hydraulic pump shimming to increase/restore pump #6  
My friend and I have matching NH TC 45 Ds. He just checked his hydraulic pressure by mounting a gage on a quick coupler and attaching it in one of the rear remotes. It was set at 2200 psi. I read it is supposed to be around 2500 and this one was shimmed to 2700. They sell a small pack of shims that you can add to the main control. Pretty simple process. I know the factory sets them low for the warranty period.
 
   / hydraulic pump shimming to increase/restore pump #7  
I have 2 955s. Spec is 2500 psi, but one measures 2350 and the other 2200 at the loader. It seems that relief valve springs get tired easily or the pressure when new was way off. Be aware that you may have another relief valve in your remote valve, which will likely result in a lower guage reading at the remotes.
 
 
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