tweaking pressure relief on 8A backhoe
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    tweaking pressure relief on 8A backhoe

    I recently bought a used JD 970 with a 8A backhoe. The FEL works fine but the backhoe is weak on all operations. I don't know where to adjust the pressure relief up a little. Anyone know where this adjustment migh be located ?

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    Jet Dr.'s Avatar
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    Quote Originally Posted by kidbuffalo View Post
    I recently bought a used JD 970 with a 8A backhoe. The FEL works fine but the backhoe is weak on all operations. I don't know where to adjust the pressure relief up a little. Anyone know where this adjustment might be located ?

    I would be interested in the fix for this as well. I have a 375A backhoe that I think could stand a boost in pressure. I thought the system pressure was adjusted at the loader joystick, but that may be for those tractors that have an integral joystick.

    Jeff
    2018 3046R - Deluxe Cab, air ride seat, R4 tires, 3rd ESCV, diverter valve with 4th and 5th SCV's, mid PTO, 72D autoconnect MMM with independent lift, power beyond, 375A backhoe, 320R loader with 3rd function lines, L&R external mirrors, Frontier 60" 4 in 1 bucket and factory stereo with dedicated Sirius tuner.

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    Captain Hook Kennyd's Avatar
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    Quote Originally Posted by kidbuffalo View Post
    I recently bought a used JD 970 with a 8A backhoe. The FEL works fine but the backhoe is weak on all operations. I don't know where to adjust the pressure relief up a little. Anyone know where this adjustment migh be located ?
    Looking in http://www.jdparts , they show the PRV (pressure relief valve) breakdown this should be located near the inlet of the valve stack. You would add shims to increase pressure, the use of a gauge is highly recommended.
    Attached Thumbnails Attached Thumbnails 8a.JPG  
    Kenny

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    Captain Hook Kennyd's Avatar
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    Quote Originally Posted by Jet Dr. View Post
    I would be interested in the fix for this as well. I have a 375A backhoe that I think could stand a boost in pressure. I thought the system pressure was adjusted at the loader joystick, but that may be for those tractors that have an integral joystick.

    Jeff

    This is the PRV, but there is no breakdown for it:
    Attached Thumbnails Attached Thumbnails 375.JPG  
    Kenny

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    Jet Dr.'s Avatar
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    Quote Originally Posted by Kennyd View Post
    This is the PRV, but there is no breakdown for it:
    Ken,

    So this is on the backhoe control pedestal?

    What about system pressure?

    Something else I noticed. The cylinder for the dipperstick is at least 1" (possibly even 1.5") larger in diameter than the bucket curl cylinder. Changing the curl cylinder to a larger diameter cylinder would help also. The dipperstick cylinder seems to be larger than the boom cylinder also?

    Jeff
    2018 3046R - Deluxe Cab, air ride seat, R4 tires, 3rd ESCV, diverter valve with 4th and 5th SCV's, mid PTO, 72D autoconnect MMM with independent lift, power beyond, 375A backhoe, 320R loader with 3rd function lines, L&R external mirrors, Frontier 60" 4 in 1 bucket and factory stereo with dedicated Sirius tuner.

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    Captain Hook Kennyd's Avatar
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    Quote Originally Posted by Jet Dr. View Post
    Ken,

    So this is on the backhoe control pedestal?
    Yes, that is where the "valve stack" is.

    What about system pressure?
    What about it? You'd still check/set it independently of the backhoe.

    Something else I noticed. The cylinder for the dipperstick is at least 1" (possibly even 1.5") larger in diameter than the bucket curl cylinder. Changing the curl cylinder to a larger diameter cylinder would help also.
    It would slow the function down, but yes it would also give it more power. Quite expensive way to add power though.

    The dipperstick cylinder seems to be larger than the boom cylinder also?

    Jeff
    Look up^
    Kenny

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    Jet Dr.'s Avatar
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    Quote Originally Posted by Kennyd View Post
    Look up^
    Thanks for the quick response Ken!

    So where would main system pressure be adjusted on a 3046R with cab?

    Jeff
    2018 3046R - Deluxe Cab, air ride seat, R4 tires, 3rd ESCV, diverter valve with 4th and 5th SCV's, mid PTO, 72D autoconnect MMM with independent lift, power beyond, 375A backhoe, 320R loader with 3rd function lines, L&R external mirrors, Frontier 60" 4 in 1 bucket and factory stereo with dedicated Sirius tuner.

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    Captain Hook Kennyd's Avatar
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    Quote Originally Posted by Jet Dr. View Post
    Thanks for the quick response Ken!

    So where would main system pressure be adjusted on a 3046R with cab?

    Jeff

    Not sure om the new 3R's Jeff, but the technical manual will tell where it is and how to adjust it.
    Kenny

    -John Deere 3720 Deluxe Cab TLB
    FEL, MMM, Artillian 42" Forks and Modular Grapple, I-Match, Ballast Box, and lots of other STUFF.
    -John Deere 455 w/60" MMM


    Bolt on Grab Hooks and other cool stuff are now for sale!!

    Visit our YouTube Channel

    My Equipment:
    John Deere 3720 Deluxe Cab, 300cx FEL, 366 Front Blade, 59" Front Snowblower, Ballast Box
    Artillian 3K Forks, Grapple, Front-Hoe Bucket
    John Deere 455, 60" MMM

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