Sheppard Relief Plunger Setting

This will be seen on a typical Freightliner, Kenworth, Peterbilt, Volvo, Western Star, Mack, and Navistar.

[@seanoclair505]

To be sure. Manual relief valves are adjusted and set with the vehicle not jacked up?

[@expressogino3971]

Auto adjusters with vehicle in air. Manual adjusters with vehicle on ground. This is what RH Sheppard states.

[@andrewm5190]

Does this adjustment help with Poppet valves

[@expressogino3971]

Not sure what you are asking, but Poppet Valves and Relief Plungers are the same thing. TRW - poppet valves. RH Sheppard - Relief Plungers. Hope this helps.

[@codym7960]

which do you adjust to get more cut when turning left / drivers side? the bottom right?

[@expressogino3971]

Depends if the worm gear is Left hand or Right hand thread with the power piston. Left hand threaded worm gear, TOP. Right hand threaded worm gear, BOTTOM. This is for standard mount boxes, output shaft on the bottom side of the box. Reversed for inverted boxes, output shaft on the top side of the box.

[@codym7960]

@expressogino3971 yea mine ended up being thr bottom . Not sure how many but I think it had to be at least 10 turns to get full travel

[@thebaycuddy]

Plungers help with hard steering?

[@expressogino3971]

The plugners will open and reduce hydraulic pressure in the last 1/2" of wheel travel towards full left and full right turns. If the plungers are not set correctly or don't work the system pressure will reach the pressure relief setting and may cause damage to steering linkage components because of the high forces. When plungers are working correctly the pressure will drop at Least 400 psi below relief valve setting. So if the relief is set at 2600 psi, just before full wheel cut to the left or right the pressure will be 2200 psi or lower.

[@ЯрославШевченко-х7й]

Can somebody explane, whats mean "the chassis should NOT FLEX"?

[@expressogino3971]

When the steering is turned full right or full left the frame/chassis should not twist/flex. Raising of the frame rail is normal as it goes through it's turn because of the caster angle. If the relief plungers are not set correctly, hydraulic pressure may reach max pressure at full turn, putting extreme stress on the steering linkage components and causing the the chassis to flex/twist.

[@ЯрославШевченко-х7й]

Thank you very much for explaning this special term! By the way, your videos about M100 helped me repair and adjust steering gear on my Inter 9800. Thanks for that too and good luck in all your ways!