Denison Problem Solving

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Denison hydrostatic pump and Denison hydraulic pump parts for the following Denison pumps, Denison motors, Denison transmissions, Denison drives, and Denison equipment, when you need replacement parts for Denison hydraulic pump repairs call us first.

Denison Problem Solving

DENISON HYDRAULIC PUMP REPAIR, DENISON HYDROSTATIC PUMP REPAIR

    • Effect of Trouble
  • Probable Cause
  • Some of the Remedies for      Problem

High wear in pump

Unwanted water in fluid

Water vapor Faulty breather, strainer Heat exchanger leakage ‘ wrongful clean-up practice Water in makeup fluid

Pressure shocks

Cogging load Worn release valve

Mechanical considerations Needed repairs

Worn compensator Slow response in check valves

Make repairs Replace or relocate

Servo pressure too low to sustain firm control

Increase pressure and check pressure drop through servo filter

Too much decompression energy rates

Improve decompression control

Excessive line capacitance (line volume, line stretch, accumulator effects)

Lower line size or lengths. Get rid of hose Bleed air

Barrel blow-off

Double check pump hold-down, rotary motion group, drain pressure

Heating of fluid

Excessive pump leakage

Look over again the case drain flow and repair as required Fluid too thin Improper assembly, port timing

Relief valve

Set too low (compared to load or to compensator) Not stable enough that is caused by back pressure, worn parts

Compensator

Set too high (compared to release) Worn parts

Pump too large for fluid needs

Choose smaller pump displacement

Heat exchanger

Water turned off or too little flow Water too hot Fan clogged or restricted Efficiency lowered by mud or scale deposits On and off hydraulic fluid flow

Reservoir

Too little fluid Entrained air in fluid Improper baffles Keeping in air blanket that prevents heat rejection Heat pickup from adjacent equipment

Revised Limits of Wear Parts

  • 11 and 14 in.3
  • Original Dimension
  • Max. Revised From Original Dimension
  • Min. Dimension After Revised

Port plate face

.725/.715″

.010″

.705″

Cylinder barrel face

5.880″

.010″

5.870″

Shoe retainer face

.4387.437″

.005″

.432″

Piston shoe face (pocket)

.020″

.010″

.010″

Creep plate face

.251/.250″

.010″

.240″

Face plate

 

None

Replace

PROBLEM SHOOTING

Part problems and circuit problems are frequently inter-related. A faulty circuit may work with obvious success but will cause failure of a particular part within it. The part failure is effect, not the reason of the problem. This broad guide is on hand to help in locating and eliminating the cause of problems by studying their effects.

    • Elffect of Trouble
  • Probable Cause

  Some of the Remedies for Problems

Noisy Pump

Air in Fluid

Leak in suction line Leak at shaft seal Low fluid level Turbulent fluid Return lines above fluid level Gas leak from accumulator Too much pressure drop in the inlet line from a pressurized reservoir Suction line strainer trying to be an air trap as well

Cavitations in pump or motor rotating group

Fluid too cold and viscous Fluid too heavy Shaft speed too high Suction line too small Suction line collapsed Suction strainer too small Suction strainer not clean Working altitude too high Boost or replenishment pressure too low Replenishment flow too small for dynamic conditions

Misaligned shaft

Faulty installation Improper in mounting Axial interference Faulty coupling Extreme overhung loads

Mechanical fault in pump

Piston and shoe looseness or failure Bearing failure Incorrect port plate selection or index Eroded or worn parts in the displacement control

Erosion on barrel ports and port plate

Air in fluid

See above

Cavitations

See above

High wear in pump

Excessive loads

Lower pressure settings Reduce speeds

Contaminant particles in fluid

Faulty filter maintenance Filters too coarse Putting in dirty fluid to system Reservoir openings Reservoir breather Improper line replacement

Improper fluid

Fluid too thin or thick for working temperature range Breakdown of fluid with time/temperature/shearing effects wrong additives in new fluid Breakdown of additive effectiveness with chemical aging

Improper repair

Incorrect parts,procedures, dimensions, finishes

Barrel and Stroking Assembly to Mounting Flange

  • 1. Establish straight thread connectors (3) and O-
    rings (4) into threaded holes in cradle.
  • 2. Fit in right and left hand pressure feed tubes
    (5 and 6) to connectors (3). Tighten connectors
     till it is snug.
  • 3. Place the mounting flange (9) with the large
    open end facing up and Put together two dowel pins
    (8) in the cradle mounting area and four
    locating sleeves (10) in the outer edge of the
    flange.
  • 4. Mount the rocker cam and cradle assembly (7)
    over the dowel pins (8) in the mounting flange.
  • 5. With  cam  and  cradle  put in, place
    mounting flange on the side and install two
    3/8-16 x 2 screws through the seal retainer
    surface into the cradle. These screws do hold in
     the rocker cam assembly in
    place and will be taken out later.
  • 6. Bring back the mounting flange to an straight up an down position
    and slant the rocker cam to both extremes of 
    attitudes in the cradle.
  • 7. Situate the barrel and auxiliary shaft assembly
     (1) directly over the pistons. Beginning with
    the uppermost piston, steer them one at a
    time into the barrel bores. Going back to the cam to a
    level position in the cradle.
  • PARTS LIST

    No.

    Q!y.

    Pirt No.

    Explanation

    1

    1

    See Fig 3

    Barrel & auxiliary shaft ass y

    2

    2

    033-71609

    Override pressure lubes

    3

    2

    492-15265

    Connector

    4

    2

    691-00902

    0-ring

    5

    1

    S1 3-43967

    Tubing ass y (right sidei

    6

    1

    S1 3-43966

    Tubing ass y (left sidei

    7

    1

    See Fig. 2

    Rocker cam & stroking ass y

    8

    2

    324-23216

    Dowel pin

    9

    1

    033-71546

    Mounting flange

    10

    4

    033-72664

    Locating sleeve

  • No.

    Qty.

    Pirt No.

    Description

    1

    2

    033-49825

    Face plate pins

    2

    1

    033-71921

    Barrel face plate P1 1 P only

    1

    033-71575

    Barrel (ace plate P1 4P only

    3

    1

    033-71602

    Housing gasket

    4

    1

    See Fig. 5

    Housing assembly

    Hydrostatic Parts and Denison Hydrostatic Repair

    1. Put in the faceplate pins (1) in the holes given
    in the barrel face.
    2. Apply lubrication to the surface of the barrel
    and place l the faceplate (2) over the faceplate
    pins.
    Warning
    Make certain the faceplate is correctly seated on the barrel and pins with the steel side towards the barrel face. The faceplate has one side bronzed and this should be toward the port plate. If needed, remove coating from edge of plate to settle on bronze side.
    3. Put in gaskets (3) over the two dowel pins in
    the mounting flange.
    Put together the housing assembly (4) over the bar
    rel and auxiliary shaft assembly. Cautiously
    guide the override tubes and pressure feed
    tubes (items 2, 5 and 6, Figure 4) into the
    housing assembly. Place the pressure feed
    tubes in the slots in the housing face

    Guidelines for Replenishing Circuit Isolation Plug

      • WARNING
    • The isolation plug together with this is to be used only if an external filter circuit is not offered DO NOT operate this unit with the isolation plug put in unless an outside line has been provided.
     
     

    When the outer filter circuit is not used, dispose of the isolation plug.

    When the outside filter circuit is used, fit the isolation plug under the plug in the face of the port block. Use a 3/16″ hex wrench, 4″ minimum in length. Insert the isolation plug and tighten to 80-120 in./lbs. torque.

    Warning

    Filter should have a bypass and bypass indicator and Hydrostatic Transmission Service,LLC which offers Denison recommends that it be sized four times for projected flow.

     

    Barrel and Auxiliary Shaft Assembly

    1.  Fit in the barrel (1) with the bores facing
       down on a clean area.

    • Place the hold down spring (3) into barrel counter-
      bore.
    • Put in spring retainer (5) into counter bore and
      seat next to spring.
    • Place the retaining ring (6) into barrel counter-
      bore groove. Align retaining ring so that it is fully
      seated in groove.

    Fix the barrel stop (4) over auxiliary drive
    shaft (2). Rotate barrel on side and put the auxiliary
     drive shaft and barrel stop into the barrel
    spline and hold down spring.

    • PARTS LIST

      No.

      a piip

      ».

      P14P

      Part Number

      Explanation

      1

      1

      –

      513-45381

      Barrel & sleeve assy Pi 1 P only

      –

      1

      S13-43965

      Barrel & sleeve assy PHP only

      2

      i

      1

      033-71603

      Auxiliary drive shaft

      3

      i

      t

      033-71562

      Holddown spring

      4

      1

      1

      033-71561

      Barrel stop

      5

      1

      1

      033-71560

      Spring retainer

      6

      i

      1

      033-71564

      Retaining ring

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