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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 HYDRAULIC PUMP REPAIR, DENISON HYDROSTATIC PUMP REPAIR
High wear in pump
Unwanted water in fluid
Water vapor Faulty breather, strainer Heat exchanger leakage ‘ wrongful clean-up practice Water in makeup fluid
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
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
Set too low (compared to load or to compensator) Not stable enough that is caused by back pressure, worn parts
Set too high (compared to release) Worn parts
Pump too large for fluid needs
Choose smaller pump displacement
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
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
Port plate face
Cylinder barrel face
Shoe retainer face
Piston shoe face (pocket)
Creep plate face
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.
Some of the Remedies for Problems
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
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
High wear in pump
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
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
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
- 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
See Fig 3
Barrel & auxiliary shaft ass y
Override pressure lubes
Tubing ass y (right sidei
Tubing ass y (left sidei
See Fig. 2
Rocker cam & stroking ass y
Face plate pins
Barrel face plate P1 1 P only
Barrel (ace plate P1 4P only
See Fig. 5
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
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
- 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.
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-
- 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
Barrel & sleeve assy Pi 1 P only
Barrel & sleeve assy PHP only
Auxiliary drive shaft
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