16H, 120G, 130G, 140G, 140H, 160G, 160H Motor Graders; and D4H, D5H, D6H, D8L Track-type Tractors
Summary of Revisions
Page Description
All Revised Format.
IntroductionThis Guideline enables dealers and their customers to benefit from cost reductions made possible through an established parts reusability and salvage program. Every effort has been made to provide the most current and relevant information known to Caterpillar Inc. Since the Company makes ongoing changes and improvements to its products, this Guideline must be used with the latest technical information available from Caterpillar to ensure such changes and improvements are incorporated where applicable.
For questions or additional information concerning this Guideline, contact Caterpillar Service Support Division, Dealer Support (309) 675-5156.
SummaryThe purpose of this Guideline is to give visual guidelines to see if piston pump and motor parts can be used again. When used in the same application, parts that can be used again can be expected to give normal performance until the next overhaul.
Never install a part that this Guideline shows cannot be used again. During reconditioning, correct any conditions that might have caused the original failure.
References
Reference Material
Form Title
SEBF2000 Metal Spray Guide
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Pressure air can cause personal injury. When using pressure air for cleaning, wear a protective face shield, protective clothing, and protective shoes. The maximum air pressure must be below 200 kPa (30 psi) for cleaning purposes. Use all cleaning solutions and solvents with care.
Before a part is inspected, wash it in a clean solvent which is made from petroleum. Wash each part separately. If several parts are washed together, there is a possibility that a machined surface can be damaged. Use compressed air to dry the part. Put hydraulic oil on the part to prevent rust or corrosion. Put the part in a clean container. Use a lint-free towel to clean the part before assembly. Be sure to put oil on all of the parts during assembly.
Inspection ProcedurePiston pump and motor parts normally have wear patterns that can be seen but can not be felt with a fingernail or lead pencil after the salvage procedure. This type of wear has no effect on the performance of the part. Unless stated in this Guideline, parts that have wear patterns that can be felt with a fingernail or lead pencil after the salvage procedure can not be used again. Throughout this Guideline, the fingernail or lead pencil inspection will be used to see if a part can be used again.
Touch Lapping ProcedureIn this Guideline, the touch lapping procedure is used on some parts so they can be used again. The touch lapping procedure will not give a part a "like new" surface or surface flatness. It is used only to remove discoloration and very small surface marks.
Use 4/0 emery polishing paper manufactured by the Minnesota Mining and Manufacturing Co., or by Norton Co., or an equivalent emery polishing paper. Put the emery paper on a ground surface plate (7B0337 Plate) so the paper is smooth. Do not use any other surfaces. Make the emery paper wet with a clean solvent made from petroleum. Put the part on the emery paper with the surface to be "touch lapped" on the
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paper. Move the part in a pattern like a number "8". Normally it is not necessary to make more than 10 complete number "8" patterns.
Wash the part in a clean solvent. Let the part dry at room temperature. Put hydraulic oil on the part and then put the part in a clean container.
NOTICE
When you handle or put pump and motor parts in storage, care must be taken to prevent damage to the machined surfaces.
Illustration 1
Touch lapping procedure used on a piston slipper face.
Power Lapping ProcedurePower lapping can remove wear patterns and surface scratches. This will provide a "near new" surface flatness on parts. The power lapping machine in Illustration 2 can be used on a wide range of parts that require very flat, very smooth surfaces. Power lapping can produce lap flat surfaces within tolerances of one light band (0.00295 mm or .000116 in). Consistent surface finishes of 2 to 3 RMS (root-mean-square) with absolute uniformity are easily attained.
Lapping machines are generally easy to operate. However, some very general guidelines must be followed. Check the lapping plates periodically, preferably every morning before starting production, to ensure lap plate flatness.
Fill the slurry tank with a lapping vehicle. The vehicle is usually purchased premixed and a lapping compound should be added to the vehicle at a rate of eight ounces per gallon. Run the machine without parts for a period of four to six minutes. This allows the compound to mix evenly in the vehicle.
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Load the parts to be lapped inside the conditioning rings. The parts should be free to move about within the ring, and not packed such that they remain stationary. Lapping times will vary according to the severity of the flaw that is to be removed. Minor scratches or warpage can usually be removed within 30 to 60 minutes. In order to inspect the flatness of the lapped part, remove the dull finish that is caused by the lapping compound. Wash the part thoroughly. Polish the lapped surface, using 600 grit emery paper on a 4/0 polishing stand, until it will reflect light.
Illustration 2
A 914 mm (36 in) Caterpillar 4C5043 Power Lapping Machine.
Testing For FlatnessA monochromatic light source and an optical flat are required to determine flatness (see Illustrations 3 and 4).
Test for flatness by observing the light, emitted from the monochromatic light head, reflecting from the surface being checked, up through the optical flat. A series of dark bands and light spaces will be projected. The dark bands are not light rays, but show where interference is produced by reflections from the test piece in the optical flat. Inspect the light bands for straightness. If the bands are straight and parallel, the surface is absolutely flat. If the bands are curved, the surface is not absolutely flat but may be flat enough for your particular needs.
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Check to see if the slipper will move by hand on the piston ball. The slipper can feel loose or tight but must move in all directions without binding. If binding is felt, do not use the piston assembly again.
Note:
Be sure the lubrication port is not plugged. Use a wire to check the hole.
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Measure the thickness of the slipper face with a 0 to 25 mm (0 to 1.0 in) micrometer. If the dimension measured is less than the piston slipper thickness given in Chart A, the piston assembly can not be used again.
Illustration 24
Measurement of the slipper face thickness.
Illustration 25
Measurement of slipper thickness. See Chart A.
Chart A. Piston Slipper Thickness
Reference Piston Diameter
Minimum Slipper Thickness
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The slipper faces of all the pistons from a single pump or motor must be measured. There must not be a difference of more than 0.02 mm (.001 in) between the thickest and thinnest dimension in a set of pistons.
If a new piston assembly is used in a set with used piston assemblies and the new piston slipper is more than 0.02 mm (.001 in) thicker than the other pistons in the set, the touch lapping procedure can be used to make the new slipper thinner.
Illustration 26
Piston slipper thickness between thickest and thinnest dimension.
Piston Assembly End Play
Check the end play of the piston assembly with a V-block, two other pistons, a dial indicator and a flat plate. Put the piston to be measured in the Vee of the V-block with the V-block on the slipper back faces. Put the dial indicator into position with the pointer on
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the end of the piston. Push down on the piston and set the dial indicator at zero. Pull up on the piston. End play movement cannot exceed 0.13 mm (.005 in).
Illustration 27
Measurement of the piston assembly end play.
Illustration 28
Slipper end play limits.
(H) Pull up.
(J) Push down.
(K) Endplay of 0.13 mm (.005 in).
Barrel Assembly
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Wash the barrel assembly and piston in a clean solvent. Use compressed air to dry off the barrel assembly and piston.
1.
Illustration 35
How to check the side movement of a piston in a barrel assembly bore.
1.Put a piston into one of the bores to the maximum depth that the piston will go into the bore during operation.
2.
Feel for side movement of the piston in the bore. Do this for all of the bores.3.
If no movement or only very little side movement can be felt in all of the bores, the barrel assembly can be used again.
NOTE:
Use a piston in a new barrel assembly to see how much side movement can be permitted.
If necessary, use a dial bore gauge to measure the bore diameters. If any of the bore measurements are more than the maximum measurement given in Chart B, the barrel assembly can not be used again.
Chart B. Barrel Bores
Reference Piston Diameter
Maximum Barrel Bore
17.04 mm (.671 in) 17.07 mm (.672 in)
19.23 mm (.757 in) 19.29 mm (.759 in)
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The barrel face can not exceed a surface finish of 0.20 µ m (8 µ in).
The barrel face must be flat within 0.0013 mm (.00005 in).
Barrel Assembly Splines
If no wear can be seen on the barrel assembly splines, the barrel assembly can be used again. If necessary, use two pins and an inside micrometer to measure the splines. Put the pins 180° apart in the worn area of the splines. For barrel assemblies that have an odd number of spline teeth, put the pins in splines as near to 180° apart as possible. Use clay or masking tape to hold the pins in position.
The diameter between the measuring pins must not be greater than the dimension given in Chart D. Use two 4C5856 Pins, 2.74 mm (.108 in), for the spline measurement. These pins are not an actual pump part but a tooling device and can be ordered through Caterpillar Parts system.
Chart D. Barrel Splines
Reference Piston Diameter
Max. Dimension Between Pins1
17.04 mm (.671 in) 24.71 mm (.973 in)
19.23 mm (.757 in) 32.59 mm (1.283 in)
20.90 mm (.823 in) 35.79 mm (1.409 in)
23.04 mm (.907 in) 38.96 mm (1.534 in)
26.11 mm (1.028 in) 45.34 mm (1.785 in)
1
Use two 4C5856 Pins, 2.74 mm (.108 in), for the spline measurement.
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Retraction PlateCheck the retraction plate to make sure it is flat. Put the plate on a surface plate (7B0337 Plate). With fingers and thumb, push down on opposite edges and see if any rocking motion can be felt. If rocking motion can be felt, the plate is not flat and can not be used again unless made flat by grinding.
Illustration 38
Test to see if the retraction plate is flat.
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This plate shows damage from slipper "lifting". Also, polished or scored surfaces on the area where the spherical washer rides is not acceptable.
Do not use again
Wear Plate
Illustration 42
Wear plate with a scratch across the slipper seat area that can be felt with a fingernail or lead pencil. Wear plates should not be used again without first power lapping to remove scratches.
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The surface shown in Illustrations 60, 61, and 62 can be power lapped a maximum of 0.38 mm (.015 in). Metering notches must be altered accordingly. Bearing must be removed and replaced.
Illustration 61
Erosion on face.
Use again -
after power lapping (See Note).
Illustration 62
Fine scratches and corrosion.
Use again -
after power lapping (See Note).
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Shaft with wear on the splines. Wear steps can be seen.
Do not use again
Illustration 72
Shaft with excessive wear in splines.
Do not use again
Spline Measurement
If the splines have a visible wear step, the shaft can not be used again. If necessary, measure the splines. Use two pins in splines 180° apart. For those shafts that have an odd number of spline teeth, put the pins in splines as near to
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180° apart as possible. Put rubber bands around the pins and shaft to keep the pins in place. Use an outside diameter micrometer to measure across the pins.
Illustration 73
Measurement of both pump shaft splines over pins. See Charts F and G.
Illustration 74
Measurement of the shaft crown splines over pins.
The crown splines of the pump shaft must not be less than the dimension given in Chart F. Use two 4C5855 Pins, 3.05 mm (.120 in), for the spline measurement. These pins are not an actual pump part but a tooling device and can be ordered through Caterpillar Parts system. Crown spline measurements must be taken from the center of the splines to assure accuracy (See Illustration 73).
Feel for a wear step with a lead pencil or finger nail. If a wear step is evident, be sure to position pins in the worn area.
Chart F. Crown Splines of Pump Shaft
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Grooves in the seal area that can be felt with a fingernail (as shown in Illustration 74) can be removed to make the part usable again.
Note:
Follow the metal spray manufacturer's directions carefully in the application of metal spray to the shaft seal area.
Basically, the salvage procedure is as follows:
Measure the shaft outside diameter at the seal area and the shoulder radius (if present) and make a note of each dimension.
1.
Restore the surface to the original size by using metal spray or an equivalent procedure. Metal spray is a recommended method. Each step in the procedure is critical in achieving the desired coating bond and surface finish.
2.
See Caterpillar's Metal Spray Guide, SEBF2000, about Metal Spray repair procedures. For complete information, contact the Metal Spray engineer, Caterpillar Inc. Service Development, Service Support (309) 675-5434.
3.Grind the restored seal area to the diameter measured in Step 1, ñ0.05 mm (ñ.002 in). The surface finish must be 0.40 to 0.80 µ m (16 to 32 µ in). The wheel radius must be the same or greater than the shoulder radius measured in Step 1.
4.
Other Components In The Rotating Group
Illustration 76
Inspection of pins and spherical washer in the rotating group.
(19) Pins,
(20) Spherical Washer,
(21) Plate,
(22) Retainer,
(1) Barrel Assembly.
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Pins (19) shown in Illustration 76 must be straight and of equal length on the 9T6857, 9T0290, 4T1029 and 4T6895 Hydraulic Pumps. Replace all pins if one is defective.
For those pumps with a 17.04 mm (.671 in) reference piston diameter, inspect spherical washer (20) shown in Illustration 76 for burrs, wear and damage due to pin breakage.
Summary ChartsThe following charts summarize all of the specifications listed in this Guideline and provide a single specification sheet for new dimensions for piston pump components.
