Nexus Gear Pump Porting{5073} Caterpillar

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Introduction

This guideline enables dealers and the dealers' customers to benefit from cost reductions. The benefits are made possible through an established reuse and salvage program. Every effort has been made in order to provide the most current information that is known to Caterpillar Inc.. The latest technical information is used in order to accommodate any changes or improvements to the company's products.

Caterpillar Inc. provides a line of Nexus gear pump products that highlight universal blank pump parts. These universal pump parts can be ported to the specifications for the required pump configuration. This gives an advantage to dealers and customers. The advantage lowers the requirements of the inventory. The advantage also lowers the cost of rebuild.

Contact Caterpillar at (309) 675-8970 for questions or additional information concerning this guideline.

Summary

The guideline will discuss steps of correctly drilling the Nexus hydraulic pump parts.

The pump parts in this document are of the P51 series. Drilling and porting should only be done on the following components: P30, P31, P50, P51, P75 and P76 series of gear pumps.

The pump parts can be found in the Nexus Catalog by the pump or model codes. The Nexus Catalog displays pump identification and the configuration of flow for gear pump porting. Part numbers that are required to assemble a gear pump are in this catalog.

Caterpillar offers products which allow dealers and the dealer's customers to build pumps from blank parts. Building pumps from blank parts can result in faster service for the customer. Building gear pumps from blank parts requires the necessary tools also.

References

Table 1

References
Media Number	Title
PECP9071	Nexus Product Catalog
GECJ0001	Caterpillar Shop Supplies and Tools
	Hydraulic Information System

Tooling and Equipment

Note: The following list of machinery and tooling is a recommended list. The procedure for porting can be completed by using equivalent tools.

Table 2

Required Tools
Part Number	Part Description
	Common Vertical Drill
	Insert Type Tool Holder
156-0927	Air Gun
	Solvent Wash Out Tank
1U-8805	Cutting Oil
	Taps (standard & metric)
	Fractional Size Drills
	De-Burring Tools
	STOR Contour Cutter
9U-6075	Toolmaker's Ink
162-5791	Shop Towel

Taps

• It is possible to cause damage to the internal walls of the pump part. Select a tap for this procedure with caution.

• A tap with a rake angle of 5 to 7 degrees is most applicable for this procedure.

• The Caterpillar Shop Supplies and Tools Catalog contains an available list of taps for this procedure. The media number for the Caterpillar Shop Supplies and Tools Catalog, GECJ0001.

Porting Tools

• Straight thread ports are required for high pressure hydraulic fittings. The ports and threads must be in compliance with commercial specifications.

• Contour cutting tools may be purchased from most local suppliers.

Jig Drawings

Jig drawings that are needed to port the various sizes of the required split flange are located within the Hydraulic Information System (HIS) web site.

• Open the HIS Web page.

• Click on the "Pump & Motor" link.

• Click on the "Nexus - Gear/Vane" link.

• Click on the "Tooling" link.

• Open the "Jig Drawing PDF" file.

Fabricating Instructions for Port Locating Plates

1. Fabricate a 10 gauge steel plate with the dimensions listed in illustrations 1 and 2.

• Two tools are required to cover the porting of all recommended series. One tool for the P30-P51 series of port end covers and another tool for the P75 and P76 series of pumps.

• Mark the center punch side of the steel plate, shown in illustrations 1 and 2.

Illustration 1	g01137515
Fabricated tool for the center punch of P30, P31, P50, and P51 series of port end covers. (E) 45.21 mm (1.78 inch) (F) 127.00 mm (5.00 inch) (G) 45.21 mm (1.78 inch) (H) 90.42 mm (3.56 inch) (I) 35.05 mm (1.38 inch) (J) 31.75 mm (1.25 inch) (K) 15.88 mm (0.625 inch) (L) 88.90 mm (3.5 inch)

Illustration 2	g01137702
Fabricated tool for the center punch of P75 and P76 series port end covers. (M) 165.10 mm (6.50 inch) (O) 41.15 mm (1.62 inch) (P) 82.55 mm (3.25 inch) (Q) 101.60 mm (4.00 inch) (R) 32.51 mm (1.28 inch) (S) 65.02 mm (2.56 inch) (T) 15.8750 mm (0.625 inch)drill

Important Safety Information

Most accidents that involve the machine's operation, maintenance, or repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills and tools in order to perform these functions properly.

The improper operation, lubrication, maintenance, or repair of this machine is dangerous. Improper methods could result in injury or death.

Hazards are identified by a safety alert symbol. Safety alert symbols are followed by a signal word such as "Warning" that is shown below.

Illustration 3	g01032906

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NOTICE
Notice labels in this publication identify operations that may cause product damage.

The following is the meaning of this safety alert symbol:

• Pay Attention!

• Become Alert !

• Your Safety is Involved.

The message that appears under the warning explains the hazard. The message will be written or pictorially shown.

Operations that may cause product damage are identified by "NOTICE" labels on the product and in this publication.

Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. Therefore, the warnings in this publication and on the product are not all inclusive. If a tool, a procedure, a work method or an operating technique that is not specifically recommended by Caterpillar is used, you must ensure that it is safe for all personnel around the machine. You should also ensure that the product will not be damaged or that the product will not be made unsafe by the operation, lubrication, maintenance, or repair procedures.

All of the information, specifications, and illustrations that are in this publication are based on information that was available at the time of publication. The following could change at any time: specifications, measurement, illustrations and other items. These changes can affect the service that is given to the product. Obtain the most current and complete information before you start any job. Caterpillar dealers have the most current information that is available.

Pump Identification

Nexus Catalog

• Parts for the assembly of all Nexus gear pumps can be found in the Nexus Catalog, PECP9071. The Nexus Catalog can be found on the HIS under the "pump and motor" link. Within the Nexus link, the Nexus Catalog is located on the "Service Guides" page.

• The Nexus Catalog is the source for the different configurations for porting and codes for parts ordering.

Hydraulic Information System

• The HIS web site features the "Pump Builder Program" that produces a bill of materials required for a complete pump build.

• The bill of materials includes Caterpillar part numbers, a description of the part, the reference number, and a price.

Porting Procedure

Port Locating Procedure

Table 3

Port End Cover Center Punch
Model	Port Size	X	Y
P30	3/4"	31.75 mm (1.25 inch)	31.75 mm (1.25 inch)
	1"	35.05 mm (1.38 inch)	35.05 mm (1.38 inch)
	1 1/4"	35.05 mm (1.38 inch)	35.05 mm (1.38 inch)
P31	3/4"	31.75 mm (1.25 inch)	31.75 mm (1.25 inch)
	1"	35.05 mm (1.38 inch)	35.05 mm (1.38 inch)
P50 & P51	3/4"	35.05 mm (1.38 inch)	35.05 mm (1.38 inch)
P75 & 76	1"	41.15 mm (1.62 inch)	41.15 mm (1.62 inch)

Illustration 4	g01136824
Center Punch Measurement for port end covers.

1. The port locations must be identified before drilling is started.

   Note: Notice that the bearing bore with the counterbore (1) needed for the ring seal in illustration 5. This is the top of the pump part.

2. Label the drilling cavity (C) for the left hand port. Label cavity (D) for the right hand port. This is shown in illustration 5.

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Illustration 5	g01138078
(1) Deeper counterbore (C) Left internal oil passage (D) Right internal oil passage

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Illustration 6	g01158504
Port End Cover sprayed with 9U-6075 Toolmaker's Ink

3. Spray the external porting face of the port end cover with 9U-6075 toolmaker's ink

4. Clamp the port end cover to the table of the vertical drill.

5. Find the center punch location for the port end cover. Refer to table 3 for the dimensions.

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Illustration 7	g01158507
Fabricated tool bolted to a Port End Cover for finding the center punch

6. Use a 5/8 inch bolt, washer and nut in order to secure the tool on the porting face.

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Illustration 8	g01132063
(B) Center punched port end cover

7. Establish the correct port location with the marking on the fabricated tool. Mark the center punch location on the external face of the port end cover. This is shown in illustration 8.

8. Remove the fabricated tool and the hardware from the bolt holes.

Pipe Thread Porting Procedure

Table 4

Pipe Thread Drill and Thread Depth
Port Size	Drill Depth	Thread Depth	Drill Size
3/4"	27 mm (1.1 inch)	14 mm (0.5 inch)	23 mm (0.92 inch)
1"	32 mm (1.3 inch)	17 mm (0.7 inch)	30 mm (1.16 inch)
1 1/4"	34 mm (1.4 inch)	17 mm (0.7 inch)	32 mm (1.25 inch)
1 1/2"	34 mm (1.3 inch)	17 mm (0.7 inch)	38 mm (1.5 inch)

1. Center the drill over the center punch.

2. Check that the drill outside diameter will not be within 4.76 mm (0.19 inch) from the outside of the housing.

3. Lock the horizontal axes of the drill and drill the housing according to table 4. Make sure of proper connection to the internal cavity "C"or "D" shown in illustration 5 of the Port End Cover is reached.

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Illustration 9	g01138083

4. Clean the port end cover of all metal shavings.

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Illustration 10	g01147510

5. Do not move the drill or port end cover from the original drilling location. Chamfer the end cover port with the correct size chamfer tool "6" as shown in illustration 10.

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Illustration 11	g01147509
Chamfer the hole for threading.

6. Clean the hole and the surrounding areas in order to prepare for tapping.

7. Locate the correct tap and mark the tap with a wax pencil.

   Note: The proper thread depth is listed in table 4.

8. Secure the marked tap into the spindle.

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Illustration 12	g01138080

9. Lower the tap into the hole until the minimum thread depth is reached.

10. Clean end cover ports and the internal passages with a solvent type cleaner.

11. Cover the port end cover with a lint free cloth.

S.T.O.R. Porting

• Table 5 shows the correct thread size for each straight thread o-ring port.

Table 5

S.T.O.R. Porting
Port Size	Thread Size	Drill Depth	Tap Depth	Drill Size
3/4 inch	7/8 inch-14	27 mm (1.06 inch)	17 mm (0.66 inch)	20 mm (0.79 inch)
1 inch	1 1/16 inch- 14	32 mm (1.26 inch)	19 mm (0.75 inch)	24 mm (0.95 inch)
1 1/4 inch	1 5/16 inch-12	32 mm (1.26 inch)	19 mm (0.75 inch)	27 mm (1.06 inch)
1 1/2 inch	1 5/8 inch-12	32 mm (1.26 inch)	19 mm (0.75 inch)	30 mm (1.18 inch)

1. Spray the pump face with 9U-6075 Toolmaker's Ink .

2. Mark the center punch with the correct fabricated tool shown in illustration 1 and 2.

3. Drill until the minimum drill depth is reached.

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Illustration 13	g01148268

4. Remove the drill bit and replace the bit with the correct size o-ring porting tool. This is shown in illustration 13.

5. Lower the drill until the O-ring cutter contacts the port end cover porting surface.

6. Apply pressure and stop when a completely smooth spot face is made around the port hole.

   Note: The contour of the O-ring seat should not be more than 0.40 mm (0.02 inch) deep.

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Illustration 14	g01148269
Spot face contour cut on a port end cover

7. Remove metal shavings.

8. Secure the tap which is indicated in table5 into the spindle.

9. Lower the tap until minimum tap depth is reached.

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Illustration 15	g01148271
Port end cover with S.T.O.R. porting

10. Clean pump part of all metal shavings using a solvent wash out tank.

11. Rinse the finished part and cover it with a 162-5791 lint free towel .

Bearing Carrier Relief Drain and Gear Housing Porting Procedure

Bearing Carrier Relief Drain Porting

Table 6

Relief Drain porting dimensions
Pump Model	Angle (degrees) - W	Thru Hole Dia. - X	Angled Hole Dia. - Y	N.P.T. Plug Size - Z
P30 and P31	10	685.8 mm (27/64 inch)	76.2 mm (3/16 inch)	1/4 inch
P50 and P51	10	685.8 mm (27/64 inch)	76.2 mm (3/16 inch)	1/4 inch
P75 and P76	11	685.8 mm (27/64 inch)	76.2 mm (3/16 inch)	1/4 inch

Illustration 16	g01137432
Bearing carrier relief drain internal drill (W) 10 degree angle for the P30, P31, P50, and P51 series of pumps 11 degree angle for the P75 and P76 series of pumps.

Note: Bearing carriers with a relief drain use the manufactured center punch of the external surface as shown in illustration 18

Note: Table 6 lists dimensions of each series of pumps and the drill sizes.

1. Check that the drilling of the angled hole is drilled into the deeper bearing hole. This is shown as "1" in illustration 5.

2. The drilling must be done at an angle in order to connect with the 11 mm (27/64 inch) through hole shown as "X". This is shown in illustration 16.

3. Align the drill with the center punch of the surface of the bearing carrier.

4. The angled hole is to be drilled into the bearing bore wall.

5. Any rough edges due to drilling must be filed off.

6. Drill hole "Z" to 20 mm (0.79 inch) at the same angle as hole "Y".

7. De-burr hole "Z". Chamfer the hole for tapping preparation.

8. Insert the correct tap into the spindle.

9. Tap the hole 10 mm (0.39 inch).

10. Fit a 1/4 inch NPT steel plug in order to check for proper fit.

11. Clean the pump part using a washout tank.

12. Dry the pump part and cover with a 162-5791 lint free towel .

Internal Cross Drill

Illustration 17	g01137434
Bearing carrier center punch dimensions

Table 7

Bearing Carrier Internal Drill Dimensions
Series	A	B	C - Crosshole Dia.		D
P30 & P31	45 mm (1.78 inch)	35 mm (1.38 inch)	5/8 inch for "C" and "D" codes		45 mm (1.78 inch)
P50 & P51			15/16 inch for "A" and "U" codes
P75 & 76	82 mm (3.25 inch)	41 mm (1.62 inch)	1 3/1 inch for "A" and "U" codes		32 mm (1.28 inch)

1. Locate the internal passage in order to drill the correct porting configuration.

   Note: Table 7 and illustration 17 show the dimensions for all recommended bearing carriers and gear housings to be drilled. The dimensions for the center punch of the internal passages are shown.

2. Find the center punch measurements which are taken from the bolt holes.

3. Center punch the internal hole.

4. Center the drill over the center punch.

5. Lock the horizontal axes of the drill in order to prevent the pump part from moving during drilling.

6. Turn on the spindle.

7. Lower the drill until the drill contacts the face of the housing. Check the alignment of the drill.

8. Drill completely through the housing.

9. Reverse the drill out of the housing.

10. De-burr the drilled edge of the hole.

11. Thoroughly clean the inside of the drilled passage.

Bearing Carrier Porting

Illustration 18	g01148217

1. Locate the existing center punch mark on the housings. This is shown in illustration 18.

2. Insert the correct drill into the spindle and secure the drill in place.

3. Clamp the housing onto the table and align the drill with the center punch.

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Illustration 19	g01147507
Drilling of the external port face of the bearing carrier

4. Lower the drill into the housing. This is shown as "B" in illustration 19.

5. Drill until a complete connection with the internal passage is reached. Shown as "C" in illustration 19

6. Retract the drill from the housing.

7. Remove all burrs with a file or the de-burring tool.

8. Clean the passages with a solvent washout tank and cover with a 162-5791 lint free towel

SAE Split Flange Porting

• The table 8 shows the flange sizes, thread depth for the bolt holes and thread size for the bolt holes.

• SAE split flange drill jig drawings are located on the HIS web site under the "Tooling tab".

Table 8

SAE Split Flange
		Center Hole	Bolt Hole
Flange Size	Drill Size	Thread Size	Drill Depth	Thread Depth
3/4 inch	19 mm (0.74 inch)	3/8 inch- 16	25 mm (1.02 inch)	14 mm (0.55 inch)
1 inch	25 mm (0.99 inch)	3/8 inch- 16	25 mm (1.02 inch)	14 mm (0.55 inch)
1 1/4 inch	32 mm (1.24 inch)	7/16 inch- 14	30 mm (1.18 inch)	17 mm (0.67 inch)
1 1/2 inch	38 mm (1.49 inch)	1/2 inch- 13	32 mm (1.26 inch)	19 mm (0.67 inch)

Illustration 20	g01148221

1. Refer to the ""Jig Drawings " " in the ""Hydraulic Information System " " section of this guideline.

2. Locate the correct template. Lay out the pattern for the flange holes.

   Note: If the Jig Drawing templates are not available: Dimensions for the various flange bolt holes are found in tables 9, 10 and 11. Tables 9 through 11 correspond with illustration 21. Drilling and thread depth for the bolt holes are listed in Table 8.

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   Table 9

   Caterpillar Split Flange bolt dimensions
   Flange Size	A	B	C	D
   3/4 inch -12	23 mm (0.9 inch)	51 mm (2.0 inch)	12 mm (0.5 inch)	25.4 mm (1.0 inch)
   1 inch -14	28 mm (1.1 inch)	57 mm (2.2 inch)	14 mm (0.6 inch)	28.7 mm (1.1 inch)
   1 1/4 inch -20	32 mm (1.2 inch)	67 mm (2.6 inch)	16 mm (0.6 inch)	33.3 mm (1.3 inch)
   1 1/2 inch -24	37 mm (1.4 inch)	80 mm (3.1 inch)	18.3 mm (0.7 inch)	38.1 mm (1.5 inch)

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   Table 10

   SAE Code 62 Split Flange bolt dimensions
   Flange Size	A	B	C	D
   3/4 inch -12	23.9 mm (0.9 inch)	50.8 mm (2.0 inch)	11.9 mm (0.5 inch)	25.4 mm (1.0 inch)
   1 inch -14	27.7 mm (1.1 inch)	57.2 mm (2.3 inch)	14.0 mm (0.55 inch)	28.7 mm (1.1 inch)
   1 1/4 inch -20	31.8 mm (1.3 inch)	66.5 mm (2.6 inch)	16.0 mm (0.6 inch)	33.3 mm (1.3 inch)
   1 1/2 inch -24	36.6 mm (1.4 inch)	79.5 mm (3.1 inch)	18.3 mm (0.7 inch)	38.1 mm (1.5 inch)

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   Table 11

   SAE Code 61 Split Flange bolt dimensions
   Flange Size	A	B	C	D
   3/4 inch -12	23.9 mm (0.9 inch)	50.8 mm (2.0 inch)	11.9 mm (0.5 inch)	25.4 mm (1.0 inch)
   1 inch -14	27.7 mm (1.1 inch)	57.2 mm (2.3 inch)	14.0 mm (0.55 inch)	28.7 mm (1.1 inch)
   1 1/4 inch -20	31.8 mm (1.3 inch)	66.5 mm (2.6 inch)	16.0 mm (0.6 inch)	33.3 mm (1.3 inch)
   1 1/2 inch -24	36.6 mm (1.4 inch)	79.5 mm (3.1 inch)	18.3 mm (0.7 inch)	38.1 mm (1.5 inch)

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Illustration 21	g01145026
Split flange: four bolt pattern uses the same dimensions.

3. Center punch the holes

4. Follow the same drill, chamfer, and tapping methods use in the port end cover porting procedure.

5. Clean the part with using a solvent washout tank.

6. Rinse and cover the pump part or bearing carrier with a 162-5791 lint free towel .

Illustration 22	g01138081
Finished split flange port face