Description

Bosch Rexroth A4VSO 1997 Technical Manual – Factory Specs for Variable Displacement Pumps

Let me save you some trouble. If you are rebuilding or installing a Bosch Rexroth A4VSO 1997 Technical Manual is the only document you should trust. I’ve seen too many good pumps turned into scrap because some schmuck used a generic viscosity chart from the internet. This is the real deal – factory-published, 40 pages thick, and covers sizes 40 through 1000 in series 1, 2, and 3. No guesswork, no aftermarket reprints. Just the specs that came out of Rexroth’s engineering department in 1997.

Hydraulic Fluid Selection and Viscosity Requirements

Page 4 of this manual lays out the exact hydraulic fluid requirements. Mineral oil is the baseline, but they also specify which HF fluids (with the exception of Skydrol) are acceptable and under what reduced parameters. If you’re running a system that sees cold starts or high temps, the selection diagram on page 5 tells you the viscosity range at startup and operating temperature. I’ve had guys tell me “it’s all hydraulic oil” – that kind of thinking gets you a $4,000 repair bill. Get the fluid right from page 4.

What Torque Values Are Listed in the Technical Data?

The technical data section on page 5 includes a table of values with nominal pressure (350 bar) and peak pressure (400 bar), displacement per revolution, and the relationship between input speed and flow. You won’t find torque values for individual mounting bolts in this manual – that’s not what it’s for. But the input power and flow curves on pages 6-8 let you calculate the torque required at the shaft based on your operating pressure. Need the charge pressure? That’s in the summary of controls. Don’t go looking for a bolt torque chart where it doesn’t exist. Use the manual for what it is: a system specification document.

5 Control Device Options Covered

From pages 20 to 23, the summary of controls breaks down the factory wiring and plumbing for pressure control (DR/DP), flow control (FR/DFR), power control with hyperbolic curve (LR2/LR3/LR2N), and electro-hydraulic controls (MA/EM, HW/HD, HM 1/2/3, HS, HS1, HS3, EO1/2/DS1). Each one gets its own schematic. If you’re retrofitting a machine or replacing a control block, you need the correct porting and pilot pressure specs. This is not a generic “hook up the pressure line” guide – it shows you the actual Rexroth valve stack.

Read the Installation Notes Before You Mount This Pump

Page 9 – Installation notes. I cannot count the number of pumps I’ve seen ruined because someone ignored the mounting position restrictions or didn’t follow the suction line requirements. The manual tells you the maximum permissible shaft loads, the allowable mounting flange torque for the series 1, 2, and 3 housings, and the oil fill procedure. Factory spec says 350 bar continuous, 400 bar peak. You exceed that because you skimped on the install? That’s on you. Read page 9.

Through Drive Dimensions: Matching the K-Type Flanges

If you’re stacking pumps – A4VSO + A4VSO or A4VSO + A10VSO – the unit dimensions pages (25-26) and through drive pages (27-39) give you the exact SAE flange patterns, shaft extensions, and pilot diameters for K31, K33, K34, K35, K77, K43, and dozens more. Machining your own adapter plate? You better have the drawing from this manual. I’ve seen homemade adapters destroy a pump in 20 hours because the pilot depth was wrong. Use the OEM numbers.

Related Manuals:

• Bosch Rexroth A10VO Axial Piston Variable Pump Data Sheet
• Bosch Rexroth A10VSO Series 32 Technical Manual
• Bosch Rexroth External Gear Pumps Series F

For drivetrain integration, reference Manual Transmission and Manual Transmission for shaft coupling compatibility.

Frequently Asked Questions

Does this manual cover the A4VSO 1000 size?

Yes. Size 1000, series 3, is covered on page 19 with full dimensions and control options. The input power and flow curves for size 1000 are on page 8.

Can I use HF fluids with this pump?

The manual lists HF hydraulic fluid (except Skydrol) as permissible under reduced operational parameters. Page 4 spells out the restrictions. Do not run HF fluids at full 350 bar without consulting the fluid viscosity selection chart on page 5.

What is the difference between DR and DFR controls?

DR is a simple pressure control – the pump destrokes when pressure hits the setpoint. DFR adds a flow control compensator that maintains constant pressure while adjusting flow to demand. The schematics on pages 20-21 show the pilot line connections for both. If you need power control, look at LR2 instead.

How many pages are in this manual?

40 pages.

This manual is not a toy. It’s a 1997 factory print from Bosch Rexroth that gives you the same data the factory technicians use. If you work on A4VSO pumps – any size from 40 to 1000 – this is the reference you keep on the bench. Don’t trust some third-party reprint. Access the Factory Manual.