Bosch NG 6 Technical Manual – Factory Hydraulic Specs for the 22-Page OEM Document

If you’ve ever tried to tune a proportional valve using a photocopied aftermarket schematic, you know the pain. The coil resistance is wrong, the pressure ratings are rounded off, and you end up with a spool that sticks at the wrong current. That’s why you need the actual Bosch NG 6 Technical Manual – 22 pages of factory-sourced data that Bosch themselves used on the assembly line. Forget the third-party PDFs that reprint blurry tables. This is the real deal: the same document that Bosch stamped with their part numbers and pressure limits.

Proportional Pilot Pressure Valves: What You Get on Page 1

On page 1 of the manual, you get the full ordering range for the NG 6 proportional pilot pressure valves. The table lists every variant: without position control (0.8 A / 2.5 A), with LVDT position control, and with lag – each with its own part number and max pressure in bar. Need a valve that handles 315 bar at 1 l/min? It’s there. The manual also gives you the coil resistance (RL = 20 Ω or 3 Ω depending on the version) and the mounting bolt spec – M5 x 30 DIN 912–10.9. Tool list? You’ll need a torque wrench that can hit the right ft-lb for those bolts; the manual doesn’t give the torque value directly, but the bolt grade tells you where to set it. Don’t guess – use a fastener spec chart.

Pressure Relief Valves and the Ordering Range

The pressure relief valve section (page 3) covers the pilot stage with Qnom = 1 l/min. You get the same part-number breakdown: 1-P, 2-P, 3-P, and so on, with pressure ratings from 50 to 315 bar. Each variant lists the amplifier type needed – AS 0.8 – V, AS 2.5 – V, 1 M 0.8 – RGC1, etc. If you’re retrofitting an old system, this table tells you exactly which amplifier card to order. The manual also includes the plug connector pinout for the OBE (onboard electronics) – a 7-pole plug that matches the LVDT feedback. Wire it wrong and you’ll fry the coil. Safety warning: always verify the coil resistance with a multimeter before applying power.

Does This Manual Cover the Wiring and Amplifier Types?

Yes. The manual dedicates a full page to amplifier technology – what Bosch calls “Verstärkertechnik.” You’ll see the alphanumeric codes: AS 0.8 – V (voltage input), AS 2.5 – mA (current input), and the RGC1 and RGC3 variants with ramp functions. If you’re tuning a proportional valve for a press or a conveyor, the ramp settings prevent pressure spikes. The manual doesn’t hand-hold you through every wiring scenario, but it gives you the pinout and the electrical specs so you can build your own control circuit. Treat this like a wiring diagram – trace each connection before you power up.

3 Key Specs You Need Before Tuning the NG 6

First, the flow rate: the manual lists Qnom values from 0.8 to 3.7 l/min depending on the valve type. Second, the maximum pressure: 315 bar for the heavy-duty versions. Third, the ambient temperature range: –20 to +50 °C. If you’re working in a hot Texas shop in August, you’re pushing the upper limit. Make sure the fluid viscosity matches the OEM recommendation – the manual references hydraulic oil as the medium, but doesn’t give a specific grade. That’s where you cross-reference with the machine’s service manual. And don’t forget the mounting torque on those M5 bolts – use a thread locker if the manual says so (it doesn’t, but I always do on hydraulic manifolds).

Understand the NG 6 Hydraulic Connections

The manual shows the port pattern: NG 6 (ISO 4401) plate mounting. That means the valve fits any standard NG 6 manifold. The symbol drawings on each page tell you whether the valve is normally closed, normally open, or proportional. For a DIY guy swapping a stuck valve, the ordering table on page 2 is your cheat sheet. Match the part number to your existing valve – don’t rely on the paint color. And if you’re replacing a coil, the manual lists the correct coil resistance (e.g., 20 Ω for the 0.8 A version). Measure your old coil with an ohmmeter; if it’s open, you’ve found your problem. Safety: always depressurize the system before removing a valve. The manual doesn’t say it, but I’ve seen what 3000 psi does to a hand.

Related Manuals

• Bosch NG6, NG10 Technical Manual – 204 Pages of Factory Hydraulic Specs
• Bosch KTS 550 2004 Technical Manual – Factory Specs
• Bosch 147, 156, 159, 166, 2400 2011 Technical Manual | Shop Specs

If you need a broader reference on valve spool operation, check out the Manual Transmission article on Wikipedia for a mechanical analogy. For additional reading on hydraulic control fundamentals, the Manual Transmission page (again) covers basic sliding-gear principles that apply to spool valves.

Is this manual available in English?

Yes, the manual is trilingual: German, English, and French. All tables and key terms appear in all three languages.

What specific hydraulic valves are covered?

The manual covers proportional pilot pressure valves and pressure relief valves in the NG 6 size range. It lists over 30 part numbers with accompanying flow rates (0.8–3.7 l/min), max pressures (50–315 bar), and amplifier types (AS, 1 M, PV, PDL). It also includes the 7-pole connector pinout for the OBE and the mounting bolt specification (M5 x 30, grade 10.9). For detailed ordering info, see pages 2–3.

Don’t waste billable hours chasing bad data. If you’re working on a Bosch NG 6 hydraulic system, get the actual factory documentation with confirmed specs. Download the Factory Manual from AutoRepairManuals today.