VTM42 and VTM42A steering vane pumps: model code, flow and relief settings
VTM42 is a vane-type mobile pump built as a complete steering power source. The flow-control valve and the relief valve are inside the pump, so a steering circuit needs no separate valve block. The code is short but every position changes what you receive — and it is a different code system from V10 and V20, so the two must never be read with the same table.
The short version
- Two builds: VTM42 (threaded shaft, no SAE flange, reservoir or manifold) and VTM42A (SAE A two-bolt flange, splined shaft, no reservoir or manifold position).
- Shaft type and model are tied together: thread only on VTM42, spline only on VTM42A.
- Ring sizes run 10 to 60, written as ten times the flow class — 10 = 1.0 USgpm, 20 = 2.0, 60 = 6.0.
- Flow control is a separate position from ring size: the ring sets what the pump can deliver, the orifice position sets what the steering circuit receives.
- Relief setting is a two-digit position from 05 (35 bar) to 20 (140 bar).
- Maximum pressure 140 bar, weight about 6.4 kg across the range.
- Return lines are hose and clamp connections, not threaded ports — and they must be air tight.
How to read a VTM42 code
Take VTM42-20-15-20-F11-R1:
| Position | Value | Meaning |
|---|---|---|
| Type | VTM | Vane-type mobile pump |
| Series | 42 | VTM42 series |
| Mounting flange | A | SAE A flange. Omit for VTM42; include for VTM42A |
| Ring size | 20 | 2.0 USgpm at 1200 r/min and 7 bar |
| Control flow | 15 | Orifice setting: 6 L/min (1.5 USgpm) at 1500 r/min and 7 bar |
| Relief setting | 20 | Cracking pressure 140 bar (2000 psi) |
| Reservoir filter | F | Filter element instead of the standard baffle; omit if not required |
| Reservoir or manifold | 11 | 1884 mL (115 in³) reservoir. Not available on VTM42A |
| Rotation | R | Right-hand (clockwise); L = left-hand |
| Shaft | 1 | Threaded shaft — VTM42 only. VTM42A uses 38, the splined shaft |
Control-flow settings
This position sets the flow the steering circuit receives, not the pump’s full output. The published settings, at 1500 r/min and 7 bar:
| Code | 15 | 20 | 25 | 30 | 35 | 40 | 45 | 50 | 55 | 60 | 65 | 70 | 75 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| L/min | 6 | 8 | 9.5 | 11 | 13 | 15 | 17 | 19 | 21 | 23 | 25 | 26.5 | 28 |
| USgpm | 1.5 | 2 | 2.5 | 3 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 6.5 | 7 | 7.5 |
Relief settings
| Code | 05 | 07 | 10 | 12 | 15 | 17 | 20 |
|---|---|---|---|---|---|---|---|
| bar | 35 | 52 | 70 | 86 | 100 | 120 | 140 |
| psi | 500 | 750 | 1000 | 1250 | 1500 | 1750 | 2000 |
Ring sizes and performance
| Ring (code) | Displacement cm³/r | Max speed at 7 bar | at 100 bar | at 140 bar | Max pressure | Weight |
|---|---|---|---|---|---|---|
| 1 (10) | 3.4 | 7000 r/min | 5000 | 4250 | 140 bar | about 6.4 kg |
| 1.5 (15) | 5.1 | 7000 | 4500 | 4000 | 140 bar | about 6.4 kg |
| 2 (20) | 6.2 | 7000 | 4200 | 3800 | 140 bar | about 6.4 kg |
| 4 (40) | 12.9 | 7000 | 2800 | 2800 | 140 bar | about 6.4 kg |
| 5 (50) | 15.7 | 6000 | 2600 | 2300 | 140 bar | about 6.4 kg |
| 6 (60) | 19.3 | 5000 | 2500 | 2000 | 140 bar | about 6.4 kg |
Note how sharply speed falls with pressure at the larger ring sizes: a ring 6 unit turns 5000 r/min at 7 bar but only 2000 r/min at 140 bar. Size the steering system from the pressure the circuit actually holds, not from the no-load figure.
Reservoir and manifold choices
Position 8 selects how the pump is fed and returned. Two reservoir sizes are published — 1147 mL (70 in³) and 1884 mL (115 in³) — along with several manifold forms, including units with and without a bypass line, a 90° tank connection, and a transport-closure-only version. VTM42A has no position 8 at all: it is supplied without a reservoir or manifold.
Ports and drive: different from the industrial pumps
- Pressure port: .750–16 UNF-2B, minimum 14.2 mm (.56 in) deep, for a .500 in tube with a standard SAE fitting and O-ring.
- Return on the reservoir version: 2.3 mm I.D. hose with a clamp, and it must be air tight.
- Manifold inlet: .750 NPT. Manifold return: .621 in I.D. hose with a clamp, again air tight.
- Tank bypass: only on the MF manifold (.250 NPT). Installations that run against the relief setting for more than 15 seconds at a time must use it, and the connection must sit below the oil level.
- Drive: VTM42 has a threaded shaft (.500–20 UNF-2A) with a standard SAE Woodruff key. VTM42A has an 11-tooth 16/32 spline shaft and an SAE A two-bolt flange with a 3.250 in pilot. Coupling, belt or gear drive are all published; a pulley must be centred on the drive wheel and stay inside the stated envelope.
Four things that go wrong when ordering
- Reading a VTM42 code with V10 / V20 tables. The systems are unrelated, even where a thread size happens to look familiar.
- Confusing ring size with control flow. The ring sets what the pump can deliver; the orifice position sets what the steering circuit gets.
- Leaving out the reservoir or manifold position. It decides whether the pump is a complete power source or needs external plumbing — and VTM42A cannot take one.
- Ignoring the tank bypass rule. Any installation held at relief pressure for more than 15 seconds needs the bypass port, connected below the oil level.
Send us the nameplate code
VTM42 codes are short, so a single wrong character usually changes the flow setting, the relief setting or the shaft. Send the complete string and we will confirm the replacement before you order. All units we ship are new aftermarket replacements, quality checked before dispatch. Contact us with your code.
You can also browse the family: V10 · V20 · V200 · VTM42 series.
