944 Steering — Power-Steering Service Data & Tightening Torques
Factory steering figures for the 944 — power-steering fluid type and delivery pressure, the fluid-level and bleeding rules, and the tightening torques for both manual and power steering. Torques switch between N·m and ft·lb and the delivery pressure between bar and psi; the rule-of-thumb fluid-level distance is a fixed dimension in millimetres.
The factory steering figures for the 944 — the fluid and pressure numbers behind a power-steering service and the torques for putting the steering back together. For the jobs themselves see removing and installing the steering gear, replacing the power-steering pump, and rebuilding the rack. Torques switch between N·m and ft·lb and the delivery pressure between bar and psi; the fluid-level distance is a fixed dimension in millimetres.
Power-steering service data
| Figure | Value |
|---|---|
| Hydraulic fluid | ATF Dexron II D |
| Delivery pressure (engine at idle) | 100 bar1450 psi to 120 bar1740 psi |
| Supply-tank fluid level when filling | approximately 40 mm from the top edge of the tank |
The supply tank is on the right-hand wheel-house wall inside the engine compartment. With the engine warm, the level on the dipstick must sit between the two marks; top up with ATF Dexron II D as required.
Do not dismantle the gear or pump. Both the rack-and-pinion steering gear and the power-steering pump are exchange parts. Where no exchange scheme exists they may be reconditioned only by an authorised ZF dealer.
Checking the system
- Drive-belt tension — check the power-steering pump belt (the same belt-tension method used elsewhere on the engine).
- Leaks — with the engine at idle, turn the steering to full lock and hold it there to build maximum line pressure, then check every line connection for tightness. Hold lock for no more than 10 seconds at a time, with a short pause between checks.
- Delivery pressure — connect a pressure gauge between the pump and the pressure line. At idle, briefly close the gauge's shut-off valve to read the delivery pressure, then open it again immediately. Do not keep the valve closed for more than 5 seconds — longer closure wears the pump. The specification is 100 bar1450 psi to 120 bar1740 psi; if it falls short, replace the pump. Grunting noises when turning, or foaming in the supply tank, indicate a lack of fluid and/or air in the system — cure any leak before topping up.
Bleeding
After fitting new steering components or lines, or after a large fluid loss, bleed the system: start the engine briefly and switch off immediately several times, topping up continuously with ATF Dexron II D so the supply tank never runs empty. Then run at idle and turn the wheel rapidly lock to lock several times to drive air out of the cylinders, without pulling harder at the end stops than needed. When stopping the engine the level must not rise by more than 10 mm — a larger rise means trapped air remains.
Manual-steering tightening torques
| Location | Thread | Torque |
|---|---|---|
| Steering gear to cross member | M8 | 23 N·m17 ft·lb |
| Axle shaft to steering gear and steering column (self-locking nut) | VM8 | 30 N·m22 ft·lb, then a further 5 N·m4 ft·lb |
| Tie rod to rack (manual steering) | M22 × 1.5 | 50 N·m37 ft·lb |
| Tie-rod joint to tie rod (manual steering) | M14 × 1.5 | 30 N·m22 ft·lb |
| Steering wheel to steering column | M16 × 1.5 | 45 N·m33 ft·lb |
| Column switch to outer tube | M8 | 15 N·m11 ft·lb |
| Outer tube to body | M8 | 23 N·m17 ft·lb |
| Mount to body | M6 | 7 N·m5 ft·lb |
Power-steering tightening torques
Values not listed here are the same as for cars without power steering.
| Location | Thread | Torque |
|---|---|---|
| Tie rod to rack | M14 × 1.5 | 70 N·m52 ft·lb |
| Tie-rod joint to tie rod | M14 × 1.5 | 70 N·m52 ft·lb |
| Feed and return lines on the steering gear (hollow union bolt) | M12 × 1.5 | 20 N·m15 ft·lb |
| Feed line on the power pump (hollow union bolt) | M14 × 1.5 | 30 N·m22 ft·lb |
| Ring hose nipple for the intake hose on the power pump | M16 × 1.5 | 45 N·m33 ft·lb |