All vehicles except the M5 use automatic transmission fluid (ATF) as the power steering fluid. Use DEXRON®II type ATF.
The M5 has a self-leveling suspension that shares a hydraulic fluid reservoir with the power steering system. Use the hydraulic fluid printed on the reservoir. DO NOT use ATF, brake fluid or engine oil.
Those models requiring special power steering fluid will have a sticker on or around the reservoir.
See Figures 1, 2, 3 and 4
On 1970-74 models, at 8,000 mile (13,000 km) intervals, check the level of oil in the steering box. Carefully pry up the plastic cap on the steering gear cover and check to see that the oil level reaches the lower edge of the filler aperture. Top up as necessary with SAE 90 hypoid gear oil.
On 4-cylinder models build in 1975 and later years, the vehicle is equipped with a rack and pinion unit which requires only greasing. On 1975 and later 6-cylinder vehicles (with the exception of the 528e), check the power steering fluid as follows at every oil change:
- With the engine off, remove the wing nut located at the top of the reservoir. The oil level should be just above the mark on the reservoir. If necessary, refill with a DEXRON®II or III type automatic transmission fluid.
- Start the engine and watch the fluid level. If the fluid drops below the line level, add fluid until the level just reaches the line. The, shut the engine off and observe that the fluid level rises to slightly above the line.
- Reinstall the reservoir cover, making sure the seal seats properly. Check for any leaks in the steering box.
The 528e has a translucent plastic reservoir similar to a brake master cylinder reservoir. To check the fluid level in this reservoir, simply unscrew the cap and check that the level. The correct level is between the 2 marks on the reservoir. If the level is not correct, add fluid in the manner already described for previous models.