The system should hold roughly 2 qts.

Use power steering fluid, not ATF. Though the ATF bottle says it is compatible, they are now formulated differently from 1987, with additives that are tough on the seals. PS fluid is like ATF fluid without the dye or additives.

There are two ways to change the fluid. The easiest and most popular is to suck the fluid out of the reservoir and refill with new fluid. Do this a few times and you'll have most of the fluid changed by dilution.

The other method - which I prefer - is by flushing the old fluid out while refilling with new fluid. Here's the procedure. You'll need a helper. The steps are rather simple.

1. Lift front tires off the ground.
2. Disconnect the ps return line, drain ps reservoir.
3. Plug open connection at the reservoir.
4. Secure the return line to a generously-sized container (at least one gallon). If needed, add a length of hose.
5. Fill reservoir.
6. Line up your bottles of new fluid for quick pouring.
Here comes the fun part...
7. Have helper turn car on, and immediately have him go through full range of steering motion (left and right) and shut off car, all the while you are trying to keep the reservoir filled.
8. Button everything back up.
9. Clean up mess.
10. Top off fluid.

The front tires must be off the ground so the system is unloaded, otherwise a lot of fluid is pumped out with a lot of force. The return line must be secured to prevent a big mess. Keep at least a gallon of ps fluid on hand. The helper must know what they are doing.

If your system is like mine, there's a replaceable ps filter at the bottom of the reservoir that you may want to change.

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95 E320 Cabriolet, 169K