IT IS ATTACHED TO THE PUMP AT THE FRONT OF THE ENGINE
A 1991 VW Jetta's power steering reservoir is located towards the front of the engine bay. The unit can be seen placed on top of the power steering pump.
Lift the hoods, find the lid to the power steering reservoir and remove the lid. Attached to the lid is the dipstick to the power steering fluid, read the level and decide if more needs to be added.
Power steering fluid or Automatic transmission fluid
In the power steering pump
To check the power steering fluid on your 1991 Caprice remove the cap on the power steering pump fluid reservoir and check the level on the fluid level indicator. If the fluid is warm(about 170 degrees)the fluid level should be at the "Full Hot" mark. If the fluid is cool(about 70 degrees) the fluid level should be at the "Full Cold" mark.Always use the correct power steering fluid to avoid damage to the hoses and seals which will result in fluid leaks. It should be noted that the reservoir (pardon my spelling) is located under the alternator (On my '91 with the 305, that is) - So you can't do it while the car is running.....Kenny
It does not matter on that year, just make sure that it is POWER STEERING FLUID.
It would be located over on the right (passenger) side of the car, and it will usually be a semi-white reservoir, with a black cap. The top of the cap should even say "power steering" on it. The only other reservoir that would be on that side of the car, would be the window washer fluid, and it would be a much larger reservoir, white, with a bluish tint because of the fluid color. It would be pretty hard to get these two confused.
Check carefully, it may be power steering fluid from the reservoir just above and to the left. Look for a leaking hose or a cracked reservoir.
It is in the frunk next to the battery on the passenger side
both power steering fluid and transmission fluid are hydraulic fluids, but it would be best to get some power steering fluid. its cheap and its the right stuff. 91 buicks take just plain Jane power steering fluid.
On top of thr pump, on the front of the engine
Regular power steering fluid, available at any part store and places like Walmart.