It’s a Matter of Pinion -
The easiest way to think about rack-and-pinion steering is as two gears. One round. One flat. The round gear is called the pinion and is connected to the end of the steering wheel shaft. As the steering wheel turns, so does the pinion gear. The flat gear is called the rack. As the pinion turns, the rack travels either left or right. The front wheels are connected to the rack by way of tie-rods and steering knuckles. The rack and pinion are enclosed in a housing and mounted to the chassis. It’s the miracle of steering!
Before rack-and-pinion steering became standard equipment on many fine cars, such as the Ford Pinto, steering chores were handled by way of a recirculating ball steering box. As the steering wheel turns, a worm of recirculating ball bearings moves around in the box. This action makes an arm at the end of the box turn left or right. As anyone who has ever attempted to service one of these boxes knows, the worm usually purges its ball bearings all over the garage floor as soon as the box is cracked open. Replacing or rebuilding steering boxes is another story.
While the rack-and-pinion is a much simpler setup than the recirculating ball steering box, it still moves and meshes around a great deal. All moving parts that come in contact with each other will eventually wear out. Also connected to the steering rack are the inner tie-rod ends, also known as drumsticks. Rubber boots that protect the inner tie rod ends and steering rack can crack and allow moisture and crud to get in, and grease to get out. Once the boots break, steering rack wear accelerates. When ordering up a replacement steering rack, make sure the rack comes complete with drumsticks and rubber boots.
Feel the Power
Power steering adds a layer of complexity to steering rack replacement. Before deciding that a steering rack leak is where all that power steering fluid is going, check the power steering pressure and return hoses for leaks. A $300 replacement steering rack won't fix a $20 broken hose! If the car has power steering then inspect all the components before replacing the rack. Flush the system and fill with fresh power steering fluid before sending dirt and crud into the new power steering rack on startup. The pump and system may also need to be bled after installation.
In the case of this old Toyota, the rack boots had long since cracked, and the rest of the suspension components have seen a few presidents. Since the steering rack is at the center inner tie rod ends, outer tie rod ends, ball joints, and so on, it makes sense to inspect and replace everything as long as the front end is apart. If the rack is wrecked then the other components can't be that far behind in wear. This maxim is especially true for those of us who drift toward driving 20-something year old cars.