Below you will find instructions for changing the pressure switch for the Teves brake system.
The GM part number for a new Pressure Switch is 25533700.
The pressure switch is sometimes difficult to get at. It takes a 36 mm deep socket which most owners do not have. You can try channel locks, but room is a problem.
36 mm deep (thin wall) sockets are not easy to find. A second choice would be a 1 7/16 which is close enough to work. They also make some deep plumbing sockets that come in a set of 5....they are used to run nuts on faucets and one of those work.... however you must buy the set, they are not available individually, but they are fairly cheap.
At the top is a 36mm deep socket that was machined to clear the pump motor.
Deep impact sockets are the only 36 mm I have found and the wall thickness is too great to clear the pump motor.
The next two are plumbing sockets made by Chicago Specialties. They normally come in sets of 5 different size sockets but I have found singles at big plumbing stores. A set usually runs $10 to $15 and singles are $4 to $5 each..... you might find singles at swap meets or junk stores.
The inch size is 1 7/16 and are worth having if you own a Reatta with Teves brakes.