How to Replace a Water Pump on a 1970 Firebird 350

When inspecting the water pump on a 1970 Pontiac Firebird with a 350 cubic inch V-8, check the front water pump bearing by attempting to wobble the cooling fan. With the engine off, grab the fan blade and move it fore and aft, feeling for freeplay in the water pump shaft. Another indication of a failing water pump is a leak from under the water pump. There is a hole on the bottom of the pump called a weep hole. If the bearing fails, water will exit through this hole.

Instructions

1

Disconnect the negative terminal on the battery using a wrench. Place the drain pan under the radiator. Open the drain plug with pliers and remove the radiator cap. Allow the radiator to drain into the drain pan. When finished draining, close the drain plug with the pliers.

2

Loosen the alternator pivot bolt on the bottom of the alternator. Loosen the upper adjustment bolt on the slotted bracket. Rotate the alternator toward the engine to relax the tension on the belt. Remove the belt from the alternator pulley.

3

Loosen the power steering pump adjusting bolt on the slotted part of the right side of the bracket, as you face it, using a socket. Loosen the lower pivot bolt. Push the power steering pump down to relax the tension. Remove the belt.

4

Remove the bolts securing the power steering pump bracket to the water pump and cylinder head using a socket. Remove the adjusting bolt and move the pump toward the drivers side fender. Do not remove the hoses or fluid. Support the pump from the rear power steering support bracket using a piece of rope.

5

Remove the four bolts in the center of the fan hub using a socket. Pull the fan off and place it on the lower part of the fan shroud or remove it from the engine compartment. If the fan has a viscous clutch do not lay it down or it may leak. Stand it up.

6

Pull the fan spacer off the nose of the water pump pulley and remove the pulley. Loosen the lower radiator hose clamp at the water pump using a screwdriver and pull the hose off. Loosen the heater hose clamp at the top of the water pump and pull the hose off the nipple.

7

Remove the alternator support bracket bolts using a socket. There is a bolt in the top of the intake manifold, one in the water pump and the adjuster bolt. Remove the bracket and leave the alternator on the lower pivot bolt.

8

Remove the four bolts securing the water pump to the engine block using a socket. Take notice to the size differential in the bolts so they may be installed in the same positions. Tap the nose of the water pump with the palm of your hand to break it loose from the block. Remove the pump.

9

Scrape all remaining gasket material from the engine block water pump mounting surfaces. It is essential to have these clean to prevent leaks. Spread silicone sealant on both sides of the new water pump gaskets and place them on the new water pump. Install the bolts before attempting to install the pump. This makes it easier to align the bolt holes without disturbing the gaskets.

10

Install the new pump making sure to keep the gasket surface from touching the engine block until the bolts are installed and threaded in slightly. Slide the pump against the block and torque the bolts to 15 foot-pounds of torque.

11

Install the heater hose to the top nipple on the water pump and tighten the clamp with a screwdriver. Install the lower radiator hose to the pump and tighten the clamp. Install the alternator support and adjustment bracket. Tighten the bolt in the intake manifold and the one in the water pump to 30 foot-pounds of torque. Leave the adjusting bolt that passes through the slot in the bracket into the alternator loose for adjustment.

12

Install the power steering pump. Tighten the two bolts securing it to the engine to 30 foot-pounds of torque. Leave the adjuster bolt loose for adjustment. Install the water pump pulley and fan spacer followed by the fan. Align the holes between the three pieces and install the bolts. Tighten the bolts to 20 foot-pounds of torque.

13

Install the belts over the power steering and the alternator pulley. Swing the power steering pump in its bracket to apply tension to the belt. Use the small prybar to assist in acquiring the proper tension. Increase the tension on the belt until it becomes difficult to twist the belt in between pulleys, more than 45 degrees. Tighten the adjuster bolt to 20 foot-pounds of torque.

14

Swing the alternator up away from the engine to adjust the tension. Pull up on the alternator until the belt is difficult to twist more than 45 degrees between pulleys and tighten the adjuster bolt to 20 foot-pounds of torque.

15

Reconnect the battery negative terminal and tighten it with a wrench. Fill the radiator with a 50/50 mix of antifreeze to water. Start the engine and allow it to warm up to normal operating temperature. Once it has reached normal temperature, shut the engine down and allow it to cool. Top off the radiator with the mixture of antifreeze and water and install the radiator cap.