bertjnovak

I am going to attempt to replace the power steering pump on a 1991 LS400 myself. I have a new pump and pressure hose and belt.
Any hints or things to look out for when doing this repair? Is it best to remove from the top or bottom? Can it be removed without draining the coolant? What is the best way to purge the old fluid out of the system?
I plan to remove the alternator for inspection also.
I have not been able to locate any removal instructions on line.

Thanks for the help
Bert

RODDMOD

Hi
I did this job twice, it is just removing bolts, you might want to consider leaving off the idle up valve on the pump, unless you bought a new one yours will leak at sometime and you will have to pull the altenator again to change it. In my last Lex I left it off and didn't notice any change. The reason I did it twice is that I put on one of those rebuilt pumps from e bay and the seal blew all over my new altenator,o joy. Make sure that the altenator plug snaps back in when you reinstall, it goes in tight. You will have to pull the power steering hoses out of the way, you will see when you are under the beast. I am sure you will pull the battery lead off before starting. Good Luck.

bertjnovak

Thanks to "roddmod" for your advice.

bertjnovak

Power steering removal on a 1991 LS -400

Parts required (suggested)
Pump with reservoir.
Pressure hose with copper crush washers.
2 feet of return hose (3/8).Will be cut to size later.
6 ft. section of (cheap) 3/8 hose for flushing the system (2 small hose clamp).
3 quarts power steering fluid (Dextron II compatible).
2 small cable ties to tie down alternator wiring.
Tools
Metric, open end and box wrenches and sockets

Disconnect battery
Jack front wheels off ground
Remove plastic windshield under car and 2 side shields
Drain radiator
Remove air filter and duct
Loosen nut on power steering pump pulley
Remove radiator hose on power steering pump side
Disconnect vacuum hoses from power steering idle up valve
Disconnect pressure hose near the steering rack to drain fluid from pump reservoir
Cut off return hose. (replace with new 3/8 hose) from rack
Remove serpentine belt. (make a drawing of how the belt routes) if not on a decal under hood.
Remove the bolts at each end of the sway bar in each wheel well
Remove bolts clamping the pressure hose to the chassis
Disconnect wiring from alternator (1 connector, 1output cable)
Remove alternator through the bottom. (2 bolts) (rotate sway bar as necessary)
Disconnect Pressure hose from pump and remove
Remove 3 bolts on steering pump from the bottom
Cut off return hose at reservoir. (replace with new 3/8 hose later)
Remove 1 nut on a stud from the top through a hole in the steering pump pulley
If you can remove the pump pulley first, the pump can be removed through to top
If not remove through the bottom.
Remove idle up valve from pump and pulley if not already removed.

Re installation of Power steering pump

Suggest that new pump has a new reservoir already installed.
( The reservoir had a fine mesh screen in the bottom that gets clogged from the breakdown of the pressure hose. If you are confident
that you have flushed it completely and want to reuse it, make sure the O-ring is replaced at the base of the reservoir before reassembly)
Reinstall idle up valve on pump body.(or install a plug if you chose to disable this function)(this valve is known to fail resulting in power steering fluid being sucked in the intake manifold causing smoke at startup)
Install new pump through the top without the pulley.
Install alternator and all electrical connections. (make sure multi connector seats fully)
Install pressure hose using new copper compression washers.
Install new return hose near rack if not already done.
Reinstall pressure hose tie down brackets.
Reconnect sway bar.
Cap reservoir return port.
Install 6 ft length of hose to return tubing from the rack near the pump.
(this will be use to bleed and flush the system)(lead to a 2 gal bucket)
Install pulley. (tighten the nut after the belt is re routed)
Re route the serpentine belt. (check torque on steering pump pulley )
Fill steering reservoir and put the end of the 6 ft. length of hose in a bucket.
Turn the wheel stop to stop and observe dirty fluid is pumped to the bucket.
Refill reservoir as necessary until fluid going to the bucket is clear.
Allow fluid level to drop below the return port and install 3/8 return hose after removing 6 ft. section.
Reconnect radiator hoses and refill with antifreeze.(check for leaks)
Reconnect the battery
Fill the reservoir and install the cap (If you don't, air in the return will foam and over flow the reservoir). Start the engine and turn wheel left to right several times to purge any remaining air from the system.
Re-service the reservoir to the proper level.
Check for leaks (fix as required)
Reinstall air duct and other plastic cowling
Test drive.
Check for leaks. (fix as required)
Check all fluid levels.
Reinstall bottom windshields.

Clean up and have a well-deserved beverage!

RODDMOD

Nice post !! I am sure we all thank you. The only thing I did not do was drain and pull the Rad hose.