After searching the forum heavily for hints on why my P/S pump started growling after a timing belt replacement, I found the most common answers were (1) bleed the system (2) flush the fluid (3) Replace the inlet nipple o-ring. I came upon a fourth possibility if you have just removed and reinstalled the pump without disconnecting the hoses. My theory is that if the front pump bushing/bearing is at all iffy, tightening the belt too much MAY cause enough misalignment to let it suck in a little air through the seal. I had the wrong P/S belt when I did the timing belt so used the old one. P/S pump made tons of noise. Tried all the fixes to no avail. As it turned out, when I got the new P/S belt, I noticed that I had put the old one on too tightly. After replacing the belt with correct tension, I bled the system (engine off, front wheels off the ground, 100 turns lock to lock) and the noise seems to be gone. This may be a rare occurrance, but worth considering as a last resort before replacing a pump.

 

Thanks for posting.

PS noise can be tricky. A slow leak can lower fluid level in reservoir to point where air gets pulled in also.

good luck

 

There is an updated hi temp (red) o ring on the inlet side. .94 cents. Try that. My old one did not look bad.