VanKo

Just replaced the power steering pump (AC Delco reman) and the hydroboost (AC Delco new). I followed the instructions I found on RockAuto’s website for bleeding. It seems to have stopped taking fluid and has remained at the full line after much turning the wheel and pumping the brakes. If it turn the wheel lock to lock, it makes noise when hitting full lock like it normally does. However, when I push the brake pedal, it makes the noise that full lock makes. It seems as if this noise is coming from the hydroboost but I can’t be sure. I don’t remember if it made this noise with the old pump and booster as I never listened for it. Any ideas?

SteveROntario

Do they call for you to pull vacuum on the system? That is common on Mopars to get the air out of the power steering.

VanKo

I have not found anything calling for a vacuum. These pumps are described as “self-bleeding” and only require moving the wheels back and forth and pumping the brakes. I only changed the pump and the hydroboost and did not touch or drain the steering gear box so there shouldn’t have been a lot of air in the system. I filled the pump and the reservoir and then followed the bleeding instructions but it’s still making a little noise. I also found a few articles that said this will happen until every single bit of air is out of the system which may take a few days. I will say however that the brakes are working so much better than before, I didn’t know how bad it was until I installed the new hydroboost.

VanKo

Update: it's been 3 days and about 100 miles and it's still making noise. The PS pump is making the noise. No bubbles at all in the fluid. It's new (ACDelco reman) - did I get a bad pump?

tech2

did you start the engine before performing the manual bleed? if you did the pump will pull air into the system. try vacuum bleeding it.

VanKo

I cranked it without starting as the instructions indicated. After doing that a few times I started it and went lock to lock (wheels off the ground) and pumped the brakes in the manner described. Apparently that wasn’t successful. I’m going to try vacuum bleeding it now.

tech2

any type of cranking pulls air into the system if you haven't manually bled first. you have to manually turn the steering wheel stop to stop 20x...top up fluid and repeat until the fluid level stabilizes.

when you vac bleed...pull a vac on the reservoir...wheel straight for 5min, wheel at stop to right for 5, left for 5 and straight for 5

VanKo

When I vac bleed it for the 3x 5 min, is this with engine running or off?

I’ve found several sets of instructions for doing this and they all say something different.

tech2

start will off.3 x5. start it, if still noisy, do it running

VanKo

I just started over from the beginning. Jacked it up, went lock to lock with the wheels 20 times with the ignition off.

Then did the vacuum 3x 5min center, right, left, then center. Checked the fluid, still full, no bubbles.

Then I started it, applied the vacuum, then did 10x lock to lock. Checked the fluid again, still full, no bubbles. Applied vacuum again and did the 3x 5min center, right, left center with the engine running. Still full, no bubbles.

Applied vacuum again and did 10 more lock to lock. Still full, no bubbles. At no point did I lose vacuum so I’m assuming that means no leaks.

Put it back on the ground and it’s still making noise at the same intensity. It makes more noise when I hit the brake pedal than when I turn. I’m new to hydroboost - how much noise is normal? Should it be totally silent? I’m at a loss here, I don’t know what else to do but change the pump again. To be honest the noise doesn’t bother me, it’s the trouble that usually follows power steering noise. If this noise is normal, or if I can add something like Lucas to quiet it down, I can live with the noise.