Author Topic: Power Steering Pump Problems - bleeding air from the pump or damaged pump?  (Read 11957 times)

Dave69x33

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I recently rebuilt the 302 in my 69Z.  During the process, I removed the power steering (PS) pump and hoses, and all the engine pulleys, misc brackets, etc. were stripped and repainted.

I installed the PS pump and connected the hoses, filled the PS pump reservoir and bleed the reservoir by hand rotating the pulley counter clockwise.  The reservoir was topped off to about 2" from the top, or somewhere between the "cold" and "hot" level marks on the cap stick. 

When I fired the engine for the first time for the 20 - 30 minute break-in period, I failed to only run the engine for a few second and check the PS level, as I was concerned about a small fuel line leak, checking the timing, and setting the carb idle to 2000 - 2500 RPM.  When I shut the engine off after the break-in, and checked the PS fluid level, it was very low but the reservoir still had about ˝” - 1" of fluid.  I topped off the fluid level and continued the PS steering system bleeding process with the front tires off the ground and turning the steering wheel back and forth between the locks with the engine running at 1500 RPM.

The engine runs great but I may have damaged the PS pump.  The pump works fine with the tires off the ground but it squeals and intermittently loose power steering if I turn the wheel with the tires on the ground.  I bled the pump and system again but this did not help.  It helps if the motor RPM is increased while turning the steering wheel but the problem still exists.

The PS belt has stretched and the pump bracket is adjusted near the end of the slot.  The belt is snug but not tight, with about ˝” or less up and down movement midway between the pulleys.   The pump worked fine before the engine was pulled for the rebuild. I’ll try a new belt but I am not hopeful this will cure the problem.

Could there still be air in the system?

Is it possible the PS pump rotor or housing was scored during my engine break-in creating a pressure leak path?

Per the maintenance manual, a V-8 Camaro with the variable ratio needs 1350 – 1450 p.s.i. pump pressure to function properly.  I don’t have an in-line pressure gage to check the pump pressure as outlined in the service manual.

If the pump is damaged, can it be rebuilt or should it be replaced?


 

tmodel66

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Do you have paint in the groove of the pulley? I have seen paint cause the belt to slip so bad it's not running the pump at the right RPM. New belt and clean the paint out of the groove.
Daniel  
'69 SS 350/4 speed  Fathom Green--POP

bertfam

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Dave, I just went through this on my son's 68. (He ruptered the pressure hose so we had to start basically from scratch)

1. It's easier if you have two people do this because when you top off the fluid, once you start the car it's going to go down. In our case it went down a LOT!! I had to keep adding until it finally stabilized.

2. When you turn the wheels lock to lock, don't go very fast. I found it's better if you go fairly slow.

3. And again, when you go lock to lock, DON'T actually hit the stops. That puts additional pressure on the system and can cause damage.

Our system must have been totally empty because it took just under 2 quarts to get it back to the correct level, and around 20 minutes of bleeding back and forth!

Ed
Ed "Bert" Bertrand
email me!

Boston14

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This is a method that has worked for me for over 40 years as a professional tech.  First, fill the reservoir, start the engine, turn the wheels lock to lock, then shut the car off and let it sit to allow the air bubbles to rise to the reservoir ( about 10 minutes or so).  Then top off the fluid and repeat the process until bubbles are gone.  As Ed stated, there is no need to max out the pump pressure by holding the wheels against the stops.  After following this process 2 or three times, the air will be gone from the system and it should be smooth and quiet.  Also make sure your belt is clean and tight.

boston14
boston14

1969 SS/RS 350 Convertible
Dover White with Black Top and D90 stripe, Red Standard Interior

Dave69x33

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Thanks Guys. 

My pulley does not have paint in the V-groove but my used belt has stretched and may not be tight enough. It is a Quanta restoration belt (item #29-B-453) with the GM emblem and part number 3848263 embossed in the belt.  It looks good for show and originality, but I’ll replace it to test for a slipping belt issue.  I’ll perform the bleeding again as Boston14 and Ed have suggested.   I have performed this bleeding method twice but I’ll do it again slowly with time in between the bleeding cycles.

I dissassembled my original PS pump yesterday to see how the pump works.  I took some pictures and I’ll post them sometime soon for reference.  My original reservoir has some dents and rust pits in it and not in “show quality” condition, and it leaked from the o-ring seal between reservoir and pump.  I buying a new PS Pump Seal kit, and if the problems persist with the PS pump I have on the car, I'll swap the pumps in my good reservoir, bleed, and test the original pump.

Below is an informative link regarding the flow and pressure requirements for N44 Z28 fast ratio PS pumps.  It includes modification needed if you purchase an aftermarket remanufactured PS pump that may not be calibrated correctly for a Z28 with N44.  Last summer, I performed these modifications on the pump I have on my car now, and the power steering worked flawlessly up until I recently pulled the pump and hoses during the engine rebuild, and detailing of the pulleys, brackets, etc.  Prior to making these modifications, the PS would intermittently squeal and loose power steering if I made a parallel parking maneuver.  Maybe this is all due to a slipping belt!

I’ll keep you posted.

Link: http://www.pozziracing.com/camaro_steering.htm#Steering


Dave

Dave69x33

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I fixed my power steering (PS) pump problem.  A tech tip from Cardone was helpful, which is a major US manufacturer of new and reman pump and various other automotive components. 

Here is a link to the tech tip I followed to fix my issue: http://www.cardone.com/tech-help/steering/how-it-works-best-practices/steering-system-flushing-use-the-buddy-system

Before removing and replacing my pump (which worked prior to removing it before pulling and rebuilding the engine this past summer) I thought I would try Cardone's PS pump flush process then bleed the system again.  I followed the flushing process and replaced the PS belt to make it was snug, and my PS now works great.

I did not have a "buddy" to assist as the Cardone's tech tip suggested, so I had to take my time to do the process solo.  To flush the system and remove any trapped air in my PS gear box, I followed this process.  It is similar to the process that Boston14 and Ed have offered above.  Removed the PS pump return hose from the pump and directed it into a catch pan.  Quickly after pulling the hose pushed a rubber plug over the outlet tube on the PS pump reservoir.  It is a messy process so you have to prepare.  I lined my front suspension area under the pump with a plastic trash bag and some paper towels to catch and absorb the leaking fluid.  Top off the PS reservoir level to within about 1” from the top of the reservoir.  Disconnect the coil wire to prevent the engine from starting, and crank it for about 10 seconds.  Check and top off the PS fluid level as needed.  Check the fluid in catch pan to see if it is dirty or discolored. 

I did not get much drainage while cranking the engine because I did not want to continue to crank the engine for extended periods while turning the steering wheel lock-to-lock to pump the fluid thru the PS gear box.  After cranking the engine, I left the key in the ON position so I could turn the wheel lock-to-lock 2 – 3 times which pumped and flushed the old fluid out of the PS gear box.  I continually checked and topped off the fluid level in the reservoir, then cranked the engine again for about 10 seconds, followed by rotating the steering wheel lock-to-lock 2 -3 times.  I followed this flushing process 3 – 4 times which completely flushed the PS gearbox and reservoir of the old fluid until clean fluid was observed in the catch pan.  Drain and wipe the catch pan clean each cycle to help determine if the fluid drained is clean. You may use up to a quart of PS fluid during the flushing process so it wise to have two quarts on hand.  You will learn on Cardone’s website that not all PS fluids are created equal so buy a quality fluid.  PS fluids are not regulated with API Service ratings like motor oils so chose your fluid wisely and do your homework.

Once you verify the fluid is clean from flushing process, reinstall the PS return hose the reservoir and make sure the holes clamps on both ends of the holes are tight so they do not suck in air.  If your hose is old, hard, and brittle, is wise to replace it. 

Now follow the bleeding process as outline in the Chevrolet Service Manual which involves lifting the front wheels off the pavement.  Reconnect the coil wire and verify the PS fluid level is at the correct level (some where between the COLD and HOT level on the cap stick) Start the engine for only about 2 – 3 seconds then top off the fluid level if necessary.  I stated my car again for only about 5 -10 seconds and the verified the fluid level was correct. It is critical that you do not rotate the pump and suck the reservoir dry of fluid and damage the pump.

Start and run the engine at 1500 RPM (temporarily set your idle speed if necessary to maintain 1500 RPM) and then SLOWLY rotate the sheering wheel lock-to-lock several times.  Do not hold the wheel against the stop for extended period as this only generate high pressure in the system and does not help the bleeding process.  Simply rotate the steering wheel slowly toward the locks to get full gear box rotation. Shut off the engine and allow the PS fluid to settle and verify the level on the cap stick.  Check for bubbles in the fluid or foaming.  Foaming in the fluid may be a sigh of other problems that you can read about on the Cardone website. Restart the engine and follow the bleeding process 2 – 3 more times, shutting off the engine in between the bleeding cycles.  Always make sure the fluid level is maintained.

After bleeding is completed, lower the car with the front wheels on the pavement, preferably a smooth garage floor.  Start the engine and rotate the wheels under the resistance of the pavement and you should experience smooth PS action lock-to-lock with no squealing or grinding sounds.  If you continue to have PS system issues, it may require bleeding again so be patient. 

This process helped me and I hope you find it helpful.