Help me diagnose a power steering issue

LaRea

Recommissioning my 370 after a major rebuild with new transom assemblies ... the power steering feels stiff and jerky.  It goes through the full range of motion, but the steering effort is too high, and it feels jerky and uneven.

It's not a pump issue.  Today I swapped the port steering pump over the starboard side, and it didn't help.  The hydraulic fluid is new.  I don't see air bubbles in the steering fluid reservoir, and I've already worked the wheel back and forth about 1000 times.  I fixed a slight kink in the hydraulic line to the cooler ... no joy.  

What would make the steering feel jerky and uneven?  

aero3113

What happens if you raise the RPM’s? It shouldn’t matter but it might make a difference in you situation.

Dream_Inn

Something maybe with the power steering cooler?  Could be inhibiting flow?

aero3113

Were the steering arms easy to move by hand on your new transom assemblies?

Handymans342

Definitely a blockage. Hard to find with out gauges

Handymans342

It could also be a valve sticking in the hydraulic assist arm. 

LaRea

I'll try to describe it in terms of force are needed to turn the wheel:

No power steering, 20 pounds
Normal power steering, less than 1 pound
My steering:  5 pounds, but sometimes it briefly drops to 1 pound 

That's why I say it feels jerky.  While I'm turning the wheel, sometimes it will feel "normal" for just a fraction of a second, then back to 5 pounds of effort.  

A problem with the steering cable or transom assemblies would be a constant force, so I think it has to be hydraulics.  @Handymans342 it could be in issue with the ram after sitting in my attic for five months.  

How would I test the pressure?

PickleRick

You had it all apart and empty, what's the chances it just needs to be bled more? air pockets in the lines = no power steering until they pass.  

Start the motors at the dock, idle rpm and slowly clock the steering from left to right for the duration of your favorite power rock ballad.  "Don't stop believing" that it's something simple. 

I just rebuit my trim cylinders and it took maybe 10 min up and down working  to get it to stop  whining under load.  

Ive had cars that needed a few days to fully purge after swapping a power steering pump

goalie59

Larea, does it make any difference if you have the wheel tilted. I have a bad u-joint in my steering tilt mechanism and if the steering tilt is not completely straight it causes an issue, it's a long shot but something you might want to check

LaRea

@PickleRick I will try that today.  "Red Streamliner" by Little Feat is five minutes long ... that ought to do it.  

davidbrooks

I am agreeing with @PickleRick really sounds like you are chasing an air bubble. I'm sure you've done this but keep turning the wheel hard starboard and hold it under pressure and then hard port and hold it under pressure at least a dozen times and see if it helps to smooth things out.

Handymans342

It will probably go away after Hotel California and a cold beer. As far as checking pressures, its impossible with out the proper gauges installed. There are no ports. Your Ram is probably ready to be replaced 

Liberty44140

Whatever you listen to just make sure there ate lyrics. I am close to writing in a complaint to the Margaritaville channel about Santana like songs with no lyrics. I'd listen to a rock station of I wanted that crap. Good luck LR....

Grahamu

I would run the engine at 1000 RPM going thru full turns both ways several times bring the drives to center and remove the vented reservoir cap to let any air escape or check for bubbles. You might have to do it more than once.

Grahamu

This might help, not your engine but I think the process would be the same.

Filling And Bleeding - Mercury MerCruiser MCM 4.3L ALPHA Service Manual [Page 16] | ManualsLib

aero3113

Can you bleed the lines in different areas? Crack them open and let some fluid out under pressure.

LaRea

I just got my second upper-body workout of the day -- no joy. 

I ran the engine at high idle and cranked that wheel every way I could for about 15 minutes:  slow, fast, pinned against the end stops, you name it, I tried it.  There are no bubbles in the reservoir, and it's still really hard to move the wheel.  

@goalie59 the wheel tilt position didn't change anything.  

aero3113

@LaRea , was any work done to the actuator? Was it rebuilt? 

LaRea

To my knowledge, no work has ever been done on the actuator.  Do you think I should look at rebuilding or replacing it?

Handymans342

Did you disconnect the steering cables and turn wheel?

aero3113

Maybe you have a weak hose collapsing?

Handymans342

I guess @LaRea dissapeared. 

Handymans342

@Alswagg will know the answer for this

LaRea

Ok definitely not the cable. What could cause binding in the transoms?

aero3113

Steering pin too tight?

Grahamu

Did you disconnect the tie rod and try the steering with one drive connected?

LaRea

Pump problem is unlikely (Swapped power steering pumps port to stbd, no change.)

Not a steering cable problem (Wheel moves freely when cable is disconnected from actuator.)

Not a problem with the port transom assembly (Port steering pin moves freely by hand when disconnected from tie rod.)

Not an autopilot issue (Autopilot cable moves freely by hand.)

No visible interference or binding in the tie rod or other components.

By process of elimination, it has to be the power assist actuator.  There's still an air bubble, or maybe a piece of debris somewhere inside the actuator.  

PickleRick

Any chance a hose was twisted/over extend or pinched/kinked causing the issue?  I don't know if having hoses at the steering ram crossed is possible or would affect anyting if it was. 

LaRea

It's not possible to cross-connect, but I'll double-check the hoses. 

Dream_Inn

Well. I mentioned the power steering cooler earlier with no response.  Chance there is s clog or kink inside ot?  Not the water cooled side but the fluid coil side.

212rowboat

Iirc there is a little flat spot on the ram that needs to be matched up with the top of the ram body.... er... uh... something like that.  If it isn't, you'll get herky jerky steering... I can't recall exactly, but indexing the eyelet to the body makes a big difference, however it's done.  I'm sure it's in a manual somewhere, which is where I recall it from.  I bought a new system last year when the steering cable snapped, and found the one on it was fine- jist wasn't indexed correctly.