Pesky Power Steering Problem

[cjwagner1962]

2003 Chaparral Signature 240. VP 5.7 GXi 320 hp. VP DPSMHP. Engine and drive have less than 200 hrs. I bought this boat 3 years ago and have been dealing with stiff power steering ever since. There is some power assist, especially when turning the wheel quickly but then it stiffens up again. I disconnected and pulled the steering cable rod out of the power assist cylinder. The steering wheel turns freely and easily with no binding. The rod is well lubed and moves back and forth freely as the steering wheel is turned. I disconnected the drive from the power assist cylinder. The drive moves freely by hand from side to side so no binding issues there. The shuttle valve moves freely by hand the required distance, about 3/16" each way from the neutral position. It settles into the center position after moving it. It does require some effort to move the shuttle valve from side to side and as it returns to center, I imagine the return springs are in good order. There are no leaks in the system. The fluid has been drained and new fluid added along with some fluid conditioner. They system has been bled. I rigged a pressure gauge inline with the high pressure line. While running at idle, the pressure is 75 psi. When I move the steering wheel, the pressure does not increase much. When I hit the turning lock on the steering wheel, the pressure spikes to 800 plus psi.

The stiffness in the steering is fairly constant. No surges, pulsations, etc. Doesn't change going either left or right.

This system acts like it is not getting enough pressure. What is the correct pump idle pressure? 75 seems low. The manual says 50-100 psi. When moving the wheel, what should the pressure rise to? I don't see any rise. I believe there is something keeping the pump from building pressure with normal steering inputs but does spike to over 800 psi when the steering lock is hit.

Can someone please help?

Thanks,

Chris

 

[Bondo]

Ayuh,.... Welcome Aboard,..... It certainly sounds like you've covered all the usual bases,....

Dumb question, but is the belt tight,..?? very old or grazed,..??

75 psi sure sounds alright when 50 to 100 psi is called for,....

 

[cjwagner1962]

Ayuh,.... Welcome Aboard,..... It certainly sounds like you've covered all the usual bases,....

Dumb question, but is the belt tight,..?? very old or grazed,..??

75 psi sure sounds alright when 50 to 100 psi is called for,....

Belt is good. No slipping. I went ahead and replaced the power steering pump yesterday thinking for sure that was the problem. It wasn't. No change. One thing I forgot to mention in my first post. When turning the steering wheel hard and quick in either direction, I seem to get nice power assist for a brief moment, then it goes away again. With small inputs to the steering wheel I get no power assist. Maybe it is the shuttle (spool) valve on the power assist cylinder. How do I check this? It appears to be moving correctly in both directions with input to the steering wheel.

Thanks, Chris