Testing later model power steering booster

[dave8311]

I have the Mercruiser Service Manual #14 for sterndrives, but the instructions for the booster cylinder test are for the old style, nothing for the new style.

There are instructions for other tests on the new style but they don't include the booster test for the new one, unless I'm missing something.

Is there a different manual for the new style?

 

[flashback]

I guess we would need to know what new style you have?

 

[dave8311]

 

[04fxdwgi25]

Not sure you will find a manual on the breakdown / repair of the unit. Mercruiser manual states that section is "non-servicable" and must be replaced as a unit.

As a side note: I believe that the biggest engineering / design failure of the assy is there are no alignment guides or even alignment marks indicating exactly when the steering tube / valve shuttle channel cutouts are properly aligned in the assy. Just hold it straight with a wrench (and eyeball it) when tightening the steering cable. Nothing prevents it from twisting and getting out of alignment except the steering cable housing. The retaining nut torque on that spring must also be precise to maintain proper alignment.

 

[dave8311]

Yeah, I understand all that, and I know you can't repair it, nor would I even want to, I'll just swap it out for another unit. But when you get to the testing and troubleshooting section of the power steering system, there is a section to test the old cylinder to rule out that being the failure point. There is no such test for the new type cylinder, so I guess you are supposed to replace the cylinder, and hope that fixes the problem.

 

[04fxdwgi25]

The pressure test on the line from the pump would be the same.

I tested mine by disconnecting the steering cable and manually moved the steering tube / slide back and fourth (carefully because it can bite your hand) to see if it actuated the steering assist and it did.

Eliminated it or pump being the problem and it was the cable.

 

[dave8311]

Ok, with the clevis pins removed the drive swings freely from side to side, the pump pressures test good, the valve moves in and out manually ( I push and pull on the cable housing, so my fingers are out of the way) and the ram extends and retracts, and with the pin back in it swings the drive back and forth, then it has to be the helm/cable? The cable seems to be usable as I can turn the wheel with one finger, but I guess I'll try that, first.

 

[flashback]

The cable sheath is probably grooved and binds up. Have a helper create some resistance and then give the helm a spin..

 

[04fxdwgi25]

Ok, with the clevis pins removed the drive swings freely from side to side, the pump pressures test good, the valve moves in and out manually ( I push and pull on the cable housing, so my fingers are out of the way) and the ram extends and retracts, and with the pin back in it swings the drive back and forth, then it has to be the helm/cable? The cable seems to be usable as I can turn the wheel with one finger, but I guess I'll try that, first.

Has the pump pressure been tested? Process should be same on old and new.

Has the inside of steering tube been cleaned really clean and lubed up with new grease? 12 Gauge shotgun brushes work well. If there is any binding in there, it screws everything up.

 

[dave8311]

Ok, so the test that begins on page 6A-27 Boost Cylinder Test does not apply to the new style cylinder and there is no similar test for the new style.

If it passes the pump pressure tests then the cylinder is considered to be good and doesn't need replacing?

 

[04fxdwgi25]

Ok, so the test that begins on page 6A-27 Boost Cylinder Test does not apply to the new style cylinder and there is no similar test for the new style.

If it passes the pump pressure tests then the cylinder is considered to be good and doesn't need replacing?

Didn't say that. pump pressure test gives the pump a pass.

In the absence of a clearly defined test procedure:
After removing clevis pin from cable end, removing cable from tube and manually moving the steering tube, while engine is running, will see if the assy moves hydraulically. That will verify the assy is working.

Only thing(s) left if you get a pass on those 2 is the steering cable / helm.

 

[dave8311]

Yes, all tests passed.

I guess I'll try a new helm and cable.