Logo
FULL SITE MENU

Power Steering issue

W

Wilton

New member
On my 5.0 GL the low pressure hose developed crack and pin hole leaks. Lost fluid in reservoir. I replaced with fuel line hose rated at 72 psi and hose clamps on both ends. Hose burst. Replaced with 400 psi hose and it blew off one of the clamped ends. Bought factory replacement hose with swagged on fitting. It blew off the hose clamp end. What will cause excess pressure in the power steering system to result in these experiences. What is proper way to bleed the air out of the system? Could air cause excess pressure build up? Could original leaks be from excess pressure?
Thanks.
 
You are asking about a Power Assist steering system, correct? Not a Hydraulic steering system, correct?

If yes..... the return hose should not be under any substantial pressure.

Air should self purge with the operation of the slave valve.... I.E., turning the helm wheel.
 
Thanks Rick.
Yes - Power Assist. What can cause excess pressure. I did turn the wheel several times so hopefully air was purged. But hose still blew off the hose clamp end.
 
Without actually seeing your system, I can't answer that question. Sorry!


The belt driven pump at the engine is a hydraulic vane pump.
It supplies hydraulic fluid pressure to the slave valve.
When the slave valve is actuated (by the steering cable), hydraulid fluid and pressure is delivered to one side or the other of the hydraulic cylinder.
The cylinder then "assists" in the movement of the spindle or tiller arm.
Any returning fluid, or by-passing fluid, is sent back to the pump's reservoir.
This would be via the "return" line.
This return line should see only mild pressure.


.
 
Last edited:
My SWAG would be a stuck valve in the slave cylinder... assuming you didn't somehow get the inlet and return lines swapped.
 
Capt Bob
Thanks. Your SWAG could be accurate. One question though. Is it possible that if the system were not bled properly of air that pressure could build up in the return line. I don't think it is possible to swap the inlet and return lines since they appear to have different size fittings, but also the inlet line has not been removed. When this first happened, the boat was operated for about 30 minutes and with each subsequent loss of fluid, it was operated for a short time. Could that contribute to the stuck valve possibility.
 
Wilton said:
Capt Bob
Thanks. Your SWAG could be accurate. One question though. Is it possible that if the system were not bled properly of air that pressure could build up in the return line. I don't think it is possible to swap the inlet and return lines since they appear to have different size fittings, but also the inlet line has not been removed. When this first happened, the boat was operated for about 30 minutes and with each subsequent loss of fluid, it was operated for a short time. Could that contribute to the stuck valve possibility.
Click to expand...

Ayuh,... Is this happenin' at the Pump's return port,..??

That port should be Open to the reservoir,.....

The P/S system is bled/ purged by turnin' the wheel full lock a couple of times,...
With the motor, Not runnin',....

Is there a P/S Cooler in the system,..??
 
bondo said:
Ayuh,... Is this happenin' at the Pump's return port,..??

That port should be Open to the reservoir,.....

The P/S system is bled/ purged by turnin' the wheel full lock a couple of times,...
With the motor, Not runnin',....

Is there a P/S Cooler in the system,..??
Click to expand...

Yes - there is a cooler. This is all new territory for me so I probably don't communicate all that is needed. However, based on the experience I have had (mainly that one hose I installed blew out while both ends remained connected) says that there is way too much pressure in the hose. Which probably speaks to an internal part failure that sends high pressure down that hose.
 
Bill makes a good point.

At the return side, fluid must make it's way back to the reservior.

But let's look at the pressure side for a minute.
Pressure is delivered from the pump to the slave valve. If the slave valve is not called upon, this pressure remains minimal, and the fluid simply returns to the reservior.

When the slave valve is called upon, pressure/volume is delivered to the hydraulic cylinder, where it then provides movement to the cylinder piston.
And again, what is not used, is returned to the reservior.

Now comes the fluid cooler that is in the seawater path.

All return goes through the oil cooler prior to returning to the reservior. This is where heat is dumped.
This is considered to be the low pressure side.
If there was a restriction at either the oil cooler inlet, or at the reservior inlet......, this low pressure side now becomes pressurized beyond it's capability.
Since the low pressure side hoses and/or fittings/clamps are not intended to handle more than low pressure, something would have to give!

This takes me to either the oil cooler inlet, or to the reservior inlet.
Unlikely.... but possibly a hose that has encountered interior delamination.


I'll suggest that you look into the return side. Hoses.... cooler inlet... reservior inlet!


.
 
Last edited:
Back
Top