Power Steering Troubleshooting Steps

[BLAD]

My 1988 3.0L Merc has always had a slow p/s leak (refill 1 to 2 x per season) but no other problems. Boat was warm garaged for last 10 years and now p/s doesn?t work at all. Reservoir now runs dry after only a few hours of operation and no p/s even when I refill. Can?t spot an obvious leak so maybe it?s in the oil cooler. Bilge is oily (I think) b/c of clumsy oil changes.

First startup after 10 years was with outdrive removed so I wedged garden hose directly into water intake on bell housing. Could I have damaged the oil cooler with high pressure from garden hose?

Since there is no p/s even after fluid is topped up and no high pressure leaks to be found, would you assume pump is definitely shot now or could a low pressure side leak or blockage cause this to?

Fairly sure steering cable and ram are OK - steering feels same with engine off as it always did. I had changed out the shift/throttle control and then tie-strapped the cables to steering cable but later removed them when I learned this was a no-no.

I'm out of ideas, is there more troubleshooting I can do or do I begin installing new parts one at a time?!?! Not sure of my next steps!


Thanks,
Brian

 

[Bt Doctur]

Re: Power Steering Troubleshooting Steps

The P/S system is a sealed one so there should be no loss of oil, clean the bilge spotless, especially around the steering unit. Oil cooler is possable to lead fluid into the raw water feed, simply remove and pressure test.P/S pump is usually a long life item and any leak would be visable.

 

[Bondo]

Re: Power Steering Troubleshooting Steps

Ayuh,... You've gotta find the Leak 1st,..
Then,...
You can remove the little Return line from the pump, direct into a container, start the motor,+ have someone turn the wheel...
You should see a nice solid flow....

I'd disconnect the end of the steering cable,+ make Sure there's no corrosion in the aluminum tube at the transom...

 

[gadget73]

Re: Power Steering Troubleshooting Steps

Just make sure its a decent size container, and the person at the helm can kill the ignition quickly if needed. Those pumps move a lot of fluid under full flow, and it won't take long before it runs the reservoir dry. If the container isn't large enough, it will just overflow and make a big mess.

 

[BLAD]

Re: Power Steering Troubleshooting Steps

Will definitely clean that bilge after I check the flow on the return side (sounds like a potentially messy test). Assuming I get low or no flow what would that tell me. . .blockage, big leak, pump shot etc?

 

[Don S]

Re: Power Steering Troubleshooting Steps

Why don't you go up to the adults only sticky at the top of this forum, and download the OEM service manual for your drive (manual #6) there is a whole section (6-A) in the manual on the power steering system. And in section 1-C there is troubleshooting tips.

 

[BLAD]

Re: Power Steering Troubleshooting Steps

I don?t see the ?adults only sticky? and haven?t been able to find manual #6 in a search, can you tell me where to download?

Cleaned the bilge this weekend and still couldn?t find leak but did find one loose and one missing bolt on the power steering pump. Belt still turned the pulley but maybe new/tightened bolts will do the trick.

There?s also a bit of play on the power steering unit where the steering cable goes in. The unit sways about 3 inches toward and away from the transom while steering. I believe some sway is normal but not sure how much?

 

[Don S]

Re: Power Steering Troubleshooting Steps