Cannot bleed power steering system

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Jul 16, 2018 | 09:29 PM

mkoecher

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Cannot bleed power steering system

I have a 1976 F250 with the power assist steering system in it. In the last year I have replaced the power steering lines from the control valve to the power cylinder. I've also had Lars rebuild my control valve and installed it. When I installed the control valve I had no issues bleeding the system and did it in a couple of minutes.

I just barely got a rebuilt power cylinder from Lars and installed it over the weekend, but now it is practically like I have no power steering at all. I figure there is still air in the system but I have tried bleeding for quite a bit. On rare occasion it gets really easy and smooth just for a second which makes me think there is still air in the system. Here are the things I 've tried:

Bleeding by lifting the tires off the ground and turning the wheel stop to stop with the engine off
Doing the same thing with the engine on
I read that someone recommended turning the wheels with the engine off. I did that but if I did it too fast fluid would come out of the fill neck. (is this to be expected? I might have had it overfilled at that time)
I learned that it should have Type F ATF instead of power steering fluid so I pulled the return line from the pump had my buddy crank it while I filled it with Type F to replace the power steering fluid.
Tried re-bleeding
I even loosed the line at the power cylinder to see if it was red with the new ATF instead of clear with the power steering fluid and it was so I think fluid is getting there.

I'm at my wits end. I dont know what else to do. Should it be this difficult to bleed the system? Any other ideas what to do?

Jul 17, 2018 | 07:05 PM

flatbedfordguy

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You have properly bled the system multiple times, no question. If I am reading your post correctly this all started after installing the Lares power cylinder, correct?

So that's where I would focus my attention. I hate to be the bearer of bad news but Lares rebuilds are dubious at best, they are akin to a "reseal and repaint" rebuild you would buy from the likes of Checkers or Autozone.

If you can I would get a refund and buy a power cylinder from Blue-Top Steering Gears. Much better quality than Lares. Blue-Top Steering Gears, Inc.

Jul 17, 2018 | 08:59 PM

jakeharp

Fleet Mechanic

Joined: Aug 2004

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From: Nevada

Bleeding on my 76' was easy peesy, just turned the wheels to lock both directions with truck on jacks and done... Im with FlatBed, you may have a bad re-build. Had Box, Cylinder and Valve rebuilt last fall and then bled after install and zero issues.. I hope we are wrong and you can track it down... That whole system is a chore from start to finish so i understand your frustration...

Jul 20, 2018 | 08:31 AM

mkoecher

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I was afraid that was the answer. I didn't know about Blue-Top Steering so I was afraid I didn't have any other options if the Lares one was bad. Thanks for the heads up. I'll bite the bullet on price and start the process of returning and getting the one from Blue-Top and let you guys know how it goes. Thanks for the help.

Jul 21, 2018 | 07:39 PM

flatbedfordguy

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If I had to guess I would guess the piston seal is leaking, if that's the case you can bleed the system repeatedly and it will still feel like you have no power steering because the hydraulic fluid is simply bypassing the piston seal.

Lares Corp does not cut these cylinders open and rebuild the internals, they simply re-seal the rod end and re-paint the cylinder, that's it! some times that may be enough. But if the piston seal is leaking it's not enough!

Ryan @Blue-Top cuts open the cylinders and rebuilds the internals (piston seals) whether they need it or not, he also machines a new hardened chrome rod, whether it needs it or not, he then welds the cylinder closed, This rebuild also includes TWO seals on the rod end (double the factory) and new seats for the hydraulic hoses.

This is far more than a simple "rebuild" it's actually a "new" cylinder when he's done. For $280 you cannot go wrong in my opinion.

Jul 26, 2018 | 11:29 PM

mkoecher

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flatbedfordguy you were right. I put the Blue Top power cylinder in and everything is right in the world again with the power steering. Thanks for the help.

Just for those that may read this in the future. My original power cylinder worked well except that it leaked. I noticed when I took it out that it was pretty difficult to push and pull the rod in and out. I didn't know if that was good or bad.

The Lares rebuilt power cylinder was very easy to push the rod in and out. Based on the results of installing and it not working it I believe this indicates a bad internal seal.

The Blue Top rebuild was very tough to push in and out by hand as well and it works great. So long story short if you get a rebuild and you can easily push the rod in and out it probably is bad.

Jul 27, 2018 | 12:10 AM

mark a.

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If you think there is air in it and you just cant get it out then you need to put vacuum to it. Mityvac makes an adapter for their hand pump and a small plastic catch can usually comes with their hand pumps. You can use engine vacuum and make up a catch can and some way to get it hooked up to the pump without it leaking, you don't want to suck fluid into the engine. Go to youtube and type in bleeding powersteering there are lots of videos on it.