Purge/bleed power steering system

[ncrobb]

I put a new power steering gear, pump and lines on my ‘73 Road Runner. I added fluid and started the engine then shut it off to check the fluid level. I added some and I guess put too much in. Then I started the engine and did the turn it lock to lock to try and purge the air out. I turned it lock to lock for at least 5 minutes and when I stopped it was still making noises and resistance to turning still varyied. When I went to check the level the fluid had frothed up and pushed out of the reservoir. I let it sit over night, did not add any fluid and didn’t the same procedure getting the same results. When I checked the fluid it didn’t seem as frothy. I wiped up the mess and went for a test drive. The steering is firmer than before I changed the components and still makes some noise when turned. Is there a trick to purging the system? At least it isn’t pushing out the cap and the fluid doesn't look as frothy.

 

[Master Gunner]

Turning lock to lock is the only way I have ever done it, but it will take a while to work all the air out. As long as the fittings are tight, and the gear seals are good, it should smooth out.

Mark

 

[Don Frelier]

5 minutes is a long time.
I usually just go back and forth about 3 or 4 times and then drive it.
Did you have it jacked up initially?

 

[ncrobb]

5 minutes is a long time.
I usually just go back and forth about 3 or 4 times and then drive it.
Did you have it jacked up initially?

No, I had the tires on pieces of cardboard on concrete shop floor. I’m going to do the lock to lock process again and will jack up the front end.

 

[Don Frelier]

No, I had the tires on pieces of cardboard on concrete shop floor. I’m going to do the lock to lock process again and will jack up the front end.

I would think that the air entrainment would have worked it's way out by now. Try leaving the cap off and watch it.

 

[RJRENTON]

I put a new power steering gear, pump and lines on my ‘73 Road Runner. I added fluid and started the engine then shut it off to check the fluid level. I added some and I guess put too much in. Then I started the engine and did the turn it lock to lock to try and purge the air out. I turned it lock to lock for at least 5 minutes and when I stopped it was still making noises and resistance to turning still varyied. When I went to check the level the fluid had frothed up and pushed out of the reservoir. I let it sit over night, did not add any fluid and didn’t the same procedure getting the same results. When I checked the fluid it didn’t seem as frothy. I wiped up the mess and went for a test drive. The steering is firmer than before I changed the components and still makes some noise when turned. Is there a trick to purging the system? At least it isn’t pushing out the cap and the fluid doesn't look as frothy.

Out of curiosity, what type of fluid dud you use? Hopefully not ATF (any variety). Power steering fluid is actually hydraulic oil, modified to approximately SAE 20W viscosity, with anti wear, anti foam additives for temperature and pressure stabilization. Usually specified as ISO-VIS 46 (International Standards Orginization or an API equilivant).......but NOT ATF......in spite of what you've been told or heard.......
BOB RENTON

 

[ncrobb]

It’s Prestone brand power steering fluid. Says it’s compatible with all types and manufacturers.

 

[ncrobb]

I took the cap off to watch what was happening and saw the pump was picking all the fluid into the system and emptying the reservoir. When I shut the engine off all the fluid rushes back into the reservoir and over flowed. I took a chance and added fluid with a long funnel while it was running thinking the worse that could happen was it would just get forced out. Some magic happened as I turned it lock to lock - I guess the level was above the ports and the air lock got pushed out. She’s back to working like it used to.

 

[themechanic]

If I recall correctly, you purge the system without starting the engine.

 

[Don Frelier]

If I recall correctly, you purge the system without starting the engine.

No you need to run the pump.

 

[themechanic]

No you need to run the pump.

Right. Brain fart.

 

[themechanic]

This may be helpful.

Steering Box install question(s)

I ordered a new steering box, hoping to get rid of some of the slop in my OE steering (the coupler has already been rebuilt). 1969 Road Runner 383 with Hedman headers & power steering... Questions (my first time doing this): 1) Looks like the battery tray & power steering pump will have to...

www.forbbodiesonly.com

 

[ncrobb]

This may be helpful.

http://[URL]https://www.forbbodieso...box-install-question-s.181655/#post-911395549

[/URL]

Good info. I bet that “spin the engine without coil connected” process would have saved me some grief.

 

[Kern Dog]

Out of curiosity, what type of fluid dud you use? Hopefully not ATF (any variety). Power steering fluid is actually hydraulic oil, modified to approximately SAE 20W viscosity, with anti wear, anti foam additives for temperature and pressure stabilization. Usually specified as ISO-VIS 46 (International Standards Orginization or an API equilivant).......but NOT ATF......in spite of what you've been told or heard.......
BOB RENTON

Rick Ehrenberg, another "engineer", stated that with the Borgeson steering box, any P/S or transmission fluid is fine.....even cheap Wal Mart ATF.
He is wrong about that?