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Replacing power steering pressure line - questions

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Old May 24, 2017 | 02:44 AM
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Replacing power steering pressure line - questions

Hello

I'd like to replace the power steering pressure line myself. I already have the new line. I wonder, will there be a lot of fluid coming out, when I remove the old line so that I'll have to replace all the fluid? And is there anything critical to know about this replacement? Like things to know about pulling the old line and getting the new one in? Is there enough room or will I have to remove something e.g. the alternator?

Thanks,
Thomas
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Old May 24, 2017 | 09:49 AM
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Re: Replacing power steering pressure line - questions

You will lose some fluid, but as it's on the pressure side of a positive displacement pump it will not drain the reservoir. On the other hand it's always good to change the fluid. I think most people just use Dexron - I use synthetic Amsoil trans fluid that is compatible with many specs including Dex III, etc.

It's certainly not a difficult job at all. Probably less than an hour.

GD
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Old May 24, 2017 | 11:13 AM
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Re: Replacing power steering pressure line - questions

Thanks! The part that I'm most afraid of, it to not overtighten the nuts as I can't use a torque wrench on the lines. But well, I think, I would see it, if it's not tightened enough. So I'd rather stay on the not too tight side.
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Old May 24, 2017 | 12:22 PM
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Engine: 350 Vortec, FIRST TPI, 325 RWHP
Transmission: 700R4 3000 stall.
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Re: Replacing power steering pressure line - questions

Leave it as loose as you dare and tighten just till it stops leaking.

Or as my old industrial shop forman used to say - tighten till you hear the casting crack then back 1/4 turn.

GD
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Old May 26, 2017 | 08:29 AM
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Re: Replacing power steering pressure line - questions

One last question: If I bleed the system... my manual doesn't say anything about whether to put the cap on the reservoir while idling the car and turning the wheels from right to left and vice versa. Does the reservoir have to be open while doing that to correctly bleed the system or does it HAVE to be closed with the cap?
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Old May 26, 2017 | 02:35 PM
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Re: Replacing power steering pressure line - questions

You can bleed it with the cap off or on. I put the cap on.

Not necessary, but you may want to lift the front of the car to get the tires off the ground while you turn the steering wheel.
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Old May 26, 2017 | 07:39 PM
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Re: Replacing power steering pressure line - questions

lift the front of the car to get the tires off the ground
^^^ This ^^^

The system is constant-flow. That is, the pump is pumping its full capacity of fluid at all times, through the HP line to the gear and back through the return line to the reservoir. If there's no load on the steering (i.e. the wheels are floating in the air) then the fluid flows and pushes all the air out. The pressure increases when there's load on it (i.e. a parking lot situation for example), it will go to several hundred psi. It SKYROCKETS to something like 1200 - 1400 psi when you turn the steering wheel to full lock and you hear that psssshhhhh sound of the bypass valve. BUT... if the pressure is allowed to become very high while there's air in the system, then the air gets pressurized TOO; and when the return fluid, all full of pressurized air, comes back to the reservoir, the air EXPLODES it into a foam, just like shaking up a bottle of champagne except about 50 times worse. That makes the fluid SPEW mercilessly.

I'd STRONGLY recommend replacing the return line while you're working on it. No sense changing the one line out, then 2 weeks later having to go back in again and do the other when it fails. Use REAL power steering return hose, NOT fuel line. Transmission fluid cooler hose will work too, it's the same stuff.

Lift the wheels; fill the reservoir as full as it will go; start the engine; add fluid until it's full. Turn the wheel back & forth almost all the way from lock to lock but DO NOT allow it to hit the stops!!! Keep adding fluid, make sure it stays full.

I usually leave the cap off so I can see if there are any bubbles. If there are, I shut the engine off and wait a few minutes until they all come to the top and the fluid itself is clear, then start it back up and continue the above process. Shouldn't take more than a few minutes to get all the air out.

Last edited by sofakingdom; May 26, 2017 at 07:43 PM.
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