Best way to flush/bleed power steering fluid?

[Beetle-Kill]

Pump went out on my '83 Chevy K-30. New pump is in place, and I'll need to bleed it tomorrow.
Ideas? I do NOT want to yank the hi-pressure line off the pump again.
It is tied into a Hydro-boost master cylinder, if that helps.
Thanks, JB

 

[nate379]

Pull off return pump, cap the pump. Put return in a pail. Fill reservoir, have helper fire up truck while you pour fluid in. Shut off before it runs dry.

 

[Beetle-Kill]

Thanks Nate.
This pump has 2 returns, and a remote resevoir.
I need to do this on my own, my "help" are either out of state or working tomorrow. Just my luck.
I'm thinkin' the far end run return will go into a jar of fluid, with the pump fitting capped off. Crank and bleed, get some of the air out and when I see fluid out of the far end hose, re-fit it to the return. That's my plan as of now.

 

[nate379]

Also after you flush it put front end on jack stands and turn it lock to lock 5-6 times without engine running.
Do the same with engine running, also hold the brake pedal down a bit (will bleed the hydro boost). Just keep an eye on the fluid level. If it gets foamy, shut it off and let it sit for a bit.


With 2 returns can pull them both. I'm guessing one for steering box and one for brakes? It's been a few years since I worked on an older hydro boost Chev.

 

[nate379]

Return just needs to go in something to collect it. Keep putting new oil in till it comes out clean. Can cycle the steering lock to lock as well.
It's not really critical to get a 100% flush unless something tore apart and sent a bunch of chit in the system or the oil is REALLY bad.

 

[WES999]

When I flushed the PS fluid on my Ranger I cobbled up a reservoir out of PVC pipe and stuck in the fill
opening, it held about half a quart. It made it easier to flush without the possibility of reservoir running dry and sucking in air.

 

[Highbeam]

Doing it yourself would suck. My truck has hydroboost and PS off the same pump. Two returns. I pulled the HB return line off at the HB unit and ran a clear line to a bucket. Truck on stands and wife pumping brakes while turning lock to lock while I kept the reservoir topped up which is not as easy as it sounds.

With two people is was a pain. With just one I would pass.

Do you have a problem? Is the need to bleed it due to lack of something? It should bleed itself over time.

 

[Beetle-Kill]

Gentlemen, thanks for the advice.
First off, this sucks by yourself.
Put it on jack stands, worked the wheels L/R a few times with engine off. Add more fluid.
(I should note that yanking the return lines was not feasible, all the fluid in the pump ran out)
crank the wheel again, add fluid.
Start motor and crank the wheel again. Add fluid because I didn't tighten cap fully and lost some to blow out. *sigh*
Tighten belt, again.
Cycle wheel again, no belt squeek until at full lock, but brakes are still an issue, stomp on them hard and belt squeals.
Pump brakes, top off fluid- repeat. really glad I bought a gallon of PS fluid.
TOMORROW-
check fluid level, re-tighten belt, work the brakes. Hopefully, the bubbles will work out overnight but we'll see.
then address the oil pressure sensor I wracked while wrenching.
I love old trucks.

 

[Highbeam]

Yeah, at the HB unit the return line is above the level of the reservoir so it doesn't drain the res. After doing a full flush to synthetic fluid, since the fluid in my PS system was really stinky and brown (ford uses atf), I feel like so long as you keep the res full and just drive that you will eventually work out the bubbles. The pump is in the res so as long as it is submerged in fluid it will pump into the lines and push bubbles out.

 

[nate379]

I suppose I didn't explain well enough, but I meant to say when you pull the return line off you need to cap that fitting on the reservoir.

What WES999 talks about is a good idea. I'm usually too cheap or lazy to fab up stuff like that unless I HAVE to. I'll go bug a friend or neighbor for help before that

 

[Beetle-Kill]

I suppose I didn't explain well enough, but I meant to say when you pull the return line off you need to cap that fitting on the reservoir.

What WES999 talks about is a good idea. I'm usually too cheap or lazy to fab up stuff like that unless I HAVE to. I'll go bug a friend or neighbor for help before that

Oh, so now you tell me. (facepalm)

 

[Beetle-Kill]

Tried to add an UPDATE to the header, didn't work, and this is just an FYI-
In my case, the pump turned out to be fine, it was the Hydroboost unit that went south.
If anyone ever needs to replace a Hydroboost, make sure it has the factory backing plate installed.
If you have to swap the backing plate yourself, you'll need a special socket that cost's about $145+ S/H
Instead, use a 4wd axle nut 4-prong socket, cut off the socket driver part, and weld on a "T" handle out of whatever you have laying around.
It works fine, took 30 min. to make, and cost $25.
Just wanted to pass this on.