Flushing the PS system
 

Admit it, we all change our oil, and most of us change the ATF (probably out of fear if nothing else), some change their brake fluid, but how many have flushed their power steering system?

I ripped (& modified for the SVX) a procedure from the BITOG forum (credit where credit is due) - haven't tried it yet, but it makes sense - probably will try it in the next few weeks.

-jack up the front so the wheels are off the ground.
-locate the PS return line (the rubber hose toward the rear of the tank - metal line in front is the "output" line) and disconnect it from the reservoir. Have a cup ready to catch the fluid that drains out of the reservoir.
-after the reservoir is empty, plug the return port with something: a plastic cap, some plastic and an elastic band, use your imagination - you're going to be putting fluid back in the reservoir.
-attach an extension hose (3/8" ??) to the return line, suggest use of a barbed connecter. Have rags handy because a little oil is going to leak out.
-place the other end of the extension hose in a drain pan, empty milk jug, whatever.
-refill the reservoir with fresh fluid
-turn on the key to unlock the steering wheel and begin turning the wheels lock to lock while monitoring the level in the reservoir. You don't want to let it go dry and suck air into the system. If you have someone help you, they can pour in new fluid while you're turning the wheels.
-continue turning the wheels and flush through as much fluid as you like. 1 quart should be enough, maybe 2 if your old fluid was very dirty.
-re-connect the return line, top up the reservoir, start the engine, cycle the wheels a few more times and recheck the level.

I probably average doing around 10-12 p/s flushes per week. Of course it's a little easier when you have a dedicated machine. *s* With it are two small hoses that both go into the reservoir and the machine has a small electric pump to do the exchange while the engine is running. First I pump out the reservoir and add a p/s flush, let it run then pump out, add fluid back, cycle the wheels side-to-side, lather, rinse, repeat (several times.) Takes about 15-20 minutes and does a nice job.

Wow!

does your shop do this as a part of 60/90K miles service or are people actually asking for it?

P.S. Do you reckon the procedure would work for the home guys?

What I do to mine is, use a turkey baster, syphon about a quart of fluid from the PS resavoir, put the new automatic fluid in, drive it for a couple of days, and do it again. Usually by the third time, any whining or shuddering, has gone away.
I also use a new turkey baster to syphon brake fluid out of the master cylinder before I bleed it too.
If I had more time, Lee, yours is the better method. Tom

Tom suggested this procedure to me several months ago when I got a p/s whine. After 4-5 drains of my p/s reservoir, the ATF fluid was perfectly clear. The whine went away after the very first drain and replacement with new ATF.

I also used this procedure to fix a whine on AmazonParrot's '92 LS-L and it worked like a charm as well.

-Chike

I used a similar method to fluch my PS system last week. I disconnected the return line and pulled it down and aimed it into a 5 gal. bucket. Then I topped off the pump w/ ATF. Then as I was ready w/ a 5 quart jug of ATF and a funnel, I had my friend start the car and turn the wheels as I kept adding fresh fluid.

Now I am concernd that I may have let some air into the system. If so, how would I remedy that? Wouldnt the air eventually make it's way into the resevoir via the return line? I still notice a shudder sometimes when performing parking manuevers.

Any ideas or should I not worry about air in the system. I assumed that because ATF is not designed to be compressed at such high levels like brake fluid, a little air would not be that big of an issue.

Leaving the cap off while slowly turning the wheel lock-to-lock (and don't hold against lock for more than a second or so - not good on the system) should dispell any residual air in the system. I find that turning the wheel in 90° increments yields the best results. We have a couple models that are more prone to air entrapment than others and will shudder like crazy at parking speeds. In those cases we use a handheld vacuum pump with an adaptor (read: suction cup with a nipple) on the reservoir, in place of the cap. With about 25"/hg vacuum do the lock-to-lock maneuver for a few minutes, then lower the vacuum to around 3-4"/hg and repeat. That should draw out all of the entrapped air.

Typical p/s pressure on cars ranges between 1200-2400 psi. On brakes, let's see... 4:1 pedal leverage (guesstimate) w/50# foot pressure = 200 psi. .75" master cylinder piston = 150 psi. Guesstimate around 2.5" piston area in a caliper = 375 psi. Add in whatever power brake assist. Maybe brake pressure is at the low end of what p/s pressure would run. Not trying to argue, just thinking out loud.

We normally begin recommending it at 40,000 miles. It does seem to do a world of good for most cars.

It works for us, I don't see why it wouldn't work for anyone else.

p.s. I just got ASE test results back, scored 100% in steering and suspension. Now if I can come up with a few bucks I can get a cup of coffee at Starbucks.:rolleyes:

Congratulations on the test Beav. Hope you found the $$ for the coffee. :D

As one who has never had occasion to touch his power steering reservoir in four years, what am I missing?

Ron.

Periodically changing the power steering fluid makes sense for the same reasons as changing the oil, AT or brake fluid: The fluids are degraded over time by moisture and debris, and heat breaks them down. Whether or not to completely flush the PS system would be a matter for debate, but I think routine "refreshment" using the turkey-baster method is adequate.

The PS reservoir cap is vented, so any air introduced into the system should work its way out in short order.

A few months back, my daughter was all set to have the PS pump replaced on her Ford Windstar. I changed the fluid, which took all of five minutes, and she hasn't heard a peep out of it since.

dcb

The Explorer (and related) have an acute sensitivity to air in the system. Even though you can't see any aeration in the fluid it makes itself known by a very distinct shuddering at idle to low parking speeds. The quick and easy (and only, to my knowledge) is to use the vacuum pump method. As near as any of us can figure, air can be introduced into the system when the wheels are turned side-to-side with the engine not running - such as when suspension or brake work is performed.

Ron: Keeping good fluid in the p/s is a good way to keep seals from becoming brittle and leaking and also helps the lubrication end of the situation. Everything 'feels' better when properly lubricated. (hears old reggae song in head: "Who put the pepper in the vaseline....")

More questions :D
 

Congrats on the test Beav, I have a few NATEF Compitancies under my belt and I too will be certified someday. 100% on an ASE test is an accomplishment.

Secondly, thanks for the procedure. However I did have one more question. When I slowly turn the wheels from lock to lock is the car supposed to be running or not? I'm assuming that it is because in a later post you say that a way to get air into the system is to turn the wheels from lock to lock while the engine isn't running.

Thanks for all the advice! I really appreciate it.

Elliot

Yup, definitely while the engine is running. You want the fluid to be circulating during the procedure.

:eek: :eek: :eek: :D :D