Custom method to change PS fluid

[kilou]

Hi,

I've heard all sorts of methods to change the power steering fluids such as using a turkey baster or swtiching the ignition on, turning lock to lock while pouring new fresh fluid. I don't like both method as the first one doesn't replace all the fluid and the second one is "dangerous" as there is a risk to run the pump dry.

So I'd like to propose something but I need you expert knowledge to know if this will work or not. The main idea is similar to the one of starting the engine and pouring fresh fluid in the reservoir while avoiding to let the level drop too low. As this is quite difficult to achieve when the engine is running, I propose to MANUALLY crank the engine so that it will make the PS pump "work" slowly. Therefore, the fluid level in the reservoir shouldn't drop too quickly and it should be easier to pour in fresh fluid while the old one is draining out from the disconnected return line.

Do you think this would work?

 

[TallPaul]

Wonder if it will overheat the starter?

I did the turkey baster method and my fluid came out pretty nice and new looking (was brown). True there always will be a little bit of the old left, but it was easier for me and little mess.

 

[Kestas]

I don't fret over the fluid leaving the pump with the engine-on method. It never really goes dry. It's always wet so I don't think there's any danger of damaging the pump. I also think there's a benefit to all the turbulence with the more active method.

Though every once in a while I run into a car that retains air in the system after this engine-on procedure, and takes many miles before air is purged from the system.

 

[cryptokid]

the pump can survuve find with no fluid for little spitrs of time. when i swapped my ps fluid i had the car up on a floor jack and would fill up the resivor and go around and turn the steering wheel. frequently i let the pump run DRY for 20 seconds at a time while i got back around to fill it up again. its no bid deal because the pump isnt under any load or stress as long as the wheels are off the ground.

 

[olympic]

I always use the engine running method. If the vehicle has a remote PS resevoir it's just so easy to unhook the return line, attach an extension hose with the other end placed in a drain container and start flushing.

Yes, air will get into the system and it will take a while for it to get worked out. But I see no other way to remove all the contaminants and dirty oil. Running the pump dry is a non-issue because everything remains coated in oil and there is no load on the pump.

 

[Audi Junkie]

On my Audi, I disconnect the return to pump hose at the res, insert a funnel, plug hole in res, crank with disconnected distributor spark pouring fresh fluid into funnel, drain res a few times, done and very clean.

[ June 20, 2004, 12:22 AM: Message edited by: Audi Junkie ]

 

[kilou]

Stupid question: when you disconnect the return line from the reservoir, you need to close the opening otherwise new poured fluid will go out straightly. What do you use to do this?

How much PS fluid do you need to properly change all the fluid with the engine-on method?

Otherwise, rather than to manually crank the engine, is it possible to disconnect the auxiliary drive belt and turn manually the PS pump pulley so as to pump the fluid very slowly while someone else turns the steering wheel from lock to lock? Is the PS pump pulley to stiff to be turned manually?

 

[olympic]

I use a piece of rubber hose with a bolt shoved in one end to plug the return port. Even a piece of plastic sandwich wrap and a rubber band would do.

Check your owners manual for the capacity of the system. Most hold less than a liter. So you'll need about 3 liters total, 2 to flush and one to refill. If your PS oil is extremely old and dirty, then you may want to flush through some more, maybe 4 liters.

I doubt you could turn the pump pulley effectively by hand. There's bound to be some resistance that would make this extremely slow and difficult.

If running the pump "dry" really bothers you, you could try using some sort of vacuum pump on the return line to suck the old oil out while adding new oil to the resevoir. I'm not positive if this would work though.

[ June 20, 2004, 06:31 AM: Message edited by: olympic ]

 

[kilou]

There is a nut on the P/S pump pulley. I can turn the pulley manually using a large spanner on that nut, this shouldn't be a problem.

However, do you think that manually turning the P/S pump pulley will be efficient to suck new fluid from the reservoir while ejecting old fluid out of the pressure lines?


Another quick question: my car uses ATF type F or G for PS fluid. I went to my dealer to buy it (I have the part number) but he said that this part number has been replaced with a new fluid which is Pentosin CHF II (also for power steering). I worry if it is good to replace my old ATF with that new fluid because I don't want to strain the seals in the system and I know that mixing fluids is not good. Should I stick with ATF type F,G or go with this new fluid?

 

[Audi Junkie]

Pentosin CHF 11S was the current fluid, there is a tweaked version with more anti-foam agents. I did not bother getting the new stuff for my 1998 Audi.

 

[Tremo]

How about removing the drive belt and turning the pump's pulley by hand? Will that pump the fluid through?

Also, what's everyone's fave ps fluid for GM cars? Since my car has high mileage, I'm thinking a mix of Valvoline Synpower and Maxlife.

Opinions?

 

[RavenTai]

I have the same thoughts as you on both methods. The turkey baister method is safe easy and if done enough will eventually replace the majority of the fluid just takes a wile and is not very efficient use of fluid

The other method of running the pump dry (you cannot keep up with the pump pouring from a bottle) and intentionally introducing air into a running hydraulic system is a bad idea, not only does air not cool and lubricate the running pump but unlike liquids gasses compress, at 1k+psi they compress a lot and violently expand as they pass from high pressure to low pressure areas and can damage seals and hoses. You probably wont experience a failure form this practice but wear has occurred.

read more about Cavitation

I blindly stumbled into a better method wile doing another task:

I am not sure if this will work on Rack and Pinion vehicles (someone try it and let us know) but if you have a standard Saginaw style steering box (most trucks and full size cars especially older ones) it contains a large piston and valves that as long as you are turning the steering wheel only let fluid move in the high pressure port and out the low pressure port no matter witch direction the piston is moving, the steering box is a nice slow highly controllable preinstalled pump,

Remove the low pressure return line from the reservoir, and plug the open reservoir pipe, I used one of those plastic caps that comes with brake parts, anything that will temporarily hold fluid will do, add more hose to the line with a barb and route the open end to a drain pan, raise the vehicle and secure on stands (so the steering is easy to move) make sure the tires and other steering components will not hit the stands through any of their travel or the vehicle may knock itself off the jacks.

Fill the reservoir and then turn the steering wheel lock to lock with the engine off, as you move the piston will displace fluid the valving in the steering box will port the displaced fluid in the proper direction the box will draw clean fluid from the reservoir through the pump hoses and into the box ant the same time it puses it out through the cooler and return hose, my system has a small reservoir I could only do one cycle (full one way and then full the other) before I had to fill it again, if you let the reservoir get low and air gets between the piston and pump it will loose its prime of sorts and have a harder time moving the fluid, the new fluid showed up at the drain pan after about 3 quarts, I ran about 5 total to be sure (it was inexpensive Dino)

Reconnect the line, fill the system, go lock-to-lock, (again with the engine off) check and fill the reservoir, the system will purge any trapped air out requiring fluid to take its place , repeat as necessary until the level does not drop, if you have foam in the reservoir it may get reintroduced and will cycle through several times, more sit time will let the air settle out, remove stands drive for a wile, check disturbed connections for leaks, and refill as necessary

[ June 24, 2004, 02:08 AM: Message edited by: RavenTai ]

 

[kilou]

Nice method but I suppose the new fluid will not be allowed to flow from the reservoir through the pump(but I'm not sure) on a rack and pinion system. I assume this would only drain the system below the pump but it is much better than the rukey baster method in my opinion.

I thought exactly as Tremo about manually turning the PS pump pulley after having disconnected the belt. This would produce exactly the same thing as starting the engine but by manually turning the pulley (with a large spanner on the nut), this would allow to gently pour in new fluid in the reservoir and avoiding to run the pump dry. However, is this good to manually turn the PS pump or is there any risk (I don't know which one but maybe........)? Does this produce sufficient pressure to push old fluid out while sucking new fluid in?

In my opinion, this would be the most effective and safer method!

 

[TallPaul]

quote:

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Originally posted by RavenTai:
I blindly stumbled into a better method wile doing another task:

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Excellent idea! I did the turkey baster, but next time I will try your method.

 

[RavenTai]

I have never taken apart a R&P system (never owned a car with one) so I am not sure if it will pump fluid on its own, try it and find out?

turning the pump manually wil be just fine, that was not an option for met as my PS pump is directly mounted to the engine front cover and gear driven just lke the oil pump right next to it, I would reccomend only turning it in the same directing the engine does, dont know if this aplies to PS systems but some high pressure pumps do not like to be turned backwards, it will be quite slow going, you may not need a "spanner" you may be able to turn the pulley by hand, the pressure and flow rate will be safe and low

 

[RavenTai]

quote:

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Originally posted by TallPaul:

quote:

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Originally posted by RavenTai:
I blindly stumbled into a better method wile doing another task:

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Excellent idea! I did the turkey baster, but next time I will try your method.

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Glad you like, it works good