I did this with only 1 qt and my fluid didn't turn out as red as the fluid in the DIY pics. Since the entire system holds ~1 qt doing this method with 1 qt would i theory give you a 50/50 mix of new and old fluids. Each additional quart would reduce the number of old in half so two should give you 75% new and 25% old and I think I'm going to go get one more quart. Even with 1 qt the car feels smoother through turns.

 

Actually, that is an erroneous assumption. The math is a bit more complicated then that given the way the dilution is done in this case: roughly 1/3 quart new fluid at a time with remixing in between each successive fill. This creates a more substantial dilution factor. Consequently, a more accurate result of 3 dilutions yields a final mixture of approx. 70:30 (new : old).

If you did go through a second quart (3 more dilutions), you would net a 91:9 mixture.

And if you went through yet another (3rd) quart, you'd end up at 97.4 : 2.6 mixture.

It would take a full 4 quarts to jump up to a 99.2 : 0.8 mixture.

jeez, I can't believe I still remember those solution problems.

 

^ Good point.... I didn't factor the 3 dilutions per 1 qt. So doing 2 qts should be plenty given any additional qts will yield minimal results.

 

^^ exactly, the function has a nonlinear decay, so subsequent quarts have increasingly minimal impact. One quart is pretty good; two is great. Three or more is just being ****.

 

I flushed my power steering today and after noticing the fluid wasn't getting "clean" as fast as I had hoped I decided to figure out how many times it was going to take to replace most of the old fluid. The graph below is what I came up with... This assumes the old and new fluid mixes completely between each exchange. Hope it helps.

Also I used a brake bleeder bottle and a syringe to syphon the old fluid out of the reservoir. The syringe is only needed to start the process. It is a bit slow but leaves virtually no mess.

 

nice graph to show the dilution, looks like 2qts is a perfect mix to get (~90%) mostly new fluid, after that its to slow of a change to be of any use. Ill be going with 2 qts for sure this summer.

 

Nicely done everyone! I'll update the first post to share y'all's info. I love this site, so much collaboration!

 

Nice one Mike

 

Did this today with very minimal grief. I got a $6 plastic hand pump when I bought the fluid and it made the job a hellaluvalot easier than with no pump

I also noticed that my fluid was pretty clean after the 2nd drain/fill, maybe because the pump got the majority of the old junk out, I don't know. I ended up only using one of the 2 quarts I bought.

Thanks mike!

 

Great DIY as usual Mike!
Isn't there a way to suck all the old fluid out and fill with new fluid at 1 go? Maybe with an aftermarket pump that sucks it all out from the cap or the hose?
My PS fluid is pretty black lol

BTW, how often should this be done? I'm close to 70k km's (over 3 years now) and haven't touched my PS fluid yet.

 

My car had 37000 miles, and the fluid looked good. You're at roughly 44000 miles, so it's time for a change indeed.

 

Just changed mine out today and wanted to thank mike again for his input, though its an easy DIY, having all the details like fluid, num of dilutions etc before hand makes the job that much easier.

I used the turkey baster with a pipe attached at the end, it took a little longer than pumps but no real regrets since it was easy with no mess.

My fluid was almost black with ~56k I have done three trades and its pretty red now, ill be driving around normal for a week and do a couple more next weekend just to finish off the Qt and get more new fluid in. Also the difference in steering ease/response was immediately felt, whether it was psychological or real is anybody's guess

 

Thanks

Welcome! The pump certainly helped a lot, and it can be used for other things, too!

FWIW, the fluid change really helps. I went to an HPDE recently and unless something else changed, i did not notice the fluid boil or agitate after a run (i noticed this a couple of instances in the past, was told it was just the pump circulating fluid).



I'm not sure if there's an easy way to suck it all out. You probably can if you drop in a very long narrow tube, but who knows what could happen then.

With you, i'd say it was real. I did notice it, too, so if it's psychological, we're both screwed.

I'm glad you were able to do the turkey baster method, i guess mine was of poor quality, it would just drip after that initial suction.

 

^ hahaha i guess in that case i would not want to know for sure!

 

As was mentioned before, there is the method of removing the return hose and purging the old fluid into a can while you constantly refill the reservoir with new, thereby pushing out the old with the new; pretty much the same concept as bleeding your brakes. It is a hassle though and can be really messy. I think using this DIY is more than sufficient, certainly easier, and probably cleaner.