linderpat

I'm in the middle of a reservoir replacement job and my fluid is filthy (see here for pics: https://rennlist.com/forums/928-foru...ing-fluid.html)
Anyway, I am doing a bunch of other stuff to the top of the engine, and the intake is partially off and everything is disconnected. Thus, without putting it all back together, which isn't convenient for where I am on the project line, is there a way to flush the ps fluid out of the rack and system without starting the car? Can I use low pressure from my compressor and blow it out? How about just forcing lot's of new atf fluid thru until it runs clean red?
Any thoughts welcome.

jcorenman

Eww, gross!! That is indeed yucky. Did that grit come out with the fluid or was it in the pan already?

To get a decent flush you are going to need to turn the pump and also cycle the rack a few times from stop to stop. I am sure there are a lot of theories on how to flush, what I would do is an 'open-loop' flush-- run a hose from a jug of fresh fluid to the pump inlet, and then route the return line to a drain pan. Spin the pump (I think turning it by hand would be enough if the engine is not running) while running the steering back and forth until the fluid runs bright red and clear, probably 2-3 quarts. Engine running is better (more flow), even then there is going to be some crud still trapped in the rack. The fittings are on the top of the rack cylinder, great for bleeding air but lousy for flushing. So if the rack is worn (lots of side-play at the ends) then maybe a rebuilt rack would be in order. Just be sure to flush everything carefully before fitting a rebuilt rack, and also before installing the nice pretty new reservoir.

Cheers, Jim

SharkSkin

Not much point in flushing until you get the engine running IMHO. You need the fluid velocity thhat you can only get while running. As Jim says, flush it some before putting the new reservoir on, and cycle the rack while doing so. Flushing open-loop goes through a lot of fluid but is a good way to start. Once you've flushed the worst of it, I'd say fill, run the engine and cycle the rack, then drain until it's clean, then install the new reservoir and repeat. Disconnecting the return line at the rack to drain, and cycling the rack with that line open to get more of the fluid out each time will help. The reservoir has a built-in filter, so you want to get as much crap as possible out before installing it.

linderpat

thanks guys. and yes, the pan started out clean! Really ugly stuff in there...

Mrmerlin

follow my suggestions in your other post for flushing