Power steering fluid... does it ever need changing??

[wasserleaker]

my van is 'blessed' with power steering...recently realised that the power steering fluid was very low in my van, as the resevoir looked to be at the right level, but this was just a dirt 'tide line' on the inside of the resevoir/top up pot, it looked fairly full but wasn't. filled it to between min and max mark, with new ATF Fluid, which now it has been round the system for a week or so has gone from red to dirty black!
should i find the lowest point in the system and let the old dirty stuff out and replace it, if necessary more than once until its got rid of the dirty stuff fully, or will it be ok? can't see any obvious drain plug for the system, is ATF fluid able to absorb moisture and cause corrosion if not changed occasionally, like brake fluid?

[Red Westie]

Well it isn't hygroscopic like brake fluid, so doesn't absorb water but if it has turned a dark colour there is obvious dirt/wear contamination so although not a service requirement I personally would change it.
Just be careful not to run the pump empty as it relies on the fluid to self lubricate.
Martin

[wasserleaker]

cheers for that, martin, just done a bit of googling on the subject, and one site suggests simply keep removing the fluid in the rsevoir and replacing it with new regularly over a few weeks, until the stuff remains red and the dirty stuff is gone, flushed thru the system, which seems a simple solution, i have a vaccum type fluid pump so this should be a simple enough way to clear the old crap stuff out and gradually get it all back to being nice new red stuff again.

[Aidan]

change the filter too, easy enough to drain down via the join in the lp pipe halfway along the chassis

[toomanytoys]

Or you could get a couple or 3 litres and disconect the return line from the rack at the resevoir, get an assistant to start engine and run while pouring in the fresh... as soon as the clean stuff comes out of the return line (or run out of clen fluid to add) get the assistant to switch off... of course the steering could do with being turned back and forth a couple of times whilst running... to flush out whats in the rack... this could be a little tricky to perform, but I reckon you will use a lot more "clean" by changing the resevoir qty every day... as it will only dilute the dirty stuff by a small amount.. the pump draws from the res...

[wasserleaker]

Aidan... Wasn't aware that there was a filter, so thanks for that, will def locate it and change it, and Toomanytoys... that does sound like a quicker way of getting rid of the old contaminated dirty fluid... many thanks for the advice to those who have replied!

[toomanytoys]

But as said.... DO NOT let the pump run "dry"

[wasserleaker]

looking into the job further, and it seems the seals in the power steering rack have gone... the rubber gaiters either end of the rack are half full of ATF fluid! they've been doing a good job of containing the fluid so no tell tale leaks to show that the seals had gone.
had a look at whats involved with a rebuild of the rack on a genuine manual disc, assuming all replaceable seals are still available, anyone tackled a rebuild sucessfully before?
i have access to a press which looks necessary from the detailed manual, and work in an engineering workshop, so any oddball tooling needed can be made up no problem, but is it more cost effective to swap for a re-con rack, if anyone does them? ?
oh, and i now know where the filter is, in the bottom of the resevoir, but thats the least of my worries now!

[Aidan]

Had a couple done by Western Power Steering in bristol, seal kit nla from VW, ZF awkward to deal with, one rebuild still leaks, ongoin discussions with ZF about making parts or making them available again, but it's old technology. No info to have a go myself, if you've got the procedure then as long as the bar isn't scored or pitted should be doable.
Corrosion of the banjos on the racks pipes seems to be an issue for dissasembly
New rhd rack from Germany about £1500 a few months back

[wasserleaker]

Many thanks for the info, very helpful as always, Aidan! .... found the number for western power steering in brizzle, and a couple of others that offer a years warranty on a rebuild, so will ring around for a price tomorrow, a second hand one is another option i suppose, but anything second hand always seems a bit of a gamble, so i reckon sending mine off for a rebuild might be best, if genuine parts are no longer available, i suppose they'd use generic, other brand parts that are common in other racks, the parts shown on the disc i have that *must* be replaced on rebuilding the unit include teflon support rings and 'O' rings, as well as seals. but as you say, if the rods important diameters are scored/pitted i suppose new seals aren't going to be a permanent fix.