Flushing the Hydraulic circuit

[s2driveruk]

As I now have a fully refurbished pump (Thanks Alex) I want to purge all the old goo2000 from the system and refill with the new 4000 fluid. I cannot seem to locate a how to but seem to remember there was one at some point. Is it just a case of remove the return line from the reservoir and drain to a container and ensure that the new fluid to flush with is added until it runs clean and clear?

[S2central.net]

Sounds logical enough method - as long as you have clean oil supply coming into the new pump (from the reservoir as long as its return is blocked off) - you can manually crank the pump to purge old fluid from the rack & servo - not sure how long that would take unless you can fashion something like an air tool or hand-held drill to manually turn the pump (before you connect the pulley and belt that is - I expect you would have the front panel and such removed already). I also think you need the rack to go lock to lock a couple of times to purge all that old goo out.

[varia]

https://www.youtube.com/watch?v=_586QV7ewt4

[Error404]

I remove the accordion hose from the tank and drain out the old fluid, then remove the return to the tank and direct into an old drain billet or similar, around 2L and clear so you can see in. Clean the tank and filter, then plug the return on the tank, refit the accordion pipe and refill with new fluid. Then run the engine at idle turning the steering lock to lock a few times until the fluid runs clean, keeping the level topped up of course. It helps to have an assistant. Normally takes around 2L of fluid in my experience

[igor136]

Is new 4000 oil good for our cars? Because is it not mineral

1-2-4-5-3

[s2driveruk]

Oh? I thought 4000 superceded 2000 and could be mixed etc?

[S2central.net]

Oh? I thought 4000 superceded 2000 and could be mixed etc?

Apparently they can be mixed but the new g4000 stuff does look very watery compared to the gloopy old g2000.

I think Pentosin still makes their version - CHF11S if I remember right. Pls don't take my word for it - check with others.

[s2driveruk]

Hmmm, just bought 3ltrs from local stealer...better go do some homework dont want to destroy the rack or anything else lol

[igor136]

After flushing hydraulic system with g004000 my steering rack makes noice. It is not the same oil

1-2-4-5-3

[S2central.net]

Thats a worry - is there a definitive thread on this anywhere - in any Audi forum ?

[Lago Blue]

Re possible "definitive hydraulic flush thread", yes I think I can find one of Mance's I used, I'll be right back.

(Just want to say how thankful I am to those who keep this forum clean & sparse looking, despite what must be obvious pressures to not keep it that way, as I am reminded every time I go back to look at something in a forum which has lost it.)

Here, I've used this for both B3 & B4:

https://www.audiworld.com/forums/audi-90-80-coupe-quattro-cabriolet-22/little-%22how-%22-power-purging-power-steering-hydraulic-system-2130893/

[s2driveruk]

After flushing hydraulic system with g004000 my steering rack makes noice. It is not the same oil

1-2-4-5-3

yes I read that the two are in fact not miscible after all. I am looking for the Febi M6162 which I believe is the original 7.1/G002000 fluid and am going to use that instead of the 4000. Was actually thinking the other day that I did actually top up the system some time back and the oil I used was visibily and physically 'thinner' than the old goo, so wonder if i have already inadvertently mixed the two before.

Either way, will flush and refill with a known G002000 variant now and hopefully it will be clean and kind to the PS circuit and rack.