[urq] Hydraulic reservoir filter questions...

Alan Pemberton alan_pemberton at telus.net
Mon Apr 5 13:03:18 EDT 2004

My 85 is the same and, from previous posts, there are others with the same

I ended up stacking 3 oil filters 857 422 385 so that I was sure there was
enough filter area.  Been running this way since April 96 but haven't
checked inside to make sure everything is Ok.


85 urq (Canadian)

 ----- Original Message ----- 
From: "Paul Lethbridge" <paul.lethbridge at ansys.com>
To: <urq at audifans.com>
Sent: Monday, April 05, 2004 9:10 AM
Subject: [urq] Hydraulic reservoir filter questions...

Dear List,

Sorry, no high HP mods discussed here, just hydraulic fluid

I recently replaced the suction hose on my hydraulic system (steering &
bomb), and with the system drained I decided to replace the oil filter
in the hydraulic reservoir. To my surprise, after removing the oil
strainer and spring, there was no filter element other than the sintered
ring (oil filter) in the bottom of the reservoir! Hmmm!

The FA lists the following filter items within the reservoir for the

    Oil strainer: 857 422 388
    Filter Element: 857 422 384
    Oil Filter: 857 422 385

I ordered a replacement filter element, P/N: 857-422-384. This
apparently fits inside, concentric with the sintered ring ( oil filter).
The part received was about twice as tall as the sintered ring and
didn't allow the metal strainer cap to seal against the sintered ring as
fitted originally. I didn't seem correct!

Since FA/ETKA lists at least three sintered ring (oil filters) types I
decided to order P/N: 857 422 385, guess what, NLA! Damn!

Another curious fact is that the central rod holding all these items
together inside the reservoir is not threaded like my previous '83, but
is smooth, and circlips are used.  There are two possible metal fluid
container assemblies:

    857 422 371 A
    443 422 371 F

I do not know which one I have,  the P/N is not visible. Is "857"
threaded and 443 not?

So, I am looking for your feedback & comments on my options here:

1) Put the system back together as it was and forget about this filter
element....The system has been working fine (apart from the
aforementioned leaky hose). Risk of piece of nastiness occurring now
that I know a filter is not present!

2) Try the 857 422 385A and 443 422 385A  variants of the oil filter?
(If they can be found!)

3) Switch the reservoir over to the later plastic style (used on '85
model year etc...) and install known and available filter components.
Will the std '84 pressure accumulator (bomb) function with this newer
style reservoir or is the newer style "bomb" & brakes servo needed here?
Arghhh! Sounds like a lot of work already!

Kind regards,


'84 UrQ
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