quattrostan

I have a 93 S4 20vt, and it had a power steering leak so I put a new P.S. pressure line on and ever since there has been a loud growling when I turn the steering.
I had a hose made to save some money and it is high pressure hose, and looks like the same size.The system drained while it was off i've tried bleeding the system( all the ways I could find, running, not running, car jacked, not jacked, tilted, flat ground) and still making the noise.
I read one thread that said it may be a check valve in the return line, but don't know where it is, and can't find a listing for one.
If anyone has any ideas, it would be appreciated.
Stan

s4.branden

I had this EXACT same thing happen to my 93 S4. I bought the car with aftermarket power steering lines already installed. I drove it this way for a year and was always annoyed with the constant growl the car made when turning at low speeds. I ended up replacing the steering rack (thinking that would cure the issue.) Nope! About a month ago I replaced all my power steering lines with "OEM" lines and there are no longer any noises! Get rid of the home-maid line! You can thank me later lol!

Lyman_T

If the system is sucking air (or cavitating air), it's going to growl.

scarman

I doubt this is a bleeding problem. The system will self-bleed just by operating it. This high pressure line seems
to be difficult to rebuild to original specs to prevent noise. There is a restrictor in the original hose that appears
to be the item that helps prevent this noise. It is contained in a hard plastic insert installed in the hose and may have been left out of your rebuild. You are not the first to suffer the noise after a rebuild of this hose. The OEM
hose 4A1 422 893 Q is available from www.genuinevwaudiparts.com for about $216. This is a San Diego
dealer (Miramar Audi) that discounts heavily on the online sales web site, but the catalog is poor. Having the
part # to enter the search helps since you can't get these prices by calling. A couple of crush washers for the
rack end and o-rings at the pump I believe and a little knuckle busting will have a new hose installed and the
problem resolved. Just ask for the washers and they will add them to your order.

Rebuilding the brake pressure line seems to be trouble free if the restrictor is retained there. When that need
arises, House of Hose in Spokane WA has this process down pat, also keeping the insulation intact to reduce
any noise. This is the hose to rebuild since it lists at $605 and is $435.60 at genuinevwaudiparts.com.

s4.branden

I bought a used hose for $50 bucks off audifans. No leaks, and no more grunting noises. I guarantee that's the issue.