Writing this up to assist with anyone looking to service their DRC suspension due to hydraulic leak. I am by no means a professional so take this as you want.
Skip to “Technical” portion if you just want to see the DIY portion.
Background: 2018 RS5 w/ ~65k miles. Driving over railroad tracks, I took a bump pretty hard going ~25mph. We have shitty tracks all through town. Driving through town I started to notice a rattle noise from rear drivers side, which seemed weird because I had taken the hit on the RR on front passenger side. Made it home and parked in garage, where I noticed fluid leaking from front passenger wheel well.
Found out the hydraulic line was cut near the midpoint connection.
After finding, I began calling around the area dealerships to see what it would cost to have repaired. Of course, could NOT get a straight answer as none of the 4-5 dealers would commit to a price before having the car brought in for diagnostics. Finally got one of the service managers to give an estimate range, $1k-$2k for the diagnostic and pressurizing the hydraulic lines for the suspension system. This literally took me 2 days to pull from them. Additionally, I was told by all area dealers that it would take ~3 weeks before they could repair because there were no replacement hydraulic lines State side and would have to be ordered and shipped from Germany. At this point I decided to handle things myself.
TECHNICAL: Below are listed the parts I needed for repair and tools I used for DIY. Observe the notes below pictures, as some of these oversights from me added additional wait times to perform the repair that you can avoid.
Audi parts;
Hydraulic replacement hose - 8W0-616-712, priced at $260.37 from dealer (3-week lead time for shipping), found online for ~$135 and 7-day shipping (was told this was last one in the States)
Hydraulic fluid (VW) - G-052-731-A2, dealer priced at $43.31, online for $20.63 (AudiUSA, make sure your supplier will ship fluids), I bought 2 quarts, only used ~1/2 qt.
DIY/conversion parts;
I had to convert the hydraulic connections as I was unable to find the proper connector to what is stock on the hydraulic hose lines. Changed to the following with necessary adapters;
Hydraulic Male Fitting Pipe 1/8“ NPT To M10 M10x1 M10x1.0 Inverted Flare Brake
ONE FOR EACH CONNECTION POINT NEEDED. I ordered 2 since I was just charging one hydraulic set of the car (front driver/rear passenger)
https://www.ebay.com/itm/203762412437
1 Set 1/8" ISO-B Hydraulic Hose Quick Disconnect Couplers Brass - (ISO 7241-1 B)
ONE FOR EACH SET OF HYDRAULICS BEING SERVICED. I ordered one set.
https://www.ebay.com/itm/262738372202
This replaces the connectors on the hydraulic hose. I used ptfe tape for adapter to connector and blue thread sealant for adapter to hose connection.
1/4” SAE tee connector; all male threads
https://www.amazon.com/Anderson-Meta...00BOA0DC&psc=1
1/4” SAE male coupler; to connect hose extension together
https://www.amazon.com/Flare-Connect...BFR43CP1&psc=1
1/4” NPT female swivel adapter to 1/4” SAE female NEED 2 (x2)
https://www.amazon.com/BEITERSTOE-65...ob_b_ts_rp_1_t
Tools;
Most of my tools came from Harbor Freight
Hydraulic pump - PITTSBURGH 4 Ton Portable Hydraulic Equipment Kit
https://www.harborfreight.com/4-ton-...kit-58204.html
AC manifold kit - PITTSBURGH R134A A/C Manifold Gauge Set
https://www.harborfreight.com/r134a-...set-58776.html
YOU WILL NEED EXTRA LINE EXTENSION TO REACH BOTH HYDRAULIC CONNECTORS.
Fluid extractor - HOLT INDUSTRIES Deluxe Manual Fluid Extractor and Dispenser
https://www.harborfreight.com/deluxe...ser-70795.html
ALREADY HAD FOR MY OIL CHANGES.
PROCESS: suspension must be set to comfort mode. Raise car off suspension during service.
Assume all lines/connections are pressurized and must be decompressed before servicing.
From AC manifold, high pressure (red) connects to hydraulic jack hose with swivel adapter. Jack must be positioned hose face down to pump in oil. Back end removed to pour in oil.
From AC manifold, low pressure (blue) connects to fluid extractor.
From AC manifold, center connection leads down to adapter tee which ties into the two hydraulic line connectors. FOR MY VEHICLE (2018 RS5) the DRC system is comprised of two compression pistons. Each piston is linked to opposite corners of the suspension. Driver front to passenger rear, and passenger front to driver rear. Each system must be serviced individually by connecting the correct connections together.
Once connected, open the low pressure side (connected to fluid extractor) and pump down to 0.9 bar (approx. -30 in/Hg vacuum). Should see remaining hydraulic oil pumping out. Hold for a few minutes to make sure there are no leaks, which could mean issues with strut/hose/hydraulic cylinder/ or connections.
Then close low pressure valve. Make sure new hydraulic oil is in pump for high pressure side. Once valve is opened, new oil will be sucked in until pressure equalizes. DO NOT LET OIL LEVEL GET TOO LOW TO ALLOW AIR OR WILL HAVE TO RESTART WHOLE PROCESS.
Open high pressure valve (red) and hydraulic pump valve. Observe oil level and refill as needed until pressure equalizes. Pump pressure up to 22 bar (319 psi). Hold pressure and make sure system stabilizes ~5 mins. Add as needed. Check for leaks.
Once stabilizes, slowly release pressure back to 16 bar (232 psi) by opening/closing hydraulic pump valve. Stabilize at 16 bar and close high pressure valve. Disconnect from hydraulic lines quick connects. REMEMBER LINES WILL STILL BE PRESSURIZED.
Repeat for other system side, as needed.
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