Last fall my SL55 blew a pressure line from the pulse dampner/accumulator behind the LF wheel. I purchased a new line, both large accumulators, the pulse dampner, and the small air cell (rear valve body), as well as oring kits for frt/rr valve bodies and a re-manufactured tandem pump. I decided that the car being 17 yrs old would eventually be needing these replaced so I went ahead and did everything at once, including a fluid flush/filter with Pentosin. While shopping the usual outlets for the best prices on these components, I came across an AC-Delco Remanufactured tandem pump for $199.00 plus free shipping through Summit Racing ($50 core). It is part number ADO-36P1050 through them, and Delco part #36P1050. It also has a 12 month/12K mile warranty. With the recent 'rona shut down at my shop, I had the free time to replace all these components and get it bled out. I did a couple things differently than the sticky on pump replacement, simply to avoid oil spillage. I removed the metal plate by the reservoirs separately in order to remove the tanks and hoses independently after siphoning to allow a catch container underneath. Also, the line from the ABC reservoir to the pump has a small upwards curve to it that traps air. I pushed down on this upon initial filling and heard air bubbles trapped in it bubble into the tank. I spun the pump by hand while pressing down on the line and had no issues on start up. When the red abc "drive carefully" light came on during cycling the suspension, I shut the car off and pressed down on the line to hear bubbles once again. Started the car and the light was gone. After sitting over night, I topped off the fluid, pressed the line (bubbles again!) and drove the car about 35-40 miles without further issue. Anyways, just posting this for posterity. No need for cheap chinese ebay pumps when you can buy quality replacement through Summit, and air becoming trapped in the reservoir hose can be displaced by pressing it (squeezing) down to force trapped air into the tank and allow the fluid to get to the pump. Hope this helps someone, and the job is not difficult if you have a mechanical background or aptitude. It's a hydraulic system. Period. Just gather the proper tools outlined in the stickies, torque your fittings back good and tight, and don't rush it. If it takes a week or a month then that's what it takes. No worries!