All in all a very productive weekend with the S500. Saturday started with the construction of a set of ramps. I couldn't bear to part with $40 or $50 for the metal Harbor Freight models, so I went to Lowe's and bought a couple of 2x10x12s and made my own by cutting progressively longer pieces that I stacked on top of each other to form a ramp. A pass on the end of each board with a 45 degree angle, plenty of glue and deck screws between each layer and a pair of very functional ramps were now ready for my car. Next I took on my Craftsman floor jack that has been acting up for some time. The "speed lift" function hasn't been working, and it has been lifting less and less as time goes on. I had done some research as far as adjustments and repairs, but these yielded no results. I suspect I might have been low on fluid, but for the life of me I couldn't find a place to fill it. Finally, after a very thorough inspection, I found a plastic plug in the side of the hydraulic cylinder. I pried the plug out and realized that this was the fill port. After I put almost 6 ounces of hydraulic fluid in it, it was once again lifting as it had in the past. I still don't have the "speed lift" function, but I'll compromise in order to have full lifting capabilities again. And now to the car.... Previous inspection had shown that the front flex disc had some hairline cracks in it, but the rear was starting to fail with tears and cracks readily apparent. Not having done a flex disc since a W126 I was in for a surprise. The W140 has 8 bolts rather than 6, and the flex disc in front is a lot more difficult to access than ones in earlier models. Thank goodness for pry bars and magnetic pickups. The rear flex disc was far more accessible, especially after the "guard" or strap was removed. It appears that on this chassis there is a metal strap that wraps around the drive shaft to prevent it from lashing around should it break loose. While you can work around this, it's fairly easy to unbolt one end and bend it out of the way to better access the bolts on the rear flex disc. Again, lots of brute force and use of a pry bar to get everything apart. It goes without saying that I have not been on a creeper for such a long time in a great while. When I woke up Sunday morning I was hurting in places I didn't even know I had. Fortunately, I had saved the simpler tasks for Sunday. First order of business was the fuel filter. Since I had removed the cover that protects the fuel pump and filter to access the nut that holds the strap around the driveshaft yesterday, access was a simple matter. With the judicious use of rubber plugs and caps I was able to swap the fuel filter with a minimum of fuel loss. A pretty simple operation. With cover back in place I was ready to move on... Next was a flush and fill of the SLS system. I had noted that the fluid was very dark and there was some sort of black crud in the screen, but I hadn't looked much beyond that. I put some clear tubing on the return line and ran it into a clear bottle. I removed the cap and screen and proceeded to run the engine to pump the reservoir down to the bottom. I found a bit of black crud in the bottom and sides of the reservoir, which I was able to clean out using a dust-free cloth wrapped around the end of a piece of coat hanger. I would have liked to remove the reservoir and cleaned it more thoroughly, but my Mercedes Martha Stewart-ness was on the ebb by this time. After a liter or so of fresh fluid I was getting clear fluid out of the system. I shut it off and topped up the reservoir. Now to the filter/screen. There was a large slug of the black crud in the bottom of the filter screen. When I separated the screen from the cap, imagine my surprise when I saw what appeared to be the remains of a large rubber O-ring in the bottom of the screen! This was the source of the black crud in the system - the O-ring was apparently not something that should have been in contact with hydraulic fluid, as it was breaking down and was soft and falling apart. I had mistakenly ordered a replacement screen/filter, thinking that this system was like earlier SLS systems that had the small pleated paper filter elements in them, but in this case my lack of attention worked in my favor. The SLS system in the W140 has a fine mesh screen that filters the hydraulic fluid, and it's not a consumable item like the older pleated paper filters are. I could have cleaned the old screen and it would have been perfectly passable, but since it was covered with the remains of the broken down rubber part that was lodged in the base of it, I elected to put the new screen on and leave the old one to the rubbish. Reassembled the screen and cap, put it back on the reservoir, attached the return line and checked the level. All is well. Lastly, I wanted to clean the connections on the instrument cluster, as the coolant temperature gauge was flakey. It might read accurately for a few seconds, then flip to full scale, then down, then back etc. While I knew that coolant temperature was within operating limits, if you're trained to watch your instruments, scanning them on a regular basis and seeing one at full scale catches your eye immediately, even if you know it's an aberrant reading. I had tested the sender and wiring, so I knew it had to be an issue in the cluster. Getting my handy home made instrument cluster pullers out, the cluster came out easily. Unlike earlier models, the W140 has four connectors, two large round octal-like sockets, one on each side, and two small black rectangular sockets, each located near the larger sockets. These came apart with some effort and the cluster was free. With the cluster safely located on top of a towel on the kitchen table, I removed the back cover (secured with some small Torx screws) and was faced with a circuit board of a complexity I have never seen in a Mercedes. Yikes! Further inspection showed that this board was held on to the cluster with only three small Torx screw, after which were removed left nothing but the pin and socket connectors for the various cluster elements. With the circuit board removed I got out my Kaig DeOxIt and some Q-Tips and went to work. I cleaned all of the pins along with a skinny contact strip that provided connection to the board from the cluster. I cleaned the sockets on the board as well. Once reassembled, the cluster went back in after each connector in the car received a good shot of Kaig DeOxIt. I reconnected the battery, turned the key, and everything lit up and appeared to work. I then set out to reprogram the radio and reset the power windows and sunroof. The drive to work this morning revealed a working coolant temperature gauge which now reflects the proper reading and doesn't make me panic when I scan the gauges... A postscript: For those who read the posts about my experiences with this car, please do not construe my near obsessive behaviors as an indication that there are defects with the car or that I am somehow unhappy with it. For some twisted reason some members of the list have interpreted my questions about it and the work I have done as such and have been suggesting to the former owner that I have been experiencing a myriad of problems and am unhappy with the car. This is not the case, and never has been. I would suggest that those of you who have taken it upon yourselves to interpret my experiences as such and then "tattle" to the former owner get your shorts out of a knot and mind your own business. Those of you who know me well understand that I am borderline obsessive about my cars and as a result go to great lengths to understand them as well as keep them in near perfect condition. The excessive questions I have posted are merely a result of my lack of knowledge of this particular model, and an effort to understand how it works and resolve those questions or concerns that I have. I have an ongoing discussion with the former owner who has been a great resource in helping me understand how this very complex car works. I am very pleased with the car and the purchase. 'nuf said. Dan _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/
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