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Originally Posted by BETO  I searched, but couldn't find a write-up on how to change the pump. Any help?
In addition, should a get new or rebuilt, any brand, new design?
I don't feel like paying $600 for 2-3 hours worth of labor. |
I hope it is not to late for you. I had my power steering go out and the resevoir would not hold fluid. After performing on-line research I found pumps for $350 to $600. A call to the local Advanced Auto Parts store found a rebuilt unit in stock for $198 plus a $50 core charge. Once I got it home I found an on-line service manual for about $25 at alldatadiy.com. $25 buys a one year subscription. It did provide the sequence of events to remove the pump. However it does not inform you of certain basic items, such as how to remove the belt or that the idler tension pully must be removed to access one of the pumps torx bolts. It does not tell you that the idler tension pulley has a tamper proof torx head fitting to remove the belt. Leave it to MB to not want to allow you to change your own belt. Discouraged after a trip to find a tamper proof T50 torx bit, I went ahead and removed the resevoir. Remove the engine top cover and one torx bolt (bottom left corner of resevoir), one hose clamp (return line on rear of resevoir) and one clip (resevoir to pump inlet, use thin wide blade screwdriver, place in notch and twist out) and the resevoir slides right out (about 5 to 10 minutes). Have a rag handy for residual fluid. There is an o-ring where the resevoir feeds the pump. This o-ring does not come with the pump. MB sells it over the counter for $2.50 (the next day of course). After a good cleaning and inspection of the resevoir, hose and the pump housing I tried the resevoir to pump o-ring first. Lube the new o-ring in power steering fluid (Dexron III, ATF), slide it on the pumps inlet port, insert the resevoir into its guides and reinstall the torx bolt secring the resevoir to the engine block. This will also push the resevoir in far enough to reinsert the clip that holds the resevoir to the pump. Insert the clip next. I had cleaned all the surfaces and wirebrushed the clip so it would go in easier. Due to the low pressure return line inlet placement it can be tricky to insert the clip. I used a 90 degree needle nose pliers to gain leverage and it slid in the first attempt. Reattach the low pressure hose and your ready to fill the resevoir. Per MB fill the resevoir almost to the top and turn the engine on for about 5 seconds and turn it off, check the fluid level. It should be low. Perform this process 2 or 3 times (I did it 3) before the level stabilized. I filled the level to the top line of the dip stick and started the motor looking for leaks. After a successful leak test I took it on a test drive. MB says to turn the wheel from lock to lock 30 times to push the air out of the system. Fluid may look frothy due to air coming up, mine did. Afterwards recheck your level and you should be good. If your like me return the unused pump. Total repair was $2.50 for the o-ring, $25 for the manual and $5 for fluid. MB uses Automatic Transmission Fluid (ATF) Dexron III for the power steering fluid.
One other thing to check, not found in the manual, the low pressure line runs through a cooler in the radiator. Trace the low pressure line from the resevoir to the radiator and check these connections. My bottom connection had become loose and was abount to come off. MB had a recall on the original hose clamps used at the factory. They may need to be replaced.
Hope this helps others....Good Luck and don't ask MB for advice...They wanted $1,200!!
