The high-pressure power steering hose uses "field attachable" fittings (Gates). You can disassemble the fittings simply using box wrenches.



  1. Mercedes W123 High-pressure Power Steering Hose Replacement, High-pressure Power Steering Hose: step 1, image 1 of 1
    • Use an open-ended wrench or flare wrench (better) to unscrew the high-pressure tube nut (gold, inverted flare) from Vickers power steering pump. I found an 11/16" SAE wrench fit best.

    • Unscrew the tube nut from steering gear, using a 2nd wrench to keep the adapter in the gear from turning.

  2. Mercedes W123 High-pressure Power Steering Hose Replacement: step 2, image 1 of 1
    • To remove each fitting, secure the outer shell in a vise or such. Use an open-ended wrench or flare wrench (better), to unscrew the mandrel tube from the ID of the hose. It is a normal right-hand thread. Once out, unscrew the hose from inside the shell. That is a left-hand thread, so turn as if you were tightening a bolt to unscrew.

    • Factory instructions for the fitting may be document "Gates Field Attachable Coupling Installation" (search), but note the shell there screws onto the hose OD with right-hand thread.

  3. Mercedes W123 High-pressure Power Steering Hose Replacement: step 3, image 1 of 1
    • For high-pressure hose, I used SAE 100R5-8, 13/32" ID, 2000 psi, 1-wire (blue jacket). Cut w/ hacksaw or cut-off disk to 21" length.

    • A better choice might be SAE 100R3-6, 2 fiber braids, 3/8"ID, 0.75"OD, 1125 psi (Gates 6G3HXCTN), since more flexible and still adequate pressure. The factory hose had fibers, not steel wire.

    • For return, I used Parker 611HT-8, 1/2" ID, 400 psi (black jacket). Another choice is SAE 100R6, 1 fiber braid, 1/2" ID, 400 psi (Gates 8GTHXCTN).

  4. Mercedes W123 High-pressure Power Steering Hose Replacement: step 4, image 1 of 1
    • Assembly is reverse order. Lubricate the hose OD and ID with power steering oil to make it easier.

    • Start screwing the new hose into the shell a few turns. It is a left-hand thread so turn ccw. As soon as you have room, push the tube mandrel into the hose ID and turn in 1 turn cw to get it started. Don't wait until the shell is all the way on or you may not be able to get the mandrel into the hose.

    • Continue screwing the shell onto the hose (ccw) until the end of the hose bottoms out in the shell, then unscrew 1/2 turn (cw). Then, continue screwing the mandrel into the hose ID until the mandrel bottoms out against the shell. Re-install hose on pump and gear, routing so it doesn't touch the car's body.


To reassemble your device, follow these instructions in reverse order.


William Grissom


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Hi, I am currently in the process of changing my high pressure power steering line for Mercedes ml270 w163 2001... I was wondering if you could assist with any links or names to parts that may be of any help. The only part I can find online is 400 dollars.

Ebony x - crwdns2853112:0crwdne2853112:0



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