w123 steering box issue - PeachParts Mercedes-Benz Forum

michael0584 · #1 05-20-2019, 02:29 AM

The power steering box on my 85 300d was leaking from the input seal. To make things easy, I just swapped in the box from my 83 300d parts car. The box didn't appear to have any leaks and did not have any slop. Once installed, it steers too easy to the left and not easy enough to the right. Comparing to the old box I'd say 50% easier steering left and 50% harder to the right. It steers way too easy to the left and just slightly easier than manual steering to the right. this is not just from center either, steer all the way to the left easy and as soon as you start turning right it's harder and vice versa.

Any idea what would cause this? Worse case scenario I'll just reseal my old box but would like to fix this one if possible.

Stretch · #2 05-20-2019, 05:07 AM

Quote:

Originally Posted by michael0584

The power steering box on my 85 300d was leaking from the input seal. To make things easy, I just swapped in the box from my 83 300d parts car. The box didn't appear to have any leaks and did not have any slop. Once installed, it steers too easy to the left and not easy enough to the right. Comparing to the old box I'd say 50% easier steering left and 50% harder to the right. It steers way too easy to the left and just slightly easier than manual steering to the right. this is not just from center either, steer all the way to the left easy and as soon as you start turning right it's harder and vice versa.

Any idea what would cause this? Worse case scenario I'll just reseal my old box but would like to fix this one if possible.

Three possible problems that I can think of

1) There's something wrong with the rest of the steering system - steering dampers for example can cause some weird **** - probably not the case if it was all working well before but I thought I'd mention it

2) Pitman arm - check to make sure the same P/N - ID on the new steering box is the same as the old one. There are subtle differences - all explained (ad nauseam) in the FSM

3) Shuttle valve got a bit of crud in it

I did a bit of a big DIY a few years back on the steering box here =>

http://www.peachparts.com/shopforum/diesel-discussion/303379-what-feeling-will-properly-adjusted-w123-w116-w126-power-steering-box.html

If you have the time to read it there's probably more than enough information in that thread for you...

martureo · #3 05-20-2019, 07:56 AM

Quote:

Originally Posted by michael0584

The power steering box on my 85 300d was leaking from the input seal. To make things easy, I just swapped in the box from my 83 300d parts car. The box didn't appear to have any leaks and did not have any slop. Once installed, it steers too easy to the left and not easy enough to the right. Comparing to the old box I'd say 50% easier steering left and 50% harder to the right. It steers way too easy to the left and just slightly easier than manual steering to the right. this is not just from center either, steer all the way to the left easy and as soon as you start turning right it's harder and vice versa.

Any idea what would cause this? Worse case scenario I'll just reseal my old box but would like to fix this one if possible.

The o-ring on the end of the pitman shaft is leaking badly. It's not allowing part of the box to pressurize and essentially reducing the power assist when turning right.

You need both boxes rebuilt. One due to the external leak, the other due to the internal leak.

michael0584 · #4 06-04-2019, 12:11 PM

Thanks guys, I ended up ordering a seal kit and have resealed my original box. Now I just need to swap it back in. I may open up the other box at some point and see if I can see the issue.