Author Topic: URGENT - need help with high-pressure power steering hose  (Read 1695 times)

Jan S

  • Classic
  • **
  • Posts: 102
  • W116 Enthusiast
  • Location: Norway
This year's 3-week summer road trip with the W116 in danger  :o

A few days ago I noticed a leak in the high pressure power steering hose.

A workshop in the area suggested to put in a new rubber hose and mount it to the 10 mm and 8 mm pipes at each end (where the old hose was attached, but with new hydraulic adapters/connectors between pipes and hose). Sounded as a good idea. However, by pure mistake the mechanic cut the 10 mm pipe at the power steering pump inlet at the wrong spot. Ggrrrrrrr!

Now I'm in dire need of the hard line (part of the hose) at servo steering pump end. I don't need the rubber hose and the hard line at the steering box.

If you have this part around and would be willing to sell it I would ask UPS to pick it up.
1975-mod W116 450 SE with 6.9 engine

Randys01

  • Classic
  • **
  • Posts: 267
  • W116 Enthusiast
  • Location: adelaide australia
Re: URGENT - need help with high-pressure power steering hose
« Reply #1 on: 30 June 2021, 05:32 PM »
Get the local Pirtech or equiv mobile hyd hose repair service to visit you.

Jan S

  • Classic
  • **
  • Posts: 102
  • W116 Enthusiast
  • Location: Norway
Re: URGENT - need help with high-pressure power steering hose
« Reply #2 on: 01 July 2021, 06:39 AM »
I found the hose on ebay, and the seller in Germany have shipped it with 24 hours over-night delivery service. Fingers crossed the part fits my car  :)
1975-mod W116 450 SE with 6.9 engine

Jan S

  • Classic
  • **
  • Posts: 102
  • W116 Enthusiast
  • Location: Norway
Re: URGENT - need help with high-pressure power steering hose
« Reply #3 on: 15 July 2021, 03:20 PM »
The hose fits, but leaks  >:(

The problem is the mounting surface between power steering pump (convex surface) and the high pressure hose (concave surface).

Both the pump and the hose surfaces have some scoring. When fit together it will not seal properly ..... probably.

How to fix this?

Any experience with sanding/polishing both surfaces? What tools to use?

Can this part of the pump be "reconditioned"?
1975-mod W116 450 SE with 6.9 engine

Alec300SD

  • Classic
  • **
  • Posts: 202
  • W116 Enthusiast
  • Location: San Mateo, CA
Re: URGENT - need help with high-pressure power steering hose
« Reply #4 on: 15 July 2021, 05:06 PM »
Use a copper aviation conical crush washer to seal the union.
79 W116 300SD 'Stormcloud' new as of 10/22/2017
78 W116 300SD 'Desert Rose' new as of 01/26/2014
83 W126 300SD 'Rena 2.0' with engine from 82 W126 300SD Rena' (SOLD and crushed 11-20-2017)

raueda1

  • Vintage
  • ***
  • Posts: 804
  • Assimilated. Resistance is futile.
  • Location: Salt Lake City, Utah
Re: URGENT - need help with high-pressure power steering hose
« Reply #5 on: 15 July 2021, 09:17 PM »
Use a copper aviation conical crush washer to seal the union.
And tighten in one motion without stopping or reversing.  Cu washers can be used just once.  Otherwise heat it to glowing with a torch and quench in water (annealing?).  Can you post a picture of the problem?
-Dave
Now:  '76 6.9 Euro
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

Jan S

  • Classic
  • **
  • Posts: 102
  • W116 Enthusiast
  • Location: Norway
Re: URGENT - need help with high-pressure power steering hose
« Reply #6 on: 22 July 2021, 02:16 PM »
Thanks to both of you for advice!

I will try to get some "copper aviation conical crush washers" when I'm back after the summer vacation (the summer road trip went down the drain  :( )

Alec300SD: How does a washer like the one you mentioned look like? Can you send a link to a picture?
1975-mod W116 450 SE with 6.9 engine

Alec300SD

  • Classic
  • **
  • Posts: 202
  • W116 Enthusiast
  • Location: San Mateo, CA
79 W116 300SD 'Stormcloud' new as of 10/22/2017
78 W116 300SD 'Desert Rose' new as of 01/26/2014
83 W126 300SD 'Rena 2.0' with engine from 82 W126 300SD Rena' (SOLD and crushed 11-20-2017)

Jan S

  • Classic
  • **
  • Posts: 102
  • W116 Enthusiast
  • Location: Norway
Re: URGENT - need help with high-pressure power steering hose
« Reply #8 on: 28 July 2021, 11:22 AM »
Great!

I included two pics. The first from the convex connection at the steering pump (outer thread is M16), the second from the hose/pipe flaring (the pipe is 10mm at base).

I'm a bit confused with the size of the washer. The Amazon-link says 1/2'' Tube OD .... OD probably stands for outer diameter. Do they mean the outer diameter of the washer? Will that washer fit the connection?

What do you think, Alec300SD?
1975-mod W116 450 SE with 6.9 engine

Alec300SD

  • Classic
  • **
  • Posts: 202
  • W116 Enthusiast
  • Location: San Mateo, CA
79 W116 300SD 'Stormcloud' new as of 10/22/2017
78 W116 300SD 'Desert Rose' new as of 01/26/2014
83 W126 300SD 'Rena 2.0' with engine from 82 W126 300SD Rena' (SOLD and crushed 11-20-2017)

3l33ter

  • Classic
  • **
  • Posts: 108
  • W116 Enthusiast
  • Location: San Francisco bay area
Re: URGENT - need help with high-pressure power steering hose
« Reply #10 on: 29 July 2021, 08:41 PM »
I'm glad to now know that conical washers exist.

I guess the scoring happened when the fitting was tightened down with some dirt/debris in there.
'75 280S
'77 6.9
'82 300TD

Jan S

  • Classic
  • **
  • Posts: 102
  • W116 Enthusiast
  • Location: Norway
Re: URGENT - need help with high-pressure power steering hose
« Reply #11 on: 30 July 2021, 12:11 PM »
Perfect - I ordered both 3/8" and 1/2" to be on the safe side.

Thanks!

I will keep you posted how it goes.
1975-mod W116 450 SE with 6.9 engine

Jan S

  • Classic
  • **
  • Posts: 102
  • W116 Enthusiast
  • Location: Norway
Re: URGENT - need help with high-pressure power steering hose
« Reply #12 on: 19 August 2021, 12:28 PM »
The 3/8" conical copper washer finally arrived and fitted perfectly, it seems (the 1/2" washer was to big).

I did a short test drive tonight and couldn't see any leakage. I guess I need to monitor the situation closely for the next weeks and months. So far so good.

Thanks for the tip, Alec300SD!
1975-mod W116 450 SE with 6.9 engine

Jan S

  • Classic
  • **
  • Posts: 102
  • W116 Enthusiast
  • Location: Norway
Re: URGENT - need help with high-pressure power steering hose
« Reply #13 on: 28 September 2021, 02:34 PM »
The copper washer works fine -- no leakage!
1975-mod W116 450 SE with 6.9 engine