Author Topic: Power seering box replacement advise  (Read 2820 times)

afibbe

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Power seering box replacement advise
« on: April 20, 2022, 20:39:54 »
I am looking for some advise on is I should replace my power steering gear box.

Background:
- I have the entire front suspension removed for restoration and I have easer access to the gear box than I will have in the future.
- The existing unit is leaking and will need some new seals.
- The steering is lose but the steering linkage components will be replaced when I reinstall the front suspension.
- I plan to replace the steering wheel bushings and realign the turn signal switch with the wheel position.

Do you have any recommendations on how to test the gear box?  The pitman arm and steering column are is still attached.
Because of easy access now and a new (rebuilt) unit would destroy the budget, would you replace it?  I assume it is the original unit.

Alex Fibbe
1966 230SL
USA, Cincinnati, OH

ctaylor738

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Re: Power seering box replacement advise
« Reply #1 on: April 26, 2022, 13:35:38 »
On my cars, the leak has usually been from the large but thin seal between the bottom plate and the housing where the steering shaft comes out.  To remove the bottom plate, you take the pittman arm off, and remove the screws.  Have a pan handy to catch the fluid.  The seal is probably dried out.  It is difficult to remove, but with a dental pick and some patience you can remove it. Press the new seal in and reassemble.

To get a new seal, you will need to buy an overhaul kit.  I get mine from Authentic Classics.

Misc tips.  Mark the pittman arm and shaft before you remove it.  Get a  M8x1.0 bolt (hard to find) and grind or file the end to a point.  Remove the top bolt from the steering box, center the steering, and put the new bolt in, to engage the steering shaft to hold it in the centered position.  Don’t forget to remove it before driving the car (LOL).

Good luck,

CT

Steering play can be caused by worn bushings in the coupler between the steering box and the steering shaft.  To remove and replace the coupler, undo the five bolts at the inside firewall that hold shaft’s cover.  Pull the cover up to expose the hex bit screws.  Remove the screws and slide the coupler down and off.  Replace the bushings and re-install.  Be sure to have both the wheels and the steering wheel centered.  An unpleasant job.
Chuck Taylor
1963 230SL #00133
1970 280SL #13027 (restored and sold)
1966 230SL #15274 (sold)
1970 280SL #14076 (sold)
Falls Church VA

yves

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Re: Power seering box replacement advise
« Reply #2 on: April 26, 2022, 16:57:45 »
Alex here is the centering pin i made and what i did to keep the steering wheel straight ....  ;)
And be focused about the torque of the nuts  ( don't ask me why ....!) my DIY tool worked fine  ;)
Happy owner of a 69 blue 280SL ,  63 FHC  osb E-type , 55 FHC XK 140 to be restored...

Pawel66

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Re: Power seering box replacement advise
« Reply #3 on: April 26, 2022, 17:13:50 »
Fancy!  ;) ;)
Pawel

280SL 1970 automatic 180G Silver
W128 220SE
W121 190SL
G-class

Kevkeller

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Re: Power seering box replacement advise
« Reply #4 on: April 27, 2022, 00:01:29 »
I replaced all my seals and put it back together. I know there’s a drawing of torque settings but there is some confusion whether they’re correct or not.

What torque numbers did you use?

Kevin
1970 280 SL

dirkbalter

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Re: Power seering box replacement advise
« Reply #5 on: April 27, 2022, 02:15:48 »
Kevin,
Check the BBB. I think its pretty clear.
(I only have the German version)
Dirk
66 230 SL
70 280 SEL
53 CHEVY 3100
18 C300 COUPE
05 HD FLSTNI

Kevkeller

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Re: Power seering box replacement advise
« Reply #6 on: May 09, 2022, 05:03:26 »
Thank you Dirk,
I just checked again in the English version of the BBB and don’t see anything for the power steering box. There might be a little info on the manual steering. Unless I’m missing it of course. The German version must be different. Could that possibly be the manual steering box?

Several years ago I did take mine completely apart to replace seals and tried using some of the numbers from a drawing someone made up but they didn’t seem to be correct.  I reinstalled it.  My car has been off the road for a while but I drove it in a few circles until I saw my axle was leaking fluid and put it away again.

I did buy another used one because one of the special purpose bearing races in the original box had flaked and will probably fail in the future.

Eventually I’ll get around to putting replacement seals in the new box. 
1970 280 SL

dirkbalter

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Re: Power seering box replacement advise
« Reply #7 on: May 10, 2022, 01:09:39 »
Kevin,
If you PM me with an e-mail, I send you what I got. Its in German though.
Dirk
66 230 SL
70 280 SEL
53 CHEVY 3100
18 C300 COUPE
05 HD FLSTNI

afibbe

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Re: Power seering box replacement advise
« Reply #8 on: May 13, 2022, 16:04:29 »
After reading the different post, I decided to replace the steering box with a rebuild from C&D. It id easy to do now.

Thank you all for responding.
Alex Fibbe
1966 230SL
USA, Cincinnati, OH

lowpad

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Re: Power seering box replacement advise
« Reply #9 on: May 25, 2022, 04:48:21 »
Please forgive my ignorance -- who is C&D?
1966 230SL (6/66 build)
French export
4-speed manual
158 Exterior / 040 Hardtop
2001 SLK230
1996 Porsche 993
1991 Acura NSX

ja17

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Re: Power seering box replacement advise
« Reply #10 on: May 26, 2022, 13:23:52 »
You must keep the orientation of the steering column exactly correct, or the turn signals will not cancel correctly. When everything is correct, the slash mark on the end of the steering column (under the horn pad) will be oriented exactly upward and the front wheels will be straight ahead. Also the rotational turns of the steering wheel (from straight ahead) to each side full stop, will be equal on each side. In addition the steering lock will engage when the wheels are straight ahead and the steering wheel is centered. Review all the information on this site to save yourself a lot of frustration. Pay attention on how to lock the steering box on center during installation. Some cars also have a place to pin the steering column on center also during installation.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

afibbe

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Re: Power seering box replacement advise
« Reply #11 on: June 01, 2022, 00:37:30 »
Thank you Joe for the advise. As I removed the steering wheel I could see the mark on the spindle. It was not point big up.  When it goes back together, it will be pointing up and my turn signals will work correctly.

Thank to all for the information in this forum. It has been a great help as I journey through this car.
Alex Fibbe
1966 230SL
USA, Cincinnati, OH

ja17

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Re: Power seering box replacement advise
« Reply #12 on: June 01, 2022, 03:05:54 »
Your welcome, get a volunteer to help you. That steering box can get heavy for one man to handle while trying to keep everything aligned.
Joe Alexander
Blacklick, Ohio
1969 Dark Olive 280SL
2002 ML55 AMG (tow vehicle)
2002 SLK32 AMG (350 hp)
1982 300TD Wagon turbo 4spd.
1963 404 Mercedes Unimog (Swedish Army)
1989 flu419 Mercedes Unimog (US Army)
1998 E430
1974 450SLC Rally
1965 220SE Finback

zoegrlh

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Re: Power seering box replacement advise
« Reply #13 on: June 01, 2022, 20:55:08 »
Had my box replaced. My old box was leaking, thought about rebuilding it, but why do that when you can get a rebuilt box for $450. plus core. Took rebuilt to my garage of 20 years, they replaced it and re-align front end. Did not have to take steering wheel off. Now there is no play in the steering but it does seem harder to turn at parking.
Robert Hyatt
Williamsburg, VA.

W113, 1970 280SL, Red leather 242 on Silver Gray Met. 180, 4-speed stick, Euro spec, restored
R172 2012 SLK350, Black Premium leather 801 on Mars Red 590, 7-speed auto
W211, 2007 E320 Bluetec, Cashmere MB Tex 144 on Arctic White 650, 7 speed auto