Author Topic: New 6.9 rear suspension spheres and other work  (Read 579 times)

rumb

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Re: New 6.9 rear suspension spheres and other work
« Reply #15 on: 26 February 2020, 07:02 AM »
Classic example is the front suspension upper control link which is steel over alloy.
huh!

6.9 front upper control arm is also aluminum.
'68 250S, '77 6.9 euro, '91 300SE, '98 SL500 '14 CLS550

daantjie

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Re: New 6.9 rear suspension spheres and other work
« Reply #16 on: 26 February 2020, 09:11 AM »
Classic example is the front suspension upper control link which is steel over alloy.
huh!

6.9 front upper control arm is also aluminum.

I think they were steel from the factory if my memory serves.  I replaced mine with some Lemforder ones, and I think you can now only find the alloy ones, though I stand to be corrected...Part number 123 330 4606/4707 for LHS/RHS
Daniel
1977 450 SEL 6.9 - Astralsilber

gavin116

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Re: New 6.9 rear suspension spheres and other work
« Reply #17 on: 26 February 2020, 10:24 AM »
Sadly Adam, the underside no longer looks quite so pristine. I do use the car in all weather, and it has done two France trips since that suspension works were done. Those trailing arms were stripped and then repainted silver just to be a little different. Apparently if you bought replacements from Mercedes they were 'raw aluminium'. They were originally sprayed black from the factory.

TJ 450

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Re: New 6.9 rear suspension spheres and other work
« Reply #18 on: 27 February 2020, 04:04 AM »
The original 6.9 upper arms are cast iron although quite a few would have been replaced by alloy ones now (mine included). I have two sets of cast iron ones around.

The procedure for the rear trailing arms was to paint them prior to assembly/ fitment.

6.9 trailing arms are cast alloy like the 450SE/L and the upper end W126s. Lower spec cars had welded steel sheet metal arms.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Randys01

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Re: New 6.9 rear suspension spheres and other work
« Reply #19 on: 28 February 2020, 12:22 AM »
The original 6.9 front upper control arm was steel. I bought the last one some years ago. Alloys were used on the lighter models..now very avail from anyone and everyone and doubtless finding their way onto 6.9's as the only viable option. Situations like this make me wonder where one stands in an Insurance Claim. 


adamb

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Re: New 6.9 rear suspension spheres and other work
« Reply #20 on: 29 March 2020, 02:01 PM »
The fuel pump replacement task is completed. Phew.

I started the work on changing the propshaft coupling, i.e. the rubber donut connecting the prop to the diff. But sadly I've had to give up. The last time I had the coupling off was a long time ago when I took out the diff. I tried disconnecting the diff from the suspension assembly today but got stuck. The diff body is mounted under the rear suspension assembly with 4 nuts. I could not undo one of the back ones. I just can't get enough force onto the spanner while lying under the car. It's very tight under there. I wonder if I did it up too much when I was reinstalling the diff... Anyway, I'm going to have to give this job to professional mechanics. As a matter of interest, I assume that it's possible to replace this coupling by lowering the prop. Is that right?


daantjie

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Re: New 6.9 rear suspension spheres and other work
« Reply #21 on: 29 March 2020, 02:47 PM »
To remove the flex disk you must of course remove large bolts connecting the prop shaft to the diff, then you need to pry it off with a long lever.  The prop shaft telescopes and by undoing the large collar nut you can make the shaft collapse into itself which gives more room.  Doing this on the ground is very hard, and you pretty much do need a lift for this job.
Daniel
1977 450 SEL 6.9 - Astralsilber

ptashek

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Re: New 6.9 rear suspension spheres and other work
« Reply #22 on: 30 March 2020, 10:18 AM »
Not sure I'd want to drive Gavin's car on dirty roads. The underside doesn't stay that pristine for long.


It's not that bad actually. Goldie still looks pretty clean despite now nearly four years and 16k all-weather non-winter miles on the road post-resto.
The semi-transparent wax it's coated with all-over underneath does slowly, but surely, accumulate stone chips which I patch up once a year, and road grime on the surface so it'll get manky with years for sure. Doesn't matter as long as it keeps rust away :)



1993 "Pearl Blue" W124 280TE
1979 "Icon Gold" W116 450SE (history, resto)

rumb

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Re: New 6.9 rear suspension spheres and other work
« Reply #23 on: 30 March 2020, 10:31 AM »
I suppose a factor in bottom side cleanliness is how wet or dry the roads are where you live.
'68 250S, '77 6.9 euro, '91 300SE, '98 SL500 '14 CLS550

adamb

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Re: New 6.9 rear suspension spheres and other work
« Reply #24 on: 30 March 2020, 02:45 PM »
For the flex disk, the nuts go at the diff/trans end from memory, however not 100% sure to be honest. Lots of posts online on other forums too, like W126 peachparts as well as Benzworld, as the methodology is the same across many models 116 126 107 etc. Make sure you place the washers correctly, there is only 1 right way to do this.  Wherever you have a "raised" section, you do not place a washer underneath the bolt head or nut.  Washers only go against the "flush" portion, if that makes sense.


My replacement flex disc has this handy picture showing the direction of the bolts. I no longer recall how they were fitted back when I first had the diff out so I fitted them the same as in this pic.


adamb

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Re: New 6.9 rear suspension spheres and other work
« Reply #25 on: 30 March 2020, 02:59 PM »
One more task while the back of the car is in the air is to change or top up the diff oil. The drain bolt on mine is seized. No amount of hammering would move it. The only way to drain would have been to remove the rear diff plate. The oil was changed only 18K miles ago and the oil still looked very fresh. So I decided not to bother draining.

Top up was achieved with this handy purchase from a local motoring store.. This cheap hand pump refills your diff with oil in a few minutes.



rumb

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Re: New 6.9 rear suspension spheres and other work
« Reply #26 on: 30 March 2020, 03:02 PM »
o I recently found that an impact wrench made quick work of removing drain and fill plugs.
'68 250S, '77 6.9 euro, '91 300SE, '98 SL500 '14 CLS550

ptashek

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Re: New 6.9 rear suspension spheres and other work
« Reply #27 on: 30 March 2020, 05:45 PM »
My trick is to wind some PTFE (plumbers) tape on the plug threads, minimising the chance of seizing, and leaks too. Never had any issues with it.

Adam, what's the name for that pump? Might check my local Halfords if they have one.
I did it the hard way a couple weeks back, won't ever bother again :D
1993 "Pearl Blue" W124 280TE
1979 "Icon Gold" W116 450SE (history, resto)

daantjie

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Re: New 6.9 rear suspension spheres and other work
« Reply #28 on: 30 March 2020, 06:26 PM »
I also had a major wrench dance with the drain plug.  Had to resort to drilling and easy out.  It was nasty but I got my man ;D
Daniel
1977 450 SEL 6.9 - Astralsilber

adamb

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Re: New 6.9 rear suspension spheres and other work
« Reply #29 on: 31 March 2020, 04:27 AM »
My trick is to wind some PTFE (plumbers) tape on the plug threads, minimising the chance of seizing, and leaks too. Never had any issues with it.

Adam, what's the name for that pump? Might check my local Halfords if they have one.
I did it the hard way a couple weeks back, won't ever bother again :D

I have an impact wrench but not with me at the time. I used the old fashioned technique of a spanner and a large hammer. It still wouldn't budge.

I also uses boss tape white for threads. It's a smart move. Stops leaks too!

This is the pump I bought : https://www.halfords.com/tools/hand-tools/automotive-tools/laser-multi-purpose-mini-pump-121841.html