Author Topic: Hydro compensator compressor  (Read 12078 times)

wwheeler

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Hydro compensator compressor
« on: April 10, 2013, 14:43:32 »
I am installing the compensator on the rear axle on my '68 W111 and the mounting bolts won't align without compressing it per the manual. Does anybody know how to install this without the compressor? Does anybody have a hydro-compensator compressor that I can borrow? 

Thanks!

Wallace
Wallace
Texas
'68 280SE W111 coupe
'60 220SE W128 coupe
'70 Plymouth Roadrunner 440+6

280SE Guy

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Re: Hydro compensator compressor
« Reply #1 on: April 10, 2013, 15:55:48 »
Wallace,

When I installed my new Hydro Compensator I didn't have the tool you are referring to and did not have the difficulty you are experiencing. Perhaps you could try lining up the bolts before the passenger side trailing arm is fastened to the underside of the body mounting point allowing the swing axle more downward movement.

Regards,

Bob

1971 280SE, 6 Cyl MFI, Anthracite Grey with Grey MB Tex

JPMOSE

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Re: Hydro compensator compressor
« Reply #2 on: April 10, 2013, 17:54:20 »
You guys are brave!!  Every one I've ever spoken to about installing this on my 280SE 3.5has talked me out of it.  I have one that I purchased used in nice condition, but almost hate to remove the compensating spring, as the car sits perfectly level.   My understanding is they failed at an alarming rate back in the day -- the MB Dealer ofter replaced them with springs!   BUT!!! I wish I could trust it and install it on my car...I like everything to be original.

Best of luck!
Best Regards,

J. P. Mose
1968 250SL
1970 280SE 3.5 Cabriolet
1987 560SL

wwheeler

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Re: Hydro compensator compressor
« Reply #3 on: April 10, 2013, 20:23:49 »
With the axles hanging as low as they could with no springs or shocks, the bolt holes were still misaligned by a 1/16". I wonder because my axle is rebuilt, if it has less play and therefore won't move that last little bit. Bob when you installed the compensator, was your axle rebuilt at that time?

The spring compressor is shown in the manaul so it must be needed in some cases (probably like mine). I can make one but was just hoping to save some time and trouble.

My axle had the spring when I got it. If the new compensator fails too soon, it will be back to the spring. I think it is just for keeping the wheel camber in check when heavily loaded and the ride probably won't be a whole lot better. Imagine seeing this new, very expensive Mercedes driving down the road with five people and the back wheels kicked out. Not exactly the image the top brass at Mercedes wanted.

The pagoda only seating two, wouldn't have the rear loading that the sedans and coupes had and therefore the spring was fine.   
Wallace
Texas
'68 280SE W111 coupe
'60 220SE W128 coupe
'70 Plymouth Roadrunner 440+6

280SE Guy

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Re: Hydro compensator compressor
« Reply #4 on: April 10, 2013, 21:37:15 »
Wallace,

Yes my rear axle was rebuilt as yours was at the time I replaced the rear compensator. The old compensator had failed after a drive one day as I pulled Anthracite into the garage and heard a pissing noise coming out of the rear axle. Upon a further look it was the oil coming out of the compensator. The replacement lead into the refurbishment of the rear axle as it looked like it could use a little detailing.

A misalignment of 1/16" shouldn't be too hard to overcome, perhaps you could have your wife help you with the installation  ;D.



Good luck,

Regards,

Bob

1971 280SE, 6 Cyl MFI, Anthracite Grey with Grey MB Tex

71Beige280SL

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Re: Hydro compensator compressor
« Reply #5 on: April 12, 2013, 15:02:50 »
280SE Guy,

Having seen pictures of your beautiful, pristine garage...flat panel, etc. (I share that passion BTW)...your first thought must have been, "what is happening to my Baby, Anthracite"! Your second thought must have been, "look what has happened to my beautiful floor"!  :D
- 1971 280SL Beige/Cognac Leather
- 2019 Mercedes AMG C43 AMG Mojave Silver         
  Metallic/Magma Grey Leather
- 2016 Porsche Cayenne Black/Tan Leather

wwheeler

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Re: Hydro compensator compressor
« Reply #6 on: April 12, 2013, 16:43:31 »
That's a good one Bob :D

But in all honesty, my wife probably had more muscle at the end of the rear axle installation day than my friend and I combined. That was exhausting. Thank goodness for beer and it's rejuvenating properties.

So maybe now that I have recooperated, I will give the compensator another shot before I make a compressor. That's what weekends are for anyway.

Looks to be a low of 50F, a high of 75F and sunny this Saturday. Doesn't get much better than that for working on the cars!
Wallace
Texas
'68 280SE W111 coupe
'60 220SE W128 coupe
'70 Plymouth Roadrunner 440+6

280SE Guy

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Re: Hydro compensator compressor
« Reply #7 on: April 12, 2013, 16:45:57 »
71Beige280SL,

Thanks for your concern but fortunately that event happened back in 1990 or so . . . . w a y before the garage remodel which was in 2011. It also happened before Anthracite had a name !

Regards,

280SE Guy
1971 280SE, 6 Cyl MFI, Anthracite Grey with Grey MB Tex

280SE Guy

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Re: Hydro compensator compressor
« Reply #8 on: April 12, 2013, 17:00:37 »
Wallace,

Could something like a furniture pipe clamp help you to get that 1/16" you need? You can get them almost everywhere, you just need to buy the pipe.



Have a good and successful weekend.

Bob
1971 280SE, 6 Cyl MFI, Anthracite Grey with Grey MB Tex

wwheeler

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Re: Hydro compensator compressor
« Reply #9 on: April 15, 2013, 03:39:29 »
So the compensator is now on! It took several iterations to finally line it up. Thanks for everyone's input.

The axle is hanging from the center mount with the shocks helping to support the axle ends. I also have the cross adjusting rod on for stability.The trailing arms are on but not the springs. I Left the left shock on but removed the right shock to get full rotaion from the right axle. I ended up NOT tightening the ball stud compensator mount because the travel of the ball joint was not enought to allow the compensator to move into position. Proir, I had it tightened. Both bracket bolts then JUST barely lined up and that was that.

Getting the right shock back on was a chore since the compensatot was now on. I did end up having my wife help with that!     

Wallace
Texas
'68 280SE W111 coupe
'60 220SE W128 coupe
'70 Plymouth Roadrunner 440+6

280SE Guy

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Re: Hydro compensator compressor
« Reply #10 on: April 15, 2013, 10:23:43 »
Congratulations Wallace, glad you got over the hurdle.

Sometimes an extra set of arms and hands make the job easier.

Regards,

Bob
1971 280SE, 6 Cyl MFI, Anthracite Grey with Grey MB Tex

wwheeler

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Re: Hydro compensator compressor
« Reply #11 on: April 15, 2013, 15:59:27 »
Yea and brains.
Wallace
Texas
'68 280SE W111 coupe
'60 220SE W128 coupe
'70 Plymouth Roadrunner 440+6

280SE Guy

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Re: Hydro compensator compressor
« Reply #12 on: April 15, 2013, 18:52:27 »
Yea and brains.

Yes, that is usually the way things go  :) Sometimes you just need added input.

Now that I've been thinking about it for a few days I believe that my Hydro Compensator was installed prior to installing the shocks and springs (after the axle vertical center link was fastened to the chassis). The springs were the next thing to secure to the trailing arms followed up by the cross strut then the shocks for anyone else that might be interested in the sequence..

Your wife deserves a prize.

Regards,

Bob
1971 280SE, 6 Cyl MFI, Anthracite Grey with Grey MB Tex

wwheeler

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Re: Hydro compensator compressor
« Reply #13 on: April 15, 2013, 21:43:36 »
She got one......me :D
Wallace
Texas
'68 280SE W111 coupe
'60 220SE W128 coupe
'70 Plymouth Roadrunner 440+6

JPMOSE

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Re: Hydro compensator compressor
« Reply #14 on: April 21, 2013, 16:53:54 »
Wallace,

How do like the Hydro Comp  so far?  I am curious if you notice any ride change?  I still have mine in a box, but have doubts I'll install it (due to lack of time and usually 2-3 people in the car at most..and that's rare).

I also know that the unit has a better chance of leaking from just sitting un-exercised.    I wonder how beneficial it would be to pull the rod in and out a few times once a month...or is this just a waste of time?
Best Regards,

J. P. Mose
1968 250SL
1970 280SE 3.5 Cabriolet
1987 560SL

wwheeler

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Re: Hydro compensator compressor
« Reply #15 on: April 22, 2013, 03:06:19 »
JP,

It will be a while (2 months) until I can test the compensator, so I can't be much help there. I did ask several people about the benefits before I went to the trouble of rebuilding. From what I found, everyone agreed it helps keep the rear wheel camber near 0. No agreement on ride improvement. Some said it did and some said no effect. Nobody said it was detremental though. I think the rear wheel alignment was main reason MB went to trouble and expense for these units. After all, the swing axles had a reputation for that.

I don't really know much about these mysterious units so I can't say for sure if contracting the rod from time to time will extend its shelf life. Others may have a better idea. I do know this; it requires some serious force to compress that rod. I used a hydraulic press. If you have it, you should put it on. It won't last forever in the box.   
Wallace
Texas
'68 280SE W111 coupe
'60 220SE W128 coupe
'70 Plymouth Roadrunner 440+6