Re-bushing rear suspension : now with pictures !new!

[s class]

Guys, this weekend I intend to rebush the rear suspension of my W116.  I have been putting this off for a while now because the misery value will be high.  THe worst will be the bushes between the trailing arms and the subchassis.  I have tried to replace them in the past "in situ" by unbolting one mounting point at a time, but it was impossible because the bushes were frozen in their locations.  So I have decided there is no other option than  to remove the trailing arms one at a time (which means removing the dampers and springs) so that I can get the traling arm to the press.

I will try to take some pics - may be useful to others. 

Cheers, Ryan

[Tomi]

Wau, this must be one of the most nasty jobs to do, have no experience of this one. Probably you have to disconnect the shaft too. Are you experiencing steering problems or what

I thought you were getting married  , then I realised that it must have happened in the past (in th other topic). this is not a honeymoon job, not at all.
good luck and I will be interested to see pics. Tomi

[oscar]

I thought you were getting married  , then I realised that it must have happened in the past (in th other topic). this is not a honeymoon job, not at all.

Gee whiz, that would lead to a quick divorce.

I will try to take some pics - may be useful to others. 

Cheers, Ryan

Ryan, I'd love to see pics and even a "how-to" if your up for it.  I have trouble naming all the parts of my suspension.  There's a bit of noise on bumps and after braking from front and back and I'm not 100% sure on where the probs are except to say the front end has had some work(can't remember off hand what was done) and most rubbers etc need replacing.

Any insight into DYI would be most appreciated.

[s class]

Yes I have been married now about 18 months, so I am a family man and that makes it difficult to come by time to do jobs like this.  I only managed to grab 2 hours, so I replaced the bushes on the one side of the rear suspension only.  I will do the other side next week.  I have pics of everything including removal of the rear spring.  I will post them in the gallery later this week when I get a chance. 

The reason I have undertaken this job is that the car is suffering from an incorrect rear thrust angle.  So even when the front wheel alignment is correctly set, the car still pulls to the left.  I am hoping that new bushes at the rear will correct the problem.

I completely overhauled my front suspension about a year ago, and sorry, no pictures, but I can describe it roughly if anyone wants to know.  Anyhow, let me first post the procedure for the rear end. 

Cheers, Ryan (still with 10 fingers despite playing with compressed springs)

[s class]

Heres some pointers on changining rear supension bushes. 

The process must be done one side at a time.  don't try and unbolt everything any both springs at once.  The description below refers to the left hand side. 

1) support the rear of the car on good stands.  Position the stands under the rear jacking points (provided they are not too rusty), not under the the rear subchassis mounting points since we need to unbolt them later.

2) W116 trailing arms have "end stops" welded onto their leading edges which prevent them dripping too far below the rear sub chassis when the car is jacked up.  As you can see in the pic below, someone in the pasy cut mine off.  What this means is it is now the shock abosrber which stops the trailing arm deflecting all the way down when the car is jacked up.  So I will leave shock absorber removal for later in the process (I need it now to keep the spring in check.)


3) remove the left rear brake caliper and support it out of the way - the rear anti-roll bar is a convenient place to support it. 


4) remove the crown nut in the centre of the left rear hub and press or tap out the drive shaft (shouldn't be too difficult).  Support it as well, making sure you don't let it hang under it's own weight as this can damage the joints.


5) disconnect the left rear anti roll bar hanger.  Before you do this try to ascertain whether it is under tension or compression so that you can avoid nasty surprises when you disconnect it.  If necessary you can lever the roll bar up or down to relieve forces. 


6) NB place a suitable jack under the left rear trailing arm to bear the force of the spring once the shock absorber is removed.  Actually a stand is better than a jack.  you need some upward force under the trailing arm to slightly compress the spring and relieve the tension off the shock absorber.  Obviously don't jack up the trailing arm so much as to unsettle the car's resting place on its own stands. 

7) remove the rear seat back to access the strut top.  Remove the left rear strut top retaining nuts. 


remove the left rear shock absorber's lower mounting bolts and withdraw the shock absorber downwards through the trailing arm.  See the picture below.  I the picture, the blue stand is supporting the car, the green trolley is supporting the trailing arm against the force of the spring.  I was a bit naughty - a stand would be much safer here.


9) take a deep breath, make sure the car and trailing arm are very securely supported.  Insert the spring compressors up the inide of the left rear spring from the bottom.  Engage them and tension them.  The task of compressing the spring is greatly eased if you trap as many turns as possible in the compressors.  THis is the dangerous part of the job and why I say make double sure everything is well supported an braced. 


10) Now you can gently lower the support under the left rear trailing arm.  If you car has the trailing arm end stops in tact, this will limit the downaward travel.  If the end stops are missing as in my case, lower the arm gently - but not too much as the spring will jump out. 

11) withdraw the spring.  This may require further compressing it.  So don't use the rubbish compressors like I used - I once had one explode on me and release a compressed spring - still some plaster missing on the garage wall.  See below - the removed, compressed spring.  You can see how much strain the cheap compressors are taking.  I would not stand too close to this lot for any length of time. 


12) aah at last - picture shows the left rear trailing arm now just resting on a stand since the spring is out. 


13) position a good jack under the left rear subchassis near the left mounting point under the rear door.  NOte the car is still supported on it's own stands.  remove the bolts holding the left mounting of the subchassis (sorry, I forgot to take pics of this).  With the other side (right side) of the subchassis still mounted, you can lower the jack supporting the loosened left side about 3 or 4 inches.  Replace the subchassis mounting bush.  Leave the subchassis left side lowered for the next step.

Now the left trailing arm is secured to the subchassis at 2 points- remove these bolts and free the trailing arm from the subchassis - be careful - its actually quite heavy when it wants to drop down. You need the subchassis lowered to access the outboard bolt

14) see the crusty old trailing arm bushes


15) press out the old bushes - I did this lying under the car so as to avoid having to disconnect the hand brake cable.  If you must take the arm to a bench, then between steps 4 and 5 above, disconnect the hand brake cable.

16) press in the new bushes with the aid of red rubber grease.

17) as they say in all the manuals : "refitment is the reverse of the removal process"

Just note the following :
WHen remounting the trailing arm to the subchassis, use new split washers. 
When refitting the brake caliper, use locktite and new locking plates.
When refitting the spring, ensure the rubber spring top gasket thingy is properly positioned.  I greased the top of the spring with red rubber grease to ease fitment
Ensure the lower end of the spring coil is properly located in its hollow.

Then its time for the right hand side which is the mirror image of the above.

After that you can also replace the rear diff mount if you choose - its the third and final mounting point of the subchassis and fairly self explanatory.

Disclaimer - I offer these tips to other members to use at your own risk - I take no responsibility for people using these tips.  Realise that working on supsensions is dangerous.  Do not attempt to work around compressed springs without the proper tools, or if you are unsure what you are doing.  At each step of the process, I was careful to take a step back, think about what I was doing, make sure everything was properly supported and that my next intended move would not release a compressed spring. 

Above all this was actually a fun job.  I'd be interested to hear if anyone else attempts this. 

[oscar]

That's excellent Ryan.  Thanks.  Not my next job but great reference.

[s class]

Big Richard - I envy you guys without springs. 

For what it's worth, removing the rear springs is child's play compared to front springs.  The fronts are much stiffer, taller and narrower so they want to "boing" oit to the side when you compress them. 

Cheers, Ryan

[Andrew116]

My dad has a 300D from 1980 with a 5 inline diesel engine. From that starts my passion for classic mercedes.
So now... I have 280 se from 1978     - 6 in line... also have LPG mounted on in... works just fine
This one is in quite good condition...
Just have a problem: it leaks the cooling fluid from the water pump, I think. So I have to give it a closer look if I don't want to keep adding 1litre of fluid each 100 kms.
I'm interested in this cars so.... hope we keep in touch.
Nice job with the bushes! 
And excuse my english... I might have some mistakes.. Bye

[s class]

Andrew,

Welcome to the site.  Don't worry about the english - here we welcome all W116 fans, and we have quite a range of nationalities represented. 

I hope you can solve your coolant leak - there are many experienced members here who may be able to provide some tips.

Ryan in South Africa

[Andrew116]

We took care of that quite easily. With the car down (not suspended and not using jacks), steered max left (for the left spring), and with 4 men on the hood  to help compress the spring, we took a strong chain and tied it up, fixing the links of the chain with screws.
And so we got rid of the bouncing problem you were talking about. The rest is suspending and unmounting screws and bars.

[Andrew116]

Thanks a lot. I know what it means to own Mercedes so I think all on this forum are great people.
Also thanks for the tip. I might just ask Ryan about that.

[Denis]

Hi fellows

Can I add to Ryan's superb DIY repair show ?

Considering their cost, use TWO sets of cheap spring compressors ! The stress is far less, it is far safer and does no cost much more. Auto stores around the world sell the same chinese garbage these days 

When I did this, I also added more safety with a slightly silly idea : clamps on the spring coil on each side of the jaws to keep the outfit from suddenly moving. IOW, I simply added some small hose clamps on each side of  the jaws thinking that nothing would happen "very suddenly" if the jaw were strained into shifting on the coil. Advance warning is always a safety factor.


A warning to my anglo-saxon friends : NO beer while doing these jobs...me ? cognac of curse 
Just joking...

Denis

Paris, France