KYB shocks........its got to be said

[n/a]

I have been fighting with myself over new shocks for months....I live in the country over a very rough road. The car bottoms frequently. I installed aluminum blocks in the front springs to get more clearance between the body and the rubber snubbers. these helped a little. I spent HOURS reading all about the Bilsteins, Bilsteins and more Bilsteins...Well money is hard to come by when you are retired and maintaining 3 more restored muscle cars...so I compromised? and bought the KYB gas adjust for less than 82.00 a piece....well what a surprise the car rides like one of my big wheelbase convertibles, you would swear you are riding on 4 pillows..Now for the final...would the car ride better on Bilsteins, probably not..would it corner better with the Bilsteins..most likely but that was not the purpose..anyway I love my car again..new shocks make a world of difference.

[enochbell]

Glad to hear the KYBs worked for you, sounds like you have a special requirement for adjustable shocks for your rough roads.  I just installed Billsteins from a recommended source on this board, cost was $64.95 each.  What a difference (I think my old shocks were the ORIGINAL shocks, making them 42 years old!).  

g

'64 230sl, fully sorted out...ooops, spoke too soon

[JimVillers]

G .... Were the old shocks that you removed from your car gas pressurized shocks?  I am trying to understand if the original shocks were pressurized or not.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[enochbell]

It is just my assumption that they were original, judging by their condition.  Yes, they were gas shocks...but as you can imagine there was zero pressure in them. I just collapsed them and tossed them in the trash.

The BBB shows procedure for installing gas shocks, so it would not surprise me if they were original but I can tell you this: original shocks are NOT going to win you points on the concourse :-)

Greg

'64 230sl, fully sorted out...ooops, spoke too soon

[A Dalton]

quote:Originally posted by JimVillers

G .... Were the old shocks that you removed from your car gas pressurized shocks?  I am trying to understand if the original shocks were pressurized or not.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

Jim
 I forgot to answer that one in an email..

 If they are Bilsteins , they are gas.. if they are standard , they are not..
 BBB 32/8

[Bob G ✝︎]

I heard good things about KYB gas adjust shocks. I want to get  a pair for my two toyota's glad they work out for your SL good choice.

bob Geco

[JimVillers]

Arthur ... Thanks.  After following your lead, I figured out that 230SL and 250SL had the standard shocks, non-gas while the 280SL had the Bilstein shocks (Gas).  That answers why the confusion.  My thesis is that putting gas shocks on a car not designed for them results in a slight lifting of the front.  The gas shocks would have less of an impact on the rear because of the suspension configuration.   I believe that this was the cause of my "rear sag" that I fought for several years until I replaced my front springs and shocks.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[A Dalton]

According to my ref. , 230/250 had Gas Bilsteins or Standard shock, determined by which road springs were used .. The heavy spring unit used reg shock. Standard springs used gas.
 A lot of rear sag  on swings is also caused by worn rubber in the  upper and lower hanger mounts.  
I also always use 6mm comp spring end mount rubbers on both sides of comp to increase pos camber and help w/sag. [ Ray paul suggested these years ago and that is all he stocked]

[JimVillers]

Arthur .... At Ray Paul's suggestion, I installed the thicker (my old bushings were the same thickness) rubber bushings but that did not correct my "sag".  Replacing the center differfential mount also helped a little but not enough.  I finally decided that the problem was that the front was too high.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[A Dalton]

Many guys I have seen over the years have had luck with the Konis on the back , cranked up to to suit.  They still used the Bilstiens up front.
 I also hear that the sedan springs help , but I have never tried it ..I personally think the rear spring rate goes soft with age..
 ..and that lower mount on the hanger will fool you .. if the pivot pin bolt head does not look centered with the mounts outer casing , change it.. it makes as much difference as the trunk mount...and much better handling b/c the orig mount was hollow and the replacement is rubber full through, giving much more support as axle swings through the arc.. this is not just a hanger, it is actually a flex joint and the outter and inner parts are fixed and do not turn, but flex under camber change load.

[enochbell]

Arthur, when you reference the pivot pin bolt head are you talking about the lower shock mount or the swing axel?

Thanks,
greg

'64 230sl, fully sorted out...ooops, spoke too soon

[A Dalton]

Pivot pin is the long ror that goes trough the swing joint of the hanger and right axle casing. It is the swing hinge pin, so to speak.
 It is also the reference point for axle centralization , which should be 36mm +/-2mm offset to the right of chassis C/L.
 These usually get eaten out from long time pinion seal leak/seepage..

[JimVillers]

Arthur .... I have not changed those items: #143 and #153.  I'll take a look at them.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[A Dalton]

The part I refer to is #111.  This is the hanger lower mount.
 The others are cross strut link mounting rubbers .

[enochbell]

Now I see, said the blind man.  I am sure mine is perfectly fine.  That is to say, if it is not, I ain't going there without a little more experience.  Thanks,

Greg

'64 230sl, fully sorted out...ooops, spoke too soon

[A Dalton]

Originally posted by enochbell

Now I see, said the blind man.  I am sure mine is perfectly fine.  That is to say, if it is not, I ain't going there without a little more experience.  Thanks,

Greg

 I hear ya, .. it is a little tricky job, but only the first time.

 I only mention it b/c it is one of the few suspension parts that one can tell if it is bad by simply eye-balling its center in reference to the pin bolt center.. Just an easy obsevation that can be made when under a loaded suspension chassis. I can spot a bad one from 20 feet away ..and should always be checked when one has a known leaking/seeping rear pinion seal...along with the vent.

[Vince Canepa]

Arthur is correct on the shocks.  According to the Technical Data Books 1963 and 1969, all W113 SLs equipped with "standard" springs were equipped with Bilstein B36 gas shocks at the front and B46 gas shocks at the rear.  F & S gas shocks are also listed, but I don't think many cars were delivered with F & S - I've never seen one.  The only cars fitted with a quote "standard" shock were the ones delivered with "harder springs for poor road conditions".

One thing to keep in mind about ride height on any M-B.  They don't worry much about the actual height.  The specs always refer to suspension geometry such as the angle of the lower control arm in relation to some other reference point.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex

[JimVillers]

Thanks Vince.... I was mis-reading the data.  So much for my theory that gas shocks are contributing to the "ride height problem".  While I have fixed the ride height on my car with replacement springs, I still wonder if there is a generic cause to the common "low in the rear or high in the front" condition.  

When you are over on the 27th, bring you gages to measure suspension angles.  We should have 4-5 pagodas to compare.


Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[Vince Canepa]

After reading Arthur's comments on the hanger mount, I examined mine.  Not good.  At the rear of the rubber mount the connecting bolt (pivot pin if you like) is at the bottom.  In other words, the connecting bolt is off center to the bottom, 6-8 mm by eye.  At the front it looks more centered.  

So my project install my new rear axles has stopped until I pull the assembly and fix this.  Without the assembly in the way I can take care of some other stuff that has been on the worklist for quite some time.  Actually, I have known the rubber mount was going bad for quite some time - I just didn't want to face the project.  So Arthur's reminder probably saved me a bunch of frustration down the road.

Interestly, my pinion seal has never leaked, but this will be the second time I've had to replace this mount in 146,000 miles.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex

[A Dalton]

Vince ,
 I just did a tutorial on this mount over at MercedesShop that I think you followed, so just a few comments here .
 There are two reasons for premature wear on this mount aside from the rear seal leak. The first is that the original mounts are not rubber cored the full length of the casings. They are on the ends only.[ Hollow]
 Even early OEM replacements.  But the new ones now have full rubber insert, resulting in a robust mount. I have not seen these fail.
 The other fail rate comes from install error. This mount must be cinched down only after the suspension is loaded and the hanger is set at 90 degrees to the C/L of the left axle. This gives the proper flex , both +/- on the swing to the flex of the joint.  There is also a location measure for lateral set, but that can be premeasured to the old in most cases. The right angle is the important one. If  you have the rear out of the car , the loaded suspension does not apply, only the angle.. it is also important that the cinch bolts are tightened BEFORE any adjustments are done with the axle centering cross strut, as that also comes off the side of the same hanger.

[Vince Canepa]

Thanks for the guidance, Arthur.  I understand the "zero" preload adjustment angle.  It is much like any rubber suspension bushing - the idea is to set it mid-range of movement.  All this was done way back when the dealer did this job (I watched).  I do think this bushing sees some longitudinal stress also.  It looks to me like the trailing arms and this hanger form a triangle that resists the torquing of the axle assembly.  Without the assembly out of the car, it looks like a very shallow triangle, and thus, maybe it is not as strong as it could be.  I say that because the last time it failed, I could feel the axle rotate through a range and then "thunk" (sounded like a baseball bat rolling in the thrunk) when accelerating from a stop.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex

[A Dalton]

<< I do think this bushing sees some longitudinal stress also. >>


 That is correct .. and that is the other measure I mentioned .. again, set at zero load [ as you say, mid range, between +/- ]
 That can easily be measured with unit out from the front flange surface back to the hanger top face..

.. ..as I said, the new replacement is solid through rubber , so the fail rate is now nil.. and the camber swings are much tighter due to
more load needed to flex the same angles..
 The thunking is the first sign of failing rubber and is usually heard in tight corners under acceleration...
The top mount also relieves some of the lateral force you mention, as do all the parts..
 .. another reason I think [ and insist on my own cars] that axle centralization is an important spec that most just dismiss...

[Vince Canepa]

I've got everything stripped except for the shocks and top mount.  Tomorrow I will fashion fixture to support the assembly and drop it down.  I looked carefully into the split on the support and it looks like the two piece setup.  The rear bushing is really bad - even worse that it initially looked.

I have to fashion the centering fixture.  I had the side support bushings replaced and the centering checked back in '89.  I didn't disturb the seting, so hopefully it will be close.  You are right to be concerned about centering the axle - the car simply can't drive right without attention to such details.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex

[JimVillers]

Arthur .... Here is the tool design that you passed me years ago for the 190SL http://www.190slgroup.com/tech/images/121axle.jpg.  It is still posted.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

[A Dalton]

quote:Originally posted by JimVillers

Arthur .... Here is the tool design that you passed me years ago for the 190SL http://www.190slgroup.com/tech/images/121axle.jpg.  It is still posted.

Jim Villers
190SL, 230SL 5-Speed, 190E 2.3-16 Kompressor

 Holy Smoke  .. That was a long time ago.

 That was a modification design of my 113 rear axle centering tool specially  speced for 121 chassis... They have a little different layout/offset , but the concept is the same .. I wonder if any of the 190 guys ever made one up and used it . Would you know ??
 Glad you kept it posted... might be a classic someday