W126 420SEL Ride Height?

[JamesDean]

Hey everyone,

I've just completed the front end rebuild on my 420SEL. All new rubber and parts up front. Originally I installed the wrong spring (126 321 18 04) which made the car sit way too high in the front.

I ordered a set of 126 321 17 04 based on the points system in the manual and the availability online. It seemed that where ever I punched in 420SEL the 17 04 spring came up.

I also installed the 4-nub coil spring shim based on the point system and indicated availability online.

I got these installed last night and the front end still seems to be sitting higher than it should.

Now, all the front end parts were removed and replaced so the location of the lower control arm's eccentric bolt might not be where it "should" be and the same as the guide rod. I am not sure how much these effect ride height on these cars.

Also the rear spring are 116 324 11 04 with the 3 nub coil spring shim. These numbers agree with the 32-240 PDF. So the rear springs are correct..

[Stretch]

Have a look at chapter 40-300 in the (W126) FSM and see if you can replicate the procedure for measuring the height of the front suspension.

[hookedon210s]

Based on your pictures it is too high. Did you install HD shocks in front? Were the replacement springs color coded and do the pads match the code on the springs based on your point score? Finally, did you tighten all suspension bushings with the front end under normal load, not jacked up? Mark

[JamesDean]

Originally Posted by hookedon210s

Based on your pictures it is too high. Did you install HD shocks in front? Were the replacement springs color coded and do the pads match the code on the springs based on your point score? Finally, did you tighten all suspension bushings with the front end under normal load, not jacked up? Mark

HD Shocks = Yes, had them on back in 2011 or so.

Color Coded = No color code on new springs.

Bushings were tightened under no load / jacked up. I think THAT might be the problem. I completely did not even think of it. What would be my next step in doing this properly?

[hookedon210s]

A drive on lift is best but you can approximate this by jacking up the front of your car, removing the front wheels, loosening the upper and lower inner control arm nuts to the point where the rubber bearing can move freely, jacking up 1 lower control arm at a time with a floor jack that is positioned under the outer most part of the lower control arm (lower ball joint area) until the suspension will not compress any further but being careful not to knock your car off of the jack stands and then tightening all inner control arm nuts. Alternatively you can drive your car up on ramps and follow the above procedure (without removing the wheels of course) but have the front 2 seats occupied while tightening the CA nuts. Be careful!

Mark

[JamesDean]

Thanks Mark. I think that was the trick. I was able to get it to lower a little bit. In doing so I screwed up the wheel camber pretty bad as I let the bolt move.








I've since corrected the camber so its not that bad but its still not right...

Since its going to need an alignment anyway I'm just tell the dealership to set ride height properly and whatnot. Far easier with proper setup (drive on lift) versus me and a floor jack.

Anyways thanks for the help!

[hookedon210s]

It looks better but I think you may need to reduce your pads by one nib. If the dealer gives you a hard time just ask them to align it the best they can at the given ride height. Camber may be out of spec but the rest can be set correctly and tire wear won't be a problem. Mark

[JamesDean]

Originally Posted by hookedon210s

It looks better but I think you may need to reduce your pads by one nib. If the dealer gives you a hard time just ask them to align it the best they can at the given ride height. Camber may be out of spec but the rest can be set correctly and tire wear won't be a problem. Mark

Aye. I think you might be right. I might try to call them tomorrow and schedule something up for Saturday or next week and see. I really am not all that excited about taking the springs out for a third time lol.

They should be able to work with it...based on all the parts websites..those are the correct combination (none of them had any pads less than 4 nubs for the 420SEL)..

[Whiskeydan]

Has anyone else noticed that at some point in time the Gen 2 W126 cars had a lower front end stance? To me all the 1st gen W126s look to be too high in the front, sagging in the rear.

[JamesDean]

Well I got it back from the dealership. Its aligned now. Ride height in the front is a LITTLE lower but stil about 1-1.25 inches higher than my buddy's 560SEL.

A few thoughts:

1 - I'm pretty sure I've got the correct front springs on the car. 126 321 17 04. (Based on the points system in the PDFs)

2 - Im not sure I've got the correct pads on the front. I picked the same that were on before. 23mm / 4 nub. Actually that was all that was available when I selected a 420SEL. I was thinking about going to a 8 mm / 1 nub pad..that might do the trick.

3 - Could the rear springs be too weak causing the back end to sag and pull the front end up? The rear springs are NEW as of 2-3 years ago. They are the correct spring part number for this car as well. I do see that other part websites list a "heavy duty" rear spring which I actually have installed in my 300SD.

What would your next move be?

I know that the driver's side front shock is broken..in a rather odd way/place. Its right in the middle. You can grab the end of the black tube bit and shake it and the rod shakes. It actually sounds like the lower mount is loose but its not. No movement at all.

EDIT:

I was reading the FSM and the color code for pad thickness determination is on the bottom rungs of the factory spring. I found a picture of my original springs:



Clearly RED. Note the caps are on the opposite end. The springs are upside down, you can see this by look at the bottom and seeing how its tapered off.

With 50 points on the car, that points me to the 17 04 spring with the 23 mm pad!

Anyway.. Thoughts?

[JamesDean]

Alright here are some more pics, post dealer alignment etc and my rough height measurement with a wooden ruler...clearly not super accurate but gives you an idea...

[Stretch]

Still way too high in my opinion - though I think going from 4 to 1 nubs is possibly too extreme. Did you ever get round to reading about the relative heights of the suspension parts in the FSM?

[JamesDean]

Originally Posted by Stretch

Still way too high in my opinion - though I think going from 4 to 1 nubs is possibly too extreme. Did you ever get round to reading about the relative heights of the suspension parts in the FSM?

Possibly too extreme how? The difference is only 15mm wouldn't that just drop the car 15mm? or does it have a more profound effect?

I did read it a bit. It looks like they measure the control arm height...from the eccentric bolt to the bottom of the arm just before the ball joint area. The distance between the two is supposed to be about 45 mm +10 - 15.

EDIT: Talked with my mechanic, he said that unless you buy the springs direct from Mercedes, they are indeed a bit stiffer. I'm gonna drop the car off to him and see what he thinks about changing the pads to achieve proper ride height

[Stretch]

I read somewhere that the pad thickness does have a more profound effect - let me do a bit of head scratching I might be able to work it out, though I'll probably need you to measure the spring in its compressed state...

...and then there's the length of the brake stay and how far forward the wheel is within the wheel arch...

[whunter]

Originally Posted by JamesDean

Hey everyone,

I've just completed the front end rebuild on my 420SEL. All new rubber and parts up front. Originally I installed the wrong spring (126 321 18 04) which made the car sit way too high in the front.

I ordered a set of 126 321 17 04 based on the points system in the manual and the availability online. It seemed that where ever I punched in 420SEL the 17 04 spring came up.

I also installed the 4-nub coil spring shim based on the point system and indicated availability online.

I got these installed last night and the front end still seems to be sitting higher than it should.

Now, all the front end parts were removed and replaced so the location of the lower control arm's eccentric bolt might not be where it "should" be and the same as the guide rod. I am not sure how much these effect ride height on these cars.

Also the rear spring are 116 324 11 04 with the 3 nub coil spring shim. These numbers agree with the 32-240 PDF. So the rear springs are correct..

Every picture shows your car squatting in the rear, this will cause the front to ride high.

.