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Well have just completed my revamp on the front suspension and brakes of my SLK230. Everything fine I thought until I lowered the car onto road wheels so I could tighten the various pivoting bush points on the upper and lower control arms. Was I shocked at the 'new' ride height......something clearly isn't right :surprise: On a positive note I've clearly been consistent in my screw up because both sides are identical!


I have replaced the shocks with Bilstein B4's (24-100878) which are listed as replacements for the standard OEM shocks. I did notice shocks were longer....maybe 1" to 1-1/2" but put that down to the original shocks being shot with very limited travel. I also replaced the upper control arms and fitted new bushes in the lower control arms. I reused the old springs and the upper spring mounts which are 'four dot' which I understand were standard fitment.


Wheel Fender Gap by Gary Laird, on Flickr


Front Right Wheel by Gary Laird, on Flickr


I've seen the questions asked many times on various forums about the 'standard' ride heights of r170 SLK's with no definitive answer. Is there some MB data for this as I have never been able to find? Regardless of that clearly something is wrong :crying:


Now my understanding is that only the springs can effect ride height and that any ride height problem can be put down to incorrect springs or poor fitting. I have check and double checked the spring mountings and they are all within a 1/4" of the intended location both upper and lower. I've taken pictures of the lower mount showing spring location but impossible to get any meaningful picture of the upper mounting.


Front Right Lower Spring by Gary Laird, on Flickr


Front Left Lower Spring by Gary Laird, on Flickr


I used some zinc primer to height light the spring ends and pockets so they could easily be seen during installation.


The only other possible issue was that after replacing the lower control arm bushes the refitting was tight and the had to be knocked back into place so I could insert the long bolts through the bushings. I had use rust treatment and underseal to clean things up when the wheel well was totally clear so not surprised things were a bit sticky going back in. Having said that, once installed I was operating the lower control arm by hand when installing the rest of the suspension components so they were not seized or bound in any way.


Other than that, the car has been up on axle stands for the last two months front and rear together. In the pic above I used wooden blocks under the wheels while the rear is still up on axle stands. At that the car is fairly level.


So I am at a lost to understand what I've done here. Any ideas/suggestions?
 

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Discussion Starter #3
@stu32 on an earlier thread you had mentioned replacing your suspension with Bilstein B4's. Do you still have note of the Bilstein part number you used for the fronts?
 

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For starters, it is probably experiencing camber push. That is, when you let the weight back onto the road wheels the tires could not "slide" outwards allowing the suspension to relax. On the floor, we roll it back and forth a foot or two to allow the vehicle to settle. As far as specs goes, I found a thread over at benzworld about it. If I'm a bad guy for linking it, break out the wet noodles.



https://www.benzworld.org/forums/r170-slk-class/1457583-ride-height-slk-sport-2.html
 

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Not for linking, not signing up for the Florida Meet! :D
 

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Discussion Starter #6
Can you check the actual height of the car Gary?

Mercedes-Benz SLK-Class (R170)
Width 1,715 mm (68 in)
Height 1,289 mm (51 in)
Kerb weight 1,195–1,461 kg (2,630–3,220 lb)

Right, assuming this is from ground to the highest point of the car. Hard to do with any degree of accuracy as car is up on blocks/stands so a lot of 'eye balling' but I get to 52-/2"
 

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Discussion Starter #8
For starters, it is probably experiencing camber push. That is, when you let the weight back onto the road wheels the tires could not "slide" outwards allowing the suspension to relax. On the floor, we roll it back and forth a foot or two to allow the vehicle to settle. As far as specs goes, I found a thread over at benzworld about it. If I'm a bad guy for linking it, break out the wet noodles.



https://www.benzworld.org/forums/r170-slk-class/1457583-ride-height-slk-sport-2.html

Thanks @Bamanut for that link. This confirms that the 4 knob spacer is 17mm. While I could understand that suspension would need to settle/readjust and rolling car back and forth would potentially drop the car a few mm it seems to me, just by appearances that suspension needs to drop around 3" Wish I had measured the old setup before I started but I do have this old pic which was intended to show the rust problem but it clearly shows the massive different in the tyre/fender spacing.


IMAG0401 by Gary Laird, on Flickr
 

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Discussion Starter #9
You need to put all the weight of the car on the wheels and move it around. My guess is everything is fine.

Thanks @Turdo2, wish I could share your optimism :smile:. If you look at the picture of the old 'before' picture I just posted you can see there is a massive difference. Really can't imagine the suspension would really settle that much. Having said that I am totally stuck as to what else could be causing this.
 

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Regardless before you can move forward is lower car to ground
Drive car let suspension settle down .
Then go from there .


You still have the car jacked up !

So no weight of car on suspension components !
 

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Discussion Starter #11
Code:
Regardless before you can move forward is lower car to ground
Drive car let suspension settle down .
Then go from there .


You still have the car jacked up !

So no weight of car on suspension components !
Sorry, not sure I understand what you mean, the weight of the front of the car is on the wheels, at least the fronts are. The car is resting on the front wheels and rear axle stands. Anyway I don't want to tighten up the bushings until I get the level as close as possible to that expected. Is it OK to drive with the bushing bolts loose?
 

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What a screw up!

The correct ride height is easy to determine, two to three fingers between the top of the tire and the fender rim.

The shocks should be the same length. There just isn't that much movement in any shock, new or old. You should have carefully compared them and made sure there wasn't any mistake in the part numbers.

All suspension components should freely move up or down. The control arm you replaced may be a bit stiff, but they should freely move with a little force on them. Did you use a torque wrench? They may be binding? The springs may not be properly seated.

Finally, with the full weight of the car resting on the suspension, just how bad is the gap? You might drive the car around the block and hit a few bumps. If the suspension doesn't settle down correctly, you did something wrong. I'd suspect the shocks. If you can, examine if the springs are being compressed. Jack a corner up and let it down. Examine the gap between adjacent spring coils.:crying:
 

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The shocks will not affect ride height, unless they are faulty (no movement), or have bottomed out! Only springs affect ride height.


I agree that the suspension needs to settle, and car must be on ground and pushed back and forward a few meters (yards) so wheels settle to correct track.


Then try bouncing the suspension to prove there is movement in the shocks/suspension links.


If suspension is moving, and ride height is still way too high, then springs must be wrong, or incorrectly fitted.


If ther is no movement in suspension, then either suspension arms/links have been fitted incorrectly (and locked up), or shocks are faulty/wrong/damaged
 

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Registered 2005 SLK55 AMG & 2006 Kleemann 55K S8
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Try to measure how far up the upper spring perch is on the new struts versus the old ones. Maybe they put the perch in the wrong spot or they are the wrong struts?
 

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Discussion Starter #15
The correct ride height is easy to determine, two to three fingers between the top of the tire and the fender rim.
Right and I have a whole hand in there with still more space available!


The shocks should be the same length. There just isn't that much movement in any shock, new or old. You should have carefully compared them and made sure there wasn't any mistake in the part numbers.
Not if the old shocks were screwed! On @S/RConcepts suspension rebuild thread here https://www.slkworld.com/general-modifications-r170/438705-so-i-may-have-gone-overboard-complete-steering-suspension-refresh-slk32.html he noted exactly the same that his Bilstein shocks were longer on the front than original but in his case ride height did not change. What makes you think I did not check part numbers? The MB OEM part # for these is A1703200130 which is given on the Bilstein site as well as other suppliers site as 24-100878 for the B4 shocks. So short of Bilstein putting the wrong shock in the wrong box I'm pretty sure its not wrong!

All suspension components should freely move up or down. The control arm you replaced may be a bit stiff, but they should freely move with a little force on them. Did you use a torque wrench? They may be binding? The springs may not be properly seated.
Yes suspension parts move although, as I noted above, the lower control arms were more than a push fit to get them in place. I have not torqued the bushing pivot points yet, wanting to get the ride height correct before I do that. The springs not being seated is something I've checked 3 or 4 times and I can't see anything wrong. From the pics above you can see, at least the lower seats, are in the correct place.....more or less!

Finally, with the full weight of the car resting on the suspension, just how bad is the gap? You might drive the car around the block and hit a few bumps. If the suspension doesn't settle down correctly, you did something wrong. I'd suspect the shocks. If you can, examine if the springs are being compressed. Jack a corner up and let it down. Examine the gap between adjacent spring coils.:crying:
Well with the front wheels carrying the weight of the front of the car you can see from pic above that I can get my whole hand in there and then some as well as the dimensions I gave. While I understand suspension will settle it would need to settle around 3" to get back to where it was before. Maybe having the rear on axle stands effects all this but I would have thought two wheels and two axle stands would generate the same load on the wheels as if the car was standing on all four wheels? Springs are compressing under load that's for sure.
 

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Discussion Starter #16
The shocks will not affect ride height, unless they are faulty (no movement), or have bottomed out! Only springs affect ride height.


I agree that the suspension needs to settle, and car must be on ground and pushed back and forward a few meters (yards) so wheels settle to correct track.


Then try bouncing the suspension to prove there is movement in the shocks/suspension links.


If suspension is moving, and ride height is still way too high, then springs must be wrong, or incorrectly fitted.


If there is no movement in suspension, then either suspension arms/links have been fitted incorrectly (and locked up), or shocks are faulty/wrong/damaged
Yes, as I have read, the shocks should not effect the ride height but its the only unknown factor in all of this since I'm using the original springs. If I bounce the car there is movement in the suspension as you would expect...so that all seems normal. Agree that everything points to the springs being incorrectly installed but I'm blowed if I can see what's wrong. Maybe because only front wheels are under load and the rear is on axle stands then this is doing something to the overall suspension loading and giving false impression. I have the rear suspension to do next so I think I will get on with that then be able to get the car on the road to get a true feel for where the ride height is at :|
 

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Discussion Starter #17
Try to measure how far up the upper spring perch is on the new struts versus the old ones. Maybe they put the perch in the wrong spot or they are the wrong struts?
Hi, the r170 uses separate springs and shock absorbers not struts (spring/shock) combination units.
 

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Hi, the r170 uses separate springs and shock absorbers not struts (spring/shock) combination units.
My mistake, I thought it was an R171. Have you tried putting the car down and putting weight on the front (press on it and try to get it to move)? Maybe the shocks are just stuck.
 

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Discussion Starter #19
My mistake, I thought it was an R171. Have you tried putting the car down and putting weight on the front (press on it and try to get it to move)? Maybe the shocks are just stuck.
:smile: yes for sure, I've been bouncing it up and down but it does not seem to help, no noise, creaking. Everything seems to work as it should just the bodywork seems very high over the wheel. I've not got it on the ground, just front wheels on wooden blocks.
 

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Check out the swaybar, is that all installed correctly? If incorrect that could affect ride height as it will apply pressure to the A arm just like the springs.
 
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