Coil spring dilemma?

[Bob G ✝︎]

A couple of years ago I purchased john Olson's progressive coil spring kit.I did not choose the right mechanic  to put them in and was lacking on information of what spring pads to install. I ended up with a faciso and I am distraught as to should I go back to the orginal coil springs or have a knowen Guru Steve Marks in orange county try to figure how to raise the car back up to the orginal specifications I gave John Olson many years ago the ride height that of  my the coil springs that were in my 280SL.

I was also thinking of putting in new factory coil springs, but I will have to get Steve Marks's recommendations first as the springs have to be ordered from Germany and my cost is near $900.00 I am not sure if I need to invest in these new coil springs. I just what to get over this problems and be done with it and begin dring the car.
I know their is a difference because I can feel the tauntness  in Mr. Olson's coil springs, howerever the ride height has always been a problem and I do not want a low rider 280SL.

I am asking for some recommendations from those  people who purchased John Olsons progresive rate springs and would like to hear if you are happy annd if the ride height was able to be restored to its orginal setting and handling of thesuspension wass improved?

I have automatic trnsmission and air conditioning on my car. I am not quite sure you set the ride height with the hardtop on and a full tank of gasoline and a driver in the car what is correct?

I would appreciate any information you can give me.

Thank You
Bob Geco
krwaxbz@yahoo.com

[Longtooth]

How much lower is ride height than it was before?  Will the thickest mounting rubber's suffice to bring it back to the prior ride height?  There may be a slight compression of the mounting rubbers under load (curb wt) so the specified thickness (unloaded condition) may be slightly greater than the curb wt load condition.

The largest specified mounting rubbers listed in my Service manual (up thru the 250SL, but pre-280SL) for the front springs are 32.5 mm (1.28" ~1 1/4")--- PN 111 322 08 85; The 30 mm (1.18" ~ 1 3/16") front mounting rubbers are PN 111 322 07 85.

The largest rear spring mounting rubbers are 20 mm (0.79" ~ 3/4") --- PN 110 325 02 85.  In addition to the mounting rubbers for the rear springs, there are 3 different settings of the spring plate (at bottom mount of spring).... each correspoinding to a different height.  My Service Manual doesn't list the differences in spring plate setting heights, however.  Position 1 is the highest setting, and 3 the lowest.  The spring plate setting numbers are punched in the spring plate at the screw holes.

FYI, the Service Manual uses 2 tables to define the correct mounting rubber thickness to use.  The 1st table defines the car's weight conditions --- which are divided into several sub-tables.  The sub-tables are for cars with a) Air Conditioning, b) Without Air Conditioning, and for c), d), e) various rough road or police, or ambulances, etc.  The two tables of interest to us are usually the With Air Conditioning and Without Air Conditioning sub-tables.

Within the Weight sub-tables there are several columns --- no optional extra's, 1 optional extra, 2 optional extras, & 3 optional extras.  The optional extras are sliding roof (NA for W113's), automatic clutch or automatic transmission, & power steering.

If your 280SL With Air Conditioning, also has the optional extra  automatic transmission and power steering, then it has 2 optional extra's.... and the table defines this weight combination as roman numeral V (5) for the 250SL... IV for the 230SL.

From the designated weight combination, you go to the "Adjustment Tables"... i.e. Rubber Mounting Tables.  The rubber mounting tables list the Weight designations (I, II, III.... etc) from the weight table, and within each Weight Designation there are 3 Color Codes for the Springs (white, red, blue).  Each color code corresponds to a specific Mouning Rubber thickness and PN for it.

There are two of these Adjustment Tables... one for the Rear spring rubber mounting, and one for the Front spring rubber mounting.

I have no idea what the color codes refer to since my springs (both front and rear) have yellow markings on them... no red, white, or blue markings.

For a 250SL, Weight Designation V (2 optional extra's on a car with Air Conditioning), only 2 of the Front spring color codes are listed... red and blue, corresponding to 32.5mm and 30 mm thick mounting rubbers respectively.  The thickness value refers to the THICKEST section at the OD of the Rubber Mounting for the FRONT Springs.

For the Rear springs "Adjustment Table" (rubber mounting thickness's)for the 250SL, Weight Designation V, the white, red, and blue spring color codes use mounting thickness's 20 mm, 14 mm, and 8 mm respectively.  The thickness value refers to the THINNEST section at the OD of the Rubber Mounting for the REAR Springs.  The combination of 3 heights in spring plate adjustment (at bottom of spring)and rubber mounting thickness's provide for the appropriate ride height and rear camber adjustment with the installed spring.

[Bob G ✝︎]

LongTooth:
My mistake was that I had no pryer experience to navigate this modification and there for
did not pull the orginal springs out with the orginal pads and did not fine until the job was complete that the factory springs were taller. the orginal size pad we pulled out from the front was a 32.5 MM and rear 18MM with slight negitive camber. The john Olson springs shorter!

I took pictures of the factory springs and if I can remember the color codes were white and blue and yellow not the same colors for front and rear. The front nose appears a half inch from the orginal 25 1/2 to 24/1/2 left front and 24 inches right front. The rear gained too much positive camber likely because the mechanic doing the work had no idea of the three positions on the pearch of the rear control arms. It was 18MM we pulled out from the rear. With a full tank of gas and hardtop it levels out the rear ,but the front bears down way lower than  the 26 1/2 inches to 25/1/2 right rear and left rear 25-inches.

I am sure this problem can be solved . I also put new bushing in the front and rear suspension and fronnt sway bar. I am running Michelin Rainforce 185.TR 14 tires as stock size.
My delema that you did not  address is what are you feeling about the progressive  rate spring vs stock and if you have them was yourride height changed? Are you happy with the way the car  handles?

Since I do not know if the orginal coil springs on the car are correct would you assume that the purchase of a new set  of coil springs for my 280SL with automatic transmission and A/C and power steering be a possible investment though pricy to not  have to keep expermenting and pulling money out to pay for labor that may as well been spent keeping the suspension stock and doing this job one time again only?

Thanks for you input.
Bob Geco

[Longtooth]

Bob G.

I don't understand your height measure of 25 +/- inches... from where to where are you measuring?

Regarding my experience with Olson's progressive springs, I have none.  I cannot purchase springs without knowing their stiffeness's and if progressive springs, their multiple stiffness as function of displacement or load.... I'm not one that's inclined to trust anybody that cannot supply the functional measures required to assess the characteristics they're marketing.

For your reference, I've measured my 250SL's ride height, with 1/2 tank of gas in it and without the hard-top on it.  The measurement of interest is from CL of Wheel Hub to some part on the body... in this case I've used the underside of the front and rear bumpers at right and left sides.  I don't think using the bumpers is a reliable body part to measure since these can be adjusted, but they were immediately convenient this evening.  A better measure on the body perhaps might be the outside edges of the wheel wells directly above the hub CL's on front and rear fenders, or some other non-adjustable feature on the body.  The distance of interest to the body must be from CL of hub, since this removes all influences and differences associated with tire/wheel sizes, how well inflated they are, etc.

In my case, the front measurements could possibly increase slightly as the rear would drop when the hard-top and full tank of gas is in the car.... since the rear would drop more the angle of the car would change ... therefore the horizontal distance of the front bumper from the wheel hub (therefore front spring) is also extending the "drop" from wheel hub.

I also note a right-left difference in my ride heights.... with right side lower than left in the rear... I assume this is because the spare tire is on the right side.  Also, please note that the measures are dependant on whether or not you bounce the car Up or Down.  The proper procedure is to make two measures each after pushing front (and rear) bumper up first, then letting it settle by itself, and then pushing front (and rear) bumpers down first, then letting it settle.  The average of pushing it up and down (and after settling) is the actual most correct measure.  These "up" vs "down" pushing procedures will differ and can be significant especially on the front measures.  In my case the difference was at least an inch on the front measures.



Download Attachment: Ride Height.JPG
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[Raymond]

Bob,
Don't give up.  I have been playing with suspension for about three years now.  It's been trial and error and I am tantalizingly close to what I want.  I have used custom springs and I am currently using Olson's springs. 

I find the best way to measure ride height is to measure from the center of the star in the wheel cover, vertically to the bottom lip of the fender.  This way your measurement isn't significantly affected by tire pressure or size.  Drive the car a bit aggressively, then park it on a flat surface with a full fuel tank and hard top on.  Do this a couple of times, recording the measurements as they may vary a bit after each drive.  I am trying to get the rear to 13-inches and the front to 13-1/4. 

The ride height can be adjusted by using rubber flange gaskets as shims between the top spring rubber and the body.  They are about an 1/8 inch thick, but make a bigger difference in height because of the geometry of the suspension.  At Blacklick four years ago, Jim Villers did a good presentation on how best to do the spring changes.  Dick Mentzer videotaped it and there is a free DVD available through the club.

I would work on the rear first as they are FAR easier to remove and install.  Once you get that right, You'll know how much to add to the front and hopefully only have to do those once.

Good luck.

 

[Longtooth]

Raymond,
You're seeking ~13 inches ride height citing measurement from hub CL (center of star on hubcap) to bumper lip of fender opening.

"I find the best way to measure ride height is to measure from the center of the star in the wheel cover, vertically to the bottom lip of the fender.  This way your measurement isn't significantly affected by tire pressure or size."  I agree with your method, though I haven't measured  (recorded measurement) mine at that point yet.

My measures (hub CL to bumper undersides) are ~0.75" & 4.5" (front & rear respectively, without hard-top & 1/2 tank of gas).... see my prior post and the attachement to it. 

I'm attaching a random photo from one of the forum's pictures of W113's that I've drawn some lines on and scaled to a tire radius of 12" (center to top of tire to eliminate any inflation effects) just for an approximate measure of a random W113's front and rear ride height as measured from Hub CL to underside of bumper.

The random scaled W113 pic shows approximately 1.8" & 4.15" ride heights (front and rear respectively) as measured by your description (and my measures on my car the other evening).  These measures are approximately the same ball-park as I measured on my car. 

Scaling to the fender lip the ride height is approx. 13.4" & 12.9" (front and rear respectively), so in reasonable agreement with your targets --- reasonable because scaling on the photo is not that accurate (I blew up the picture to 400% of normal to scale it).  If I account for the lack of the hard-top, the rear would drop by 0.15" with standard 250SL/280SL springs, so the scaled values would change to 13.4" and 12.75" measured from Hub CL to lip on fenders.

Ride Height with the hard top on will drop the rear no more than ~0.1" - 0.15" wrt ground , so the scaled pic and my car's ride height at rear would drop to ~4" & 4.4" respectively from hub CL to underside of bumper.  Allowing 11.75" from HubCL to ground (owing to tire's 'flattening effect' under load) would put the random pic car at approx. 16" from underside of bumper at rear to ground. If I add my hardtop and another 8 or 9 gal's gas to my 1/2 full tank would drop my car's rear end another ~0.3" putting it at an estimated 4.2" - 4.1" from Hub CL to underside of bumper, or 16" from ground to underside of bumper. 

In otherwords both my car and that of a random sample scaled picture show front bumper underside at approx. 1" - 2" above Hub CL and rear bumper at about 4" - 4.2" above Hub CL.  .. or ~13.25" &  ~15.85" from ground (front and rear bumper undersides respectively).  ... with hard-top and full tank of gas.
 

For Ref:
Hardtop weighs 45 kg (99 lbs).
Gasoline wieghs 6.073 lbs/US gallon  (7.29/Imp. gallon or 0.71 - 0.77 kg/liter)
Standard Rear Spring (250SL/280SL) spring rate = 370.84 lbs/inch
Assumed Tire Radius (hub CL to top of tire)=12"... 11.75" from ground to HubCL.