Progressive rate springs

[Bob G ✝︎]

 My order from john Olson arrived today. Has anyone else received their springs? I would like to start a discussion group so we can all communicate on our progress with these new profgressive rate springs.

Bob Geco

[tobacco]

Mine arrived on the doorstep yesterday, each snuggled in its own foam blanket, all shiny and bouncy, tipping in at a healthy 10 pounds apiece.  My new quints.

It will be 5-7 weeks before their new host is out of body rehab, but I'll report as soon as they're safely tucked in.




'71 Tobacco/Cognac 280 SL #22375

[jeffc280sl]

Hi Guys,

Springs arrived on Friday.  One rear spring is off the car already.  Just ordered new top and bottom spring pads and bushings for the trailing arm.  The top spring pad was in good shape.  About 80% of the bottom spring pad was missing.  Trailing arm bushings were cracked pretty severly.  I've got to buy a 35mm socket to remove the trailing arm from the rear axle.  I don't know about you guys but when I'm doing a project in a certain area of the car I tend to expand out from the original let's say "spring project" into related stuff like bushings.  Projects take longer but I try and do them the right way so that I don't ever have to go back over that area again.

I put the new and old springs next to each other and they appear to be twins.  Same height and it looks like same size coil.  What makes our new springs progressive?  It must be something like tempering of the steel because nothing is obvious from an outside comparison.

Good luck,

Jeff
1970 280Sl 4 speed w/three springs

[n/a]

I always thought progressive coil springs had a tighter wind ath the ends and a looser wind in the middle. Maybe you had preogressive springs alreaady. If you have the time and the means, can you post a picture of the two side by side?


Rudy
Los Angeles
1971 280 SL

[jeffc280sl]

I'll post pics of the new and old springs later today.

Jeff

[George Davis]

Jeff, the bolts that hold the torque arms to the axle can be difficult to loosen.  I tried without success, simply could not get enough torque on them (I bent back the lock tabs, too).  Took it to a shop, the tech used a lift, a long cheater and his full body weight to loosen them.  I hope it goes better for you!

George Davis
'69 280 SL Euro manual

[jeffc280sl]

Thanks for the advice George.  I suspect it will be difficult to loosen the bolts.  I use the handle from my hydraulic floor jack when I have sticky bolts.  Fits nicely over the handle of my 1/2 socket wrench.

Jeff Clute

[n/a]

Thanks for the pic Lax, but I can't get the link to work. Sorry. If anyone else got it to work , please let us know and I'll try it again. Thanks.

Rudy
Los Angeles
1971 280 SL

[n/a]

Thanks for the pic Lax, but I can't get the link to work. Sorry. If anyone else got it to work , please let us know and I'll try it again. Thanks.

Rudy
Los Angeles
1971 280 SL

[jeffc280sl]

Rudy,  Can't seem to send a picture correctly.  Maybe because my site name happens to be an email address, I'm not sure.  Send me your email address to lax882@aol.com and I'll send you a picture of the springs.

Jeff

[n/a]

Here are Jeff's pictures of the springs. They don't "look" progressive.

Download Attachment: springs1.jpg
50.29 KB

Rudy
Los Angeles
1971 280 SL

[Bob G ✝︎]

Lets hear from one of you who installed the springs and give us a report.

Bob Geco

[n/a]

I found this interesting link. Seems accurate enough.
http://www.jontreby.fsnet.co.uk/CV/usa/Page001.htm

Rudy
Los Angeles
1971 280 SL

[n/a]

I found this interesting link. Seems accurate enough.
http://www.jontreby.fsnet.co.uk/CV/usa/Page001.htm

Rudy
Los Angeles
1971 280 SL

[jeffc280sl]

Rudi,

Thanks for posting my picture and for the article about progressive springs.  On the surface there doesn't seem to be any special construction to the new springs.  They look the same as the old ones.  I'll have to look into this a little more.

George,

Took one of the trailing arms off this evening.  It was on very tight.  For those of you planning to change out the bushings you need a 35mm socket. Believe it or not a 1 3/8 inch socket is too tight. For the outside bolt it needs to be a very shallow socket.  The lower shock absorber bracket would not permit me to use the socket driver.  I ended up putting a pipe wrench on the socket to remove this bolt.  This does present a problem in re-assembly because I can't use a torque wrench.  I'm going to have to work around this somehow.

Good luck,

Jeff

[jeffc280sl]

Thought I would let the group know about the trailing arm bushing replacement.  Old bushings were cracked and dry on the outside edges.  The inside part was in great condition and doing its job.  Don't know if the job was worth the effort.  I did notice that there is a nylon spacer which acts as the pivot point for the trailing arm.  This was caked with gunk.  My training arms were very stiff, meaning I could not easily pivot them up and down.  You need to reove the trailing arm to clean and grease this spacer.  While your at it clean up the clamp plate and lock washer.  Both were a little rusty which contributed to the stifness in this fitting.   The flexible mounting in the link arm attachment to the floor pan was very worm.  It looks like it had worn in the rear side and was a little elongated due to the force of keeping the rear axle in place.  I would definitely plan to replace this bushing.

Jeff
1970 280SL 4 speed

[JohnOlson]

Jeff and Rudi and fellow W113 Suspension Tuners,

First, I have double checked with the factory and they reaffirmed that all but one (you know who you are) of the W113 spring sets sets have progressive rate specifications. Additionally today I inspected an extra set(from this same group order) that arrived at my office: all five springs are progressive in design. This is not to say that an isolated packaging error might have occurred and anything like that will be replaced ASAP.

Rudi's link to the explanation about various kinds of springs (and various kinds of progressive rate springs too) is outstanding! Rudi, your expectation that the loops on one end will be closer together than on the other end is true, and should be true of all the springs delivered. The photo that Rudi(?) posted at of Jeff's new and old spring side by side is a bad angle to see the difference. On  all five springs at my office the space between the loops grow from a half inch up to one and a third inch before reducing somewhat at the opposite end. The progressive rate we chose, starting at 12% stiffer than standard and climbing to 25%, is not a huge change, so the difference in the loops is a little subtle, but it's there.  On the equalizing (AKA compensating) spring the change is even more subtle, but if you use a tape measure you'll see the gap between loops is over double the width toward one of the ends.

Jeff, if you lay your springs flat on their side, photographing straight at the side, the change should be disernable. If anyone's  springs fail this test contact me directly and we'll deal with it.

Mit Vollgas (pedal to the metal)!    John Olson (Inc).

[n/a]

John, I just want to make it clear that my only interest in these springs is from a technical curiosity, and in no way did I intend to imply you weren't delivering what you promised.

Rudy
Los Angeles
1971 280 SL

[n/a]

John, I just want to make it clear that my only interest in these springs is from a technical curiosity, and in no way did I intend to imply you weren't delivering what you promised.

Rudy
Los Angeles
1971 280 SL

[jeffc280sl]

Hello John,

Thanks for your email.  I'll send you some better pictures in a few moments.   All of the springs appear to be the progressive type.  One end is more tightly wound than the other.

First some measurements. I lined up the pairs of springs next to each other and recorded the following :

Rear springs
                    left         right
top loop              7/8"            13/16"

bottom loop        1 3/16"         1 1/2"

Front springs
                    left         right

top loop              1/2"            5/8"

bottom loop        1 1/8"          1"

If these variances are within tolerance great.  I have no way of knowing.  As you can see the largest variance is in the bottom loop of the rear springs.  5/16" is easily noted.  You indicate the equalizing spring change is more subtle than the front and rear.  In my set this spring is clearly the most visibly progressive.  One half of the spring is very tightly wound and differs significantly from the other half.  I'll send off the pics in a few minutes.   Please let me know if the springs are within tolerance.

Thank you

Jeff Clute

[JohnOlson]

quote:Originally posted by Lax882@aol.com

If these variances are within tolerance great ..<<snip>>.. Please let me know if the springs are within tolerance.

Thank you
Jeff Clute

Jeff,
Your new report confirms you do have five progressive-rate springs. Measurements vary spring-to-spring because the specifications are custom made spring-by-spring to comply with the deflection rates at different stages of compression. Each of your springs was tested during and after the heat treatment (hardening process) for compliance before shipment. Slight variations may also be seen in uninstalled height; that will be further reduced or gone when installed with the full weight of the car. The existence of six different front spring pads thickness' reflects inherent differences, left to right and front to back, that M-B themselves faced. Variations in the cars are also responsible for some of those unequal measurements we found in all the cars in the beginning. It goes without saying these differences can not be totally eliminated in a group order. What everyone should notice/enjoy immediately is perhaps the most important: reduced body lean and less nose-dive in braking. A less "busy" body.

John Olson (Inc.)

[jeffc280sl]

John, Thanks for your comments.  I am close to installing the rear springs.  I noticed that the top of the old rear spring straigtens out at the very end of the coil.  If I use this same orientation with the new spring the progressive end (tighter winding) will be down.

The Haynes Manual and other documentation indicates that the straight end of the front spring indicates the bottom.  If I apply this same instruction to the new spring, the progressive end (tighter winding)of the spring will be on top.

Please advise if this is correct?  Likewise how is the compensating spring to be oriented?


Thank you,

Jeff Clute

[JohnOlson]

Jeff's question, if I read it correctly asks if it matters which end of a progressive rate spring is at the top. It does not matter as springs retain their designed behavior regardless of orientation.
Side Note: I just revisited the link on coil springs that Rudy provided (http://www.jontreby.fsnet.co.uk/CV/usa/Page001.htm) and noticed that the action drawing of a progressive spring going up and down has a technical error -- it shows the wider coils contracting first followed by the tighter loops. For those of you that like this kind of minutia, it is actually the tighter wound loops that contract first as that portion of the steel is longer than the end of the coil with wider spaced loops. Said another way, if you marked the coil half way between each end (7 inches across a 14 inch coil) and then ran a tape measure from the mark out to each end of the coil, the "half" with tighter loops will be longer. The longer a piece of  wire the easier it bends.

Please direct future questions to my e-mail address. It will not be possible for me to be a regular W113 Forum participant (even though I've enjoyed three visits here in one day!). I'm often available by phone for quick questions too(612-377-0155), especially for customers and SL Market Letter subscribers!    John Olson (Inc.)    

[Bob G ✝︎]

Can someone help me out. I am more of a visual person when it comes to mechnical repair. Can someone take some detail photos of what needs to be undone to switch out the rear coil springs & pads & the compensator spring & Pad. Please also list what other parts beside the spring pads need to be purchased and should be replaced. This is given nuts & Washers.
Is the front a bigger job and what is involved. Can some one make a refference to the BBB manual pages /job I don't know if something like this is listed.
Thank you for the help.
Bob Geco
1968 280SL

[Cees Klumper]

Bob - I have not switched my rear springs but I have taken them out. IMHO, you don't need to replace any washers etc. Changing the pads should not be necessary, unless your old ones are briddle, broken etc.