Torsion Bar End Link Buffer Sticker Shock and Cure

[Tomnistuff]

For the last few days I’ve been searching for torsion bar link assemblies or even stand-alone buffers (bushings), thinking I would send out the bolt, spacer and washers for CAD plating.

I finally found the OEM buffers (111 323 00 44) for $14.25 each times eight equals $114 plus shipping plus Quebec taxes for me.  OUCH! for eight little pieces of rubber.  All the others in the suspension are about $2 each.

Being a cheapskate, but a cheapskate that can calculate, I’ve measured and analyzed the end links compared to some aftermarket Energy Suspension Universal End Links and am presenting the analysis below, along with the derivation of the Energy Suspension Part Number required for equivalence on a 230SL.  I expect the 250 and 280 are the same, but I have not researched it.

The analysis and derivation is required because the Energy Suspension buffers are shorter but stiffer than the OEM buffers (A111 323 00 44), forcing the spacer to be longer than the OEM spacer.  And because I’ve assumed the same percentage compression of the buffers, not the same dimensional compression, the spacer length has to be calculated.

If someone wants to check my calculations or calculate them for another car, I’ve provided the pictorial comparison of the two systems as well as the derivation of the spacer length required for a 230SL.  I started on the left with the length of the bolt shank, calculated the compressed buffer heights, then the compression percentage and applied that to the Energy Suspension buffers and calculated the spacer length required to keep the torsion bar the same relative to the lower control arm.

The difference in price is $114 for OEM buffers only from Mercedes or $228 for the entire OEM end link kit from one of our favorite suppliers, versus an aftermarket Energy Suspension Polyurethane Universal End Link Kit, Part Number 9.8162G for less than $20 almost anywhere they sell suspension parts. (G in the part number means black buffers instead of R for red buffers).

I’m going to buy them for my car but it will take a few months before I can report on my level of satisfaction with them.

As I used to say when restoring a vintage Ferrari, I may tend to be a purist, but I’m not a masochist.  I like saving 90%.

Tom Kizer

[ja17]

Hello Tom,

Some of us have gone to the local autoparts store (AUTOZONE or such) and have purchased a  complete poly urethane link kit for $20.00.  The metal spacer can be easily cut to the correct length, and the rod threaded more as needed.   The red urethane bushings are easily painted black as original. Not quite factory, looks close and  works great.

Not supper critical but, get the sway bar end-run close to horizontal with the suspension loaded.

[Naj ✝︎]

Hi, Tom,

One of our UK Club member recommended one of these (same source).
They do black bushes too.
Just have to measure the length of the spacer. Can't remember what it was just now.

Naj

http://www.energysuspensionparts.com/Energy-Suspension-Universal-Sway-Bar-End-Links.asp

[Tomnistuff]

Some of us have gone to the local autoparts store (AUTOZONE or such) and have purchased a  complete poly urethane link kit for $20.00.  The metal spacer can be easily cut to the correct length, and the rod threaded more as needed.   The red urethane bushings are easily painted black as original. Not quite factory, looks close and  works great.

Unfortunately we don't have Autozone (or anything as good) here in Quebec.  Auto parts stores here are small and have limited stock compared to almost anywhere in the U.S.  Almost everything has to be ordered from a warehouse somewhere.  No touchy/feely when you are looking for parts to adapt.  Like a lot of places in the U.S., the first question they ask is what is the make and model of the car.  Their second statement is always, our books don't go back that far, all of which I knew before I walked into their store.  Canadian Tire, the biggest, is more for street racers, vanity stuff and maintenance stuff than auto parts.  Also, I would rather not cut the spacer, thread the rod or paint the bushings.  I don't like to disturb the plating and I'm afraid the paint will chip off the bushings eventually, showing the red under the car.

One of our UK Club member recommended one of these (same source).  They do black bushes too.  Just have to measure the length of the spacer. Can't remember what it was just now.
http://www.energysuspensionparts.com/Energy-Suspension-Universal-Sway-Bar-End-Links.asp

The part number on my analysis is the shortest one on their list of adjustable end links, (2 3/4 -- 3 1/4)  P/N 9.8162G.  Just buying one with the same spacer length as production shouldn't work exactly the same, since their bushings are much shorter than production, requiring a longer spacer to compensate.  That's what the analysis was for, to calculate the required spacer length to get the two bushing clamp-joints the same distance apart than the production link.  I don't know why Energy Suspension worries only about the spacer length.  If their bushings are different than the production bushings, then the spacer length has to be compensated to make up for the difference, otherwise the "functional" length of the links will be different than the OEM parts.  My objective was to keep the torsion bar hole exactly the same installed distance from the lower control arm hole as with the OEM parts, while using much less expensive parts to do it.

Anyway, if the sketches and analysis help anyone, great.  I did the analysis partly to document my restoration, but mostly for myself so I wouldn't forget what parts to buy and how to use them during the months I'm waiting to get the car back from the body restorer.

Thanks for your comments.

Tom Kizer

[ja17]

I appreciate your thoughts on originality. Perfection can be costly. I always said restoration to 85 % will cost you X dollars. Restoration to 95% or more will cost you 10X dollars !

[Tomnistuff]

You're right, Joe.  In 2008, I got a Gold at the Ferrari Club of America Annual Meeting with 94.5 point '69 365 GT 2+2.  Following that, I worked on the car, fixing everything they downgraded, at a substantial cost.  In 2010, I got a Platinum at Cavallino Classic in Palm Beach, Fla, with 95 points.  It cost me several thousand dollars and hundreds of hours to earn that 1/2 point.  Never Again!!!!!

When my Pagoda is finished, it's going to look like Martijn Sjerps' 250SL, except mine is a 230SL.  But I'm restoring it to drive, and drive, and drive, for six months of the year (the other six months is winter in Québec) for the rest of my life.  NO COMPETITIONS!

Tom Kizer

[Tomnistuff]

ALERT! ALERT!  Here's and update.  Because of an error on the web site of EnergySuspensionParts.com, an independent supplier, the part I calculated is NOT the right part for a Pagoda.

Their site used the Energy Suspension Parts sketch to define dimension A for ordering parts.  EnergySuspension.com, the manufacturer of the parts, in their new products catalogue, show the correct sketch.  It's also on the back of the parts package.  The two will give different results when specifying part numbers.  I had to take the parts back and exchange them for the right ones.

Notice the A dimension in the two sketches.

The right part number, the one that matches the original Mercedes Pagoda parts, is Energy Suspension 9.8165G, NOT 9.8162G.  I've received it and verified them side by side.

Tom Kizer