With my newly rotisserie-painted 67 230SL body sitting on the four-post hoist in the garage, I decided first to Rebuild/Renew/Restore the suspension before starting to put the car back together. The body restorer had removed the entire suspension system to blast and paint it, do his body work, then mostly put it back together a little more than finger tight in order to roll it around.
In starting the suspension R/R/R, a weird (to me) story has evolved, a little like an adventure novel where with every action, the hero gets into ever-deepening trouble until the final chapter when he solves the problem, wins the heroine and rides off into the sunset.
I dropped the left lower control arm, using the long-threaded-rod technique to remove the spring, then disassembled, renewed the suspension (including wheel bearing repack) and reassembled it with new rubber and proper (BBB/Haynes/Chilton’s) procedures and torques. Great job, Tom, now do the right side.
All went well until I had a thought. Since the calipers are off, why not measure the thickness of the rotors to make sure they haven’t been turned too thin? They had. Not only were they way too thin, the left and right were different by a lot. So I ordered new rotors (Centric, since they were reasonably priced).
They arrived and I installed the right side rotor since that side was newly disassembled. Beautiful! I even blasted and painted the outside of the hub before installing the rotor. Strange---the rotor looks slightly different than the one I took off. Time to measure things. On the new one, the hat height was 4 mm taller and the rotor diameter was 20 mm smaller. The pads would have hung over the outside of the rotor, IF the caliper could even be installed with the rotor 4 mm closer in on the hub. Time to send them back and investigate some more.
Then I had another thought - consult the Technical Manual. There were no dimensions there, but at least I learned that the 250SL and 280SL had larger front rotors than the 230SL. Maybe my 230SL had been upgraded due to poor braking performance during the first 17 years it spent in Italy. Back to the parts supplier’s catalogs and an email to Centric. Sure enough, the 250SL and 280SL rotors appear to be the same dimensions as the ones I removed from my 1967 230SL Italian version.
More research! I did a search on “230SL rotors” in the forum and found a thread about rotor upgrade by IXLR8 with responses by Achim and Dan Caron. I was way too far into the problem before I thought of searching the forum – a mistake I won’t make the next time.
It was at: http://www.sl113.org/forums/index.php?topic=15519.0
Conclusion: Either (1) my 1967 Italian 230SL has had a 250SL/280SL front brake upgrade during its life, or (2) the 1967 230SL got a factory upgrade in 1967 when the 250SL was introduced, or (3) maybe it got a factory upgrade some time earlier that I can’t identify since the big rotor seems to show in the EPC as applicable to replace all previous rotors. I don’t know if I will ever know all the TRUTH!
At least I think I’m finally on the right track to replace the parts I removed with equivalent parts, whether or not they were factory original, but I'm not quite ready to collect the heroine and ride into the sunset.
Can anyone help sort out the history of 230SL brake rotors? If so, maybe we can update the Technical Manual with the information. Especially since I keep forgetting to do thread searches, and I hate those TM entries where it looks like someone took three pages of generally-related threads and just plugged them into the TM, although it is true that they are better than just an empty edit form.
Everyone be patient with me. I`ll learn eventually. The TM and the forum may not be perfect for a person restoring his Pagoda, but it's WAY WAY better than anything I've seen for other old cars.
Tom Kizer
