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Holed/ punched through clutch fork

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  • Holed/ punched through clutch fork

    Clutch actuator rod will eventually punch trough socket in the fork rendering the poor Smart undrivable.

    John's holed fork socket.


    Another photo of John's holed fork socket.


    Holed fork socket from a Canadian Smart 450.


    My fork is still OK but socket is very much eroded having clocked in excess of 170,500 km. Corrosion and erosion are deemed to be the main causes for socket wear.

    Suggested fixes:

    1) Periodically grease contact point between clutch actuator rod and fork socket. Grease reduces wear and arrests corrosion.

    2) Increase size of contact area between rod and socket.


    Clutch actuator rod and a piece of 1/2" marine bronze solid rod. Note that I've painted actuator rod in Lidl's special black actuator rod enamel. Rust forming in centre reduced diameter area of rod allows water to penetrate into clutch actuatator housing. Paint protects steel so less chance of rust and water ingress.


    Modified clutch actuator rod. Contact area with fork socket has been increased by 61%. There is much less friction between steel and bronze so should reduce wear rate significantly. Additionally, I have centre bored the rod and drilled a radial grease point. Grease can then be injected directly to the contact point using an Oregon chain saw bar grease gun or similar.
    Last edited by tolsen; 31-05-12, 06:21 PM. Reason: Added a missing "r" in bronze

  • #2
    Re: Holed/ punched through clutch fork

    You could pop a Tufnell cap between the two.

    When the actuator is at rest you may find there has been to much preload?

    Comment


    • #3
      Re: Holed/ punched through clutch fork

      Originally posted by madDan View Post
      You could pop a Tufnell cap between the two.

      When the actuator is at rest you may find there has been to much preload?
      I assume mine has been preloaded correctly since fork is still intact and clutch operation has always been smooth except when I had broken electrical control cables.

      Sachs specifies 50 N preload, nil axial play and geringe radial play. I think there will be more wear if rod is slack and allowed to rattle about.

      Comment


      • #4
        Re: Holed/ punched through clutch fork

        No try reading it correctly

        Initial 50N then 11N after the gear activations have been done. (not letting it get below that during final adjustment otherwise you have to then do it all again.)

        Comment


        • #5
          Re: Holed/ punched through clutch fork

          Originally posted by madDan View Post
          No try reading it correctly

          Initial 50N then 11N after the gear activations have been done. (not letting it get below that during final adjustment otherwise you have to then do it all again.)
          Yes, that is how I read it on second reading but see both Smart's and Sach's workshop instructions are very much cocked up in that they specify Newtonmetres for axial force. Anyway, there should be a preload as opposed to the procedures found on Evilution and FQ101 which specify no preload whatsoever.

          I see there is also a specified bolt tightening sequence starting with the left side bolt, then the aft and forward bolt last.

          There are obviously lots of opportunities for getting the mechanical adjustment wrong which in worst case could lead to rattling actuator rod causing accelerated wear of fork socket. I don't thing excessive preload will cause any more wear. More likely burnt out clutch or reduced service life of thrust bearing.
          Last edited by tolsen; 31-05-12, 06:39 PM.

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          • #6
            Re: Holed/ punched through clutch fork

            Originally posted by tolsen View Post
            Anyway, there should be a preload as opposed to the procedures found on Evilution and FQ101 which specify no preload whatsoever.
            For the home mechanic, the methods on both sites are fine.
            We've done over 200,000 miles in 3 smart cars with zero issues.

            tbh, I'm getting pretty tired at your digs (and advertising out tools?!), so how about you wind your neck in a little.

            As I've said before, helping is fine, but what becomes just a blatant slagging of does not help anyone.

            In retrospect, I suppose "supercalafragalisticexpialadocious" wasn't a great "safe word..."

            Comment


            • #7
              Re: Holed/ punched through clutch fork

              My apologies Racingsnake.

              Comment


              • #8
                Re: Holed/ punched through clutch fork

                What is a Tufnell cap please? Google didn't help...

                I have the same problem and looking for a solution!

                Bil

                Comment


                • #9
                  Re: Holed/ punched through clutch fork

                  Tufnyl (not sure why I spelt it wrong first time around?) is a brand of Nylon, hard and slippery, effectively self lubricating, you could easily make a cap to go over the rod to spread the load, a bit like the bronze above.

                  Comment


                  • #10
                    Re: Holed/ punched through clutch fork

                    madDan, I'm in for this fix! So long as we're sure it will resist the heat in the application. Now, where on earth can I get such a thing?

                    Cheers,
                    Bil

                    Comment


                    • #11
                      Re: Holed/ punched through clutch fork

                      Plastics suppliers or online as you are in Canada? somewhere like

                      http://www.jamplast.com/plastic_data_NYLON.htm

                      Comment


                      • #12
                        Here is another punched through clutch fork. 2005 Smart 450 with only 60,000 miles.

                        I tried greasing the socked not realising it was holed. Fixed temporarily by adding a short piece of 1/2" bronze round bar to end of clutch actuator rod, see next photo.


                        Clutch actuator is fairly new, less than a couple of years old. Corrosion had started where the grommet seals against housing. Now cleaned up and greased in silicon grease which does not make rubber swell. Also greased rod in way of grommet.

                        Refitted and preloaded clutch actuator and adjusted bite point using my newly acquired Delphi DS150E diagnistics kit. Came all the way from China and cost less than 27 delivered by courier to Banchory. This kit can also synchronise key fobs for Smart cars. Will diagnose lorries like big Volvos and Scanias too.

                        Comment


                        • #13
                          delphi.jpg

                          That's a coincidence. I got one last week and have been having a little play with it using the Delphi and Wurth software.
                          Attached Files

                          Comment


                          • #14
                            Looks just like mine. Now you can start covering Volvo and Scania lorries on your site.

                            As a matter of interest, where did you source Wurth software? Is that also made by Autocom? Can you read ABS/ ESP on 450s after 2003?

                            Comment


                            • #15
                              Originally posted by tolsen View Post
                              newly acquired Delphi DS150E diagnistics kit. Came all the way from China and cost less than 27 delivered by courier to Banchory. This kit can also synchronise key fobs for Smart cars. Will diagnose lorries like big Volvos and Scanias too.
                              From Banggood?

                              Comment

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