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Birkin seat lowering

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  • Birkin seat lowering

    With my brand new Ryobi grinder in hand, bucket loads of trepidation, a damp bedsheet and a small fire extinguisher I started working on lowering my driver's seat.
    I unbolted the adjustable seat mechanism and ground down the flanges that hold it in place. Sparks flew everywhere! hence the damp sheet.
    I was particularly nervous when I realized I had to take the guard off the grinder to get at parts that were so near to the car floor. I'd tried with a junior hacksaw for a while but made no progress.
    I made some L brackets with my grinder from thick steel to allow me to fit new 3" seat belts and somehow got it all to fit back in the car. I had to cut some fiberglass out of the sides of the base of the seat too.
    The seat is now about 1" 1/2 lower, the dashboard finally makes sense!
    Now I don't have to tilt my head 45 degrees to see what speed I'm doing and
    the top of my head no longer serves to lessen the impact on the roll bar should the car go over. Hope fully now it would be the other way round...

    Still working on trying to fix my transmission output/slip yoke oil leak.
    Went to my 5th driveshaft place yesterday, Wenco in Van Nuys. Apparently my yoke/universal joint is a one off made on mars some time in the distant future.
    They did suggest that my yoke was actually ok. They thought the leak could be from the edge of the seal where it meets the transmission case or the seam where the spline meets the U joint of the yoke. Also thought it could be the bushing behind the output seal. They said a good transmission shop could replace the bushing with a special tool without haveing to open the transmission up. Anyone know if this is true of the T9?
    So, some tests to do.
    If I can't sort it out soon I think I'll just cut the floor out completely and propel it flintstone style, bare feet on the asphalt!
    Attached Files
    Paul. Birkin S3 /Dunnel zetec/emerald ECU

  • #2
    You could try a funnel under the seal and a tiny sump pump that feeds the oil back into the gearbox :rolleyes:

    As for the shaft itself, did anyone ever suggest putting it on a lathe and sand/polish the scratches out? Well, assuming that this is the culprit and not somewhere else. But I still have the feeling that may be it. I can not imagine the scratches are good for the sharp rubber lip of the seal.


    • #3
      Gert, That's genius. Not much room to mount the sump pump though, I'll have to wear it as a hat with a velcro chin strap...

      Actually the guy at Wenco did give a the spline of the yoke a quick once over with a polisher and removed around 80% of the scratches. They seemed to be the most well informed and sensible driveshaft place I went to.
      Paul. Birkin S3 /Dunnel zetec/emerald ECU


      • #4

        I asked a seal engineer about the scratches on your yoke and it was his opinion that they could be the cause of the leak.

        Some options to fix the leak:

        1. put it back together and see if the polish job worked.
        2. order a new yoke from Birkin.
        3. install a speedi-sleeve. This may not fit the bushing but you might work it so only the seal is in contact with the speedi sleeve.
        4. take the entire drive shaft to the place that gave you the best service, have them take it apart and install a new yoke / U joint / Drive shaft connection. Setup to use a more readily availabe yoke.
        5. take it to a precision machine shop that does grinding, grind undersize / hard chrome plate oversize / grind to size. Probably more expensive then #4.
        6 drill a weep hole under the transmission end and let it leak. Tell eveyone it has a transmission made by Triumph motorcyle Co. BSA might be believable too.
        Last edited by Doug Liedblad; July 18, 2010, 09:36 AM.


        • #5
          Great advice, many thanks. I'll get back into it on tuesday.
          Paul. Birkin S3 /Dunnel zetec/emerald ECU