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    Manual gearbox 2 issues.

    When engaging 1st gear to take off from stop, I cant shift smoothly. The car judders. Shifting into any other gears, I don't have this problem. I have a longer gearbox nose, new clutch release bearing. New cross shaft bushes, new clutch master and slave cylinder. Does anyone know what could be causing this?

    The other issue. On occasions I can't engage reverse. I know the reverse is a simple gear, but it seems it doesn't want to slide in. To get it to slide into reverse, I shift the lever into 1st and then reverse. On occasions, if this doesn't work, I engage in 1st, move the car a bit, and then engage in reverse. Does anyone know what could be causing this?

    Some history about this gearbox, I took the best parts out of two boxes and build one, but kept the same matched set of gears. However, I might have used the best looking single reverse gear.

    Sujit


    #2
    Additional information. If the car is rolling, then engaging in first gear does not jerk.
    Sujit

    Comment


      #3
      The clutch is "dragging", i.e. not disengaging fully.

      Can't help as to why, as I run an auto, but I guess you need to start looking for "lost motion" in the mechanism.
      Header tanks - you can't beat a bit of bling.

      Comment


        #4
        Clutch is dragging, either faulty clutch cover plate, wrong length bolts securing clutch cover plate, should be 3/4 inch or not enough travel on the slave cylinder push rod, should be 5/8 inch.

        Comment


          #5
          Mine is fine but out of curiosity - I saw some threads on using a Jaguar or Rover pressure plate, any one have more info on that?
          Terry Hunt, Wilmington Delaware

          www.terryhunt.co.uk

          Comment


            #6
            I had, and still have to some extent, the same problem. The issue with mine was the flexibility in the walls of the hydraulic clutch pipe. I had an older pipe that had become soft and this effectively puts a spring between your foot and the clutch. So when engaging the clutch from stationary, any slight slight variations in the thickness or irregularities of the stationary plates causes a kind of bouncing in the clutch separation and hence the juddering. When both plates are rotating, then I guess these variations are not so great and at a higher frequency, so smoothed out. The solution for me was to get a new clutch pipe which made it very much better. It still happens slightly on hill starts, at low revs and when the pipe is hot. I think the ultimate cure is to fit a metal pipe, but it would need to have a flexible/coiled section to allow for movement. I don't know if anyone else has tried this?
            Last edited by MikeParker; 12 July 2021, 20:05.

            Comment


              #7
              Sounds interesting… LHD hose is longer as well..

              I have a new LHD pipe if you need it Sujit. it’s time I sent all the stuff saving for you anyways

              Terry
              Terry Hunt, Wilmington Delaware

              www.terryhunt.co.uk

              Comment


                #8
                Originally posted by MikeParker View Post
                I think the ultimate cure is to fit a metal pipe, but it would need to have a flexible/coiled section to allow for movement. I don't if any one else has tried this?
                Living close to the Goodridge factory, I had them make me up a new clutch hydraulic hose using the same material as their brake hoses. This was probably around 20 years ago. I am sure any capable hydraulic hose business could do similar.
                Dave
                1974 Mk2, ZF Auto, 3.45 Diff, Datsun Driveshafts. Stag owner/maintainer since 1989.

                Comment


                  #9
                  My original and replacement clutch pipes were made of red, semi-transparent, un-re-enforced plastic pipe. Is this as supplied from the factory? It seems a poor design detail.

                  Comment


                    #10
                    Just checked Rimmers site and they do a 20 plastic clutch pipe and an 80 "Goodridge Stainless Steel Braided Clutch Hose". Presumably the reason for the 4x cost is to get over this problem?


                    Comment


                      #11
                      Originally posted by MikeParker View Post
                      My original and replacement clutch pipes were made of red, semi-transparent, un-re-enforced plastic pipe. Is this as supplied from the factory? It seems a poor design detail.
                      Yes.
                      Dave
                      1974 Mk2, ZF Auto, 3.45 Diff, Datsun Driveshafts. Stag owner/maintainer since 1989.

                      Comment


                        #12
                        Originally posted by MikeParker View Post
                        Just checked Rimmers site and they do a £20 plastic clutch pipe and an £80 "Goodridge Stainless Steel Braided Clutch Hose". Presumably the reason for the 4x cost is to get over this problem?

                        Strewth, that seems pricey. But then most things have gone up in 20 years.
                        Dave
                        1974 Mk2, ZF Auto, 3.45 Diff, Datsun Driveshafts. Stag owner/maintainer since 1989.

                        Comment


                          #13
                          I’ve just ordered a Goodridge hose on eBay for just under 30. Goodridge also sell them direct at 25.82 + vat + p&p.

                          Nigel

                          Comment


                            #14
                            The clutch line is an upgraded braided unit from JP. The clutch and plate is from Bork and Beck. The bolts holding on the plate were checked so they didn't bottom out. They are slightly shorter than specified.
                            I spoke to Terry earlier today He suggested to re-bleed the clutch, while the bleed screws is loose push the rod in all the way into the cylinder. When I bled the clutch last, I used a Mity Vac vacuum pump. Will doing it the old fashion way, one person on pedal, one person on bleed screw, make a difference? I also made sure the bleed screw was at 12 O' Clock.
                            Terry also suggested to look for any play in the rod system. I don't' think I have any play. Another thing to try is to move the push rod to the first hole on the X shaft. It is currently in the middle.
                            Also suggested to test for clutch drag, is to put the rear of the car on stands, clutch pedal down, start the car, engage in 1st and see if the wheels begin to rotate.
                            I will report back over the weekend.
                            Regards, Sujit

                            Comment


                              #15
                              Clutch judder can be a PITA. one of mine does it because the front gearbox oil seal failed and slightly contaminated the new clutch plate. I had one particularly bad case some years ago caused by a flywheel with burn marks on it, probably from a previous failed clutch. Had to have the flywheel skimmed to fix that.

                              Not going into reverse is simply the reverse gear teeth banging end on and not sliding past each other. This happens all the time with non synchromesh gears. My old Ferguson tractor has the same problem. My solution is to release the clutch and try another gear first the same as you.

                              If the clutch was dragging at all you would know when you you try to engage reverse, the gears grind in reverse whereas the synchro rings on the forward gears just drag and stop you engaging the gears.

                              Neil

                              Neil
                              TV8, efi, fast road cams and home built manifolds. 246bhp 220lbft torque

                              Comment

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