S1 Gearbox 4 speed problem - Third gear jump

[khrell]

Huib, thank you for your answer. You are a well of Fulvia wisdom.

I think I understood you, in the housing I changed the two bronze bushings of the selector shaft because it was losing oil.

About the hammer, do you mean the part surrounded in red in the photo? The idea is to make it grow with welding? The problem with the latter is how much to grow

[Huib]

Right about the hammer. You need the yoke (the part that goes into the gearbox) too. The two wings (or the two anvils if we follow the hammer terminology) have dents in their surfaces where the hammer hits. You have to weld and grind those surfaces. Then the play between hammer and both anvils should be very little by welding the hammer.

Your picture shows the aluminium housing of the mechanism. The shaft (with the hammer on the other side) often has radial play. Solve that by machining bushes to put in the aluminium. Solve the axial play with careful shimming. Include at least one bent washer (made of springsteel).

Step by step check al the parts and joints for play. And play with the adjustments to get the feeling in your fingers.