Lang Tailwheel top end replacement


  1. This will help you understand how to replace the top end parts on the Lang, driving cap, driving washer, cam washer and adjustment.


  1. Remove cotter pin, castle nut and washer set aside.


  1. Pull off the driving cap (large alum part on top). Use care not to lose the parts in the driving cap (plunger/spring). Remove the steering arm, set all aside.


  1. Pull off the large iron attaching bracket.


  1. Remove the parts from the attaching bracket, attaching bracket spacer, driving washer and cam washer. Set aside.


  1. Remove the bronze bearing washer at the bottom of the shaft set aside.


  1. Clean and inspect the vertical shaft all these parts came from.


  1. Apply a light coat of grease onto the shaft.


  1. Clean and lightly grease and re-install the bearing washer. Check that it rotates freely.


  1. Remove as much of the old grease as possible from the needle bearings in the attaching bracket. If you used solvent, make sure the bearings are dry before regreasing. (pack the needle bearings). Install the attaching bracket onto the vertical shaft. Lightly grease the cam washer and install it (ramps up) and aligned with the pin that is pressed into the attaching bracket. Lightly grease the spacer (thin washer) and install it on top of the cam washer. Lightly grease the driving washer (“D” shaped hole) and install it on top of the spacer aligning it with the flat on the vertical shaft. Apply a light coat of grease on top of the stack you just put together. Set aside


  1. Driving cap assembly. Place the driving cap on the bench pin side up. Lightly grease the plunger spring and plunger. Insert the spring into the spring hole and then insert the plunger. Stop! Note that the plunger has a large radius on one end and a small one on the other end. The big radius goes into the hole on top of the spring and the small radius will be sticking out. Push up and down on the plunger checking that it has free movement. Place the steering arm over the driving cap assembly aligning the pressed in pin and the plunger. Check for free plunger movement again.


  1. Place the driving cap assembly you just built onto the vertical shaft aligning the plunger with the hole in the driving cap.


  1. Install the washer and castle nut and tighten until the assembly is binding (not free turning). Loosen the castle nut one or two slots on the nut and insert the cotter pin (don’t bent it yet). Check the operation of the assembly at this point. It should release to swivel when the steering arm is pulled the way over and lock when the arm is brought to center. There is very slight operation adjustment with the top castle nut. To loose on the nut and it will release prematurely and lock properly, to tight it will bind and not release. With proper adjustment it operates correctly and will have about .020 gap between the arm and the attaching bracket.


  1. Don’t forget! Once it is adjusted properly BEND THE COTTER PIN on top to secure all that parts.