The following is a step by step method for changing your bowden tube, a part of the clutch system on a vw bus. The bowden tube pretensions the clutch cable. If you're having clutch issues this may be one of the reasons. Replacing the clutch cable is good to do at the same time, however mine is new, so I will not. If you have replaced the cable and bowden tube and are still having problems you will have to check/replace the pilot bearing. I'll go over replacing that here: Replacing pilot bearing
Step 1: Tools
Here is everything you need... almost. You'll also need a stick or friend to push the clutch down, a container to boil water and possibly some rubber gloves.
Step 2: Out With the Old.
1. Hold clutch down
2. Locate bowden tube and clutch lever on driver side of the transmission.
3. Hook one end of ratchet strap to clutch lever and one to the frame somewhere towards the front of the vehicle. Tighten.
4. Release the clutch and pull up on the pedal to relieve tension on the adjusting wing nut.
5. Remove the wing nut. May require vise grips.
6. Remove the mounting bracket nuts 13mm and pull off old bowden tube. Save the washer and mounting bracket.
7. Grease everything, clutch cable and inside bowden tube
8. Boil some water, add rubber boot to soften
9. Install washer, then bracket, then rubber boot onto end of bowden tube.
10. Push clutch cable through bowden tube
11. Fix bowden tube over the clutch cable guide tube
12. Push clutch cable through clutch lever and thread on wing nut.
13. Re-attach mounting bracket
Bowden tube should have a substantial bend down towards the ground. Tighten wing nut until there is just under 1" of play in the clutch pedal before it engages.