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Clutch Master Rebuild


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Clutch master cylinder failure is characterized by a relatively sudden loss of clutch stiffness. It can give little or no warning as to its impending failure.
The procedure to rebuild the master cylinder is relatively simple, and only requires a minimum of tools. A clean space to work and some patience is most important.

You will need Ducati part 000047226, which I obtained for approximately $25us. The dealer informed me that there is a price increase on the way which could raise it as high as $60us.

The procedure for this rebuild is outlined below

WARNING
Brake fluid can damage the paint on your Paso. Have a rag under your work area at all times!

1. Drain all fluid from the reservoir.
2. Remove banjo bolt from back of master cylinder that leads to clutch fluid tube.
3. Remove choke cable from choke lever.
4. Remove 2 allen bolts that retain master cylinder/lever assembly and withdraw the unit.

Gather up the following tools (shown from left to right) and find a clean place to work. You will also need a bottle of new brake fluid.
19mm wrench
medium phillips screwdriver
medium slotted screwdriver
very small slotted screwdriver
strong pick (like a dentist uses)
14mm socket

5. Using 19mm wrench, remove the lever retaining nut from the bottom of the assembly.
6. Push out the retaining pin and remove the lever from the assembly.
7. Spin the choke lever off it's mount, and remove the mount from the assembly.
8. Remove the pushrod from the dust seal in the now exposed end of the cylinder.
9. The seal will need to be picked out as much as possible to proceed. Be careful not to damage the inside of the cylinder.
10. After most or all of the seal has been removed, the piston and spring should drop free. Take note of which direction the spring faces in the assembly.
11. The seal and plastic bushing and o-ring are retained within the assembly with a press-in ring. There is a small hole in the side of the bore behind this ring, and with careful use of the small screwdriver, the ring can be distorted enough to remove easily. Also take note of which direction the plastic bushing faces.
12. Ensure that the o-ring is also out of the bore, and lay out the parts that you removed.
13. Lay out the new parts next to the old ones and make sure that they are all there. You will need to assemble the piston with the brass washer and seal, and the piston receiver will need to be inserted into the end of the spring.
14. Carefully flush out the bore with clean brake fluid.
15. Install the new o-ring in the groove.
16. Insert the spring, receiver side up.
17. Grease the piston and CAREFULLY slide it seal first into the bore.
18. Now comes the tricky part. The piston must be compressed, while the plastic bushing, dust boot, and press-in ring are all installed. I found that the best way to do this was to slip the dust seal over the plastic bushing, followed by sliding the press-in ring over the dust boot. Now, slip your 14mm socket onto the phillips screwdriver, then CAREFULLY slide the screwdriver into the hole in the end of the dust seal. Holding this assembly together, use the end of the screwdriver to compress the piston, whereas the retention/dustboot assembly should drop neatly into place.
19. GENTLY tap (the wrench works nicely) on the socket to drive the retention ring home.
20. Remove the screwdriver and socket, and put the pushrod into place.
21. Re-install the pin and clutch lever.
22. Pour about 1/4" of new brake fluid into the reservoir, and gently prime the cylinder.
23. Re-install the choke mechanism.
24. Pour yourself a pint of Guinness, and marvel at your work!

paso750 wrote:24. Pour yourself a pint of Guinness, and marvel at your work!

mlindskog wrote:I had a Pilsner Urquell instead of the Guiness.