Strange clutch issue

[proffighter]

As I already talked about a clutch problem earlier (see rust combat thread) I now parted the tranny off the engine to see, what happend here.

Reason for this was shifting was getting harder from each time to time. First I thought, syncronisation failed, but then clutch started to seperat only bad and even worse each time and within a few kilometers, it did not separated at all. I readjusted (lot of play) the cable, but it only helped a few times, then It was the same. My guess was a failure of the release fork, but fork looks fine.

Here some pics:

[proffighter]

Does someone had similar problems? It all looks fine for me...

What I can see is, that throw-out bearing turned in the spring...

[pete3799]

Check the roll pin on the pedal cluster that goes through the clutch pedal. sometimes they break and allow the pedal to move without pulling the cable.
Next suspect would be the cable itself is failing.

[jwasbury]

What is the condition of the throw out bearing? Does it spin freely? The throwout bearing guide tube has been "polished" as if by friction. Perhaps this is a another sign of a problem with the throwout bearing? That guide tube needs lube in order for the throwout bearing to slide forward and back freely during clutch actuation. Without proper lubrication, the clutch pedal can become very stiff, and the clutch mechanism binds during engagement and release.

[Roby466]

Could your clutch cable have enough broken threads that it stretches causing the adjustment to work only for a few times?

[proffighter]

Thanks for that quick replies

@pete3799

That's a thing I've heard before, but forgot completly to check... Will do that next time in the garage

@jwasbury

Bearing looks fine, runs smooth and no play. But it was not lubed very much, so that's a good idea for the reassembly. As there is only very little play and the bearing is not centered except by the spring, there is the possibility to touch the tube

@Roby466

I don't think so, because the cable is only 10'000 running, but will check as well

[fredmeister]

Your cable may have stretched but not totally failed. if you had lots of slack thats the problem. Once you adjust it back to spec it should have worked fine, unless it continued to stretch every time you activated the clutch. Sometimes several strands will break in the cable so that it still works slightly but is stretched so its out of adjustment badly.
Your guide tube for the throw out bearing looks worn too which indicated an issue with missing lube for this surface and possible issues with the throwout bearing. Since its apart already I would replace the TO bearing before putting it back together.
Did you check the tranny shaft support bearing inside the crankshaft end to see if its still lubed and working? Sometimes this needle bearing fails and prevents the tranny shaft from spinning free of the crank which feels like the clutch is not disengaging making shifting difficult.
Good luck.

Fred

[proffighter]

Fred

I will check cable too. The bearing in the crankshaft is a selfmade solution, as my stock clutch had the needle bearing built in, but not the fidanza I use. Further there where no threads in the crankshaft. So I made an adapter and fitted a bearing similar to the newer versions (sealed ball bearing)

I am going now to check and will post results in about 3 hours.

[proffighter]

...pete3799 Congratulations

[proffighter]

As I found the problem, I want to ask if I should check the tranny itself too. It was running now 20'000km since rebuilt (syncronisation was replaced)

Thanks for voting

[proffighter]

Bump

No votes at all Come on guys...

[jwasbury]

I vote for "if it ain't broke, don't fix it"

[pete3799]

Originally Posted by jwasbury

I vote for "if it ain't broke, don't fix it"

+1
If there is no grinding between gears i'd leave it alone.

[proffighter]

Finally Thanks guys. It is always a good help when other share the same opinion