New trouble
Author
Discussion

lvjost

Original Poster:

183 posts

241 months

Friday 31st August 2007
quotequote all
Hi Guys,

Had to demount my gearbox...I built it in again this evening. The car drives BUT I have some trouble....
1st: When pressing the clutch pedal just a bit (so that there´s is no real actuation) I feel a kind
of vibration....
2nd: When shifting into the 5th Gear at low speed (f.e. 30 mph) and then accelerating....the car
kind of stutters quite a bit
3rd: When shfting both up and down (not always and more often when shifting down "engine breaking&quotwink
and releasing the clutch pedal again sometimes the car vibrates....
4th: A friend said he heas heard a kind of rattling when releasing the clutch pedal

Hints:
1st: Before the demount of the gearbox there was no trouble like described before
2nd: Only the gearbox has been removed...flywheel, clutch plate etc.etc has not been changed,
re-moved, not even touched....
3rd: The clutch seems to disconnect properly, there is no "hard shifting" no shifting problems
and when pressing the clutchpedal fully and keeping it pressed (letting the car roll) there is
absolutely no engine power
4rd: If the clutch itself would have been burned, covered with oil etc....the rpm would go up
rapidly without an according acceleration...kind of "spinning" but I even could go full throttle
in 2nd Gear ! and the car accel. quite normal.
5th: Problems only occur when releasing the clutch pedal and letting the pressure plate back onto
the clutch disc beside the 5th gear that also makes trouble, when the clutch is already "in"
again

I have absolute no idea....What do you think about it?

Lutz

Steve_D

13,802 posts

287 months

Friday 31st August 2007
quotequote all
Some things that could have happened.
1. The needle roller bearing in the centre of the flywheel has failed or possibly been pushed into the flywheel leaving the shaft from the gearbox unsupported.
2. The clutch release bearing is not completely connected to the release lever. I'm not sure if this is possible to have only one side of the release lever connected to the bearing.
3. The bearings for the release lever are not in their correct positions.
4. The release bearing itself has failed.

Whilst these are things that could have happened none of them really answerer the faults you describe.

Bottom line is that it has to come out again then you can tell us what the real answer is.

Steve

lvjost

Original Poster:

183 posts

241 months

Monday 3rd September 2007
quotequote all
Weekend is over...Demounted the gearbox to check everything again...

1st: The Pilot Bearing has neither been damaged nor "pushed in"
2nd: The clutch disc, the pressure plate and the flywheel...everything´s fine
....

Couldn´t find a thing.....Mounted the gearbox again bit the problem(s) reoccured !

Got another suspicion: When mounting the clutch fork pin (with the gearbox outside the car just to "practice&quotwink I realised, that on one side it is quite tight within its´ needle bearing, but on the opposite site it has a bit of "space", so could move (approx. 0,5 to 1mm)...Now my consideration was, if the problem could be the following: The clutch fork pin is pivoted "fix" on the one side and "flexible" on the other....When one and the same thing is pivoted both fix and flexible this could cause vibrations.....So I think I´ll demount the gearbox again and look after the "flexible" needle bearing, if it might be damaged or maybe has lost some needles and thus doesn´t bear the clutch fork pin "tightly"... ?!?

What do you think ?

lvjost

Original Poster:

183 posts

241 months

Sunday 9th September 2007
quotequote all
O.K. Guys....Problem found, solved and done.....
If anyone should ever have the problems I described..look after the needle bearing taking the clutch fork pin...ONe of them has been damaged all needles fell out and so the clutch fork pin hasn´t been kept tight any longer....

shithotfast

1,134 posts

297 months

Monday 10th September 2007
quotequote all
I had the same / similar problem. That bearing is a pain! Probably the cheapest part and biggest pain to change. Its a bit like shutting the fridge door.... you dont know if the light went out or not! Same with that bearing. Also the bearing has more of an "edge" to it one side. Not sure if that makes any difference when fitting the bearing? Did you notice the entry is slightly larger one side? They may have changed.

Steve_D

13,802 posts

287 months

Monday 10th September 2007
quotequote all
That would be my number 3 suggestion then!!!!

Steve

lvjost

Original Poster:

183 posts

241 months

Wednesday 12th September 2007
quotequote all
So Steve...you´re the man

gtr-gaz

5,281 posts

275 months

Wednesday 12th September 2007
quotequote all
lvjost said:
So Steve...you´re the man
They don't call him the Professor for nothing, you know winksmile

dilbert

7,741 posts

260 months

Wednesday 12th September 2007
quotequote all
If this is the G50 gearbox, then I personally think you're going to be better off with plain bearings in the clutch fork pivot pin. There are kits out there that provide all the parts to be able to implement such a solution.

When I did the clutch on the 911, I just couldn't figure out why they would bother with needle roller bearings in that situation. It just seems like needless complication to me!

http://www.pelicanparts.com/cgi-bin/smart/imgdsply.cgi?pn=101518090-M230&html=Y 
http://www.pelicanparts.com/catalog/shopcart/911M/POR_911M_Tclutc_pg6.htm#item21 

Edited by dilbert on Wednesday 12th September 13:16