Teething problems with G50 & 2nd drive - suggestions please

[dave harris]

Made the first drive in the car yesterday and everything seemed to go fine (with the exception that the exhaust hit the shift linkage preventing the use of 5th gear - - but was easily fixed.

When I tried to take the car out to test the fix & try to set up the speedometer, I've now found that I can not shift into any gears within the engine running. Worked just fine on the first trip out of the garage ???

The clutch pedal still has the "normal" feel, but I can not get it into 1st, 2nd, without the car "trying to move forward".

I've checked the clutch fluid & there's plenty in there, no apparent leaks, slave cylinder seems to move - - - -

Now what??

Suggestions of tests / checks before I have to pull the whole transmission?

Thanks

Dave

 

[Randy V]

I would bleed the clutch slave cylinder one more time.. Sometimes it only takes another millimeter of slave cylinder travel to get them to release.. It sounds like you might have some air in the system..

 

[MReid]

I agree with Randy, that is definitely a clutch issue and probably air in the system.

 

[dave harris]

Thanks guys, but i had forgotten to say in the opening post that I've re-bled the system 2x today thinking that was it as well.

Just went out and bled the system again - (Wife's starting to think of this as leg exercise at this point!).

No luck - still the same.

It does seem like the clutch is not disengaging, but I can't see anything that would prevent it ??????

Slave cylinder is direct from Porsche - -

Any other ideas?

Thanks

Dave

 

[Randy V]

Dave - What size Master Cylinder are you using?
Are you certain that there's nothing restricting the movement of either the pedal or clutch fork?
I'd love to be able to give you some measurements off of mine but it's not yet completed..

 

[MReid]

Dave, is your slave cylinder adjustable? Mine needed about 1 1/2 turns to be perfect, but I have a zf and it may be different.

 

[dave harris]

Randy,

Master is from DRB - their spec master cylinder & a stock porsche slave cylinder (per DRB build instructions.

Nothing is restricting movement - actually, I have not yet put a pedal stop on the clutch pedal and I can go a Lonnnnngggg way and still nothing.

Mark,

No adjustments on the slave that I can see??!!

I'm actually beginning to wonder if I've over centered the thing with too much pedal travel and I've bent someting inside???

It's looking like another blown weekend of taking the damn thing out again - Crap - that first drive was definately NOT long enough!!

Thanks guys.

Dave

 

[Tim]

Dave.

One more check before you pull your trans out.

Check that your clutch master cylinder is returning fully and the fluid port is opening properly. If the port is not opening properly then you might not be getting enough fluid transfer. I have seen this situation, everything will bleed up because the fluid will be pulled past the cup seal on releaseing the pedal. But you will not get a proper pedal because the master cylinder may not be full.

Check by removeing the clevis on the clutch pedal and see if the plunger comes out any further. might be a simple matter of rod adjustment or adjusting the pedal return stop.

Tim.

 

[Cliff Beer]

Dave, is your clutch master a new master? If it has been sitting around for a while then the usual open-bleed-screw-full-stroke-on-clutch-close-bleed-screw routine can tear the seals on either a) an old master cylinder which has corrosion on the surface of the cylinder past the normal end-of-stroke point, or b) a new master cylinder which hasn't been used in a long time. A better method of bleeding (particularly if you have a or b above) is to use a pressure bleeder - these are about $60 from a variety of online vendors. You're sure to get all the air out using a pressure bleeder and w/o the risk of tearing the seals.

So you can get the car in gear but there's partial clutch engagement once you do? Or, after fully depressing the clutch you grind gears?

 

[flatchat(Chris)]

Could be, that because the slave is now up side down, ie:- at the bottom of the trans therefore the bleed nipple is at the bottom as well ---so if bleeding in situe it my have trapped air in the top side of the slave---simple fix is, take out the slave and bleed it externally right way up with the fabricated plunger stop in place (a plate and a couple of bolts to stop the plunger popping out while you pump the pedal)
Hope that helps

 

[Dimi Terleckyj]

Hi Chris

Even though the transaxle has been flipped over the clutch slave cylinder is also flipped over to ensure the bleed nipple is at the highest point.

The mounting flanges are not offset so it allows mounting in the correct orientation otherwise it would be a cow to try and bleed.

Dimi

 

[Randy V]

If the slave was not reoriented as these gents say - That bleeder valve would definitely be on the bottom rather than the top.

I don't know about your car but mine came with 3 Master Cylinders - it would be really easy to put the wrong master cylinder on the clutch.

 

[dave harris]

Randy, pedals were factory installed - clutch has seperate (integral) fluid reservoir, brake masters have nipples as they share a single remote reservoir.

Chris, bleed nipple is indeed on the top - but just in case I'll remove the slave cylinder and stand it on end to make sure all air is out.

Cliff - initial bleed was with a pressure bleeder -

Tim - I'll check that first - it's a lot easier getting my fat A$$ down the foot well than taking the trans out - - again - - -

Thanks everyone - I'll let you all know what I find.

Dave

 

Hi
Check
the pilot bearing also
regards

Chris.

 

[Randy V]

Chris, bleed nipple is indeed on the top - but just in case I'll remove the slave cylinder and stand it on end to make sure all air is out.

Dave - Make certain you heed Chris' warning below if removing the slave to bleed it;

Could be, that because the slave is now up side down, ie:- at the bottom of the trans therefore the bleed nipple is at the bottom as well ---so if bleeding in situe it my have trapped air in the top side of the slave---simple fix is, take out the slave and bleed it externally right way up with the fabricated plunger stop in place (a plate and a couple of bolts to stop the plunger popping out while you pump the pedal)
Hope that helps

You may get by just by gravity bleeding it -
Remove the slave, lower it below the level of the Master Cylinder, and open the bleeder valve. This should expel any remaining air as the fluid flows.

You may want to get a measurement of the slave cylinder movement and perhaps one of the other owners of a car like yours could compare to their own working unit..

 

[flatchat(Chris)]

Another possibility is that the release fork operating shaft can break out its mounting lugs (on the gearbox) if not fitted home correctly --- a right PITA that --- can be repaired by welding and remachining though.
Unless something else has come adrift this could be the worst case scenario.

Been on this project awhile eh! Dave --- don't give up yet

 

[Ian Anderson]

Bent pushrod at either end. I managed to bend a master pushrod once and could not figure the inconsistent results I got. Yes this was on a brake master but the push rod was the same as the clutch. Once bent it flexed continuously,

Ian

 

[dave harris]

Chris - Gee, thanks for that particular possibility - - crap, that will just make my week - -

Won't have time to look at it until the weekend - -

And, yes, it's been a lonnnnngggg project - (but I'm still ahead of Farhad's schedule!)

Thanks

Dave

 

[dave harris]

Hi Everyone - Well finally got the time to pull the transmission - found the problem (Chris Melia wins the brass ring!) It was the damn pilot bearing. Apparently I had not hammered it in far enough ( I hate to put pressure on the back of a balanced & installed crank!). So, after the input shaft on the transmission finished "remachining" the rear of the pilot bearing & depositing all of the shavings it finally just seized up.

time to call Australia & have another one sent over!

Thanks for all of the inputs everyone -

Dave

 

[Jac Mac]

Dave, from reading your posts on this incident I cannot fathom how you were able to shift gears on the first drive. however in light of the fact that you have now run the motor with preload on the crank I have to reccomend that you check the center main bearing thrust for wear & damage- you wont be the first person on this forum to find out how much damage can be done in a short period of running time with this problem. better to be safe than very $$sorry.