PDA

View Full Version : Transmission 5-Speed New day, new issue - tranny/clutch



Spittybug
06-25-2011, 05:26 PM
I received my adjustable clutch linkage from Grady last week. Installed in a few minutes, and went to back out of the garage. No difference.

Some background: I have the stainless clutch line, fluid levels good, both cylinders rebuilt in the last couple of years. No leaking anywhere. New clutch plate and pressure plate in the last couple of years. I was one that despite all being in good shape, needed just a hair more throw in my peddle. I therefore shaved the stop nut off the pedal bracket and had a homemade replacement for the linker bar (that the adjustable linkage replaces) that worked fine for a year or two. No issues. One night, unexpectedly, my homemade piece snapped (simply too small a gauge metal) and I had to change gears with no clutch! This essentially meant not shifting out of second for the last mile home and going slow. I threw the old linkage back in and found that I was able to shift no problem... I've had it like this a month or two. Now all of a sudden the car won't go into gear when the engine is running and clutch engaged. Won't physically engage in forward gears, grinds tying to go into reverse. Same even though I now have the slightly extended linkage in place. I think I'm at the maximum throw that I can physically get, but I'm going to double check.

With engine not running, gearshift slides easily into all gears. With car up on lift I have visually confirmed that slave is moving with depressed clutch pedal. Of course, I can't tell for sure if it is going 100% of its available travel, but it certainly seems to be at least 1/2 to 3/4 of an inch I would guess. If I start car in the air and try to engage gears, same problem. I even put it into gear and then cranked car...I would have thought with no load (in air) it would start up and turn the wheels.. instead, I got some bucking and noise that strongly suggested I cease and desist.

Any suggestions? Any further diagnostics to try before I do the deed and drop the tranny to get to the clutch? It ought to be much, much easier now that I have the lift, but still not something I like to do.

Spittybug
06-25-2011, 06:25 PM
<<Gilda Radner voice>> Never mind......

I extended the adjustable linkage more and the problem went away. After contorting myself into all kinds of abnormal positions to get my head under the steering wheel and getting intimately familiar with all of the linkages under there, I found that even a little bit of wear to the pivot bolt/clevis on the end of the clutch piston rod "translates" into a fair bit of "length" on the Grady adjustable linkage. After a few trials, I have it so that slop in any any all pivots is taken up and the first bit of pressure on the pedal translates directly into fluid movement to the slave. Much nicer feeling underfoot.

Still not sure why I was able to drive for a while with the original bar in place, maybe there is still some stretch even in the stainless tubing that is just enough?? Anyway, I've left this post in place in the hope that anyone else experiencing this will have a way to fix it. Thumbs up to the Grady adjustable linkage, it really allows you to accommodate the minimal wear under there that can otherwise cause grief. I imagine John H.'s would as well since his is basically an adjustable clutch push rod. I don't know if his would have the same benefit of pretensioning the whole assembly or not...

David T
06-25-2011, 11:25 PM
For whatever reason you are not getting enough motion to completely disengage the clutch. I suspect something wrong in the clutch, not the pedal linkage or the hydraulics. When you do not get full disengagement of the clutch you will find it difficult to shift when the motor is running. Another possibility is a bad pilot bearing. When you pull the clutch and inspect it you will find the problem.
David Teitelbaum

content22207
06-25-2011, 11:41 PM
The clutch master cylinder piston is attached to the return spring -- variations in spring lengths will yield different piston strokes.

The master cylinder also has a stopper to shut off the reservoir -- variations in stopper effectiveness will yield different slave cylinder strokes (the slave cylinder piston will not move until the reservoir has been sealed off).

Bill Robertson
#5939

Bitsyncmaster
06-26-2011, 04:49 AM
Maybe that's why mine has no stop bolt for clutch. I have mine adjusted so the pedal sits a little higher than the brake pedal but thats how I like it. Not sure if I dropped it if it would have your problem. I did install the braided line after I bought the car.

Spittybug
06-26-2011, 10:21 AM
Dave S. made a good caution over on the other board. You don't want to over lengthen the linkage since this would have the effect of minimally engaging the clutch all the time, like when some people rest their foot on the pedal all the time.

I think Bill's comments on the nuances of the cylinders has good validity. Combined with the wear of the pivot bolts, clevis holes and the usual "slack" in the system, it could very easily explain the variances.

Dave M.; the pedal rides right up against the top stop and that was why I initially thought I didn't have any more adjustment left. Then I realized that extending it served to pretension or take out any slop before the piston actually starts its stroke. Combined with a well adjusted gear shifter mechanism, it actually makes it feel like a sports car's performance system!