Manual shift issue
Manual shift issue
12-22-2009, 11:22 AM
Shifts fine when motor off. When motor is running can not shift into gear. Just had the clutch master cylinder replaced because it was leaking and drove home from shop.
Shifting progressivley got harder to shift to point now it will not shift.
Fluid OK and I can see the rubber boot on the slave cylinder move when clutch petal is depressed.
Shop thought the clutch was hard to depress and thought pressure plate may be bad. but I am not sure.
My option right now are 1) replace slave cylinder or 2) replace clutch.
What do you all think?
12-22-2009, 02:01 PM
Overly simplistic, the pedal moves the fluid which moves the slave cylinder which moves the fork which presses on the throwout bearing which presses on the clutch springs.
Does it NOT work when the vehicle is stationary -or- when the vehicle is moving -or- both ? Is the problem intermittent ? Can you get it into reverse at all ?
Check the back corner of the your brake master cylinder reservoir and make sure it isn't low or empty. It's damned hard to see but the brake master cylinder reservoir is compartmentalized.
The clutch master cylinder if I remember right, also had lines running into the brake master cylinder, which doesn't get vacuum until the engine is running. Not sure how to integrate that component or factor into the analysis at the moment. (another rather *dangerous* thought which I cannot recommend is while the vehicle is moving, exhaust vacuum with brake depresses then see if can still shift)
If it doesn't work when stationary then I'd start with the clutch hydraulic system. If it's on the "edge," of tolerance, where it barely moves the slave cylinder enough to get it in and out of gear, then it can be temperamental where it may engage or not engage dependent upon the position of the transmission gearing; as though the synchros aren't working. Try pressing the pedal in with extra force and see if that then allow shifting. (remove the floor mat if in the way)
I personally had a bit of trouble bleeding my system and perhaps the mechanic experienced the same issue; as did this fellow (http://www.ford-forums.com/ford-escort/40846-bleeding-clutch-master-cylinder-93-escort.html).
Try bleeding the system again with the following tips...
1) The Brake Master cylinder reservoir is compartmentalized. So even though it may appear to be 3/4 full, the reservoir for the clutch master cylinder (occupying only a tiny little corner of it,) may actually be bone dry. (safety feature -- more important to stop than to go) So keep it topped off at 100% while bleeding. Add even as you notice the slightest little drop in level.
2) After pumping the clutch pedal then holding it to the floor, and releasing the air at the slave cylinder, push the slave cylinder piston back in to force out more air. While holding the piston in and the clutch pedal to the floor, only then should you retighten the bleed valve to repeat the entire process. You'll force out a lot of trapped air that way. (because the bleed valve is located a considerable distance before the slave cylinder piston -- so a lot of air sits after the bleed valve and before the slave cylinder's piston)
Pumping rapidly will create tiny air bubbles in the liquid. So pump SLOWLY and if you suspect that you've pumped too fast, let it sit a few hours or overnight to give the bubbles time to coalesce.
Also, air tends to rise to the top of any liquid. This is only a *theory* but it might help to raise the front end of the car so that the slave cylinder is higher than the master.
Automotive Network, Inc., Copyright ©2014