Mechanics

CLUTCH WILL NOT DISENGAGE

2001 Nissan Sentra

Transmission problem
2001 Nissan Sentra 4 cyl Two Wheel Drive Manual 150000 miles

I have a 2001 Nissan Sentra GXE. The other day I was at a stoplight, shifted into first to start going and heard a loud metallic " clunk" or " pop" type of noise when I shifted. I was able to accelerate and shift into second normally, but about 30 seconds later I completely lost the ability to disengage the clutch.

Now when I press the clutch there is much less resistance than there used to be, and the pedal will only come about halfway up from the floor. With the car running, there is some vibration/pulsation when I depress the pedal. Attempting to shift with the car running results in nothing / grinding gears if enough force is applied. I can shift normally with the car off. Basically, it does nothing when I depress the clutch.

I tried shifting into second and starting the car. The car moved when I started it and stalled out when I braked (which is what I would expect with the clutch engaged). I can do the same thing in reverse as well. I didn't do it much because I think it's probably bad for my transmission/clutch. But from this I am thinking the transmission is OK and the clutch plate is OK, since it fully engages and seems normal while engaged.

When you pump the clutch you can see a lever (I believe this is the " clutch bearing fork" but I could be way off) move on the transmission, but I don't know if it is moving as much as it should be. I noticed I can move the lever easily by hand an inch or two back and forth. There are no obvious leaks from the master or slave cylinder but I haven't jacked up the car and poked around underneath yet.

I have the repair manual and the master cylinder looks fairly easy to replace, but the slave cylinder requires pulling the transmission at least partly - which I'd rather not do. But if it is hard for me I'm sure it is very expensive at the shop.

Any advice? What do you think is wrong? I am thinking it's a hydraulic problem but not sure which cylinder, if either, is the culprit. I've done lots of minor repairs/maintenance on my cars but I am not familiar with this at all, as it's the first stickshift I've owned. Any help is appreciated.

Thanks,
Brian
Avatar
Bl7
March 24, 2010.




I believe the release bearing or pressure plate springs are the fault and the clutch needs replacing (see arrows on diagram) .. the slave cylinder is mounted on transmission/gearbox if you cannot see fluid leaking and the slave cylinder is pushing on the leaver when deprssing the pedal then it is working correctly !

DESCRIPTION
Clutch assembly is a single-disc type with a diaphragm-spring pressure plate. All models use a hydraulic control system consisting of a master cylinder, slave cylinder, release lever and release bearing. Clutch master cylinder is mounted on firewall, with a nonadjustable slave cylinder mounted on clutch housing. Frontier, Sentra, Xterra and Pathfinder have a clutch damper as part of master cylinder. See Fig. 1 .


http://www.2carpros.com/forum/automotive_pictures/266999_nis_3.jpg



Hope this helps


http://www.2carpros.com/forum/automotive_pictures/266999_AAA2_1089.png

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Dave H
Mar 24, 2010.
Thanks a lot. So if the clutch release lever is moving then the hydraulics are working correctly, there's no point in replacing either the master or slave cylinder? Was the noise I heard probably the clutch bearing or lever snapping, then? There is a little bit of residue around where the lever enters the housing but it looks like engine oil, not brake fluid.

Would you advise me to take everything apart first and see what's broken before ordering parts, or should I go ahead and get a full clutch kit? Also, I've heard about resurfacing the flywheel; is that something I have to do, and if so how do I go about doing it, do I need to remove it and take it to a shop?

Tiny
Bl7
Mar 25, 2010.

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