Clutch play

My 1994 Nissan Hardbody 4x4 King Cab manual transmission is experiencing some additional play in the clutch pedal. For a while about a week ago it was having trouble engaging until I pumped the pedal a bit. Now it's working OK once pumped a bit but it still has a sort of mushy feel near the floor and the additional play. Brought it to the usually reliable dealership and they want to replace the clutch, around $2,000. Normally I would just go for it but I'm having trust issues with these guys in that they misdiagnosed something else (unrelated electrical problem - $600 quote to rebuild rear wiring harness) about a year ago that I fixed myself for a few bucks (with help from you guys).

I need to have another mechanic look at it for a second opinion, but I'd like some advice on how to approach this. Don't have time for a lot of work myself and I don't know a lot about clutches, but if it's a pedal other adjustment or something else needless to say I don't want to pay more than I need to. Should I just ask another mechanic for another diagnosis from scratch - or is there a simple way I can diagnose the problem myself (adjustment vs. replacement) without using up a whole weekend?

 

Not sure why the stealership would want to replace an entire clutch assembly when the symptoms you state indicate a leak in the Master/slave unit. I did not have to do one on my hardbody back when, but on other models, Ford and Dodge, I replaced the master/slave as a piped unit. They come already charged with fluid and you don't have to bleed it out. Couple of bolts and pins and it is changed out. Not too sure how easy it would be on yours, but even if you go to a trusted mechanic, see what he thinks about doing the master/slave as a unit BEFORE diving into the clutch. On 4WD models it is a royal PITA to remove the transmission, transfer case and all the periphery just to get to the clutch assembly.

 

I was also thinking slave cylinder, have you checked it's fluid level?

It can be a struggle to find a good shop but most will be a lot cheaper than what a dealership typically charges.

 

marksr and Larry covered my thoughts.
Not sure about that specific truck, but I know some vehicles share fluid between the braking system and clutch (my Dodge SRT4 is like this).
If you are low on fluid, it may be a brake leak or part of the clutch system.

 

Thanks all. Just trying one more time - what symptoms would you expect if the clutch needed to be completely replaced?

Problem seems to have stabilized. Pedal still feels a tad weak but not so much. Haven't had to pump it in a couple of weeks or so but it seems to be staying OK anyway. Does this suggest to you that the whole clutch needs replacement?

The really strange thing about all this is there was no problem until I picked it up from the dealership after an oil change, which is when I noticed the change in the pedal. Don't know what they could have done accidentally during an oil change to cause that to happen.

Dealership trust issue here as I'm sure you've noticed. Got called out of town for work so I still haven't had time to run around for a second opinion.

Thanks.

 

First off what is the problem? When a clutch driven plate wears out the pedal gets higher on a linkage model as the position of the driving plate or clutch plate changes. Does the pedal nor release the clutch attachment allowing free shifting or does the a gear change drag and be difficult to complete. If the fluid leaks out and you get air in the system then it will be spongy and ineffective when depressing the pedal. You didn't mention how many miles are on the truck and the clutch so we have no idea as to the wear based on use. If the truck has an original clutch with 200000 miles on it the flywheel will need to be turned and everything else replaced. The labor is the main expense with r/r of a 4wd drivetrain with transfer box, I did many working on German cars as well as overhauled many master and slave cylinders as they all come as separate units and even repair parts. Dealers aren't in the business of doing partial repairs to avoid complications. I would do a lot of things to my car that I wouldn't do to a paying customers car, LIABILITY is a big deal at the dealership. For your own understand you could likely do a WIKI search for clutch function and have a much better idea as to what may be wrong. I could likely drive it and know but that would be another adventure.

 

As a rule when the clutch is done, You would have clutch slippage. You would get it in gear, let out on the clutch and it wouldn't move. The clutch pedal you have in the cab is really just for disengaging the clutch at the engine. You push the clutch down, the slave down by the clutch compresses the pressure plate and frees the clutch plate. Then you can put the tranny in gear. You let off the clutch and the pressure plate pinches the clutch plate between the flywheel and pressure plate. That completes the hookup to the transmission.

When you have problems with a clutch and the play in the clutch pedal is excessive, it indicates not so much a problem with the clutch at the engine, but in the hydraulics, that allow you to disengage the clutch; either the slave down at the clutch or the master at the clutch pedal end. The symptom, then would be not being able to get the tranny into gear.

There are a couple of other things involved, like the throw out bearing, but this covers most of it.

 

I was wrong, the cool videos are on You Tube and not Wiki