What are the common symptoms when the clutch cylinder is failing?

I finally picked up my car and drove it the 2K miles home. Towards the end of the trip, and now, it is dfficult to change gears. In reverse, from a dead stop, it sounds like the gears are going to grind (at which point I back off).

In other gears, it either blocks the shifter, or it is hard to get it in gear.

At some speeds it still shifts smoothly, but most require the appropriate elements of the trans and engine to be synchronized.

Any recommendations for tests to determine what might be at issue?

It also makes a rattling sound in idle - like a single bolt in a jar. I figure that came loose in the atypical driving I was doing. I will go hunting for that, but I suspect they are different matters.

Thanks,

 

It is the slave cylinder, or at least a leak in it; check for leaks around it, brake fluid eats rubber so be careful.

 

When mine went, my clutch appeared strong when first depressed but then faded in resistance. I would often have to pump the pedal several times before I would attempt to 'clunk' it into reverse. It's an easy and cheap fix if it is indeed the cylinder. Be sure to replace both the master and slave cylinders at the same time- as the other is likely to fail in the not too distant future. A quick test is to depress and hold the clutch pedal half way down and see if it drops its resistance and continues towards the floor.
Let me know your results.

 

OK, I ran your check. I depressed the clutch half-way and left it there...no discernable difference in resistance. It feels somewhat similar to the clutch in my other GSL-SE. I also inspected the master cylinder and what Haynes calls the "clutch release cylinder." Both are dry...dusty, but definitely dry.

I have seen brake master cylinders fail where the leak was internal, reducing pressure, but with no external leaks. I suppose the same could be true here.

I also tried double-down clutching, which Haynes recommends for worn synchromesh cones (they list the symptom as poor downshifting).

Ironically, while moving all the cars after running the tests, it seems to be normal again. Still, there was definitely something wrong, and I want to know what it was before I get stranded somewhere.

I don't want to just blindly replace the cylinders with rebuilt units unless I determine that is the problem.

I did notice that the free play in the clutch pedal was excessive, like 1.5-2 inches, instead of what Haynes lists as the spec: .02 - .12 inches.

The help is great and I would appreciate any other diagnosis tips so I can positively identify the issue.

Thanks,
BTC

 

Sounds like synchro's to me.... if I'm reading this right, you just seem a little notchy (or a lot notchy), and it wouldn't be the first time for that problem in these cars - might want to try redline tranny oil - MT90 - works wonders on tired old synchros. Also check the shifter well - if it's dry, you will have trouble - top it up to just past the push rod.
You were on the money when you mentioned what the manual says about downshifting to test bad synchro's but you didn't tell us if you were having any problem with shifting down.

 

Yes, downshifting is also blocked, and double-down shifting did not help (assuming I did it correctly).

By shifter well, you don't mean the clutch fluid reservoir, right? So, what is it...I am not familiar with it, at least not by that name.

I was reading the diagnosis section for a DaimlerChrysler transmission in another field service manual I have. It referred to something they called "hard shifting" or "slow shifting" that could be due to a low fluid level in the transmission.

They didn't really describe or define what they meant. I suppose it could be what I described, or it could be abrubt jolts when the actual transmission changes gears.

Since the car was/is unknown to me, it could very well have a small leak, or just be low. A 1700 mile trip would definite exacerbate that. In any case, I should change the transmission gear oil since I don't know the last time it was changed.

So, I will go ahead and do that to see if it clears it up first. At the same time, I can look to see what comes out...metal shavings/dust or lots of broken teeth/bering pieces.

Thanks for all the help,
BTC

 

I'll bet my money that it's the slave cylinder. I had the exact same problems you had and I replaced both the master and slave cylinder and bled the system. Problem went away.

 

I'm referring to the well below the shifter - if you pull back the boots, you can remove the 3 bolts and pop out your shifter - the well the shifter rests in requires gear oil - the mazdatrix site has an FAQ on short shifter install and will take you through the process of removing the shifter if you want to check. However, this alone would not cause the problems you are having but it could be a combination of things including low tranny oil.
Definently check your tranny fluid level - and Redline MT90 is an outstanding product for crunchy synchro's

 

Well, since it is only around $50, I could do that, and if the problem went away then I would assume that was it.

Is the slave cylinder what the Haynes manual refers to as the "clutch release cylinder" located on the left side on the lower corner near the transmission?

Did yours have external leaks?

Thanks,
BTC

 

delayed double post...please delete

 

There is a reasonable chance I might also find whatever is making that 'bolt rattling in a jar' noise right underneath the shifter.

Thanks... that is very useful, I will check it tomorrow.

--BTC

 

It could also be a bad pilot bearing grabbing the input shaft.