Strange clutch behavior
 

I should preface this by saying that I'm basically a car-moron. I know how to drive. I can change oil. That's about it.

Yesterday my 2000 Miata's clutch started acting strange. I started noticing that the clutch was engaging further down in the pedal's travel than normal, if that makes sense. There were a few inches at the top of pedal travel that didn't feel connected to anything under the floorboard. I was in stop-and-go traffic on the freeway, so there was a lot of clutching involved.

As I crawled along, this got worse and worse, to the point that the pedal was engaging the clutch in the last couple inches of its travel, and getting the car into gear was getting pretty hard. It was clear I wasn't getting the clutch all the way in, even with the pedal on the floor. I started trying to drive like a semi--leave it in first gear as much as possible, and keep a steady, slow speed.

Then two things happened. I pulled off the freeway, and it started to rain. These things happened simultaneously. I should say, it was over 95 degrees, and 100% humidity in this particular North Carolina afternoon.

When I pulled away from the stop sign at the top of the ramp, the clutch pedal was acting normal again. If anything, the clutch was engaging a little HIGHER in the pedal's throw than before. I attended the meeting I was going to (about 1 hour away from home), and on my drive home afterward I didn't notice anything odd about the clutch or anything else about the car. Didn't notice anything driving to the gym this morning either.

So.... what happened? Can heat and humidity make a clutch act like that? Do I need to get it in to the shop? The car has 33,700 miles on it. I confess, I've been a pretty agressive with the clutch (it's a Miata!) but this feels awfully early to be having trouble with it.

check the hydraulic clutch fluid reservoir (attached to or near the master cylinder) if it is low you might have a bubble in the line which could account for this behavior. if it's low a repair would involve finding and fixing the leak, and then bleeding the clutch system.

Yeah, get it to a shop. Sounds like either the clutch is wearing out, or maybe the clutch master or slave cylinder is taking a digger. Either way, it's something you'll want to check in to.

I second that motion. If it was due to clutch disk wear it would have never gone back to it's normal operation. If you have never checked the clutch master cylinders fluid level it is most likely getting low due to normal clutch wear. The master cylinder resevoir only holds a small amount of fluid (usually Dot 3 brake fluid, but check your cars owners manual or call the dealer to be sure), so be sure to check it everytime you change your oil.

Here is a link to something I found on the web about your car

A link to details on how to replace it yourself, if so inclined

so i'm sure we're all dying to know... any updates on your miata?

It's been behaving just great ever since the one incident, so I haven't gotten it to the shop yet. This week, I promise. I was confident enough to take 'er ripping around some backroads this afternoon, which should give you a sense of how concerned I am about it.

It seems pretty clear it's an intermittant issue with the clutch hydrolics, not with the mechanism itself. Makes sense--if the fluid were low and were filling the hydrolic lines in a strange way, it would exhibit strange behavior.

I'll have it in to the shop probably Wednesday, and post what they find.

hey, before you spend any money (if the shop charges to look at something), just check out the reservoir and see if it is low.

if it's not and it never happens again, then i'd probably not worry about it.

Good call.

I've got a car-smart buddy here at work (he's a ProRally driver when he's not working here) that I'll rope into helping me look at it today.

Good advice sambocom. Hope it's nothing serious.
Good luck ratbastid

The reservoir is dead-center between high and low. Given how solid it's felt the last few days, I'm going to chalk it up to Solar Rays. Hey, it works with my computers! :D

Now, my oil IS low. I'll deal with that today.

Ghost in the machine

Ah, but a recurring ghost.

Yesterday afternoon, driving from Durham to Charlotte (2.5 hour drive), I came upon heavy stop-and-go traffic again, just north of Charlotte, and <b>it happened again</b>. Exactly the same as last time--the clutch pedal throw got deeper and deeper, and when traffic finally opened up and I could get the revs up a little bit, the symptom went away.

What does this do to anybody's theories about this? It seems to be related to stop-and-go traffic.

Dude, our cars must share a past life or something. Yesterday I was in my car (1995 Geo Prizm 5-Speed) I started missing gears and was wondering what the fuck was wrong with me. Soon, I realized that my clutch was only disengaging in the last approximately 2/5ths of the pedal travel. It really disconcerted me, and I called a car-savy friend immediately. I brought it over to his house, and we checked the reservoir and checked the hard lines for leaks, but we could find none. The car ride home last night and all my driving today has been normal, with the clutch pedal only having a small amount of free play. I'm kind of thinking like ratbastid and not too worried about it cause it only happened once. I'm very interested if anyone figures out what the problem is. Thanks in advance for the help guys!

Dudes, this sounds like the same problem I posted here. I'm taking it in today to have it checked out. My fluid was pretty low--just below the minimum line--so I topped it off, but that didn't seem to help any. I'm hoping it's a simple fix, like bleeding the lines and putting more fluid in, because I really don't want to have to spend the money right now.

Good luck to all of us. :thumbsup:

Rat, your problem seems to be hyd related. The seals in you system are probably weak, Therfore when they get a little hotter, they let the fluid pass through the piston. You could try getting a turkey baster, then sucking most, NOT ALL ! fluid out of the resivour, and putting new fluid in its place, and then pumping the pedal about 10 or fifteen times, and doing this about three or four times, it may extend the life of your master and slave cylinders. Good luck

Well, I found out what my problem was. The problem reappeared yesterday, and it became really hard to get the car to change gears. I managed to nurse it to the local mechanic, and they were able to figure out that my master cylinder wasn't making any pressure. An hour (and $200) later, I had my car back and it's been performing better than ever.

Weird. About a month ago, my 88 Thunderbird started doing the same kind of thing. I kept thinking I was missing shifts and attributed me going on 3 hours of sleep. Then I started having a really hard time getting it into first and third, and the other gears were a little notchier too.

It did that on and off for 2 days in a row, but never since. I've learned many times that when cars do things like that it's NEVER "just a fluke", it will start acting up again I'm sure. First thing I'll check is the hydraulic pressure, sounds like it was having the same kind of problem. Seems like it's a heat-related, I was in stop and go traffic in very hot weather at the time.

i've seen problems like that before too and usually it's because of fluid or seals. check to see that the fluid lines aren't being passed by any exhaust pipes or anything overly hot. if it does it can carbonize the fluid and even vaporize it if it gets too hot. in either case the clutch movement is crappy. as for the seals being a potential problem... the only thing that fixes them is to replace them. i've never used any of the wonder products with any success. the few that show signs of improvement at the onset are nothing more than a bandaid and in the end just delay or even worse make the repair/replacement of a part more costly. most mechanics will say that either they don't know what is going on, that they don't believe you (it's sad but i've had mechanics tell me that they don't believe me), or that if you suggest a repair item that they will chomp at the bit to replace it and make a buck off of you even if it didn't need replacing... and if you are lucky enough... you find the mechanic who knows what he's doing... knows what's wrong and is straight forward with you and gets you what you need. i wish all mechanics were like that. good luck with the clutch problem... and better luck finding a good mechanic.

Well, I had her in the shop for her 30-k mile service yesterday, and I asked them to look. They found a slow leak in the slave cylinder, which would account for low pressure and flaky behavior.

Since the rest of the service came to $Big Bucks$, I asked them to wait on it. I've got a buddy with a pit in his garage, who says we can replace a slave cylinder easy.

Any idea how much I can expect the part to cost?