sLADe781

iTrader: (1)

So I've noticed recently that my clutch pedal engagement point has been lower than normal when shifting (IE, it engages earlier than usual). The clutch pedal pressure is good. The clutch fluid is full, clear, and bled every 6 months after about 1,700 miles of driving (I work close to home so I don't put much miles on the car). The car is a 2008 G37S and currently has about 56k miles on it. The clutch has never been replaced. The slave cylinder has never been replaced either but the master cylinder was replaced back in 2015 when it started having issues. Since the replacement however, the clutch fluid has been bled religiously every 6 months (sometimes sooner) and there hasn't been any issues until now.

Any ideas on what could be going on? Is there a pending doom that is coming?

Thanks in advance

JSolo

iTrader: (14)

If there's air in the line, I can see it grabbing sooner. Does it seem like the pedal has more dead space before resistance is felt?

I would start with another bleed - both gravity and then traditional to see if that changes anything.

If the pedal starts getting hard after about the same movement as before, then i doubt it's the slave. Beginning of internal leak in the master maybe.

Rochester

iTrader: (9)

If you think this is a precursor to a CSC that will fail on you with barely a two-pump warning before the pedal dumps to the floor and never comes up... let me tell you, that's no fun.

That said, I had no forewarning when my CSC failed. It just happened. All at once. Just as I was pulling into a department store parking lot, and I coasted to a stop. Could have been worse, I suppose. Could have been in the middle of a six-lane stop light, or stuck half way up a hill.

You've been bleeding your clutch every six months for the last 5 years? Wow.

sLADe781

iTrader: (1)

No, there's no extra dead space before resistance is felt compared to what it used to be. I've had air in my lines before so I know what you mean that it'll grab earlier if there was air in there so I'm pretty certain it's not that. I also just bled the fluid about a month ago but still no change. It's just weird because the pedal pressure feels perfectly fine and normal but it grabs a bit early as if there was air in the line.

Not sure if there is any relation here but I did notice some time in November last year that my clutch pedal started making some creaking noise whenever I depressed it. Fast forward a couple weeks later into December and that's when I started noticing the weird engagement point when shifting. Hmm...

sLADe781

iTrader: (1)

I sure hope not as this will require me taking the car to a shop as I do not know how to drop my transmission.

With that said though, if I can pinpoint that it is indeed a CSC failure waiting to happen, I'd rather take the initiative now and get it to a shop to get it worked on rather than have it go out when I'm on the road and be stranded.

Rochester

iTrader: (9)

Wait... this is more on-topic. The summer before last, a problem developed when depressing the clutch pedal. On the first cold morning of the summer, the pedal was soft at the top, and wouldn't engage until about half-way down. After the engine warmed up, the problem went away.

It was a fitment adjustment on one of the plunger switches, which was keeping the pedal from returning 100% of the way. Can't recall which one... the clutch pedal position sensor, or the ignition sensor. Apparently just enough to create a pressure problem for the fluid in the master cylinder, which was resolved when the fluid got up to temp. I'm not sure if I'm describing that correctly, but that's what I recall.

However, my switches are mounted on a RJM pedal assembly. Do you have the RJM pedal?

If not, then maybe this is an opportunity, not a problem. Get a external CSC kit and the RJM pedal. Granted, it's an expensive opportunity, but not my money.

JSolo

iTrader: (14)

^^Good point.. Does engagement point change with respect to cold vs fully warmed up (few miles of driving)?

sLADe781

iTrader: (1)

Hmm...I'm not familiar with the fitment adjustment that you're referring to. I do not have the RJM pedal but I do have Jsolo's spring that has been installed since 2014. Is this fitment adjustment "thing" something that the stock setup has? If so, is this something that needs to be commonly adjusted? Any pictures by any chance?

No, the engagement point does not change with respect to temperature. Everything feels exactly the same whether the car is cold or has been on the road for 45 minutes.

Rochester

iTrader: (9)

There are two plunger-style circuit switches attached to the clutch pedal. One is to tell the computer that the pedal is being depressed to allow for ignition, the other is to turn off Cruise Control when the pedal is depressed. Those two harnesses are attached to the pedal with a threaded metal body, held in place with a retention nut on each side. If they're not installed correctly, they can interfere with the movement or return of the pedal itself.

sLADe781

iTrader: (1)

Got it. I've never removed the stock pedal before so it's probably safe to say it's not that?

One thing I'll note is that I've always gravity bled the system when flushing the fluid but recently ran across MotorvateDIY's thread/video where he explained that you have to hold the clutch pedal down to get the air/old fluid out of the CSC. Since I haven't done a tradition bleed in about 5 years, maybe I'll start there and see if anything changes. I'll report back if it does.

In the meantime, if anyone else has any ideas on the issue I'm all ears!

Thanks to @Jsolo and @Rochester for your help this morning!!

JSolo

iTrader: (14)

^^Gravity bleeding works for replenishing the fluid in the res, rubber/hard line, but not the csc (and the little tubing leading up to it). That's where traditional bleeding comes into play.

It is possible the lower switch (starter lockout) has worn or became damaged in some way. Should be easy enough to inspect if you're small enough to get your head in/under the dash

Rochester

iTrader: (9)

Not necessarily. If the switch is contaminated with dirt so that the plunger can't depress all the way. Kind of a long shot, but they're just little pieces of plastic and metal, and they do fail. My ignition position sensor had to get replaced for intermittent failure a few years back.

Relatively easy to assess things, although you'll have to do all kinds of contortions to get down into the footwell. But you've already done that once, if you put in jsolo's aftermarket pedal spring.