Strange Clutch problem in CGT
07-08-2012, 08:41 PM
#1
Strange Clutch problem in CGT
This morning I experienced a strange clutch issue. Usually, I just start the car with the clutch engaged, wait about 7 seconds with the clutch still engaged, put the car in reverse, back out and go. The manual recommends waiting several seconds to put the car in reverse after engaging the clutch, and also says there is no need to "warm up the car at idle". However, I do drive the car at low RPM's until the car is at normal temperature.
This morning, after starting the car, I released the clutch and let it warm up for a minutes. When I depressed the clutch all the way in to put the car in reverse, I heard a bad rattling/grinding noise and my instrument panel dimmed. I released and tried again, but this time engaged the clutch very slowly. At about 75% engaged, it's as if it was hitting some point that caused this loud and bad rattling noise - (like a normal tranny rattle at idle in a race car) and once again the dash lights dimmed as if they were about to flicker on and off. The third time I engaged, I did not want to hit the 75% mark which was causing the noise, but wanted to see if the car had any trouble going into gear...no problem going into all the gears. With the car in neutral, I tried one more time being careful to just hit that awful grinding point for less than a millisecond (thinking that going through the gears might have synced something and fixed the problem). Still, it was about to grind if I went any further. I also noted that the break servo warning light was on longer than usual, and the brake warning light actually stayed on during this situation. I shut off the car and waited a minute. Then restarted and tried again. The problem was gone. I drove the car around the area in the morning, stopped for a couple of hours (to test drive the new McClaren), then drove the car home...no issues.
I remember in my race car many years ago having a similar issue just after replacing the clutch - it think the pedal distance was adjusted to fix the problem. I don't think this would be the same thing, but the symptom felt the same. Any ideas or has anyone experienced this? Could it be related to the brake servo (low fluid)? Excuse my ignorance relating to the mechanics of cars...love to drive and race them, but changing oil and wheels is about the extent of my knowledge.
This morning, after starting the car, I released the clutch and let it warm up for a minutes. When I depressed the clutch all the way in to put the car in reverse, I heard a bad rattling/grinding noise and my instrument panel dimmed. I released and tried again, but this time engaged the clutch very slowly. At about 75% engaged, it's as if it was hitting some point that caused this loud and bad rattling noise - (like a normal tranny rattle at idle in a race car) and once again the dash lights dimmed as if they were about to flicker on and off. The third time I engaged, I did not want to hit the 75% mark which was causing the noise, but wanted to see if the car had any trouble going into gear...no problem going into all the gears. With the car in neutral, I tried one more time being careful to just hit that awful grinding point for less than a millisecond (thinking that going through the gears might have synced something and fixed the problem). Still, it was about to grind if I went any further. I also noted that the break servo warning light was on longer than usual, and the brake warning light actually stayed on during this situation. I shut off the car and waited a minute. Then restarted and tried again. The problem was gone. I drove the car around the area in the morning, stopped for a couple of hours (to test drive the new McClaren), then drove the car home...no issues.
I remember in my race car many years ago having a similar issue just after replacing the clutch - it think the pedal distance was adjusted to fix the problem. I don't think this would be the same thing, but the symptom felt the same. Any ideas or has anyone experienced this? Could it be related to the brake servo (low fluid)? Excuse my ignorance relating to the mechanics of cars...love to drive and race them, but changing oil and wheels is about the extent of my knowledge.
Last edited by MikeGT; 07-08-2012 at 10:22 PM.
07-13-2012, 08:10 AM
#2
Race Director
This morning I experienced a strange clutch issue. Usually, I just start the car with the clutch engaged, wait about 7 seconds with the clutch still engaged, put the car in reverse, back out and go. The manual recommends waiting several seconds to put the car in reverse after engaging the clutch, and also says there is no need to "warm up the car at idle". However, I do drive the car at low RPM's until the car is at normal temperature.
This morning, after starting the car, I released the clutch and let it warm up for a minutes. When I depressed the clutch all the way in to put the car in reverse, I heard a bad rattling/grinding noise and my instrument panel dimmed. I released and tried again, but this time engaged the clutch very slowly. At about 75% engaged, it's as if it was hitting some point that caused this loud and bad rattling noise - (like a normal tranny rattle at idle in a race car) and once again the dash lights dimmed as if they were about to flicker on and off. The third time I engaged, I did not want to hit the 75% mark which was causing the noise, but wanted to see if the car had any trouble going into gear...no problem going into all the gears. With the car in neutral, I tried one more time being careful to just hit that awful grinding point for less than a millisecond (thinking that going through the gears might have synced something and fixed the problem). Still, it was about to grind if I went any further. I also noted that the break servo warning light was on longer than usual, and the brake warning light actually stayed on during this situation. I shut off the car and waited a minute. Then restarted and tried again. The problem was gone. I drove the car around the area in the morning, stopped for a couple of hours (to test drive the new McClaren), then drove the car home...no issues.
I remember in my race car many years ago having a similar issue just after replacing the clutch - it think the pedal distance was adjusted to fix the problem. I don't think this would be the same thing, but the symptom felt the same. Any ideas or has anyone experienced this? Could it be related to the brake servo (low fluid)? Excuse my ignorance relating to the mechanics of cars...love to drive and race them, but changing oil and wheels is about the extent of my knowledge.
This morning, after starting the car, I released the clutch and let it warm up for a minutes. When I depressed the clutch all the way in to put the car in reverse, I heard a bad rattling/grinding noise and my instrument panel dimmed. I released and tried again, but this time engaged the clutch very slowly. At about 75% engaged, it's as if it was hitting some point that caused this loud and bad rattling noise - (like a normal tranny rattle at idle in a race car) and once again the dash lights dimmed as if they were about to flicker on and off. The third time I engaged, I did not want to hit the 75% mark which was causing the noise, but wanted to see if the car had any trouble going into gear...no problem going into all the gears. With the car in neutral, I tried one more time being careful to just hit that awful grinding point for less than a millisecond (thinking that going through the gears might have synced something and fixed the problem). Still, it was about to grind if I went any further. I also noted that the break servo warning light was on longer than usual, and the brake warning light actually stayed on during this situation. I shut off the car and waited a minute. Then restarted and tried again. The problem was gone. I drove the car around the area in the morning, stopped for a couple of hours (to test drive the new McClaren), then drove the car home...no issues.
I remember in my race car many years ago having a similar issue just after replacing the clutch - it think the pedal distance was adjusted to fix the problem. I don't think this would be the same thing, but the symptom felt the same. Any ideas or has anyone experienced this? Could it be related to the brake servo (low fluid)? Excuse my ignorance relating to the mechanics of cars...love to drive and race them, but changing oil and wheels is about the extent of my knowledge.
He said it sounded 'normal'. He said the transmission in these cars can make a considerable racket at times until they get warmed up.
The transmission is a transverse unit and has extra gears to make allow this configuration and more gears means more sources of gear rattle.
I have never been in a C-GT but I know from my 996 Turbo experience its transmission can sometimes rattle in a way that has been cringing in my seat thinking pending engine failure when I come to my senses and dab the clutch pedal and release and the noise is gone.
Now I didn't have a copy of your post to quote from and I didn't mention the dash light dimming thing.
But I might be able to explain that away as some sloppy clutch work. Once in a while I get sloppy with Turbo's clutch (and even my Boxster's clutch) and engine rpms can drop enough the dash lights dim some. It usually happens when I'm driving the car for the first time after some time away from the car and coming from another car that has a different clutch feel. It takes my left leg a time or two to regain its Turbo (or Boxster) clutch feel. However, it is easier to go from the Turbo to the Boxster because the Boxster's clutch is unboosted and has just about the perfect feel. Easy to adapt to this clutch and because I have driven the car so many miles I think I could drive it in my sleep.
Now because I'm sloppy and I know I shouldn't be sloppy, this means I'm being sloppy partially because I'm not paying as close attention as I should. Tired or I have other things on my mind, etc. Because of this the fact I was sloppy doesn't come through but the engine's dip in rpms and the results of this sure catch my attention.
But I've done this often enough -- thankfully not too often though -- to have put the whole chain of events together.
Nowadays when this happens I just remind myself to pay more attention.
The Turbo is on some ways a very refined car and yet it has its rough/raw aspects too.
The Carrera GT I can only imagine is even more so in this regard.
Sincerely,
Macster.
07-14-2012, 02:07 AM
#3
Macster,
I don't think what you described is the issue (sloppy clutch work), and the noise is definitely not normal. I've been driving the CGT for years. I'm also familiar with typical tranny noise as I race Porsches frequently (RSR, Cup, 997, 996, 911.... even the Boxter Spec). This clutch issue happened when sitting in my garage. I'll be taking it to a CGT certified mechanic soon. I'll post the outcome. I really appreciate you taking the time to speak to your mechanic and posting your thoughts, thank you for that.
I don't think what you described is the issue (sloppy clutch work), and the noise is definitely not normal. I've been driving the CGT for years. I'm also familiar with typical tranny noise as I race Porsches frequently (RSR, Cup, 997, 996, 911.... even the Boxter Spec). This clutch issue happened when sitting in my garage. I'll be taking it to a CGT certified mechanic soon. I'll post the outcome. I really appreciate you taking the time to speak to your mechanic and posting your thoughts, thank you for that.
07-16-2012, 01:29 PM
#4
Intermediate
Join Date: Aug 2005
Location: Atlanta, GA
Posts: 41
Likes: 0
Received 0 Likes
on
0 Posts
I'm not very technical either but after watching techs bleed mine a few times I know the fluid is shared between the brake system and the clutch and the reservoir is up in the front bonnet under the padding/carpet if you wanted to check the level. with the servo light not going off it sounds like a valid thing to look at. of course the dimming lights and vanishing symptoms sound more like electrical/computer gremlin. I hate those "just reboot" type of issues!
07-17-2012, 04:45 PM
#5
Race Director
Agree. Sloppy clutch work seems less a reasonable explanation now than then.
The tech I spoke with is quite knowledgeable about these cars being thoroughly trained/qualified to work on them.
But the quality of his 'diagnosis' is limited by the quality of the info regarding the symptoms he gets and he didn't get very high quality info from me.
The fault is mine entirely.
I'll look to see what you post.
Sincerely,
Macster.
The tech I spoke with is quite knowledgeable about these cars being thoroughly trained/qualified to work on them.
But the quality of his 'diagnosis' is limited by the quality of the info regarding the symptoms he gets and he didn't get very high quality info from me.
The fault is mine entirely.
I'll look to see what you post.
Sincerely,
Macster.
07-28-2012, 05:50 PM
#7
Well, that didn't work. The brake fluid level was above the min and below the max. After watching the fluid drop just a bit after turning on the ignition and hearing the pump run for one minute before stopping, I then topped off the fluid. Then jumped in the car, pumped the brakes a few times (which felt normal), and started the car with the clutch fully engaged. Released the clutch and then slowly started to engage it. Sure enough, once again, after depressing about 80% down, a sudden and sever grinding noise. Keep in mind, if I start the car in gear, move the car out of the driveway and go, everything is fine. It's only on the initial start up, cold, and before I move the car at all. The sound is almost identical as if you try and put the car in gear without engaging the clutch - it's like it hits a wall and has a rotating grind.
Time to take it in and find out what's really going on... only problem is I can't duplicate it after driving the car. It must stay over night and be started in the morning.
Time to take it in and find out what's really going on... only problem is I can't duplicate it after driving the car. It must stay over night and be started in the morning.
Trending Topics
08-10-2012, 12:23 AM
#8
ALL FIXED!!
There is a place to bleed the brakes in the engine compartment. It has a little black rubber cap (you can see it below the right side of the carbon fiber wishbone when looking at the engine from the rear). My friend and I attached a hose to it, pumped the clutch a few times and out came the air. When fluid finally pumped out, we were done. No more grinding. Just double checked after the car was sitting for a few days. All good. The Brake Servo light turns off after a minute like it should, and the Brake Light on the dash no longer stays on. Looking forward to this weekend!
There is a place to bleed the brakes in the engine compartment. It has a little black rubber cap (you can see it below the right side of the carbon fiber wishbone when looking at the engine from the rear). My friend and I attached a hose to it, pumped the clutch a few times and out came the air. When fluid finally pumped out, we were done. No more grinding. Just double checked after the car was sitting for a few days. All good. The Brake Servo light turns off after a minute like it should, and the Brake Light on the dash no longer stays on. Looking forward to this weekend!
08-10-2012, 12:02 PM
#9
Rennlist Member
ALL FIXED!!
There is a place to bleed the brakes in the engine compartment. It has a little black rubber cap (you can see it below the right side of the carbon fiber wishbone when looking at the engine from the rear). My friend and I attached a hose to it, pumped the clutch a few times and out came the air. When fluid finally pumped out, we were done. No more grinding. Just double checked after the car was sitting for a few days. All good. The Brake Servo light turns off after a minute like it should, and the Brake Light on the dash no longer stays on. Looking forward to this weekend!
There is a place to bleed the brakes in the engine compartment. It has a little black rubber cap (you can see it below the right side of the carbon fiber wishbone when looking at the engine from the rear). My friend and I attached a hose to it, pumped the clutch a few times and out came the air. When fluid finally pumped out, we were done. No more grinding. Just double checked after the car was sitting for a few days. All good. The Brake Servo light turns off after a minute like it should, and the Brake Light on the dash no longer stays on. Looking forward to this weekend!
Great news. Glad you got this worked out without having to replace the clutch!!! I think I'll wipe the dust off mine and celebrate with you.
