strange clutch behavior

[woodsman]

Hi all. I had a new clutch installed by an indi . After 8000 miles the clutch pedal seems to get sucked down whenever the engine hits 4000 RPM or more. Once it's occurred, the pedal may return to it's proper place, but offer no resistance when pushed until it begins to literally, push the clutch up, or the pedal actually stays down whereupon, I can do a "speedshift" due to the decreased pedal travel. Sometimes the shift can't be accomplished at all , without first, pulling the pedal up manually with the top of my foot (under the pedal)! I bought the parts so the shop won"t warranty the job if it's because of them and the supplier won't either because too much time has elapsed, soooooooo that leaves ME and at the moment I have just pulled the tranny; The release bearing fell out in my hand (fast reflexes) and is seemly in good shape but isn't it supposed to be attached to the arm? Any help would be greatly appreciated. I should add that I had the shop bleed the system and install a new slave but there was no improvement.

[Meir]

Originally Posted by woodsman

Hi all. I had a new clutch installed by an indi . After 8000 miles the clutch pedal seems to get sucked down whenever the engine hits 4000 RPM or more. Once it's occurred, the pedal may return to it's proper place, but offer no resistance when pushed until it begins to literally, push the clutch up, or the pedal actually stays down whereupon, I can do a "speedshift" due to the decreased pedal travel. Sometimes the shift can't be accomplished at all , without first, pulling the pedal up manually with the top of my foot (under the pedal)! I bought the parts so the shop won"t warranty the job if it's because of them and the supplier won't either because too much time has elapsed, soooooooo that leaves ME and at the moment I have just pulled the tranny; The release bearing fell out in my hand (fast reflexes) and is seemly in good shape but isn't it supposed to be attached to the arm? Any help would be greatly appreciated. I should add that I had the shop bleed the system and install a new slave but there was no improvement.

My guess is your indi didn't installed it properly.
The release bearing should be seated firmly on the release lever.
My recommendation is,if you have the transmission out, put a new bearing, make sure you have the updated lever, replace the ball journal with its spring and rubber.
All the parts (including new lever if needed) shouldn't accede $100.
Which bring me to the question, if you removed the transmission, why didn't you do the clutch job yourself, to begin with?

[san rensho]

Sounds like you had a hydraulic problem, air in the hydraulic system or a bad clutch slave or master. Did you bleed the clutch before taking it apart?

[JFP in PA]

Originally Posted by woodsman

Hi all. I had a new clutch installed by an indi . After 8000 miles the clutch pedal seems to get sucked down whenever the engine hits 4000 RPM or more. Once it's occurred, the pedal may return to it's proper place, but offer no resistance when pushed until it begins to literally, push the clutch up, or the pedal actually stays down whereupon, I can do a "speedshift" due to the decreased pedal travel. Sometimes the shift can't be accomplished at all , without first, pulling the pedal up manually with the top of my foot (under the pedal)! I bought the parts so the shop won"t warranty the job if it's because of them and the supplier won't either because too much time has elapsed, soooooooo that leaves ME and at the moment I have just pulled the tranny; The release bearing fell out in my hand (fast reflexes) and is seemly in good shape but isn't it supposed to be attached to the arm? Any help would be greatly appreciated. I should add that I had the shop bleed the system and install a new slave but there was no improvement.

What brand clutch did you buy? Reason I ask is that with diaphragm design clutches, you cannot be mixing parts. Diaphragm clutches do not like to be pushed over center (when the clutch "fingers" are literally turning inside out) as it will cause the clutch cover to want to stay depressed, so the pedal stays down momentarily, even without your foot on the pedal.

Several things can lead to this problems, including miss matched parts, throw out bearing installed incorrectly, hydraulic system issues, loose clutch cover bolts, etc.

[woodsman]

When I took it back to the shop I had them bleed the system, install a new slave and check the return spring on the pedal. No change.

JFP. they installed an aluminum flywheel, a Sachs pressure plate and a Kevlar reinforced, 4 spring disc, all of which were part of a recommended kit from Clutchmasters in California that I bought because I was planning on turboing the car in the future(not anymore). And yes! there was 2 loose bolts on the pressure plate.
Now I don't know what NEEDS to be replaced. the kit cost $2084 and included a release bearing.

[JFP in PA]

Originally Posted by woodsman

When I took it back to the shop I had them bleed the system, install a new slave and check the return spring on the pedal. No change.

JFP. they installed an aluminum flywheel, a Sachs pressure plate and a Kevlar reinforced, 4 spring disc, all of which were part of a recommended kit from Clutchmasters in California that I bought because I was planning on turboing the car in the future(not anymore). And yes! there was 2 loose bolts on the pressure plate.
Now I don't know what NEEDS to be replaced. the kit cost $2084 and included a release bearing.

OK, as I have not used this setup (do not like the single mass flywheel and the problems it causes), so I am not familiar with how thick the disc is, etc. As Sachs is the OEM pressure plate, that would not seem to be an issue without seeing the unit.

I would suggest comparing your disc with an OEM unit for thickness (if the disc is too thick, it forces the diaphragm fingers inwards when fully engaged, which can cause them to go over center when depressed). I would also be looking at the throw out bearing, and trying to find out why it fell out when you removed the trans (should not have happened). I would also have to comment that NONE of the pressure plate bolts should have been loose, if the pressure plate comes loose and backs away from the flywheel even slightly, the clutch can be pushed over center very easily. At a minimum, I would get all new pressure plate bolts, Loctite them and torque them to the correct specs (never reused these bolts or the flywheel bolts).

[woodsman]

thanks for the response JFP. The pressure plate is a Sachs unit but it is supposed to have more clamping power than stock- something like 70 % good for around 400 HP. With regards to the release bearing, I see no method of attachment to the arm. There is nothing laying in the bellhousing and no hole for a spring or clip to fall through . Also they couldn't get the car to start with the new alu flywh and charged me 5 additional hrs labour for diagnosing . The old fly worked but the new would not but a week later and with another al flywh it started right up. I guess the clips got lost in the shuffle but would that be enough to actually prevent the clutchPEDAL from returning? Advice about the bolts taken.

[woodsman]

thanks for the response JFP. The pressure plate is a Sachs unit but it is supposed to have more clamping power than stock- something like 70 % good for around 400 HP. With regards to the release bearing, I see no method of attachment to the arm. There is nothing laying in the bellhousing and no hole for a spring or clip to fall through . Also they couldn't get the car to start with the new alu flywh and charged me 5 additional hrs labour for diagnosing . The old fly worked but the new would not but a week later and with another al flywh it started right up. I guess the clips got lost in the shuffle but would that be enough to actually prevent the clutchPEDAL from returning? Advice about the bolts taken.

(PS I won't tell you about the bent valves during the ims bearing install)

[Meir]

Originally Posted by woodsman

thanks for the response JFP. The pressure plate is a Sachs unit but it is supposed to have more clamping power than stock- something like 70 % good for around 400 HP. With regards to the release bearing, I see no method of attachment to the arm. There is nothing laying in the bellhousing and no hole for a spring or clip to fall through . Also they couldn't get the car to start with the new alu flywh and charged me 5 additional hrs labour for diagnosing . The old fly worked but the new would not but a week later and with another al flywh it started right up. I guess the clips got lost in the shuffle but would that be enough to actually prevent the clutchPEDAL from returning? Advice about the bolts taken.

(PS I won't tell you about the bent valves during the ims bearing install)

The realese bearing is suppose to snap on the realese lever, using a clip like strature that is part of the bearing.

[woodsman]

I guess the cage-like structure surrounding the bearing is defective. I would also like to underline the fact that the clutch BEHAVED NORMALLY unless the RPM's reached 4000. I'm afraid I'm going to have to shell out a lot more cash besides redoing the clutch job myself and this after paying $3500 for the last one. I ve got 10 000 MILES out of it!

[Homeboy981]

Hi Woodsman,

I had similar problem which turned out to be that I did not bleed the Clutch Slave properly at installation time. The Slave MUST GO IN with the Bleeder valve OPEN. Then, once assembled you bleed the Clutch Slave cylinder with the pedal mashed to the floor.

The Aasco LWFW has LESS thickness, as compared to a stock Dual-Mass Flywheel. That is why you cannot use factory flywheel bolts. So, your pedal may be off by a little on the clutch release point but should still return to the upright seated position, if bled properly.

I tried it without bleeding it first and had my pedal do similar things to what you have described. Also, I DID BLEED it for a long time - as there was plenty of air bubbles trapped deep in the Clutch slave system.

[woodsman]

Homeboy, did the symptoms show only after a certain RPM

[woodsman]

UPDATE: upon closer inspection, I can see what appears to be a (one) broken edge on the release bearings cage-like structure. Clutchmasters has requested that I send it to them and so I will. Could the solution really be this simple Hope! This would explain why the clutch worked fine for the first 3000 miles or so.

[JFP in PA]

But it does not explain why bolts were loose on the pressure plate............

[woodsman]

CLUTCHMASTERS were so difficult(cheap) to deal with that I bought a new release bearing, clutch cover and flywheel bolts from Sunset and requested the (AASCO alu flywheel specific) pilot bearing only ,from clutchmasters (they didn't even charge me!).
I've discovered that the flywheel position-sensor was about to fall out as the bolt securing it was barely threaded in!!!! $100/hr and the 'Porsche trained' mechanic forgot to tighten the bolt!! A learned in a book called 'prepare to win',long ago the concept of 'nutting and bolting'- it's where at the end of a job , or the last thing you do to a car before you deem a car race-worthy, you give each and every nut and bolt a quick pull -a double check as you've already torqued everything to it's proper rate-right?
I recently bought some real trick RS wheel spacers off of a Porsche tech and he told me that he thinks the bolts that came loose on the clutch cover did so because they weren't properly torqued!!!! ( I'm noticing a pattern of behavior) AND then the fingers were resting and operating unevenly which caused the CLIPS ON THE PORSCHE RELEASE BEARING TO BRAKE OFF!!!! Hence- strange clutch behavior!!!....now I'm feeling moody:troll: no wonder my valves got BENT when they installed the LN ceramic IMS bearing..("they shouldn't have moved...")