Deadeye
12-21-2004, 03:40 PM
If anyone has ideas about the following problem, I would appreciate your help.
Macs Performance Dual Disc Puller flywheel/clutch kit slipped and "burned out" (well not really/completely) last Friday. Craig McElfresh drove 600+ miles Friday nite and Saturday and got the truck running again by Sunday nite http://www.dieselplace.com/forum/images/smilies/rockon.gif . (Have you ever had a vendor travel 600+ miles each way to come fix a problem for you: and not charge you a dime? ) Even though it is running now, and we understand some issues and results, we still don't have a definate cause identified (installation vs kit vs OEM part???)
The History:
The original kit was installed in my garage just over a month ago by two gearhead buddies. The kit now has less than 1500 miles on it. Once installed the clutch pedal engaged tight just off the floor, held incredably tough, squealed when started from stop, and occasional shifting (due to mostly metal clutch disc pad) and a very strong pedal push required (4 to 5 times stronger than factory but we did not know at the time this was too much). It was hard to learn to start from a stop because of the pedal hardness and how grabby the clutch pads were. But it worked real well once the clutch was fully engaged and would run the HJAT at level 5, great ):h ):h ):h .
The Problem:
Last Friday the clutch slipped while passin a car on the way to work HJAT lvl 5. I thought it must be the tires. Tried again with foot off the clutch pedal at 2000 rpms and accelerator slightly pushed the rpms jumped 500-700 and squealed, mph rose from45 to 50 in 4th gear. Essentiallly the same happened in 5th and 6th. Came to stop light. Leavin, the clutch pedal came all the way out but the truck barely started moving (later learnd the clutch was not fully engaged) and I thought the truck was loosing power. At the next light the clutch engaged better but only about 1" from the end of the pedal. That nite on the way home form work the clutch did not fully engage and drivin 15 miles with the HJAT at zero and hardly using the throttle the truck would barely accelerate. I was worried about even gettin home. Stopped at a light to turn off the hiway and when I started the clutch engaged as it did the last stop before getting to work. But it was not like original or as it should be . (The next morn I moved the truck and the clutch did not fully engage again). I called Craig that nite and he told me not to drive it again and he headed out to my house w/tools, parts and a lot of mechanical experience. BTW, Friday before Craig left I examined the edge of the kit through the opening in the passenger side of the bell housing. One of the disc pads was shot (more later).
The Analysis:
Sunday morning it took Craig only a little more than 1.5 hrs to pull out the tranny and disassemble the pressure plate and clutch discs. Craig said the original kit installation looked good. The shims were measured and were correct for the original installation. The pressure plate was designed to put over 3600 lbs of static pressure on the discs. Craig check the pressure plate fingers and found no wear, cracks, or debris inside, the plate had no signs of significant heat. The floater plate had no signs of heat but did have some grooves but was not worn out. It too had the proper shims. Flywheel was visually inspected (not measured and I don't know if Craig measured the floater) and appeared ok. The front disc behind the flywheel and in front of the floater had some wear (.024" ?) but it looked even and consistent. When reassembled Craig reduced the shims by .020". The rear disc between the floater and the pressure plate had significant wear on it with the vast majority on the floater side. I don't recal the amount of wear but when reassembled Craig reduced the shims by .060" (I thnik the total wear was a little over .090").
The amount of wear on the back disc is what kept the clutch from engaging and he prooved that by putting the kit back exactly as it was with only some shims removed. It then worked a lot better than it ever did. The pedal pushing was, IMHO much like stock :ro) , and the the engagement worked and was so easy I could not believe it:D :D :D :D . It holds when engaged just like it did originally and maybe even better.
Other checks:
While it was apart we removed the slave cylinder and reconnected it to the master cylinder. Craig held it with his fingers and I worked the pedal. He believed it and the master were ok. I could hear the hydraulic fluid flowing back into the master once I pulled the pedal back out and Craig was sure there was more then enough pressure in the system. We looked at all the plates and saw no sign of any heat anywhere. all the surfaces mated to clutch pads were clean and clear with only normal grooves/ridges. The worn pad on the rear disc still had enough thickness to last more than a year, according to Craig. No new parts were installed because we found nothing that was completely failed. Plus Craig thought, and I agreed, that installing a new kit would be a waste until we could identify the cause.
Craig spent a lot of time callin and discussing this with several buddies and even went over to Clint's new shop (ATS) and talked to him. Craig's buddy, Smokin Deezul, stopped by Sunday nite and helped reinstall the tranny. Smokin' is a tech at at furd dealer in Ft. Collins but he drives a Duramax!! They discussed the issues as well.
I bought the truck used (31K miles) and it has had three oem flywheels in it and the master cylinder has been replace twice in the last year and bled at least 3 times. The DOT 3 has been switched to DOT 4 and a tranny cooler was installed by the dealer to address the hard pedal. The clutch pedal was replaced due to squeaking constantly. It now has 53K miles on it. (What if DOT 3 is mised with DOT 4? any impact?)
I installed a high idle which no longer works consistently. After the reinstall, before the test drive I turned it on but did not work. Craig and Greg looked at each other and climbed under the dash. It appeared that a plug that lost some electrical tape may have been keeping the pedal from comin all the way out. One thought was that this not only impacted the Hi Idle but might also have kept the throughout bearing putting pressure on the pressure plate fingers. Thus, keeping the clutch from full engagement. I tend to doubt as I would have expected to feel a pedal in the wrong position, but hey . . . .
Current conclusions:
The kit is currently working perfectly right now. What I now know is that the original kit installation resulted in a lot more required clutch pedal pressure than is correct (we did not know this at the time since we had no previous experience with this type of kit.) We are pretty sure that the lack of full clutch engagement caused the slip that wore out the one disc pad. This was likely because of failure to release the pressure plate fingers. (why is still a question). Clint believed that any hydraulic issue will be related to the master cylinder since it controls the simple slave cylinder and the hose, and the internal piston and return valve/port can fail due to contaminatiion/wear/damage. There was some thought that heat (from where?) may have caused hydraulic expansion and pushed the slave cylinder and throwout bearing forward???
Mods:
One idea I may try is to wrap the hose and master cylinder with a heat shield. I also intend to check the plug under the pedal (the Hi Idle failed to work one time this morning, again http://www.dieselplace.com/forum/images/smilies/mad.gif )
More:
Craig is going to ship replacement disc and when time arrives and we know the problem they will get installed. Who knows, this problem may never happen again and there may never be an explanation.
Given the original kit installation hard pedal and other characteristics, I suspect there was something wrong from the first installation. The thickness of the whole kit too great? something blocking the pedal travel? We discussed and dismissed air in in the hydraulic hose (Craig has done numerous installs on his truck and never had air in the line/hose). We discussed the length of pressure plate fingers, width/thickness of parts, etc. . . .still do not have a firm conclusion. When he gets home Craig is going to do some more investigation on the parts he has in shop. When I get some more data/answers I will post them.
Right now I have run out of info, questions, conclusions, solutions, tests . . . . http://www.dieselplace.com/forum/images/smilies/confused.gif
Any ideas?
Macs Performance Dual Disc Puller flywheel/clutch kit slipped and "burned out" (well not really/completely) last Friday. Craig McElfresh drove 600+ miles Friday nite and Saturday and got the truck running again by Sunday nite http://www.dieselplace.com/forum/images/smilies/rockon.gif . (Have you ever had a vendor travel 600+ miles each way to come fix a problem for you: and not charge you a dime? ) Even though it is running now, and we understand some issues and results, we still don't have a definate cause identified (installation vs kit vs OEM part???)
The History:
The original kit was installed in my garage just over a month ago by two gearhead buddies. The kit now has less than 1500 miles on it. Once installed the clutch pedal engaged tight just off the floor, held incredably tough, squealed when started from stop, and occasional shifting (due to mostly metal clutch disc pad) and a very strong pedal push required (4 to 5 times stronger than factory but we did not know at the time this was too much). It was hard to learn to start from a stop because of the pedal hardness and how grabby the clutch pads were. But it worked real well once the clutch was fully engaged and would run the HJAT at level 5, great ):h ):h ):h .
The Problem:
Last Friday the clutch slipped while passin a car on the way to work HJAT lvl 5. I thought it must be the tires. Tried again with foot off the clutch pedal at 2000 rpms and accelerator slightly pushed the rpms jumped 500-700 and squealed, mph rose from45 to 50 in 4th gear. Essentiallly the same happened in 5th and 6th. Came to stop light. Leavin, the clutch pedal came all the way out but the truck barely started moving (later learnd the clutch was not fully engaged) and I thought the truck was loosing power. At the next light the clutch engaged better but only about 1" from the end of the pedal. That nite on the way home form work the clutch did not fully engage and drivin 15 miles with the HJAT at zero and hardly using the throttle the truck would barely accelerate. I was worried about even gettin home. Stopped at a light to turn off the hiway and when I started the clutch engaged as it did the last stop before getting to work. But it was not like original or as it should be . (The next morn I moved the truck and the clutch did not fully engage again). I called Craig that nite and he told me not to drive it again and he headed out to my house w/tools, parts and a lot of mechanical experience. BTW, Friday before Craig left I examined the edge of the kit through the opening in the passenger side of the bell housing. One of the disc pads was shot (more later).
The Analysis:
Sunday morning it took Craig only a little more than 1.5 hrs to pull out the tranny and disassemble the pressure plate and clutch discs. Craig said the original kit installation looked good. The shims were measured and were correct for the original installation. The pressure plate was designed to put over 3600 lbs of static pressure on the discs. Craig check the pressure plate fingers and found no wear, cracks, or debris inside, the plate had no signs of significant heat. The floater plate had no signs of heat but did have some grooves but was not worn out. It too had the proper shims. Flywheel was visually inspected (not measured and I don't know if Craig measured the floater) and appeared ok. The front disc behind the flywheel and in front of the floater had some wear (.024" ?) but it looked even and consistent. When reassembled Craig reduced the shims by .020". The rear disc between the floater and the pressure plate had significant wear on it with the vast majority on the floater side. I don't recal the amount of wear but when reassembled Craig reduced the shims by .060" (I thnik the total wear was a little over .090").
The amount of wear on the back disc is what kept the clutch from engaging and he prooved that by putting the kit back exactly as it was with only some shims removed. It then worked a lot better than it ever did. The pedal pushing was, IMHO much like stock :ro) , and the the engagement worked and was so easy I could not believe it:D :D :D :D . It holds when engaged just like it did originally and maybe even better.
Other checks:
While it was apart we removed the slave cylinder and reconnected it to the master cylinder. Craig held it with his fingers and I worked the pedal. He believed it and the master were ok. I could hear the hydraulic fluid flowing back into the master once I pulled the pedal back out and Craig was sure there was more then enough pressure in the system. We looked at all the plates and saw no sign of any heat anywhere. all the surfaces mated to clutch pads were clean and clear with only normal grooves/ridges. The worn pad on the rear disc still had enough thickness to last more than a year, according to Craig. No new parts were installed because we found nothing that was completely failed. Plus Craig thought, and I agreed, that installing a new kit would be a waste until we could identify the cause.
Craig spent a lot of time callin and discussing this with several buddies and even went over to Clint's new shop (ATS) and talked to him. Craig's buddy, Smokin Deezul, stopped by Sunday nite and helped reinstall the tranny. Smokin' is a tech at at furd dealer in Ft. Collins but he drives a Duramax!! They discussed the issues as well.
I bought the truck used (31K miles) and it has had three oem flywheels in it and the master cylinder has been replace twice in the last year and bled at least 3 times. The DOT 3 has been switched to DOT 4 and a tranny cooler was installed by the dealer to address the hard pedal. The clutch pedal was replaced due to squeaking constantly. It now has 53K miles on it. (What if DOT 3 is mised with DOT 4? any impact?)
I installed a high idle which no longer works consistently. After the reinstall, before the test drive I turned it on but did not work. Craig and Greg looked at each other and climbed under the dash. It appeared that a plug that lost some electrical tape may have been keeping the pedal from comin all the way out. One thought was that this not only impacted the Hi Idle but might also have kept the throughout bearing putting pressure on the pressure plate fingers. Thus, keeping the clutch from full engagement. I tend to doubt as I would have expected to feel a pedal in the wrong position, but hey . . . .
Current conclusions:
The kit is currently working perfectly right now. What I now know is that the original kit installation resulted in a lot more required clutch pedal pressure than is correct (we did not know this at the time since we had no previous experience with this type of kit.) We are pretty sure that the lack of full clutch engagement caused the slip that wore out the one disc pad. This was likely because of failure to release the pressure plate fingers. (why is still a question). Clint believed that any hydraulic issue will be related to the master cylinder since it controls the simple slave cylinder and the hose, and the internal piston and return valve/port can fail due to contaminatiion/wear/damage. There was some thought that heat (from where?) may have caused hydraulic expansion and pushed the slave cylinder and throwout bearing forward???
Mods:
One idea I may try is to wrap the hose and master cylinder with a heat shield. I also intend to check the plug under the pedal (the Hi Idle failed to work one time this morning, again http://www.dieselplace.com/forum/images/smilies/mad.gif )
More:
Craig is going to ship replacement disc and when time arrives and we know the problem they will get installed. Who knows, this problem may never happen again and there may never be an explanation.
Given the original kit installation hard pedal and other characteristics, I suspect there was something wrong from the first installation. The thickness of the whole kit too great? something blocking the pedal travel? We discussed and dismissed air in in the hydraulic hose (Craig has done numerous installs on his truck and never had air in the line/hose). We discussed the length of pressure plate fingers, width/thickness of parts, etc. . . .still do not have a firm conclusion. When he gets home Craig is going to do some more investigation on the parts he has in shop. When I get some more data/answers I will post them.
Right now I have run out of info, questions, conclusions, solutions, tests . . . . http://www.dieselplace.com/forum/images/smilies/confused.gif
Any ideas?