another clutch question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**truckdude239** · 03-23-2008, 02:47 AM

okay guys going to buy a clutch for my 71 because the week of the 14th-19th i am taking off and hope to knock my 71 out and get the new engine in it. my problem the part store has 2 clutches listed in a ac deco brand, one has a flat diaphragm and the other has a raised diaphragm . my thinking is i need the raised one see last clutch i put in lasted a year and i had to put a spacer in the clutch rod. so i am thinking i got the wrong clutch. i do now i need and 11 inch clutch with 10t-1/8th

68gmsee · 03-23-2008, 06:29 AM

I'm assuming that by "raised or flat diaphragm" you mean the center area with the springs. Every clutch I've seen on these old vehicles had a raised diaphragm.

I guess I've never heard of a "flat diaphragm" clutch disk. I'll do a search to see if I can find one.

**truckdude239** · 03-23-2008, 07:00 AM

yes it is the pressure plate

**truckdude239** · 03-23-2008, 08:23 AM

http://www.partsamerica.com/ProductL...isc%2c+Bearing)

68gmsee · 03-24-2008, 02:44 AM

Still not quite sure I understand the theory between the two. Auto Zone had this description of the flat and or bent spring pressure plates. This was when I did a search. Just happen to pick this one for a Buick Regal 1975-87...

The diaphragm spring type clutches used are available in two different designs: flat diaphragm springs or bent spring. The bent fingers are bent back to create a centrifugal boost ensuring quick re-engagement at higher engine speeds. This design enables pressure plate load to increase as the clutch disc wears and makes low pedal effort possible even with a heavy-duty clutch. The throwout bearing used with the bent finger design is 11/4 in. (3cm) long and is shorter than the bearing used with the flat finger design. These bearings are not interchangeable. If the longer bearing is used with the bent finger clutch, free-pedal travel will not exist. This results in clutch slippage and rapid wear.

I guess I've only had to deal with one type and never have been asked whether I want a flat or bent spring one...

**truckdude239** · 03-24-2008, 02:48 AM

well i just picked up an AC DELCO clutch set from advance auto parts for 164 buxs i went with the raised diaphragm so i hoppe i got the right one

03-23-2008, 02:47 AM	#1
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	another clutch question okay guys going to buy a clutch for my 71 because the week of the 14th-19th i am taking off and hope to knock my 71 out and get the new engine in it. my problem the part store has 2 clutches listed in a ac deco brand, one has a flat diaphragm and the other has a raised diaphragm . my thinking is i need the raised one see last clutch i put in lasted a year and i had to put a spacer in the clutch rod. so i am thinking i got the wrong clutch. i do now i need and 11 inch clutch with 10t-1/8th __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

03-23-2008, 06:29 AM	#2
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: another clutch question I'm assuming that by "raised or flat diaphragm" you mean the center area with the springs. Every clutch I've seen on these old vehicles had a raised diaphragm. I guess I've never heard of a "flat diaphragm" clutch disk. I'll do a search to see if I can find one.

03-23-2008, 07:00 AM	#3
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	Re: another clutch question yes it is the pressure plate __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

03-23-2008, 08:23 AM	#4
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	Re: another clutch question http://www.partsamerica.com/ProductL...isc%2c+Bearing) __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

03-24-2008, 02:44 AM	#5
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: another clutch question Still not quite sure I understand the theory between the two. Auto Zone had this description of the flat and or bent spring pressure plates. This was when I did a search. Just happen to pick this one for a Buick Regal 1975-87... The diaphragm spring type clutches used are available in two different designs: flat diaphragm springs or bent spring. The bent fingers are bent back to create a centrifugal boost ensuring quick re-engagement at higher engine speeds. This design enables pressure plate load to increase as the clutch disc wears and makes low pedal effort possible even with a heavy-duty clutch. The throwout bearing used with the bent finger design is 11/4 in. (3cm) long and is shorter than the bearing used with the flat finger design. These bearings are not interchangeable. If the longer bearing is used with the bent finger clutch, free-pedal travel will not exist. This results in clutch slippage and rapid wear. I guess I've only had to deal with one type and never have been asked whether I want a flat or bent spring one...

03-24-2008, 02:48 AM	#6
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	Re: another clutch question well i just picked up an AC DELCO clutch set from advance auto parts for 164 buxs i went with the raised diaphragm so i hoppe i got the right one __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

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