Clutch replacement on 71 small block

[John Bauer]

Is removal of the exhaust system a requirement for clutch replacement on 71 with 350 engine? Can trans be removed from below with car supported by large jack stands? Any other suggestions or pitfalls? Thanks.

[Jack H.]

Re: Clutch replacement on 71 small block

To access tranny you need to drop the front exhaust. Note, proceedure is covered in Chassis Service Manual (a real good reference to have).

When exhaust front pipes are joined to tail pipes at frame X-member, it takes some finesse to get 'em in all the way and prevent leaks at junction. In the Assembly Instruction Manual, there's a lubricant called out (silicon grease) that apparently was intended to make 'em slide nice and facilitate removal. Most who work on cars after the assy don't use the lube and you can expect to 'fight' for separation especially if the clamps have squashed the pipes....

A reasonable trick is to heat the junction with a torch. On re-assy, heating the tail pipe and leaving the header pipe cold helps insertion. Along with a thin coating of, say, moly grease on the OD of the header pipe. And, yes, expect to drop the whole tranny to work on the clutch. Might not be a bad time to think about fresh rear seal in tranny....

[Jack H.]

Re: Clutch replacement on 71 small block

To access tranny you need to drop the front exhaust. Note, proceedure is covered in Chassis Service Manual (a real good reference to have).

When exhaust front pipes are joined to tail pipes at frame X-member, it takes some finesse to get 'em in all the way and prevent leaks at junction. In the Assembly Instruction Manual, there's a lubricant called out (silicon grease) that apparently was intended to make 'em slide nice and facilitate removal. Most who work on cars after the assy don't use the lube and you can expect to 'fight' for separation especially if the clamps have squashed the pipes....

A reasonable trick is to heat the junction with a torch. On re-assy, heating the tail pipe and leaving the header pipe cold helps insertion. Along with a thin coating of, say, moly grease on the OD of the header pipe. And, yes, expect to drop the whole tranny to work on the clutch. Might not be a bad time to think about fresh rear seal in tranny....

[Terry M.]

Re: Clutch replacement on 71 small block

Jack,

Take another look at that call out in the AIM. I do not think it is a lubricant. My recollection is that it is a cement sealant. When liquid it might act as a lubricant of sorts, but I believe the main purpose is to seal minor leaks.

I have found a suitable cement sold in tubes made by a company called Wurtz.

Terry McManmon

[Terry M.]

Re: Clutch replacement on 71 small block

Jack,

Take another look at that call out in the AIM. I do not think it is a lubricant. My recollection is that it is a cement sealant. When liquid it might act as a lubricant of sorts, but I believe the main purpose is to seal minor leaks.

I have found a suitable cement sold in tubes made by a company called Wurtz.

Terry McManmon

[Jack H.]

Good point, boss!

AIM calls out 'as required' Item 182. This translates (front of AIM for as req'd items) to GM P/N 9985020; Compound, Sealing. Guess the jury's out 'till we find the composition of this. Bottom line, we might BOTH be right!

If compound went in slippery then cured under heat BUT did not fully cure 'rock hard' it would be doing all three jobs (facilitating ID/OD slip, helping to prevent pipe junction leaks, and preventing rust from siezing the junction to help future disassembly....

[Jack H.]

Good point, boss!

AIM calls out 'as required' Item 182. This translates (front of AIM for as req'd items) to GM P/N 9985020; Compound, Sealing. Guess the jury's out 'till we find the composition of this. Bottom line, we might BOTH be right!

If compound went in slippery then cured under heat BUT did not fully cure 'rock hard' it would be doing all three jobs (facilitating ID/OD slip, helping to prevent pipe junction leaks, and preventing rust from siezing the junction to help future disassembly....

[Patrick H.]

Re: Clutch replacement on 71 small block

John,

I have removed 71 Corvette SB M20 trans WITHOUT removing the exhaust. I did it once without touching the exhaust, and once disconnected the exhaust from the manifolds as well as the mufflers from the rear of the car. Doing this allowed me to pivot out the exhaust at the motor and give a little extra room.

I just wanted you to know that it CAN be done without disconnecting the exhaust. If your exhaust is like mine, I would have had to replace the welded-together system, and I just didn't want to.

Patrick Hulst

[Patrick H.]

Re: Clutch replacement on 71 small block

John,

I have removed 71 Corvette SB M20 trans WITHOUT removing the exhaust. I did it once without touching the exhaust, and once disconnected the exhaust from the manifolds as well as the mufflers from the rear of the car. Doing this allowed me to pivot out the exhaust at the motor and give a little extra room.

I just wanted you to know that it CAN be done without disconnecting the exhaust. If your exhaust is like mine, I would have had to replace the welded-together system, and I just didn't want to.

Patrick Hulst