carbon seal and flywheel boot question

[1800chall_tim]

[/INDENT] on my challenger 1800, the port side carbon seal is much harder to separate from the stainless ring than the starboard side. what is the correct amount of face pressure between the carbon and stainless rings, and how do i determine this? i have noticed the stainless ring will tighten against the carbon seal when i pump grease into the boot on the fly wheel. but my shop manual states to stop pumping grease as soon as you see the boot move.

 

[Dr Honda]

The driveshaft just floats, and the grease is just to lube the splines. So, when you put grease in the shaft, it will shift toward the pump... but after a minute or two... the pressure from the carbon ring will just push it back into the engine. If you put in too much grease... you will burst the boot. (and make a mess)

There isn't a correct pressure on the seal. If you have an air leak... then your boot, carbon ring, or stainless ring could be bad. Checking the pressure it takes to pull the ring back isn't a good test anyway. The reason is... if the boot is old, or been soaked in gas/oil... the rubber could be hard. SO... it will feel like it takes more pressure to pull it back... but in reality, it's not pushing very hard on the seal since the rubber is "Locked" into position. The only way, to properly test a spring (regardless if it's rubber or steel) is to remove it from the assembly, and check it's free length, and tension at a known compression length.


So... with that that info... do you have a problem? Or is it just for general knowledge?

 

[1800chall_tim]

The driveshaft just floats, and the grease is just to lube the splines. So, when you put grease in the shaft, it will shift toward the pump... but after a minute or two... the pressure from the carbon ring will just push it back into the engine. If you put in too much grease... you will burst the boot. (and make a mess)

There isn't a correct pressure on the seal. If you have an air leak... then your boot, carbon ring, or stainless ring could be bad. Checking the pressure it takes to pull the ring back isn't a good test anyway. The reason is... if the boot is old, or been soaked in gas/oil... the rubber could be hard. SO... it will feel like it takes more pressure to pull it back... but in reality, it's not pushing very hard on the seal since the rubber is "Locked" into position. The only way, to properly test a spring (regardless if it's rubber or steel) is to remove it from the assembly, and check it's free length, and tension at a known compression length.


So... with that that info... do you have a problem? Or is it just for general knowledge?

no problems, i just happened to notice there was a difference in face pressure between the two carbon seals. what you said makes total sense, i think it was just a slight difference in the boots that make it feel like one is pushing the seal much harder. to date the only issue i have had with my challenger is the bad crank seals but that is another post. thanks for clearing up this little concern Doc.