Hello and thank you for choosing just answer this morning. There is a bulletin listed for this concern. If there is no fluid leaking from anywhere else in the system then it is likely the seal may have been damaged and got worse over time until now when it has completely failed.
CONDITION:Caution must be followed or clutch master may be damaged if the air bleeding procedure is not carefully followed.
CAUSE:When operating the pedal stroke for air bleeding of clutch system after releasing the clutch pedal be sure to wait 1 second or more before depressing it again. Otherwise the oil seal of operating cylinder will be damaged resulting in oil leakage.
The rapid pumping of the pedal while air is still in the system can damage the internal seal on the master cylinder piston causing an internal fluid leak that might not be visible but will allow fluid to leak past and won't build up system pressure. It would start as a small nick and then get worse over time.
On this vehicle since the slave cylinder is inside the transmission bell housing you will want to make sure it hasn't started leaking first.
I am an AAMCO Transmission shop and we are aware of the bleeding concern on installation and did it carefully. Perhaps any time later, especially if air got in, the seal could be damaged by rapid pumping.
yes that is possible. Also from time to time you may have just ended up with a bad part. Go over the system carefully and make sure there are no leaks inside the bellhousing and behind the back of the master cylinder where the rod from the pedal goes in. If you can't find any leaks you can see about filing a warranty claim on the master cylinder and let them know that you followed the service procedures exactly.
By the way I use to work for an aamco transmission shop as well.
FYI before we got this vehicle 2 after market masters had been installed. This concern happened both times right away. I think you are probably right. We need to find a leak even tho the fluid is "full." This is "The rest of the story." I think your info is good. Bill, Springfield OH
If the system isn't losing fluid then it is probably a damaged piston seal on the master cylinder. It may be hard to set up but you could hook a hydraulic pressure gauge setup inline and verify this.
We tried to do that the first time.. Hard to do. Thanks for your input.