Clutch Master Cylinder Issue

[dang]

Installed a new Ate E12 clutch master cylinder and the rear seal stuck compressed while bleeding the system. I took it apart and had to use compressed air to get it out. The seal looked bigger than the front seal. I took the rear seal out of the old cylinder and put it in the new one and it moved in and out like it should. After sitting on the bench for a few days the seal stuck in the cylinder again. I took it apart again and now the old seal looked bigger, like it's swelling.

I'm using synthetic DOT4 fluid like I've used before but something is wrong and I've run out of ideas. Try different fluid?

What do you think?

Dan

 

[bill]

I use DOT 4 (NON synthetic). I thought synthetic was not compatible with our coupes?

 

[dang]

I use DOT 4 (NON synthetic). I thought synthetic was not compatible with our coupes?

Could be. Maybe I used non synthetic in the past and didn't pay attention. I'll try that since I have no other ideas.

 

[Stevehose]

I believe all DOT 3 and 4 is synthetic, there is no non-synthetic

 

[dang]

I believe all DOT 3 and 4 is synthetic, there is no non-synthetic

Got any ideas? I've never had hydraulics do this in all the years I've been acting like a mechanic.

 

[bill]

I believe all DOT 3 and 4 is synthetic, there is no non-synthetic

Hmmm…I presume if the DOT 4 I use (Napa) doesn’t say synthetic, it isn’t synthetic. Maybe wrong?

 

[Stevehose]

Hmmm…I presume if the DOT 4 I use (Napa) doesn’t say synthetic, it isn’t synthetic. Maybe wrong?

https://bobistheoilguy.com/forums/threads/synthetic-brake-fluid-or-normal-brake-fluid.164111/

 

[Stevehose]

Got any ideas? I've never had hydraulics do this in all the years I've been acting like a mechanic.

I’ve never seen that before, sorry but that’s a mystery to me

 

[dang]

Just went to Auto Zone here in CA and synthetic is all they had. I'm sure that's what I've used before. I "honed" the cylinder with fine 3M scratch pad with lacquer thinner then brake fluid to clean off anything that might have built up. I don't know how old this "new" cylinder is. Put it back together and so far so good on the bench.

 

[dang]

Installed and working good, although the bleeding didn't go as expected. I haven't had issues with clutch masters in the past since they're so simple, but this one fought me a bit. Nice to get the car out on the road.

Dan