Black stuff in clutch master reservoir

Where did you get the new master cylinder? There were some reproduced masters that had the wrong material in the seals and the brake fluid was eating them up.

The master cylinder is not from a Pantera vendor.  Notice the square reservoir.  It is by Centric and is for an Alfa, but it also works on Panteras.  I think there are just a couple of o-rings in the clutch master.  In the morning I will check around the pedals for fluid.

I know that some of the replica Pantera clutch masters leaked at the reservoir joint.  That is why I have this one from Centric.  I also recall that the current batch of Pantera replica clutch masters have an improved grommet and no longer leak at the reservoir joint.

It is unlikely anything is migrating back from the flex line (usually PTFE lined anyway) or throwout bearing, I'd check the master seals.

Clutch master fluid turns black when the master seals are going bad. I bought a new master one year ago, reservoir has leaked since day one and after 500 miles of driving my fluid is turning black. I will be requesting another exchange. Fwiw, clutch slave is also leaking after 500 miles. Not sure who is making these garbage replacement parts. Frustrating doing things over and over.

Steve:  I have occasionally seen the same black residue in mine and my master was replaced over 15 years ago.  No leaks, just this fine black Sxxx.  I have kept an eye on it but believe it is the seals.

@Rob Fridenberg posted:

Clutch master fluid turns black when the master seals are going bad. I bought a new master one year ago, reservoir has leaked since day one and after 500 miles of driving my fluid is turning black. I will be requesting another exchange. Fwiw, clutch slave is also leaking after 500 miles. Not sure who is making these garbage replacement parts. Frustrating doing things over and over.

A year ago my other Pantera got the clutch master that leaks at the reservoir.  When I bought it I already knew it would probably leak.  I fixed it by swapping reservoirs with an old clutch master.  No more leak and it looks fine.  It does not release black residue into the fluid at this time.  The photo below shows how it looks in the car with the old non-leaking reservoir in place.

Garbage o-rings and/or bad bore finish grinding on the rings. Once the fluid is black I assume the o-ring sealing and resulting master performance goes downhill. Any vendors supplying decent parts these days??? I’m on my third master.

Like I said, my "black stuff" appeared in a master I bought probably 15 years ago. It was a direct replacement made in Italy.  Not some cheap knockoff.  I bleed it yearly and is still going strong.  Regardless of the black stuff.  

My hunch is that all of the vendors get their replica clutch master cylinders from Wilkinson.  He said his new batch does not leak at the reservoir.  There was not any mention about the seals and bore.  As I said above, the seals/bore from his prior batch are working correctly in my case although it has only been a year and usage has been light.

I will be replacing the master with the black stuff that is pictured at the top of this thread with one of his new ones in about a week and will update this thread with the outcome.

I have the new clutch master cylinder in hand and can see that the leaky reservoir issue has been resolved.  The reservoir now feels like it is solidly attached and is similar to the factory units that shipped with our cars.  I will be installing it in the next several days.  Hopefully it fixes the problem with black stuff in the fluid for a long time.

Please keep us updated! Since these are a pain to install, I bench test the leak issue for a week to see if they stay dry. My experience from last March was that they all leaked. And, 2 of 3 vendors said they never leak!

I hope you're all using Girling recommended Castrol LMA DOT4 fluid???

If not, OLD DOT3 could be simply collecting moisture and what you're seeing is metal oxide?   Newest DOT3 fluids may likely be synthetic now.

The Castrol LMA  ("low moisture absorbing" ) will tend to be darker in color with time, but we're talking a long time.... has always been synthetic near as I can tell, for some 25 years, as long as I have been working on my GOose.....one of the first jobs I had to do because ALL of the cylinders were absolute useless crap from previous owners using DOT3!

You're supposed to flush your brake/clutch fluids out every once it a while too...........????   Suction old out of the reservoirs, fill, then flush out the lines and calipers etc via bleeders....refill as needed.......

Cheers!
Steve

I am getting ready to install the new clutch master.  This should be fairly straight forward.  Under the dash I just need to pull pin and remove the two M8 bolts.  I will need to pull driver's seat before hand as well.

good luck Steve.  I remember doing this and left the seat in.  Big mistake.

If you are replacing like with like and can retain the same push rod, the job may become much easier.

John Buckman and I swapped out my all-aluminum CNC clutch master with its identical SS-lined cylinder replacement in the parking lot of Los Laureles lodge some years ago during Monterey car week.

did everything from the front trunk, did not remove the driver’s seat, did not bleed the system afterwards. Absolutely no issues at all.

and yes, we were surprised it was that easy and that successful  

you never know until you try

YMMV

Larry

From this post, it looks like I was sold a clutch master cylinder with seals that break down and fail. I installed it a couple of months ago and the fluid started to turn dark in about a week without even driving the car. I am going to take the master cylinder that was removed from the car and send it to a place in New York that can rebuild it with quality parts.

The new clutch master cylinder is installed, working correctly, and not leaking.  The only issue I had with it was the rubber dust boot was a tight fit going into the opening in the pedal box.  I trimmed the boot a little and got it to go into place.

nice job Steve

Looks good. Please report back if the fluid starts getting dark again and if (when?) the reservoir leaks. I plan on changing mine out (and the leaky slave) soon.