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.

Has anyone tracked down a seal kit for these new cylinders?   IF the castings are still good, a kit with modern seal materials could go a long way????

Steve

@Rob Fridenberg posted:

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.

I will report back in a couple of months with the status of the clutch master.

Funny , I have same issue, I have what I think is a billet Master, the fluid is turning black, I flushed it a few times and now is black again, my clutch pedal goes soft if I push it to quick. Just ordered a new Clutch master and slave from PI Motorsport, hope they dont have same issue. I will strip the old clutch master and take pics when the new item turns up.

Steve - any updates? How does your fluid look?

I just received/installed another clutch master (my 3rd in a year), and flushed the line. The current part does look better (normal) for the bottle to body joint and is still dry after a month!!!! However, the fluid is turning dark after less than 100 miles. I could see hints of darkening after the first 20 miles of driving.

Some say it does not matter, but to me it is a sign of something happening with the seals??!!  I'll drive mine a bit more and empty/refill the bottle and see if it continues to pollute the fluid.

Rob, all,

OK, I don't recall what my clutch fluid looked like 4 months ago....not even sure that I checked!   SOOOO I checked today, and my fluid is "dark brown" but not black.  No goobers or floaty bits, just maple syrup!

We have a fairly humid environment here, and I wanna say that this is "normal" absorption of water????  I have a cast iron master clutch cyl also, which could be contributing.  Now, I haven't flushed this since I worked on all of this some 2-3-4??? years ago....bad me...I know......barely drove the dang car..... vehicular abuse...!!!!

I will be suctioning this brown out, and replacing with new Castrol DOT4 before trip to Reno!  Maybe flush out the cylinder if I get cooperation......    Will also check fluid in brake M/C which I DID flush completely when all 4 corners received new seals (stuck pistons!!!)  and the M/C got a tear down only to find nothing amiss there!

I hope this helps.....!
Steve

My new clutch master failed. The fluid seemed to be turning black so I flushed it a couple of times. Then I took it on a fairly big outing to Full Throttle Panteras open house. The fluid was perfectly clear when I started the trip. About halfway through the trip during some spirited driving the clutch master begin to fail.  When I held the clutch down, it would gradually release itself.  I was able to complete the trip and make it back home but maneuvering in parking lots was very difficult.

After arriving at Full Throttle, I inspected the fluid and it was very black. The next week I removed the failed master and showed it to Wilkinson and explain what happened. He asked which brake fluid I used and I said it was DOT3. He said it has to be DOT4 and set me up with a new one. I have that in the car now. So far so good, but time will tell.

DOT 3 and 4 are "supposedly" the same other than 4 having a higher boiling point and being less hygroscopic.  But some info suggests that older systems do not "like" 4 and you should use 3 only.  I have used 4 in my car for many years now.  The brake fluid tends to "yellow" with time - been 3 years now since I last changed/bled it.  The clutch fluid seems to stay clearer and not yellow as much (why I have no idea) but occasionally I do get black stuff (not pieces but just a black slime).  My clutch master is probably 20 years old and my slave is a CNC I bought from Dennis Q. at that time.  The clutch works fine so I have just sucked the black fluid from the reservoir and refilled it and then bled the system.  

My vendor said I should be using DOT3. This is really frustrating - why can't someone make a decent master that fits these cars??? I used DOT4 on my last master (replacement #2) - fluid turned dark on that one too.

Once you have been in the Pantera community for a number of years, it becomes obvious to just about everyone that the advice from our vendors is not something that can be taken as absolute truth or always correct.

sadly, most of them will argue till they are blue in the face trying to convince you that you are wrong.

been there and done that, more times than I should have

Larry

Larry - LOL - thanks - I needed that chuckle! I have been at it for 1.5 years so I'm still a rookie!

The funny thing is, it is not like we are having a problem with a precise part like a fuel injector. These are simple parts! I am also on my 2nd replacement slave cylinder - that one was leaking after a few hundred miles.

Yet, the Corvette brake master cylinder in my car, which probably saw 100 miles of use in the past 10 years of prior ownership, hasn't polluted the new fluid (DOT 4) for the 600 miles that I have put on the car.

I am convinced it is garbage seals and/or nasty rough bores that are causing this. I can't see DOT 3 or 4 having an effect, ever, or even in a matter of weeks??

I agree with you Rob.  It is a bull shit argument that DOT 3 / 4 is causing it.  Some vendor is, as my wife says, "deflecting".  This is right up there with the threads I see on MSD electronic boxes failing right out of the box.  Cheaply made junk parts.

As for the failure of MSD boxes, just Google the phrase “counterfeit MSD ignition” and you will understand why MSD boxes have been getting bad reports

Larry

I just heard a good one for MSD = My Spark Disappeared

But the people I have seen on threads had REAL ones purchased from reputable vendors unless Summit is somehow now buying fake crap

My plan is to work through this problem with Wilkinson. If the seals are faulty I think he will resolve it. Not many people are making new parts for Panteras and I don’t think it is an easy endeavor.

Is it possible that the hardline is corroding? causing the black colour? So many people with same issue and a few different types of Master cylinders. I have a new Master to swap in but I dont think it will fix issue.

Steve B - please keep us informed with any outcome from Wilkinson. I could live with dark fluid if there were no other impacts, but my fear all along has been the failure mode that you experienced.

I am getting really fast at changing out these masters!!

refresh my memory - someone posted about the Ferrari 308 brake master as a replacement for the P.  Does anyone know about the clutch master?  http://superformance.co.uk/

Albanygt40 - my opinion - I think the masters carried by all of the Pantera vendors are coming from the same supplier (boxes look like they are from China??)?? Given the crazy low volume of this vehicle, I can't imagine that multiple suppliers are running this part with the hope of making any money.

FWIW - someone at the supplier finally mastered (copied) the technical challenge of attaching a plastic bottle to a fitting that doesn't leak. So at least there has been some improvement!

More like one vendor is selling to all the other vendors.....

The seal used in the stock type Pantera clutch master cylinder is a type of o-ring, not a "cup".  As such, the o-ring can only tolerate a very small interference fit to the master cylinder bore, something like 0.002".  Rebuilding the master cylinder by honing the bore and replacing the seal usually results in an early failure because the honing increases the cylinder's bore which reduces the interference fit with the o-ring.  

The fluid turning black is caused by extremely small amounts of material being removed from the o-ring  during normal cycling of the clutch master cylinder's piston.

John