I had spoken to a couple of you about my clutch fluid turning blackish after only about 50 pumps of the clutch once new fluid is bled through. The consensus was the dissolving slave and/or master cylinder seals probably coated the inside of the line after all these years. The car is an 86 4-speed with only 10k miles.
So, I just spent the $ and installed a brand new Rodney slave, a brand new Rodney master, and a new Fiero store line. Everything is brand new from front to back.
And guess what? After driving it just a few miles, the fluid turns black again. What's left? Is it just the lube used on the seals of the master and slave that's doing this?
What brand and type of fluid are you using in the system?
I started out with the Valvoline Synthetic Dot 3/4 stuff when doing the original bleed.
Switched over the generic Dot 3 stuff as I tried to flush this black out. Just did it again since my original post. Went for a 5 mile drive, and she's already graying up again.
Craziness. As I'm sure you can attest, running that new line was a real PITA, to say nothing of the slave cylinder, and I'm no better off for it.
If you have the original steel line on the car they will be full of rust on the inside of the lines. The only thing that solves this is changing to a stainless steel line. The seals have nothing to do with the colour of your fluid. I used to have to change out stock slave cylinders every 2 years until my steel line finally rotted out and I replaced it with a Fiero Store stainless line. I do not get dirty fluid anymore and my slave is now 4 years old and still perfect. Edit to add : sorry I did not notice you had a new line already. I am assuming that it is a stainless line. I do not know why your fluid is still dirty makes no sense to me. Drive it for 200 miles and then have another look and see how bad it gets.
[This message has been edited by wftb (edited 03-15-2018).]
If you have the original steel line on the car they will be full of rust on the inside of the lines. The only thing that solves this is changing to a stainless steel line. The seals have nothing to do with the colour of your fluid. I used to have to change out stock slave cylinders every 2 years until my steel line finally rotted out and I replaced it with a Fiero Store stainless line. I do not get dirty fluid anymore and my slave is now 4 years old and still perfect.
That's my point . . . I just changed the master cylinder, the slave cylinder and put in a brand new stainless line. All just yesterday, all brand new.
Something in these three brand new items is turning the fluid black.
Yep. Everything the clutch fluid touches is brand new as of yesterday and all at the same time. I got to assume it is the lube/grease on the master/slave seals that gets drug into the fluid. What else could it be?
I read on some Camaro forums where guys concluded that was what was causing their black fluid. I can't think of a better theory.
[This message has been edited by USMUCL (edited 03-15-2018).]
Stop flushing... you're just wasting time money and likely generating HAZMAT trash. "Flushing" can get most fluid in lines but not in calipers etc. More so w/ Fiero Rears because of Pbrake parts inside. Hydro Clutch is the same.
"Dirty" "Black" fluid IS NOT a problem. Is often loose dirt you stir up "flushing" the system. You can flush the system forever and never get all of it out. Even If you replace the entire system w/ all new parts, Fluid will look "bad" in a few months at best for many people.
Flushing can remove a lot of the water in the system but can't get rid of this either. Water in the system is chemically attach to all Glycol fluids. Is why "Wet Boil" temps are so important. Even a thin film of old fluid quickly "pollutes" new fluid w/ water but calipers etc have a more "wet" fluid in them.
You flush and watch for even a few minutes and often see wet fluid will often start to cloud up the tank's new fluid at the front back or both ports to the MC itself. Warning: If you leave tank open or tank cover or others seal are bad then fluid is so Hygroscopic you will have more problems needing more flushing. See my Cave, Brake Fluid
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Stop flushing... you're just wasting time money and likely generating HAZMAT trash. "Flushing" can get most fluid in lines but not in calipers etc. More so w/ Fiero Rears because of Pbrake parts inside. Hydro Clutch is the same.
"Dirty" "Black" fluid IS NOT a problem. Is often loose dirt you stir up "flushing" the system. You can flush the system forever and never get all of it out. Even If you replace the entire system w/ all new parts, Fluid will look "bad" in a few months at best for many people.
Flushing can remove a lot of the water in the system but can't get rid of this either. Water in the system is chemically attach to all Glycol fluids. Is why "Wet Boil" temps are so important. Even a thin film of old fluid quickly "pollutes" new fluid w/ water but calipers etc have a more "wet" fluid in them.
You flush and watch for even a few minutes and often see wet fluid will often start to cloud up the tank's new fluid at the front back or both ports to the MC itself. Warning: If you leave tank open or tank cover or others seal are bad then fluid is so Hygroscopic you will have more problems needing more flushing. See my Cave, Brake Fluid
Ogre, just to be clear, these are brand new parts from front to back. Brand new like yesterday, literally. So, no "dirt" in the system, and definitely not any material amount of moisture. And it isn't turning it black in "a few months time." It is doing it in a few miles' time.
So, my question is, what is your opinion on what would cause brand new parts to turn clutch fluid black within 5 miles?
Originally posted by USMUCL: Ogre, just to be clear, these are brand new parts from front to back. Brand new like yesterday, literally. So, no "dirt" in the system, and definitely not any material amount of moisture. And it isn't turning it black in "a few months time." It is doing it in a few miles' time.
So, my question is, what is your opinion on what would cause brand new parts to turn clutch fluid black within 5 miles?
Nope, New/Rebuilt parts can have water/dirt right out of the box. May look clean/dry to you but BF will find all of it and more. Many parts have "lube" to protect them in transit/storage.
If the Line between MC and rear isn't new then can cause same issue. You be surprise how much dirt and water stays in/on just the line walls after flushing. More so w/ any part is 30+ years old. Because clutch moves a lot more fluid volume doing its job, can show up very fast.
Plus Aluminum compounds are often dark or black. BF will find any Al "dirt" left over when making them or as Wear particles off of piston(s) etc. BF and Water "eats" these because small particles of Aluminum are very reactive. (And why Aluminum powder is a common Fuel for Thermite, Flash Powder, etc.)
Plus gray/cloudy could mean... System have a small air leak allowing air sucking in when release. Fluid is "cavitating" on release making it foam up. (Brake/Clutch Systems not made to have 5.1 Silicone fluid are known for this but any fluid can have Cavitation problems.)
It can take days to weeks of flushing to remove that because system PSI is very low. Line pressure will "swell" soft and hard lines and others a tiny bit to operate then release. Each time the new fluid pulls crap/water off/out of the parts. If it is Al etc particles then you will never get black fluid gone.
I can definitely buy the new aluminum making the fluid black. It does make me wonder whether the aluminum that Rodney uses is the best bet, versus iron or steel.
Well, it's either the seal lubrication or the aluminum.
I don't know that they are saying that the brake fluid "attacks" aluminum. I think they are saying there is a black, unseen filth on machined aluminum that comes off in the brake fluid.
It makes me think there is something to it when I think of how my hands get a funky, powdery grossness to them when I handle machined aluminum for long periods of time.
Raw aluminum oxides within minutes of machining unless it is anodized. The oxidized layer is almost invisible but comes off as black if it is polished. Unless it is causing functional problems, it shouldn't be an issue.
Raw aluminum oxides within minutes of machining unless it is anodized. The oxidized layer is almost invisible but comes off as black if it is polished. Unless it is causing functional problems, it shouldn't be an issue.
So, you’re saying the oxidized layer still on the new master and slave is coming off as black in the brake fluid?
I'm not a metallurgist, but during machining aluminum you can rub your hand on the clean part even after ultrasonic cleaning and black will come off on your hand. Moisture accelerates the process and brake fluid is hydroscopic. That's why you're not supposed to use old brake fluid after the seal is broken.
Back in the early 60's I worked for a company named Loxcreen. It was an aluminum extusion company. Raw aluminum billets, extruded counter trim, sink trim, threshold, window and door screen frames. Even though the aluminum looked good, every day we went home looking like a chimney sweep.
Out of curiosity, I just checked both my cars. They both have the original lines but the mc's and slaves on both have been replaced with Rodney's units. My fluid is as black as my motor oil at change time. Both car's clutches work just fine. But I do think I might do a little fluid refresh this spring.
Steel/Iron MC etc often have Aluminum parts inside. So don't think will be better. Steel wears Al parts then wear particles quickly "rust." Even Al Slave pistons in drum brakes and clutches wear then wear trash gets move in the inside of the bore when they are used. Aluminum MC have Al and other metal parts too. 2 steel springs plus parts to hold 1 spring to 1 piston. (Primary piston for most units.)
Plus Seals are not 100% and make a thin coat of BF to lube brake parts. Even heavy anodize/galvanize can fail w/o that and the Aluminum and steel/iron quickly have dissimilar metal rot. Same problem in boats, worse boats in salt water.
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Originally posted by olejoedad: Brake fluid does not attack aluminum.....
That and Many others will "attack" powdered aluminum like here. Aluminum is not inert. Is so reactive it oxides almost at light speeds but normally stops just as fast w/ thin coating. BF can be inert by itself but can act as a catalyst to make other things attack aluminum. BF can eat paint and others then effect how aluminum and alloy rims resist corrosion. I have an Aluminum rim now w/ damage from BF leaking on it.
In a Sealed brake system and everything is happy even w/o anodizing aluminum parts. But BF open to air will saturate w/ water and will attack everything else possible often very quickly.
Many aluminum brake parts have a very thin anodize layer applied when made. Is why many people "hone out" the bores then the parts soon fail.
Well, I’m glad I have the new stainless line, as well as new master and slave from the best (Rodney).
But, in the end, I’m not convinced I ever had the “Black Death” fluid, ie clutch fluid full of deteriorating seal matter or rust.
About 500 miles ago, I found the OEM master had a slow leak. I put in an aluminum Rodney master (changed again this time just to have all new stuff when I did the slave and stainless line), and I’m betting that brand new, aluminum master was the reason for the black fluid. I honestly don’t recall how the fluid looked with the OEM master, only that it was slowly disappearing.
I’m really surprised that this hasn’t explicitly come up on this forum before. But, hopefully, the next person has all the data to make the decision on replacing out the hydraulics if they notice black fluid.
Maybe I’ll change to ATE Super Blue so that I can’t tell, LOL.
To clarify some information presented in this thread.....
Brake fluid does not attack aluminum. Brake fluid is non-corrosive to most metals. Brake fluid will absorb moisture that may lead to corrosion of metals. Aluminum is very reactive to oxygen, but the oxide skin that forms almost immediately on bare RAW aluminum is very nonreactive. Anodizing is an electrochemical process that increases the oxide film thickness to enhance the nonreactive properties and to increase the hardness of the surface. An anodized surface may also be colored during the process for decorative or identification purposes.
I also think if you open a can of brake fluid, pour some out, and then put the lid back on, the rest does not become unusable. Even if you set it back on the shelf for a while. What you don't want to do is leave a can open a long time. But then also think about it this way, sometimes bleeding brakes takes a while, especially if you gravity bleed. The lid of the master cyl could be open and fluid exposed to the air for quite a while, the fluid in it didn't become unusable. What do you think?
I also think if you open a can of brake fluid, pour some out, and then put the lid back on, the rest does not become unusable. Even if you set it back on the shelf for a while. What you don't want to do is leave a can open a long time. But then also think about it this way, sometimes bleeding brakes takes a while, especially if you gravity bleed. The lid of the master cyl could be open and fluid exposed to the air for quite a while, the fluid in it didn't become unusable. What do you think?
Brake fluid doesn't pick up moisture instantly (unless you pour water in it), so I think opening a bottle, filling the master cylinder, closing the bottle, and then returning it to the shelf is OK.
Nomally I bleed brakes once a year, so an opened bottle will never stay for more than a year on my shelf.
To clarify some information presented in this thread.....
Brake fluid does not attack aluminum. Brake fluid is non-corrosive to most metals. Brake fluid will absorb moisture that may lead to corrosion of metals. Aluminum is very reactive to oxygen, but the oxide skin that forms almost immediately on bare RAW aluminum is very nonreactive. Anodizing is an electrochemical process that increases the oxide film thickness to enhance the nonreactive properties and to increase the hardness of the surface. An anodized surface may also be colored during the process for decorative or identification purposes.
Good info. But . . . does this mean you disagree with the theory that the aluminum master and slave are what's turning the fluid gray/black?
Brake fluid attacks many types of organic materials, including o-rings, seals, paints.....but not metals. Aluminum is so corrosion resistant that I used it for ventilation system components around nitric acid tanks. I disagree with your hypothesis.
After installing an aluminum clutch master cylinder and stainless steel clutch hydraulic line, I noticed the clutch hydraulic fluid now turns grayish-black instead of brownish. I guess that's the difference between aluminum oxide and iron oxide.
I installed the clutch master and hydraulic line about 10 years ago. The clutch still works fine. So I'm not gonna worry about it.
I made no such declaration.
