I checked my clutch fluid tonight and noticed it was black already with 9K on the clock. I'm not having any issues with the clutch, just wanted a way to get the fluid looking clean again.

I know the best way to change the fluid would be to use a bleeder kit, but thats some serious work, and I would prefer not to go there at this time.

Can I use a Mix Miser to suck out the fluid in the reservoir, and do this every few days until the fluid is clear?

Will this procedure eventually accomplish the same thing as a bleeder kit?

Also, is all DOT 3 and 4 brake fluid synthetic?

Thanks.

augydog

 

You will never get all the fluid out of the slave, but it can't hurt.

 

Gm has a notice out that this is normal for it to change color. It Will not change anything. You new fluid will be black in a few days. It has something to do with black rubber. There own tsb says to do nothing about it.

 

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[silverz06vette]You will never get all the fluid out of the slave, but it can't hurt.
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The fact that the fluid in the reservoir turns black must mean that the fluid is traveling from the slave through the system up to the reservoir. So sucking the old fluid out and replacing it with fresh fluid has to be doing some good. If you are a maintenance freak, you can have the slave cylinder bleed every couple of years. This will require dropping the exhaust and the tunnel cover to access the bleeder on the top of the slave. It's a PITA so you might want to take it to a good Corvette shop.

 

If you never launch or make high rpm shifts, then let the clutch fluid turn black and stay that way. Let that goo build up. It won't matter.

Regarding the black clutch fluid...The Syringe for changing clutch fluid in the master cylinder ...I'd suggest changing the fluid every few days until it remains clear and then before and after each time to the track and again every time it start to look cloudy.

I've followed this routine onn my 02 Z06 and have not suffered the dreaded sticking clutch pedal woes.

I'd suggest using any Dot-3 brake fluid. Following this regime, it gets changed often enough that using a higher temp fluid isn't necessary. Plus the Dot-4s I've tried have leached to black almost immediately.

Ranger

 

I need to try this. My Z06 clutch with ~5000 miles on it is not exactly exhibiting the clutch to the floor syndrome yet but it does get stiff after a hard run. I have a mitivac so I'm sure I could change a lot of fluid out at once.

 

I did the same thing and it took mine about a half dozen replacement cycles before the fluid started to stay clean. So I'd say this is a via method to keep the fluid fresh. As to how well it bleeds air out is another story.
I certainly don't think it hurts to do the turkey baster suck and replacement.
I use the same fluid I use in my brake system for the clutch system.

 

At 40k miles I had a new clutch installed, so the fluid was fresh then from the bleed then. All the while I had did the syringe method, never letting the fluid get back in the reservoir. At 60k or so I did some work to the driveshaft (rear bearings) So I installed a clutch remote bleeder line. Did a full flush with the remote bleeder line and I did get some black fluid that must of been in the slave.

Of course 2500 miles later the slave failed and it all came apart again for a new slave, z06 clutch and PP.

 

The black is from the rubber boot in the master! And thats not the culprit for the sticking to the floor problem! Unless you have a remote bleeder or suck it all out, your efforts will be wasted on getting to the bleeder for minimal results. IMO. The fluid will be black again soon.

 

There are two schools of thought on what makes the fluid black.

You and some others say it is an interaction between the brake fluid and rubber fittings in the hydraullics.

Others, including Subdriver and I, believe that the cause is HEAT.

What I know for a fact is that by keeping the clutch fluid fresh (by changing it regularly), my clutch on the '02 has behaved normally throughout its life. Lot of guys can't say that.

Ranger

 

I am of the school that heat may be a contributor to the pedal to floor syndrome but I'm not convinced the color of the fluid is related. Going to Mitivac mine this weekend and see how it affects the pedal feel.

 

I doubt you'll notice any difference.

I believe the sticking clutch issue comes from air introduction into the clutch hydraulic system from the seal on the throw out bearing. This is likely made worse by small vibrations in the clutch plates due to improper initial torqueing of the clutch plate fingers. The only real way to get this air out is to bleed the system.

Just like with brakes, as the air builds up, the system can't build up enough pressure to push the clutch pedal back up. If you've ever bleed your clutch, you will know that little spring on the clutch doesn't provide enough force to push the clutch pedal back up with zero hydraulic pressure. The more air the worse this gets until eventually the clutch pedal stays on the floor, particularly after two or three very quick shifts such as in drag racing, or in my case double gear downshifts at the end of a straight.

My thought on the turkey baster method of keeping the clutch fluid fresh is that it may help stave off this problem by removing small particulates from the fluid which may (or may not) help keep the air in solution (e.g. like carbonation in a soda - the CO2 comes out of solution faster when it has a place to do so, such as ice, a straw, your finger, etc). These particulates may also accelerate the wear of the seal increasing the air introduction rate.

Note, I have no idea if any of this occurs, but I surmise that it might, so in my opinion, changing the fluid isn't going to hurt, but may help.

 

I have to agree with Ranger on this one. I have performed the replacing fluid in the reservoir on a regular basis for nearly 3 years and have not had any clutch issues yet. And the fluid does stay alot cleaner.

 

Plus, what I plan on doing is a little different than just replacing the fluid with a turkey baster. I am going to use the mitivac to suck fluid (and air) out of the line and replace it with fresh fluid. This is similar to the clutch bleeding procedure (using a vacuum pump) that can be found documented on LS1 Tech. So not only am I replacing the fluid, I'm bleeding it as well.

I will say that when my original C5 clutch had the pedal to the floor syndrome I tried bleeding it (not replacing the fluid) and it did not help.

I'm actually pretty sure it's caused by the LUK pressure plate design so this may just be an excersice in futility. It really seems to be related to tha amount of horsepower you throw at it. Mine was more of a neusance until I started spraying. I could not even grab 4th gear (on my old/stock clutch)

 

This is a good point.

Keeping the fluid fresh through regular replacement via (1) refreshing the master cylinder or (2) bleeding is a PREVENTIVE measure. To do it AFTER long periods of filthy fluid have coursed through the hydraullics is, well, too late.

It is the regular regime that prevents clutch pedal woes.

Ranger

 

One thing I will say is that I have NEVER heard of anyone with an aftermarket clutch complain about the pedal to the floor syndrome. Has anyone else? This is another reason I lean towards the LUK pressure plate.

 

Unfortunately in SCCA T1 class, I'm stuck with stock.

So... I do the best I can - such as regular bleeding and replacing fluids.

 

Just changed out my fluid via the Mitivac this weekend. The vacuum did not get much more fluid out of the lines. The vast majority of the fluid removed was from the reservior. I got some bubbles out but I think they were from a lack of seal where the mitivac needle was not sealing against the hole where the hose meets the reservior.

When I first put the Z06 clutch in it was SUPER light pedal feel and it went back to normal (normal being my OEM coupe clutch on a good day) ove rthe course of a couple weeks. After changing the fluid the light feel seems to be back a little. Not all the way but it's noticably lighter. I plan on changing it out a couple more times over the next few months to see what, if anything, happens.

 

I put in the remote bleeder (LAPD) when I changed my MM6 for an M12 last week. I routed it down and mounted it on the frame. I also covered areas likely to rub with ribbed plastic conduit to prevent chafing of the line as I heard Dopes cut thru his fuel line. I had always removed the fluid from the resevoir regularly, but when we replaced the slave the fluid left below the resevoir was black. I think the black is a contaminate caused by the slave seal breaking down due to HEAT. The line run close to the exhaust manifold, plus it picks up heat from the clutch. I insulated the line near the manifold, and will be bleeding the slave at least every couple of months. Doug