b4i4getit

Can anyone with an M7 confirm that the clutch fluid reservoir is almost the same as the C6 ? I have heard it may be a bit larger but cannot confirm. Also wondering if the slave and master are almost the same or if they have provided for a bleeder that is accessible this time.

hxrly

Good question. Also, is the fluid getting dark after some spirited driving?

b4i4getit

I can't believe 70 something reads of this thread and nobody knows. Surely one of you has the M7 and can take a look.

shawn672

Please just tell me that we don't need to do the clutch fluid cleaning process like the c6.. PLEASEEEEE

KenHorse

Well... GM claims only 1 part was a carryover from the C6 and it ain't the clutch system.......

b4i4getit

That may be true but unless they have provided a better way to do a complete fluid exchange we are back to the same problem with pedal to the floor etc. The Ranger method is largely ineffective and mostly cosmetic as has been noted a while back.

louloumax

Looks like everyone is too busy to crawl under and see where the bleeder is. Me included.
Regarding the 'Ranger Method'. I just traded the 07 with 87,000 miles on it. never had a clutch problem. Used the ranger method for the last 4-5 years of its life. So, I am a fan of the cheap insurance of the Ranger.

KenHorse

Ranger method? Is that the procedure using the turkey baster while having someone pump the clutch?

If so, I've done that a few times on our C5Z and it does seem to help for a while

bimmerborn

Unlike C6, the Clutch reservoir in the C7 is made of black material. It is not possible to guess the darkness of the fluid by just looking at the reservoir. Even opening the reservoir is not much help without taking a sample out (and not recommended).

I have 2,1xx miles. I'm planning to do a reservoir fluid change soon. If dark, contaminated, or hydrated already I'll report. Then I also plan to change the brake fluid reservoir with a clear one on the second fluid change.

Fluid is Super DOT4.

louloumax

Suck out the old fluid when it has turned brown. Refill with fresh. Drive for a few days and do again, if necessary until the fluid remains clear after the drive around.
That's how I did it. If you drain and refill and pump the clutch it takes forever to fully 'flush' the system.

b4i4getit

Thanks for taking a look. I was curious if GM found a way to easily do a fluid change with the C7. I would imagine it is still in the manual to be done every 2 years. With the C6 it was a labor intensive process to do a complete fluid change.

KenHorse

Every 30K miles

TEXHAWK0

I changed the reservoir fluid in my C5 a couple of times a year and it never did turn dark.. Part of the secret is not to abuse the clutch with high RPM shifts, since the contaminant was found to be clutch dust that gets past the seal on the slave cylinder.

John Harry

Then how do you check the fluid level? I would hope you don't have to take the cap off.

KenHorse

Why not? That's exactly how you check the level.

Why do you think it's a big deal removing the cap to check?

stevebz06

Clutch dust getting past the slave cylinder seals? It seems like the only way that could happen would be if the seals were leaking, and you'd probably see that.

I have been assuming that this was a heat problem with all the parts getting a good heat soaking. The hose from the master cylinder to the slave gets exposed to the exhaust and I think that is where a lot of the problem comes from. I put Cool Tube on this hose and I think I've noticed that the fluid doesn't darken as quickly. I also installed a Tick Performance remote bleeder when I did a clutch change and this makes bleeding the system a snap.

shawn672

No, he was correct.. it was clutch dust getting past the slave due to a design failure... you must not have had a c6. Changing the fluid in this manner fixed the issue for a bit, had to do it every few months with a DD or the clutch would get iffy/sometimes stuck to the floor

stevebz06

What I'm wondering is how this was determined. By the factory, by an owner having fluid analysis done, by just guessing? I just have a hard time seeing dust particles going past the seal when much smaller molecules of fluid under pressure cannot get past the same seal. Maybe I lack the imagination, but this seems like an unlikely scenario.

I didn't have a C6, but I've done a fair amount of wrenching on one and I own a C5 which is basically the same design. If you look at how they route the hydraulic hose, it runs fairly close to the left exhaust manifold and has no shielding.

John Harry

I don't think it's a "big deal", but compared to a transparent container it's messy and a chance to introduce contamination. Don't you think it's more convenient to simply look at the reservoir to see the level?

KenHorse

I suppose it is. I just never thought of it as a big deal to pop the cover off and have a look.

Besides, we all keep our engine compartments immaculate, right?