Hey guys,

How tough is bleeding the clutch on the M7? I know I have to drop the tunnel cover and remove the left catalytic converter. Any 'gotchas' in the process like impossibly stuck bolts or other challenges before I tackle the job myself? I'd be doing this with my Quickjacks.

I'm handy and do most of my work myself. Just want to gauge difficulty before I embark on this one.

 

Let me first ask; Why do you want to bleed it? Just to cahnge dirty fluid or changing slave?

If you just want to change fluid, search, as there are some great DIY posts.

 

Not very difficult at all if you have a lift. Even without one it isn't that hard. Just have to remove the drivers side catalytic converter which isn't as involved as it sounds.

It's much easier than the task looks, it just takes a lot of words to clearly explain the task.

Task:
Hydraulic Clutch System Bleeding

Caution:
DO NOT use fluid which has been bled from a hydraulic clutch system, in order to fill the clutch master cylinder reservoir, due to the possibility that the fluid may be aerated, have too much moisture content, or be contaminated and may cause system or vehicle damage.

Bleeding the hydraulic clutch system is necessary whenever the level of fluid in the clutch master cylinder reservoir has been allowed to fall so low that air has been drawn into the master cylinder.

1. Clean all dirt and debris from the clutch master cylinder cap to ensure that no foreign substances will enter the system.

2. Remove the clutch master cylinder reservoir cap with diaphragm.

3. Fill the clutch master cylinder reservoir with clutch hydraulic fluid. Refer to Adhesives, Fluids, Lubricants, and Sealers See: Clutch, M/T > Electrical / Mechanical Repair > Adhesives, Fluids, Lubricants, and Sealers.

4. Remove the left catalytic converter. Refer to Catalytic Converter Replacement - Left Side See: Catalytic Converter > Removal and Replacement > Catalytic Converter Replacement - Left Side.

5. Have an assistant depress the clutch pedal fully and hold.


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6. Loosen the bleeder screw (1) on the clutch actuator cylinder to purge air.

7. Tighten the bleeder screw (1).

8. Release the clutch pedal.

9. Repeat steps 5-8 until all air is completely evacuated.
Check and refill the clutch master cylinder reservoir with clutch hydraulic fluid as necessary in order to prevent air from being drawn through the clutch master cylinder. Refer to Adhesives, Fluids, Lubricants, and Sealers See: Clutch, M/T > Electrical / Mechanical Repair > Adhesives, Fluids, Lubricants, and Sealers.

10. Fill the clutch master cylinder reservoir with clutch hydraulic fluid. Refer to Adhesives, Fluids, Lubricants, and Sealers See: Clutch, M/T > Electrical / Mechanical Repair > Adhesives, Fluids, Lubricants, and Sealers.

11. Install the left catalytic converter. Refer to Catalytic Converter Replacement - Left Side See: Catalytic Converter > Removal and Replacement > Catalytic Converter Replacement - Left Side.

If I recall it is a 8 or 9 mm box end wrench that fits the bleed screw.

 

Thanks guys. I want to bleed it because the last month or so it's been 'nipping' (kind a subtle mechanical hiccup sensation in the shifter) during gear changes unless I focus on keeping the clutch flat to the floor and pausing slightly during a shift in neutral. Figure a bleed is an easy first step in troubleshooting.

 

Before you go to that much work, try exchanging the clutch master cylinder fluid using the "Ranger" method. It really does make a big difference.

A couple of the "Ranger method" threads:

https://www.corvetteforum.com/forums...al-issues.html

https://www.corvetteforum.com/forums...tch-fluid.html

Ron

 

dar02081961,

Very interesting. So the C7 ins't a nightmare like the C5 and C6? As I'm sure you're aware the C5/C6 were nightmares to bleed. The bleed on the C5/C6 was on top of the housing and practically impossible to access without pulling the clutch or motor.

Those in the know installed a remote braided steel bleeder extension on the C5/C6 when the car was apart and the bleeder was accessible.

The way I'm reading your post the C7 looks like a piece of cake compared to the previous gens?

Rick

 

No - I just reviewed my 2016 Service Manual, and it's essentially exactly the same HUGE PITA that the earlier gens were!!!

dar02081961 says: "Just have to remove the drivers side catalytic converter which isn't as involved as it sounds."

Oh yeah - REAL EASY!!!! NOT!!!!!!!!!!!

The Service Manual procedure says to remove the tunnel plate, remove the exhaust (and you'll need some new gaskets, and I think some clamps when reinstalling), then remove the Cat, then you may be able to reach up in there - but it's still a PITA to get to the bleed valve through the bell housing. Some C6 guys made tools out of old wrenches they bent and cut, but it was still a real royal PITA - and the C7 sounds to be just the same!!!

Just do my fellow Ranger Ranger's method. Easy and it works.

.

 

You just support the intermediate pipe and only remove the cat. The bleed screw does still appear to be at 10 o’clock on the bell housing.

I’m quickly losing interest in trying to do this.

 

I tried the factory method exactly ONCE and then never tried again. I used the "Ranger" method afterward and if you do that every week or two it should go a long ways towards extending the life of your clutch hydraulics. I also put some Cool Tube insulation on the tube between the master and slave cylinders to reduce the radiant heat coming from the exhaust manifold.

 

When my service manager who I respect very much tells me the job is a bitch, I believe it!

 

I don't mean to be harsh but it is frustrating to me when I take the time to give sound advise only to have someone who obviously has never done the task try to sharp shot me.

With all due respect you don't have a clue what you are talking about.
Seems you have done your share of reading but little wrench turning on a C6 or C7.

For starters the Ranger method doesn't do a thorough job of bleeding off trapped air. It does ok at exchanging old fluid for new to remove dirty particulate that builds from the slave seal gasket/o ring from normal wear. The Ranger method exchanges fluid which isn't actually bleeding the system of trapped air under pressure. And I personally haven't had any success getting air trapped at the top of slave reservoir out with this method. The Ranger method was ok for C5's when we couldn't get to the bleed screw. Since GM made the bleed screw longer and accessible it is my opinion the Ranger method is for the lazy way out of doing it right the first time.

Secondly The manual says you have to remove the tunnel cover on a C7, but a decent mechanic can remove the CAT bolts without doing so.

I provided the service manual drawing in my original post as a PDF. It was at the bottom so you may not have seen it.

Not sure why you and others would say this is a PITA. As far as turning wrenches go this is about as simple a task as there is.

The early C5's were a pain. The later C5's? and all C6's have a protruding bleed screw at the 10 o clock position that can be reached without removing anything if the car is on a lift. I have personally bleed 4 or 5 C6's myself and none of them were hard after you figure out how to position your arm with the wrench to actually reach and turn the bleed screw.

The only difference in the C7 is the CAT is in the way so you have to drop it. And if removing the 6 bolts that hold the cat pipe on the exhaust is a PITA to you? I understand. Its 15 minutes for me, maybe less for a real mechanic. LOL.

I find it hard to believe this simple task is something you guys would call a PITA. Either you have never bleed one or your are not as well versed in turning wrenches as I give you credit for.

I speak from experience on this particular issue. Its really not that hard once you get started and actually try doing it.

That being said an Early C5 without the bleed extender is a whole nother discussion and I agree those are a PITA. For the C6 and C7 GM extended the bleeder screw and it relatively easy on the C7 and really easy on a C6.

OP research for yourself before you believe anything you may read here. Including what I say. You asked and I shared my experiences others may draw other conclusions all I can tell you is what works for me.

 

No Rick it isn't.

It was a heck of task on the C5.

It is very easy on a C6 because they extended the bleed screw so that it actually sticks out of the bell housing about 2 inches.
I bled a C6 in less than 30 minutes this past summer while a lady waited. Any decent mechanic should be able to do a C6 with little trouble.

The C7 is a bit more involved because you have to remove the left CAT (6 nuts, no big deal).

 

I’m not being critical of you! I just bailed on the plan because it wasn’t a chore I HAD to do, just one I was considering doing given some crappy clutch fluid appearance and a weird 4th gear engagement sensation. In the end it seemed like a task that wouldn’t address my issue anyway.

I appreciate your input and feedback though.

 

I'm sorry, and I apologize profusely!! No intention to sharp shoot you. I just don't agree that removing a cat is easy!!!

And you're correct - I have not bled the clutch on my C7.

But you make it sound like it takes no longer to remove the cat and get to the bleed valve than to do the Ranger method!!! But it takes A LOT LONGER to remove the tunnel plate and exhaust stuff to get in there to the clutch bleed valve.

I have done a HELLUVA LOT of wrench bending on all the Vettes I've owned. I've got a 4 post lift and I tried bleeding the clutch on both my C6 Z06 and ZR1 (never bothered on my 2005 - I didn't track it), but without removing anything there was absolutely no way I could reach in there to get to the bleed valve. As I said in an earlier post, I searched the forum and read about other members that had been able to cut and bend a wrench to sorta 1/2 azzed be able to reach it in there with difficulty, but I just kept doing the Ranger method and found that totally satisfactory.

In addition to brakes, alignments, cai's, lots of electrical stuff, etc., etc., I have swapped headers and installed Corsa exhausts on my early 2005 C6 and a buddy brought his C6 GS over to use my lift to swap his exhaust, and although the cats weren't removed, It looked like it would be rather tight to get in there even with the left cat removed. It's just a helluva lot too much for me to even consider doing that just to bleed the clutch. Removing the tunnel plate, dropping the exhaust, removing the left cat, getting a buddy to come over to operate the clutch for me during the bleed - just a lot too much to do a couple hours of work instead of a 5 minute Ranger method fluid swap, which has kept the clutches on all 4 of the Vettes I've owned working great. Matter of fact, in most of these discussions, Tech Contributor Bill Dearborn will chime in and tell how he has never done anything to the clutch fluid in any of Vettes from his early C5 on.

When my C6 Z06 blew its first LS7 I had a bleed valve extension installed during the engine replacement (I didn't do the engine swap), but I never even used it because it went through 2 more LS7's very quickly, and after the 4th engine was installed I quit tracking it and just street drove it until I traded it on my C7. I tracked my ZR1 in the meanwhile. I do all the track preps on all my cars.

If the C7 can be done by removing the left cat without needing to remove anything else, and you can do the procedure in 15 minutes, maybe that is a good way to refresh your clutch fluid - but I still just don't really want to remove a cat just to refresh fluid in my clutch.

Bottom line - I guess even though I've done A LOT of work on all my Vettes, you have a lot more experience than me if you find you can remove and replace all that stuff under the car easily enough to do something that may never need to be done (according to Bill D) and that I find is very easily done via the Ranger method.

I've already done all the prep for the track event I'm going to this weekend, but next time I've got it up I'll take a look at getting to the cat without removing all the other stuff under the car.

Again, sorry if you were insulted. I just have a different view of what needs to be done to keep my clutches working great.

.

 

Thanks. I had no idea they extended on the C6Z. I dropped a valve in my C6Z and had them install the braided extension line when replacing the engine under warranty. I didn't know it wasn't needed on the C7Z. Wish I had known then....

 

BEZ06,

I'm not sure why you keep talking about the "Ranger" method when the topic is "bleeding" the clutch. Even after the point of bleeding versus exchanging fluid was reiterated in a second explanatory post you go back to talking about the Ranger method for swapping out some of the fluid.

The Ranger method is a half assed way to replace some of the fluid in the hydraulic clutch system. It does not bleed the system of ANY air.

Accessing and utilizing the bleed screw which extends from the bell housing is the only way to "BLEED" the hydraulic clutch system of air.

I'm puzzled by your repeated posts to the contrary as I've read your posts for years and know you know the difference?

Rick

 

I added some clutch fluid to my reservoir before last weekend's track event since the fluid was quite low in the reservoir. However, I have not done anything else to the fluid which has been in the clutch system since the car was built in June of 2015. I never bled my two C5s in the 6 years I owned each of them and I didn't have any trouble with the C6Z until I had the dealer add a remote bleeder when the engine was replaced. Once I started bleeding the clutch it started sticking to the floor.

Bill

 

On my C6 I never needed to truly bleed it but I did use the Ranger fluid change method fairly regularly. On my older Camaro track car with T56, I did need to bleed it and the bleed screw was virtually inaccessible. I own a Mityvac I used for blake bleeding the race car so it was suggested to me that I use it to actually pull a vacuum on the clutch fluid reservoir and pull the air out using one of the tapered bleed screw adapters on the Mityvac. Simply put the fitting down into the bottom of the clutch fluid reservoir and pull a full vacuum and watch the air bubbles come out.

Inexpensive and it worked fine for me.

 

Yes - sorry I've been talking about the wrong thing.

But after reviewing spearfish25's post# 4, if he has a 'nipping' in clutch operation due to allowing the clutch fluid to get so low that air got into the system, then he does need to bleed it. But the concern there should be why it was losing fluid. And if fluid never was getting low and allowed air in, then he may well have a problem with the master cylinder or actuator (slave) cylinder that bleeding won't fix.

Like it says on page 17-422 of my 2016 Service Manual:

It doesn't mention any other time the clutch hydraulic system may require bleeding, but the only other time bleeding would be necessary is if damage is done to the clutch hydraulic system, or you've done replacement of parts in the clutch system. But if you've been as far in there as replacing the disc, pressure plate, or actuator (slave) cylinder, then that's a good time to install a remote bleeder.

So...sorry I was misunderstanding what the discussion was about. I thought it was about a servicing method that would prevent major maintenance problems.

If you get air in the clutch hydraulic system, bleed it.

Otherwise, like Bill D says, you may never need to do anything to it.

 

I apologize if I may have gotten a little over sensitive. After reading several of your post to the discussion I can see you were truly trying to be helpful and honestly mistaken. Believe me I have done the same more than once.

On with the discussion;
After closely looking I think I see where there is some confusion. I will try to clear that up in case someone reads this thread in the future.

C5
On the C5 the bleed screw wasn’t long enough to access at all.
I am told the newer C5's had an extended bleeder screw like the C6. I don’t know my C5 is a 98.
The fix for this was to add the extension bleeder valve when the drive train was out or apart so in the event the slave needed to be bled you could.

C6
On the C6 GM extended the bleeder valve out past the bell housing an inch or 2.
Many folks still used/added the extension bleeder as they did for the C5 as it made things much easier, however it isn’t required on the C6 or C7.

I think the book method may tell you to drop the drivers side exhaust extension with the pre CAT to access the bleed valve.

**However on a stock exhaust and at least one with long tubes I have been able to reach the bleeder through the gap at the bend of the exhaust and not remove anything. TOP PHOTO below, see gap at top left in dark area.

You have to look at the lay of the land with a bright light and possibly a mirror to see what needs to be done and how much room you are working with.
Then you must do the task by feel because you will have to contort your arm and actually may be looking away from the work area.
You will also have to adjust the lift height just perfectly so you can slide your hand and arm through the gap to the bleed valve.
The most difficult part is replacing the rubber cap on the bleed valve. Valve is 9mm. The wrench should be a fairly short box end 2 maybe 3 inches in length.

C7
Mostly everything above for the C6 applies to the C7.

1. The manual may say remove the tunnel cover. However it isn’t the tunnel cover we are all thinking.
It is the frame brace that covers the exhaust flanges (Z06 only?).
The tunnel cover (similar cover as on the C5 and C6 that we all know) is above the exhaust system which itself is between the tunnel cover and the frame brace.

2. The C7 manual as the C6 manual says tells you to remove the pre cat extension pipe (6 nuts).
The difference here is in order to remove the extension pipe they tell you to remove the frame brace that covers the exhaust flanges so you can access the nuts to pull it apart.

I have not bled a C7 yet.
But it is my belief that you may be able to eliminate both steps 1 and 2 above just as I have done in the past on the C6 and reach through to access the bleed valve.
It looks damn close and may not be possible. But so did the C6 until I tried it.
BOTTOM PHOTO of C7 (C7 non Z06 pictured for illustration) see gap between extension pipe and the bell housing (dark area).

If there isn't room to reach through with the extension pipe installed then it still may be possible to eliminate step 1 above.
I think the nuts on the exhaust flanges face toward the front of the C7. This is the opposite of a C6 which I think face rearward.
If this is the case an extension and deep well socket should be able to reach the flange nuts without removing the Z06 frame brace.
If successful the question then becomes having enough play to move the pre cat extension pipe forward enough to clear the frame brace to get it out.
If not you must remove the frame brace. Which isn't a big deal but will add about 15 minutes to the task.

Even if you cannot eliminate steps 1 and 2, if you have air tools you should be able to complete the task in an hour or so once you get the car on the lift.
None of the components you need to remove to get access is very difficult and they are fairly easy to access with air tools and extensions.

Lastly
Some of the earlier bleed valve extensions caused issues and actually created a problem where non previously existed because they seeped air or weren't closed tightly enough by the installers. This allowed the clutch to eventually bleed down slightly requiring the system be bled. I think that’s called a catch 22. LOL.

As others have said if everything is right with the clutch hydraulics you should never ever need to bleed it.

However no process is 100%. So let's say yours is marginal. Then bleeding the clutch may just resolve you shifting issue.
It is my belief that there is some small amount of variance in the process where the average driver may not notice it but there could be a slight bit of air in the system.
Bleeding the system eliminates that concern.

It's kinda like bleeding the brakes, it's never required if you haven’t opened the system or run out of fluid, but we all know bleeding the system sometimes give us a firmer pedal.

If someone has an opportunity to try these short cuts on a C7 before I do please feel free to add your comments to the thread.

We are all here trying to learn and trying to save time/effort where we can do so safely.