Theta

The following How-To covers the explanation of how to Bleed the Hydraulic Clutch System and includes specifications, schematics, etc.

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Theta

Theta

Theta

Jeff V.

I wanted to bump this thread to add some things I learned when I recently bled the clutch on my car.

The gasket between the cat and manifold is a one time use crush gasket. The part number is 15272179. A replacement is ~$20. The nuts and studs between the cat and manifold are supposed to be single-use as well. I reused both. I tried to remove the studs, but they wouldn't budge from the exhaust manifold. I didn't want to pull the manifold, and it was way too tight for me to feel comfortable putting a torch up there. I'll check it periodically and figure out a replacement plan if I find that it's getting lose or leaking.

Before you try to pull the cat, remove the center tunnel close out plate, and the thin reinforcement bar that goes from the body to the sub-frame, just aft of the front tire. Also, unbolt the ride height sensor (if you have mag ride) and remove the electrical connector. You can leave the little linkage arm connected to the control arm. Set it on top of the control arm out of the way. You may also want to remove the plastic brake cooling guide from the front of the lower control arm, just to give yourself a little more room.

Remove the nuts from the cat at the manifold and the x-pipe. It would really help to have a 15 mm offset wrench for one of the manifold nuts. You can do the job without it, but it's a tight fit. Remove the nuts between the passenger side cat and the x-pipe as well. This will give you a little slack to push the x-pipe back to gain a little extra room to get the cat out.

Once the cat is loose, disconnect the two O2 sensor connectors from the body. The sensors themselves can stay in the cat pipe. Then put a pry bar into the engine mount. (See pictures) This is why we removed the ride height sensor. Gently pry up on the engine until you have enough room to slide the cat out. You only need about a quarter inch. Any more than that and you risk damaging the engine mount.






Once the cat is out, you should be able to reach the clutch bleed valve. Be careful when you pull the dust cap off. It's possible to drop it down inside the bell housing. Guess how I know? You can block off the opening with a paper towel or rag as insurance. I was able to get mine out with an inspection camera and a zip tie. I knocked it down to the bottom of the bell housing where I was able to fish it out through the vent holes.

The bleed valve is either 8 or 9 mm. I think it was 8, but I didn't make a note of it. There's barely enough room to get in there, but it can be done. You only need about an 1/8th of a turn to allow fluid to come out.





Up on top of the car, you'll want to make sure the clutch reservoir is covered while your assistant is pumping the pedal. If you don't, fluid can shoot out and make a mess. Again, ask me how I know. I used a wide mouth funnel and then covered that with an old brake reservoir cap I had from a different car. It was less messy than taking the funnel on and off.

Bleeding is the same as any old brake system. Pump, hold, bleed, repeat. I'm really glad I did mine. It was nasty. It took a lot of cycles to get clean fluid all the way through the system. The pedal doesn't move much fluid. I'm not gonna say the Ranger Method is useless, but there's no way it's getting all the crud out of the slave cylinder.

Reassembly is pretty much just putting everything back where it goes. The manifold gasket only goes on one way. Be gentle with prying on the engine mount when you put the cat back in. Hook up the O2 sensor connectors before you start tightening the nuts.

Here are some additional torque specs that weren't reference in the original write up.

Tunnel close out plate
Small bolts: 20 lb-ft
Large bolts: 74 lb-ft

Subframe brace: 74 lb-ft

Cat to x-pipe nuts: 18 lb-ft

SnowyATX

All,,
Just finished a full clutch bleed after replacing my master cylinder (uugghh....what a PITA). Thanks to Jeff V. and Tom Ross for tips along the way. All related to this BS cloudy/gross clutch fluid that the dealer refused to work with me on. I've done like 3 pints of the ranger method with not much improvement so I dove right in. Dealer claims the master and slave are assembled with some grease that could cause it....whatever, then replace it. They wouldn't so I replaced the master to get that variable out of the equation. I did get a bunch of goo to come out until 98% clear...still some particles in the jar but not sure if they were in the hose or still stuck in the lines or the slave. https://www.corvetteforum.com/forums...tch-fluid.html

From the factory:



Here are some thoughts and experiences of my own on top of Jeff's.

1) Yes, its a pain since the cat has to come out. Worse than I recall on the C5 in terms of finally getting to the bleed screw.
2) I found that if I removed the two inboard studs I didn't have to pry the image up as mentioned above (surprisingly easy with a wrench although the nut and stud had been soaked in Liquid Wrench for a day by the time I got to them.....was tempted to not even try....I hate exhaust bolts/studs). See the image below for locations.
3) The O2 sensors connectors are total BIT#%. I broke on the retaining snaps so both are now held in AND locked using tie wraps.....oh well. The secret is to push white clip towards wires and then press down on white clip, then separate the connector. This is assuming you can get your hands on them. At this point, the cat is loose but still in the car so very little room. https://www.bmotorsports.com/shop/po...d5q03k5gq1i3j2
4) Once the cat is out it was time for a custom tool just like my C5. Pull out the propane torch and make a "blue" bend and "green" twist. Yellow circle fits on the bleed valve.
5) Move the flexible heat shield (red arrow) down to give more room for the wrench to rotate down on the "loosen" stroke. The bleed valve is the blue circle. There is a clear hose attached but you can barely see it.

Jeff V.

Nice job. I wish I had thought to make that custom tool. I just kept fumbling with an unaltered wrench.

If I ever need to replace my clutch or have the torque tube out for any reason, I am definitely installing a remote bleeder.