TacoBello

I just replaced my clutch master cylinder, but I'm unable to bleed the system. When I push on the clutch pedal, it just sinks to the floor and that's it. I try moving it up and down with my hand, a good 20 times, then open up the bleeder valve on the Clutch slave cylinder, but nothing ever comes out.

What am I doing wrong? I have some rubber flexible hose on the bleeder nipple, attached to a pop bottle full of dirty fluid to drain into (same as you'd do on your brakes) but nothing comes out.

I've also restricted the movement of the release fork, but how much do I have to do that? Do I push it all the way in?

Any help, anyone?

srg818

If you open the slave cylinder bleeder screw and leave it open for some time does it eventually gravity bleed?

Adobeman

Or open up the slave bleeder and apply a small amount of air pressure at the reservoir to "help" it along.

BTW - The cap off of a many gallon jugs is the same size/thread as the clutch reservoir and can pretty easily be modded to be a pressure bleeder cap.

justnspace

iTrader: (1)

keeping the fork restricted was the hardest part for me. I had to ask a neighbor to hold fork while i pumped clutch

Adobeman

Good neighbor! I saw how tight it is in that area and thought "PITA to get the right size/shape block of wood but NO WAY am I sticking my hand in there when anyone pushes the pedal, bleeder open or not". It's like one miscommunication over pump/don't pump from crushed digits.

justnspace

iTrader: (1)

LOL! yeah, he used a block.
no missing digits!!

TacoBello

Holding the fork down is no issue... I'm able to keep it pushed in all the way with the help of a stick. However, I think I'm bleeding the thing wrong.

This is what I did:

1. Restrict movement of the fork with a stick.

2. Pump clutch pedal about 10 -15 times (at this point it just goes down and stays down all on its own- I have to manually raise it and then push it down, every time)

3. Leave the pedal laying on the floor after pumping 10-15 times

4. Open bleeder valve to let fluid out.

5. Close bleeder valve once some bubbles come out.

6. Do the whole process again.

The pedal eventually starts to firm up and come back up on its own (after 2 or 3 full step attempts). At this point, I would do all the steps all over again, except with someone holding the pedal to the floor for me. We then did the same method another 7 times like that.

The clutch never returned to its original firmness though. About 80% of it. The clutch pedal was working enough to allow me to start the car, but I couldn't shift with ease.

I assume there is still air in the line?

Do I need to have the hose and bottle contraption on the bleeder valve? Or can I just let it spill out into the engine bay? (It'll be quickly washed out of course).

Not sure what I'm screwing up.

Si_jeff

OP, try to do gravity bleed on your slave. Here is a link to the S2 forums, I never tried gravity bleed ever on brakes until 2 yrs ago when I read a post from the S2 forums as well, the brakes I can say was a great success, the negative I can think of is it takes a lot of your time to gravity bleed brakes instead of the tried and true method of 2 person pump/hold method.

http://www.s2ki.com/forums/s2000-bra...method-993927/

TacoBello

Ok, well I redid the bleeding and there is definitely no more bubbles coming out. The pedal feels normal (at least I think it does). I was able to start the car with the clutch pushed in, however, I still can't shift normally, which leads me to believe the clutch isn't disengaging in its entirety.

So next I started fiddling with the length adjustment on the CMC, inside the car, where it attaches to the clutch pedal. I regretfully bought a CMC from rockauto, and when I pulled it out of the box, the linkage thingy was spinning freely, as opposed to the OEM one which seems to be set in place from the factory. Rather than be smart and note how long the thing is as compared to the CMC I pulled out, I just rotated it until I was able to get the pin back in (match up the two openings, insert pin)

well this time I decided to extend it outwards. I was able to get the pin in and tested it again. Pedal feels the same, however, the car wouldn't even start now (clutch wasn't disengaging obviously.) This led me to believe that this might be my issue. So now I shorten the thingy up, which in theory should now let the clutch fully disengage... Problem is- I can't get the pin in, so clearly it is too short now. I seemingly can't get it to be the same length as before.

Im not sure this is my issue, but I've exhausted all other possibilities. As I mentioned, the clutch pedal feels good and the last three bleeding cycles I did, no more air came out, so I don't think it is a bleeding issue. Absolutely bizarre.

TacoBello

Has anyone had to adjust their clutch pedal after replacing a CMC?

TacoBello

Ok, after replacing my CMC 228349751 times over the last two weeks, I figured I should share some valuable information that I have not come across on AZ.

1. Parts: Buy an OEM clutch master cylinder. It will save you headaches and grief. I bought an aftermarket one, installed it, bled the system multiple times, couldn't figure out what was wrong. Turns out the part was broken, right from the manufacturer. You otherwise couldn't tell, except that fluid was bypassing the internal seals and the clutch pedal wasn't working as it should.

While an OEM CMC is much more expensive, you're guaranteed it will work. Stick to oem. Not cheap aftermarket. Especially on a vital system like the clutch hydraulic system.

2. Bleeding: THE PROPER WAY TO BLEED THE CLUTCH.

Everywhere I looked and read on here, people were suggesting to pump the pedal multiple times. It's a hydraulic system. It doesn't build more pressure, the more you pump it!! A friend of mine is a certified Honda mechanic and told me how to do it properly:

1. Once everything is reinstalled, fill up the clutch fluid reservoir.

2. Get someone to help you. you can do it alone, but it takes more time and more effort.

3. Open the bleeder valve on the CSC. I found holding my wrench at an angle worked best. That way you don't have to remove it from the valve. Just 1/4 to 1/2 turn should suffice. leave it open, let it start slowly leaking fluid in the engine bay.

4. Have your helper beside the car, on the floor, and with their hand, have them SLOWLY push the pedal to the floor. It will stay on the floor, but have them keep pressure on it anyway. DO NOT move the pedal fast. All you do is cause the air in the lines to break into thousands of bubbles, as opposed to sitting as one solid air bubble. Note: you will be leaking brake fluid into the engine bay, but there is nothing for the fluid to destroy down there. You will also be dripping fluid on the floor. No biggie. I just put my oil change pan down there to collect it all. After I was done, I just went to the car wash and sprayed my engine bay clean, where the fluid was dripping.

5. Once the pedal is on the floor, close the bleeder valve.

6. Have your helper SLOWLY lift the pedal up to the top again, and hold it there.

7. reopen the bleeder valve again, and have your helper slowly push the pedal to the ground.

8. Repeat steps 5-7 a good 20 times!

For the 3 CMCs I installed (the failing original, the junky aftermarket one, the good new OEM one), in each instance, I had to do the open/close procedure a good 20 times before the air was all out. In fact, for the first 7-10 times, it feels and looks like nothing is happening at all. Don't worry. The fluid is slowly making its way down the line. You are doing it right.

9. on the last cycle, I would close the bleeder valve half way through the process of the clutch pedal being pushed down, just to ensure no air got back in. Not totally necessary, but hey, that's how I did it.

10. You will now have to restrain the CSC. That rubber flexible boot on the CSC MUST be restrained, using a "block of wood" as per the service manual. I had a spare wooden broom stick that I cut down to about 22.5", I believe. As per Rockstar143's idea, I put the stick on the CSC, and the other side I wedged between against the left inner wheel (not the tire, but the actual metal surface). I had the wheel turned to the left, put the stick in place, and I cut it to a length that would allow my steering column to lock with the wheels facing straight ahead when I pulled the key out of the ignition. You have to do this as there is likely just a wee bit of air trapped in the CSC. By restraining it, you're able to push it all out.

11. Once the CSC is restrained, follow steps 5-7 again, maybe another 3-5 times, just to be sure all the air is out.

Make sure that at all times there is appropriate amount of fluid in the reservoir at all times, otherwise you'll reintroduce air back into the system and you'll have to do this all over again. doing the bleeding process a full 25 cycles, I think I may have had to refill the reservoir 1.5 times. It does not use a lot of fluid at all.

WDPanda

i just replaced my cmc and slave last week as well. Talk about pain in the ass removing those 2 clips that hold the line to the body. At first i was concerned too as the pedal didnt want to pressurize. You have it correct because i kept at it and after 20 times it was good to go. I have a mity vac and vacuum the first 250ml and then turned the suction off (to keep air bubbles out) and left the rubber plastic hose on the bleeder (one man bleeding) while i opened slave, push pedal down, close slave, lift pedal, repeat.