Best way to Bleed/Bleeding your Clutch Master Cylinder. (One Man Bleeding System)

[kutseku_honda]

The best way to bleed the clutch hydraulic system is.....PATIENCE AND A 4 FOOT CLEAR TUBE.

My adventure started when I found my clutch pedal on the floor after getting back from a long vacation. My CMC failed in my 91 accord wagon and leaked all the brake fluid to the carpet floor. After replacing the CMC and also the slave cylinder (replace together based on numerous post here of slave cylinder failure after CMC replacement only) my frustration and curiosity started when I failed to bleed the hydraulic system properly.

I started to research the proper way of bleeding the system. There's quite a few of them and even tried making my own power bleeder. This one's funny from youtube.... POWER BLEEDER USING A HOUSEHOLD VACUUM CLEANER. Guess what....did not work. What cause all of them to fail I think was not giving them enough time to work. Afte 3 days of failure and thinking I might have a bad CMC or slave from autozone (by the way, they are lifetime warranty for both parts), tried the last procedure that worked.

I got a 4 foot clear tube from the hardware and put it on the bleeder screw on the slave cylinder and put the other end to the brake reservoir on the CMC. Kept the bleeder screw open and pumped away. SUCCESS!!! Pressure was felt probably less than a minute of pumping and tighten the bleeder screw. I was so amaze how simple that was that I actually did it again and even allowed air in the system and bleeded it again. Test drove the car and pressure is good.

Key things to remember:
-Use teflon tape on bleeder screw and the hydraulic line screw on the slave and CMC.
-Make sure use a snug fit size clear tube hose for the bleeder screw on the slave cylinder.
-Put a small amount of grease around the bleeder screw to avoid air leaking back into the system while open. (Good advise for those who are paranoid about leaking air back in the system but I did not do this. Read it somewhere. Teflon tape probably worked to seal the system)
-Make sure to keep filling the reservoir with brake fluid that will fill the rest of the hose until you have a close fluid circuit. (Count pumps in the beginning to see when the fluid is close to empty to avoid air in the system)

This will probably work with other cars too.

Not an active member but with this experience and how frustrated I got made me post this. Hope it helps everyone out.

[deevergote]

Thanks for the advice. That's actually the problem I have with my car right now... I can't get pressure, no matter how much I bleed the system (all new components). I think the issue might be air getting back in at the bleeder screw. I'll have to try teflon tape. I never thought of that!

[PR CB7]

you shouldn't need teflon on flare fittings, thats why theyre made
unfortunately, autozone CMC suck, take too much time to bleed
you probably had a leak thats why you put teflon, dont know why because brake fluid eats teflon

deev try bleeding through every thread possible,
have somebody pump

loosen the fitting of the hard line to the CMC, and tighten when you see good pressure, then the banjo bolt on top of the trans, then last the bleeder
since i have a straight braided line, i dont get that problem

if youre on a hurry, you can hook up a line from the bleeder to the IM and leave engine in idle, it works
just people might call it caveman style

[batever]

Good tips.

the threads on the bleeder valves are an interference fit in order to make them airtight. If the interference fit isn't working for whatever reason once they are loosend a bit for bleeding, (bad manufacturing, corrosion, or wear) then it makes sense that they can bleed fluid at the threads. In which case the teflon tape or the grease at the threads could help to keep it sealed at the threads.

Makes sense. In the case of a bad bleeder screw sometimes just opening it an eighth or quarter or a turn or whatever can be enough to open it up for bleeding while keeping a good seal at the threads.



A $9 one man brake bleeder kit makes all of this easy though. I did a friends' "new" 92 geo prism brake lines (and reman'd brake master cylinder) today with one of those kits. No need to run back and forth to the bleeder screw every press of the peda; just every like 15 presses to empty the old fluid out of the kit's old fluid reservoir. Once I had it in my hands the job went very fast. Also, if necessary, you can "bench bleed" your existing master cylinders (brake or clutch) on the car with it by jacking the car so the body of the cylinder is level, then undoing the car's hard line connections to it and hooking the brake bleeder kit to it (with the reservoir held ABOVE the bleeder screw).

With the kit's bottle and hose up higher than the brake bleeder screw, all air rises up and is eliminated from the hose so the job goes really fast. No need for a vacuum system in my opinion.

[batever]

Originally Posted by PR CB7

if youre on a hurry, you can hook up a line from the bleeder to the IM and leave engine in idle, it works
just people might call it caveman style

wow, that's clever! I guess you want to watch it though and make sure the suction line doesn't fill up and pour brake fluid into the intake manifold.

[deevergote]

I've pulled 2 bottles of fluid through, and still have no pressure... I had help, and did it for 3 hours! I've even tried with a hand pump. Maybe one of the components is faulty.

I'm just going to tow it to the dealership and have Jak Frostwhite help me. Though the vac hose trick is interesting. I never would have thought of that!

[90blackcoupe]

bleeding the clutch is pretty simple it only takes on man, just pump up and release the bleeder screw on the slave, when releaseing the bleeder valve make sure the pedal is up and not down to the floor,

to properly get the air out of the system you should release the bleeder and fill the clutch reservoir with fluid, it should run out of the bleeder valve if its bubbling theres air in the system just wait and keep filling the reservoir till it just runs out, after that you should pump up and always remember to bring the pedal back up( bleeding the clutch isn't like bleeding the bakes you don't need to hold the pedal down) and then release the valve, repeate if its still bubbling after bleeding the system start the car and pump up a few times so the system builds pressure.

[F20A CB7]

this is wat i did. i did what a member told me to do on here.

ull need 2 peeps, a cup, small hose to put over the bleeder screw, even a straw will work, and brain.


open the bleeder screw on trans, have some 1 pump the clutch CONTINUOLSY, wow i splled that wrong.. as he pumpin, pour your fluid in, dont let it go down, keep on filling, and watch the slave cylinder til you see a steady flow of fluid, once you see that have him hold the clutch in, and tightin the scrrew.

youll be golden.

edit, i re read thread, i think u may have gotten the help already.

[deevergote]

Originally Posted by F20A CB7

this is wat i did. i did what a member told me to do on here.

ull need 2 peeps, a cup, small hose to put over the bleeder screw, even a straw will work, and brain.


open the bleeder screw on trans, have some 1 pump the clutch CONTINUOLSY, wow i splled that wrong.. as he pumpin, pour your fluid in, dont let it go down, keep on filling, and watch the slave cylinder til you see a steady flow of fluid, once you see that have him hold the clutch in, and tightin the scrrew.

youll be golden.

edit, i re read thread, i think u may have gotten the help already.

He was never asking how to do it in the first place. He was providing useful information on how to do it.

Reading and comprehending the thread BEFORE you post is a good thing...

[kutseku_honda]

Originally Posted by deevergote

I've pulled 2 bottles of fluid through, and still have no pressure... I had help, and did it for 3 hours! I've even tried with a hand pump. Maybe one of the components is faulty.

I'm just going to tow it to the dealership and have Jak Frostwhite help me. Though the vac hose trick is interesting. I never would have thought of that!

Deever...just humor me and try the hose. I actually tried all of them including the IM vacuum and the hand pump. The thing is, air rises and some of them just might be too stubborn to be sucked out. By doing what I did, you are definitely just trying to circulate all the fluid and expelling all the air in the system when it goes back to the reservoir. Make sure that the other end of the hose is submerge in the reservoir but not directly to the bottom. The way I see it, if there's a leak in the system, you'll find traces of the fluid coming out along the hydraulic line. Brake fluid is corrosive but it's no acid to eat up the teflon tape upon contact. Try the grease or at least the teflon tape on the bleeder screw and open it just a quarter turn. Like I said, just try it....cost me .35 per foot for the hose then taking it to the dealership unless you have a hook up there. If the whole system is filled with fluid and you can see it circulate while you pump (make sure 1 way flow back to the reservoir) and no pressure builds up, definitely one of the two are faulty parts. Most likely the slave cylinder coz my assumption if the flow of the fluid is back and forth, then the CMC seals are faulty. Try and use a pry bar and move the clutch fork manually, just in case the clutch itself is stuck. Read it somewhere. Good Luck!!!

[deevergote]

The idea of putting the hose in the reservoir crossed my mind, but I didn't do it because it seemed so simple that it'd have made sense that EVERYONE would do it! It worked for your though, so I'll definitely give it a shot.

I managed to get half pressure at one point, before I had to remove everything to replace the clutch... so it SHOULD be good. I'll try the teflon tape and hose from the bleeder to the reservoir tomorrow. Hopefully all will work!

[kutseku_honda]

I know exactly how you feel. If I remember it correctly, read that post from another honda forum. He said he works at an acura dealership and that's how he bleeds hydraulic systems. Sound so simple that I did not do it right away and did it as a last resort then boom, it worked. If you read my post, felt stupid that I had to do it again and force air in the system by emptying the reservoir and pump air in it. Like I said, if it fails then you are fairly sure that one of them is faulty. The CMC and slave are very easy to replace. Go to autozone, I just love the fact that they have lifetime warranty on most parts. I have not encountered any faulty part so far (fingers crossed).

Anyway, do tell how things end with your troubles.

[Leung]

i bought a slave from TAS and i had to use teflon tape because the grease trick didn't work.

[deevergote]

No luck... I got half pressure, which is better than I've gotten for a while... but I can't get complete pressure. No more air is flowing through the line that I can see, though it may be leaking from the slave. My line might not be on tight enough.

Is it possible to have the clutch pedal out of adjustment? I'm not sure how all that works, because my friend did the master while I installed the slave...

[kutseku_honda]

Yes, the pedal can be adjusted by turning the rod on the CMC but it will not have any effect on the pressure. I believe if you turn it clockwise, the clearance of your clutch will be low and counter will be high.

I'll check back when I get back and see what else I can help you out.

[short1]

I just replaced my slave today. The method I use to get pressure when the pedal is COMPLETELY dead is:
1. Put tube onto bleeder screw into jar half filled with fluid
2. Loosen bleeder screw
3. By hand, press clutch fork to compress slave piston, then tighten bleeder.
(It's important to crack the bleeder before pressing the piston or it's not gonna work) I do this maybe 5 times at the slave, then break out the 2x4 to pump and hold the pedal to finish bleeding

But I do like the idea of running the tube to the cmc, if I ever have to do it again i'll give that a try.
short

[batever]

Originally Posted by short1

I just replaced my slave today. The method I use to get pressure when the pedal is COMPLETELY dead is:
1. Put tube onto bleeder screw into jar half filled with fluid
2. Loosen bleeder screw
3. By hand, press clutch fork to compress slave piston, then tighten bleeder.
(It's important to crack the bleeder before pressing the piston or it's not gonna work) I do this maybe 5 times at the slave, then break out the 2x4 to pump and hold the pedal to finish bleeding

But I do like the idea of running the tube to the cmc, if I ever have to do it again i'll give that a try.
short

Interesting. But why would it matter whether you compressed the hydraulics at the clutch fork or from the clutch master cylinder/clutch pedal? I'm curious.

[short1]

Originally Posted by batever

Interesting. But why would it matter whether you compressed the hydraulics at the clutch fork or from the clutch master cylinder/clutch pedal? I'm curious.

The times i've done it the clutch pedal was completely dead. You could pull it up by hand but if you press it, it snaps to the floor. By building some pressure with the steps I used, the clutch pedal then has enough pressure to pump. I've done it this way 4 times now, and takes about 5 minutes by myself. The first time I gave up after about 2 hours of no pressure at the pedal. Until a friend came by and showed me this.
short

[batever]

Deevergote, i sent you a PM about this, but thought I'd repeat it here: if you have no bubbles when bleeding but you're not getting much pressure, you probably have a bad master cylinder that isn't leaking fluid/letting air in through a poor external seal or bleeder screw, but is not pumping fluid well because it has a faulty internal seal on the piston. (faulty internal as opposed to external seal.) You pump it several times and it gets some pressure in the line but can't do more than that because the seal won't hold pressure against the force at the clutch release fork.

I say this not because I'm very experienced in this (i'm not) but just as a logical conclusion from the described facts. Hope it is accurate/helps.

If you're concerned that the issue is actually the pushrod length, I'd first disconnect the pedal at the pushrod, then use a 2X4 to press the pushrod in and see if it shifts first. (do this with the car running and the front wheels up). Easier than full disassembly. If it shifts like that then adjusting the pushrod length would be helpful.

Keep in mind that the force required to stretch a spring (like the clutch release spring) is a basically linear function of the spring's strength, (if you stretch it twice as far, it takes twice the force) so if your pushrod adjustment is way off and the pushrod doens't go in much, it will feel like the system isn't "building" pressure because it doesn't need much pressure to only move that lever and spring a small amount.


YOu could also shove a 2x4 against the driver's seat and clutch pedal to floor the pedal (with the car off) and then go out front and see how far the slave cylinder pushrod and release fork have moved. since you have mentioned you usually work on it by yourself.

[C91BLX7]

rubber tube and bottle full of fluid, i swear by it.