I'm screwed - bleeding the clutch

So, I was having my fiancée help me bleed the clutch and in a moment of sheer stupidity, I had her pull the pedal back up from the floor while the valve was open. Tada, huge amount of air in the system!

 

So, the pedal now flops between up & down and has zero pressure. I have spent the last several evenings trying to bleed the clutch with a vacuum pump, unsuccessfully.

 

A little background: I replaced my clutch around 70K (currently at 74K) with an ACT HD clutch/pressure plate and 06/07 WRX flywheel. At the time, I adjusted the clutch pedal so it was easier to drive. Once it broke-in, I adjusted the clutch pedal back to where it was (I think).

 

Here is my process:

 

*Attach vacuum pump system (system looks like this) to bleeder on slave cylinder (I've tried master too, but primarily slave)

 

*Pump clutch pedal a handful of times & prime vacuum system with 20-25 inches-Hg

 

*Open bleeder screw

 

At this point, a limited amount of fluid is sucked into the hose. Some air is sucked past the bleeder screw, which I can tell because of a consistent flow of large sized air bubbles. If I'm lucky, I will get a rush of super small bubbles and a few mL of fluid into the hose.

 

*Close bleeder screw, pump clutch pedal again, start from the top

 

Through this process, I have gotten about 100mL out of the system, mostly through the slave. I got a little out of the master cylinder, but it's not consistent or in any great volume.

 

I was giving it another go this evening, and now I'm not able to get ANYTHING out of either the slave or master. I was getting tired and frustrated, so I could've been doing something wrong or just plain hallucinating.

 

Despite bleeding 100mL of fluid, the pedal has not changed AT ALL.

 

I have also tried gravity bleeding (over night) with zero effect. I have tried moving the slave pin manually while applying vacuum; this ejects some more fluid & some bubbles, but not a huge amount.

 

Here are my next steps:

 

*Try adjusting clutch pedal rod to see if I can get it to move more fluid when the pedal is actuated

 

*Have it pressure bled with a compressor & appropriate fittings (I do not have this - would have to come have someone do it)

 

*Have the car towed to a shop for them to eff with it

 

Does anyone have any suggestions? Am I missing anything? Is there anything troublesome with our clutch hydraulics?

That's a lot of vacuum.

 

Try putting some kind of thick oil around the threads of the bleeder. Motor honey is what I've used in the past (motor assembly lube), but any kind of higher viscosity oil should do the trick.

 

Dollars to donuts, you are pulling air past the bleeder threads and not out of the system.

 

Otherwise, remove the master cylinder, bench bleed it, then reinstall and bleed correctly.

I'm definitely pulling air past the bleeder screws and I have put grease on the threads. It stops the extra bubbles, but doesn't help get any more fluid out of the system.

 

Am I using *too* much vacuum somehow? Pressure building up at a certain point occluding the system or something? The hand-pump in the vacuum system has a gauge that goes up to 30, it's pretty easy to pump it to 20, a little extra required to hit 25. I can't get it much past 25 with it connected to the bleeder screw.

 

I would agree on bench bleeding the master, but if there is fluid in the rest of the system what does that do? I guess it would ensure the MC is air-free and if I bleed from the slave, it would have a completely air-free source to suck fluid from?

 

I guess that could help...sorry, I'm kind of disillusioned with all this.

I haven't done this on a Subi, but usually best practice is to bleed from the slave as it is at the end of the hydrolic system. Usually you compress them with a c-clamp or by hand if possible and bleed it compressed. Then you close the valve and let the slave decompress. That ensures that there is no air bubbles left in the slave cylinder. Did you leave the fluid reservoir opened? They are usually sealed pretty good and will not flow if the cap is on.

Yeah, I was primarily trying to bleed from the slave, though I did not consistently compress the pin.

 

The master reservoir was definitely open too.

 

I'm going to pull the master today, bench bleed it, then reinstall and bleed the rest of the system with the slave pin clamped. If that doesn't work, I'll have it towed on Monday.

Use a pressure brake bleeder.

Well folks, I have given up.

 

I pulled the master and as far as I can tell, successfully bled it. I reinstall it and the pedal is ever so slightly improved. It still sucks straight to the floor, but it doesn't land with a resounding thud.

 

First I tried vacuum bleeding the slave as usual. Pumped the shit out of the clutch pedal. Attach vacuum system and build up 20-25 inHg. Compress slave pin as much as possible. Open bleeder.

 

I get a bit of fluid and a lot of small bubbles. Eventually this flow stops (even though it's under vacuum), so I close the bleeder and re-pump the clutch. Oh noes, the clutch pedal is just as dead and floppy as before! MOTHERWTF??!?!!?!!

 

So I pulled the master AGAIN and bench bled it AGAIN so I could retry with just gravity bleeding. Clutch pedal is again slightly improved after bench bleeding, so I pump it up, put a hose on the slave bleeder, and open the slave bleeder. A fair amount of bubbles with very little fluid. Close bleeder and go back to the clutch pedal - IT'S DEAD AND FLOPPY AGAIN.

 

And, I'm throwing in the towel. I suppose if I was so inclined, I could pull the entire system (there's only one additional mounting point for the hard lines, and they are very short lines) and try to bench bleed THAT, but I fear that too would be fruitless.

 

I'm calling a guy I know to see if he's able to bring a portable compressor and pressure bleeding system, otherwise I'll have it towed to a shop.

just drill a small hole in the reservoir cap and attach a basketball inflator needle to it. any bike pump will do the trick at this point. when you are done, all you need to do is put a small dab of silicone sealant over the hole. just make sure the hole is small enough that you can friction fit the the needle in the opening.

I just went through a clutch bleed with a friend on my car last night, here's how we did it:

 

You need one guy under the hood with access to the bleeder on the slave cylinder, and one guy in the driver's seat.

 

Hood guy opens bleeder and says "open."

Driverseat guy pushes pedal to floor, holds it there, and says "down."

Hood guy closers bleeder and "closed."

Driverseat guy lifts pedal and says "up."

 

At each step, each guy waits for the other guy to confirm that he's done with his step before proceeding.

 

Repeat the cycle 4-5 times. You're pumping fluid (possibly mixed with air) into the cylinder and out the bleeder each time you push the pedal down. Closing the bleeder ensures that no air gets in when you lift the pedal. After a few rounds, the fluid coming out of the bleeder should be pretty clear. I was the driverseat guy so I didn't actually get to see the fluid change from frothy to clear, but I'm told that it did.

To close this out, I had a mechanic I know come by to finish this. He had a cool little system that uses the air from your tire to pressurize the system - neat eh?

 

He had some trouble at first as well and it turned out that the master pin was advanced in a little too far and was blocking the port. He pulled the master cylinder off the firewall a bit to pull the pin out and it bled like a charm.

THANK YOU ece_tim!! I began yesterday with what I thought would be a simple slave cylinder replacement. I tried every method I could find on any forum to bleed the clutch and it just wouldn't bleed. I spent probably 5 or 6 hours. All the other threads end with "If this doesn't work, I'm taking it to the shop."

 

I loosened the bolts holding the master to the firewall and within 5 minutes my clutch pedal was no longer sitting on the floor. I really really appreciate your follow-up!

Glad it helped! Sure is a bitch huh

Thanks from me too, the unbolting of the master cylinder worked like a charm. Just a thought though, now that I've bolted it back up, won't it still be not letting fluid go from reservoir to lines when necessary? Should I replace the master cylinder? (if so, I've heard that replacing the slave at the same time is good practice, does that sound right?)

 

Thx,

Andy

any updates on this guys? problems all solved?

Yeah great info..ill be doing this tomorrow.

Just bled the slave cylinder successfuly, wasn't terribly hard like it was made out to be. Thanks for the write up.

Ok instead of starting a new thread because I am having the same problem this guy did. 05 Legacy gt, I have bleed plenty of clutches and this one is a pain in the ass. Why is this being so difficult? I started out having a friend holding the clutch down, opened the bleeder nipple, closed it, then pedal up. Did it a second time, after that no pressure, pumped and pumped the clutch, nothing. Repeated all the steps and still nothing. The line from the master to slave is the shortest one I have seen on any car so I wouldnt think it would need a lot of pumping steps repeated. Does anyone have an easier way to get this done.

It's a push type clutch, open the zerk, push the pedal to the floor, close the zerk and pull up and down by hand a few times you may have to repeat it a couple times. Important to hold it all the way down and close the fitting.

Right, so I did that both at the master and slave, still got nothing. Although this is the first clutch system I have seen a nipple on the master, should I be messing with that one at all?

If fluid is coming out of the slave smoothly I would think that eliminates the clutch master cyl, slave not holding? I have never had to mess with a fitting on the master until priming it before a reinstall.

If fluid is coming out of the slave smoothly I would think that eliminates the clutch master cyl, slave not holding? I have never had to mess with a fitting on the master until priming it before a reinstall.

 

I cant get any fluid to come out and the fluid level in the reservoir never changes. So why is the master cylinder not pulling more fluid in?

It functioned before I attempted this. The reason for trying to bleed the clutch was it was hard to get in gear sometimes and clutch engagement was an inch off the floor and when it was -12 degrees the other day it took me 5mins just to get it in first.

Perhaps you had the same issue as me, your clutch might not be set correctly. Make sure your clutch is neither resting on clutch switch (to far out) nor is there a huge gap (> .25 in is too short of a rod setting) at rest. You can make the adjustments on the clutch master rod, just above the gas pedal. Start from there.

My clutch rod was adjusted too "short" and did not allow the fluid to flow freely between the clutch and slave so my engagement point got higher as the car got warmer (and the corresponding fluid in the line expanded).

Alright guys I finally got it. Dont know why I had to do it this way but it worked. First I started out by getting some small clear hose, Redbull can, and a brake bleeder vacuum bottle with a nipple port out the top.

 

Steps:

1. Fill the vacuum bottle with fluid then attach a 12in piece of clear hose to the top nipple, tip the bottle upside down filling the hose with fluid (make sure you have no air bubbles in the clear hose)

 

2. Attach the other end of the clear hose to nipple on the clutch master cylinder (again making sure no air bubbles are there)

 

3. With the clutch pedal in the up position open the bleeder nipple and you will see fluid go into the master cylinder, close nipple. Pump clutch 4-5 times and it will get stiffer, repeat with pedal up open bleeder more fluid will go into master cylinder, repeat until no more fluid will go into master cylinder when you open the nipple about 3 times should do it (making sure no air bubbles enter with fluid) pressure will return to pedal

 

4. Attach a 6-8in clear hose to the slave cylinder nipple then into the can.

 

5. Now having someone pushing the clutch down open the slave cylinder nipple, fluid will now come out into your can of choice (Redbull for me) then close right before fluid is finished flowing out.

 

6. Now you will back to no pressure at the pedal, (DONT WORRY) Repeat step 3 and pressure will return.

 

7. Now when you get pressure back repeat step 5.(again will be back to no pressure at clutch pedal, why the fluid wont pull from the reservoir not sure but repeat step 3 again.

 

8. Repeat step 5

 

9. Repeat step 3, you may repeat steps 3 and 5 as many times as you desire,(make sure your ending step is 3 adding fluid to the master cylinder to top it off) I did it 4 times and perfection. Clutch is 100 times better than it was before I started this task, slides right into every gear and clutch engagment is more around 2inches from the floor. Also I installed my perrin shifter bushings (round front ones and rear position) also made a big difference.

I can provide pictures of any tools if anyone needs.

Yes I did remove intercooler for easier access to slave cylinder.

Alright guys now that I have my clutch working again. I jumped in this morning to start her and clutch was a little softer than yesterday, about 25 degrees out but after she warmed up it got better. So I am going to bleed it one more time but before I do can any one tell me if the cold weather is affecting it do i have bad seals in the master or slave cylinder? I have already ordered a stainless steel braided line so if need be I will just replace both master and slave cylinder 130k on them.