The plastic clutch line on my truck got a gash in it and all the fluid leaked out of the reservoir. I bought and installed a new line, put fluid in the master cylinder reservoir and cracked the bleeder on the hydraulic throw out bearing. I have fluid coming out of the bleeder, and the reservoir has fluid, but my clutch pedal still has no pressure at all. Like, none. Push the pedal and it stays down, I can't even pump it up to get pressure. The fluid isn't leaking anywhere. What am I doing wrong?

 

Sounds like you're doing everything right. I wonder if you might have to bench bleed the master cylinder again.

 

Some of these clutches will really try your patience. Some make you think they will work and then they don't. They can be frustrating.

Which system do you have? Can you put the whole system on the bench and bleed it? Loop a hose from the bleeder back into the master cylinder.

Another approach is to make an airtight connection with a line to the bleeder and run it straight up so the air comes up and out but the fluid stays down in the tube. Sometimes the "airtight" connection is with a tapered fitting and is just as airtight as you can get, not perfect.

I get a lot of use out of a mighty vac bleeder.

The last one I messed with I bought a pre-bled system for $40 on rockauto. I tried to bleed it and wasted too much time first.

 

I have a Mazda M5OD with internal slave cylinder/hydraulic TOB.

I pulled the master cylinder and the new hose back off the truck (can't pull the slave without pulling the transmission) and I was gonna try to bench bleed it, but I can't get the new hydraulic hose to come off the master cylinder.

I think I may just buy a new master cylinder and a new hose and see how it goes. Any brand
​​​​recommendations?

​​​​​​I've never had luck with vacuum bleeders before but I'll keep it in mind if all else fails. Any other tips are much appreciated. This is a PIA.

 

i have the same set up and transmission. Don't pull the slave, keep trying what you have. pre bleeding master cylinder may help ( there is a video on doing it), but can be done without it.

My tips, after reading what you have done already.

1) make double sure you have the connection to the slave cylinder correct. IE that the tab has reengaged. The way to make double sure is to give it a reasonable but firm pull to see if it will come off.

2) When pumping the clutch pedal, you may/will have to push it down AND pull it back, somewhat briskly both ways, manually. Have someone help watch the reservoir while doing this (make sure the rubber diaphragm is out of the reservoir) ..... they can make sure the reservoir is staying full and also letting you know if they are seeing tiny bubbles while you manually push clutch pedal down and pull up. It may take a large number of pumps until the tiny bubbles stop ...... like 10 rounds of 10 pumps, or more if it's full of air.....keep reading.

3) While it sounds like your pedal is engaged....make sure the rod the pedal pushes is correctly engaged (under the dash by your feet) with the cylinder rod coming through the firewall.

4) When you do think you have bubbles out up top, top it to the line in reservoir (no more or it'll run out when you put dia back in), put rubber diaphragm back in and finger tighten (not too tight) reservoir lid. then turn to slave cylinder. Whenever you slightly crack open the slave cylinder to bleed it....it is just that...crack it barely open, see a little flow, and shut it while someone is putting light pressure on the clutch pedal. IF you leave it open too long, or if you leave it open and your helper takes pressure off the clutch pedal, it'll suck air back in. Bottom line, crack it and shut it while pressure on clutch pedal. IF a lot of air comes out of slave bleed, you may have to repeat the pump process up top and repeat.

Lastly, if you get it close to where you want it. Be done.....trying to get that last 1/4 inch of clutch pedal moved closer to driver can be problematic. The way I make sure I have it ..... is I get under truck and spin drive shaft by hand while helper has clutch to the floor. If I can free spin it when on floor, I know I am disengaged. Then I tell helper to SLOWLY let clutch pedal out while I am spinning drive shaft. I tell helper when I feel engagement....and tell them to tell me how far they have let the clutch out until I am happy. We then change positions so I can double check that I get complete disengagement when to the floor, and complete engagement before letting all the way out.

The last thing I do is remove window rubber on bell housing and watch the slave cylinder while someone operates clutch (engine off). On mine, I don't know the exact measurement, but it looks like it only takes around 3/4 inch of movement (depression of fingers), maybe slightly less, to do the job. I am guessing the exact measurement is in the book. But again, I physically rely on drive shaft test to know I am there, and watch it last to make myself feel better.

It can be frustrating, keep repeating steps 2 & 4 until you get it ..... and have a helper.

Finally, if you get totally frustrated .... let it set overnight, bubbles will actually rise and collect helping the process while you cool off.......or at least this is what I have told myself and it (walking away) can work wonders lol.

hope something here helps you

 

Thanks for all the replies they have been very helpful. Here's what I decided to do. I cleaned the master cylinder really well and reinstalled it.
I filled it up and and opened the bleeder until fluid steadily flowed out. Then I closed the bleeder and topped off the fluid.

​​​​​​Then I pumped the pedal until some bubbles(some not many) came out of the master cylinder reservoir.

Then I had my dad pump and the pedal and hold while I opened the bleeder(standard pressure bleed.)

All of this consumed not quite an entire pint of brake fluid. The pedal now has some pressure, and I can see the slave cylinder moving. The pressure isn't as strong as it was before, but the pedal isn't dead on the floor either. I haven't tried starting the truck up and moving it yet. Tomorrow I am going to try pressure bleeding it some more and see if we can get the pedal as firm as it was. It was getting late and we were getting low on brake fluid so we wrapped it up for the day. Any more tips or suggestions?

 

You are on the right track, might have to repeat top and bottom a couple times as I mentioned before. The fact you are getting some pressure now and your pedal is staying off the floor is a great sign.

Last tip........ Make sure in neutral and STAND CLEAR AND HAVE ROOM the first time you start, and beginning driving....(basically don't trust it and be ready to grab neutral or brake stall) Just in case clutch isn't disengaged or doesn't disengage just down the road.
Keep checking fluid level first few days of driving and leave yourself driving room until you know you got it good. If your pedal throw starts getting a little deep/long after the first couple tanks of fuel, just do the top end pedal trick again until bubbles stop again, that should bring it back. You shouldn't have to do the bleed slave again once you get it done right.

I still like the drive shaft test before operating

 

 

Well I spent some more time bleeding the clutch today. There is a solid stream of fluid with no bubbles when I open the bleeder. Still the pedal is engaging way too close to the floor. Its driveable, but it's a bit awkward. Not sure if I'm gonna keep trying to bleed it or take it somewhere. It's pouring rain now so either way I'm taking a break.

 

 

Well I dropped it off at a shop this morning and had them bleed the clutch. They reverse bled it, which is pretty much fool proof. The pedal doesn't feel a whole lot different, but it maybe seemed less awkward to drive. I had one of the guys at the shop take it for a ride with me, and he said it's grabbing hard, and fully releasing so there is nothing wrong with it even if it feels a little different. He said it felt great to him. So I'm gonna keep driving it and keep a close eye on it. Thanks for all the help everyone. Much appreciated.

 

Mine was a bear to bleed, and didn't feel the same as the original. But it's been working for 3 years now so I guess it's bled right.

 

Well glad to know I'm not the only one.

It's probably a long shot, but I'm wondering if maybe having clean fluid in the system might have something to do with it. The fluid that was in it was filthy black, possibly original.