clutch master and slave cylinders

[gushaman]

Ok, my van has been down for 2 weeks now. I replaced the clutch master cylinder (a huge pita to remove the dash and everything for access btw) if anyone wants details of dash removal i can reply with that or make another thread.

I replaced the seeping slave cylinder last year.
replaced the clutch master cylinder 2 weeks ago. Have not been able to make a successful bleed. I tried messing with the adjuster, all in and all out, no change. Pedal goes to floor. My sisters husband was here today and pumped my pedal. I bled the master at the flare nut. Got some bubbles out. Then bled the slave. The first 5 cycles or so no change. Just a dribble. Then a more powerful squirt with air bubbles. I was getting good pressure and powerful squirts from the bleeder, but it was still foamy and bubbly. then all of a sudden nothing. Not a squirt, barely a dribble from the bleeder. Res was full.

Maybe im doing something wrong? I just noticed right before i gave up and came inside that my brake master is seeping down the front of the booster. Obviously they share fluid, but could a leaky brake master cause loss of clutch line pressure? Gonna order a brake master maybe a booster combo depending on price, and a rebuild for my old clutch master incase this new one blew during bleeding procedure. Any ideas or help is very appreciated.

[Burntboot]

Is your "new" master actually new or a rebuild?
Sometimes the rebuilds are less than perfect.
The manual should tell you how to adjust the pushrod properly and (usually) it isn't something that needs to be messed with.

If memory serves, I seem to remember that theres a union where it passes through the firewall that has caused issues for some.
Brake master leaking doesn't usually introduce air into the clutch side unless the level drops too low, if the brakes are mushy though it might be an indicator??

Did you bench bleed the clutch master before installing?
It's a simple system and if your getting good pressure without bubbles from the master and still have issues trying to bleed at the slave, trace the line till you find the rusty spot or a blown union and you should have your problem identified.

Boosters are pretty hardy, if it holds vacuum, it should be good (there also damned expensive).

[gushaman]

Im sure its a rebuild. Is it possible to blow it out if the pushrod (which wasnt attached to the clevis so i had to mess with it some) if my helper was a little vigorous in pumping? What is the procedure for bench bleed? Upon install i had the res hooked up, and pushed it in until only fluid came out of the flare. So there is a union somewhere? And im not sure if i know what you mean by firewall!

[Burntboot]

Firewall is indeed the wrong term.
While I haven't been there yet, where the clutch line passes through the body work, I understand there is a junction,
I forget who had the issue but there is a thread on it somewhere in the archives.
If you were to trace (follow) the line from the master down to the slave, you will find it (if it is still there)

I always bench bleed masters (clutch or brake) before installing them, mount in a vice and push on the piston with an appropriate tool until you eliminate the air,
then instal, I then bleed it again at the line fitting before moving onto the other end.
By eliminating any air as you go, you eliminate the guesswork.
The upside of bench bleeding, if the master has an issue, you'll save the hassle of installing the defective unit.
I like to work through things in as logical a manner as I can, just to eliminate the guesswork after the fact that can happen by taking short-cuts.

No idea if its possible to damage a master as you describe.

If the replacement was a brand new unit, the odds of getting a bad one are pretty slim, with a rebuilt unit, those odds increase dramatically, all depends on how careful the rebuilder was. I prefer to go new whenever possible and if rebuilt is the only option, I prefer to do that work myself, so I know exactly what I am dealing with.
(most rebuilders are paid piece-work, so volume often trumps quality)
BB

[djshimon]

I had a problem bleeding mine because I thought the clutch reservoir (that is connected to the brake reservoir right?) was full when it was empty. So I was sucking air. You have to keep filling it up in order to reach the slave cylinder, it's a pretty small reservoir.

[timsrv]

I don't know if there's any merit to this claim, but I've heard a couple people say they had a similar bleeding problem due to the front tires being on ramps (van was high in front). Both people claimed that it bled easily once the van was level. The 1st time I heard this claim I discounted it as a coincidence. The 2nd time I raised an eyebrow (I've heard stranger things). It might be total BS, but if your van is jacked from the front only, it might be worth a shot to level out.

In reading this thread I can feel your pain. I've never had this problem, but like BurntBoot I always bench bleed before installing masters. I always bleed with my rigs fairly level too. No particular reason for being level, I just like my rigs to be level and up on stands when I work underneath . Tim

[Ian R.]

This may be something you already know. I may also show my n00bery.

But it took me some time to figure out that the clutch/brake/CC reservoir has different fluid compartments. So when I was bleeding the clutch I thought I saw the fluid level full. I could not for the life if me figure out why I could not properly bleed the clutch.

So I found out that the clutch compartment is in the front of the reservoir. I was emptying it out, while I though it was full.

Make sure the reservoir is completely full . Ha, FWIIW.

[gushaman]

Update. I bought a janky master cylinder bleeder kit at the auto parts store. Junk, because itnonly comes with one of each size nipples. I left the new/rebuilt master in the van and bled them there using only the outer/higher/on the end brake fluid line to let air out. Brakes feel a little soft but they work now. I have a rear wheel cylinder seeping so i ordered a new one.
After fighting with an air powered bleeder and getting nowhere i had a friend pump the clutch and i bled at slave. Finally i got substantial movement at the shift fork. Yay! Yeah right.

So now im trying to understand the procedure to adjust the pushrod. Does a longer pushrod equal more movement of fluid or is it the other way around? Do i want the pushrod out as far as possible or in as far as possible? Im sure the clutch is older and worn, but it was engage/disengage at about 1/2 way to the floor. Now i am lucky if it lets me shift when its on the floor, and the shifter almost feels like it is blocked from moving to the port side, but moves easily to the starboard (port being gears one and two, starboard being 5 and reverse)

Any ideas? These slaves arent adjustable are they? Doesnt seem like it. I just need the pedal, when pressed, to move the piston a little further. Right now i have the adjusting rod almost all the way out, is that correct?

[Burntboot]

Hydraulic's are generally self adjusting.
The "adjuster" is there for setting things up for proper clearances at the get go.
Generally speaking, there is no need to ever change that adjustment but there is a procedure detailed in the manual, IIRC.

You want to have just a titch* of clearance at the end of the pushrod, there should be NO pressure on the pushrod, at rest.
( * - a titch is "a wee tiny bit", a smidgeon, enough to feel and hear but not really see.)

Once you get the rod length set, just keep bleeding, the fact that you have some pedal is hopeful.
You're just not getting enough travel because there is still air in the system.

General rule of thumb for hydraulic clutches, a high pedal is caused by friction materials, a low pedal will be hydraulic related.
You're having trouble shifting because the clutch isn't fully disengaging, it's really best not to force it.

Top up the reservoir religiously as you're bleeding.
Once you start to get a decent pedal, remember to check for leaks at all the connections, just to be sure.
BB

[gushaman]

I hope you are right about just air in the line. I havent removed the pass seat and access panel because i have most of the dash right there. I wonder if toyodiy has a clutch hydraulic line diagram I'm gonna look now.

[Burntboot]

Not even the factory manual has a detailed diagram of where the lines run.
Mostly you want to check anything you have already disturbed (connections at master and slave)

The only other part you'll want to inspect for leaks would be that mysterious junction block through the body structure.
Probably be easier to trace back from the slave end to find the point where it passes through the sheet metal.

As far as adjusting the "linkage" goes, from CL-3 of the manual =>

Pedal height (from asphalt sheet to top of pedal pad) - 6.73-7.13in (171-181mm)
Pedal freeplay - 0.20-0.59in (5-15mm)
Push rod play at pedal 0.04-0.20in (1-5mm)

Lastly, are you reusing the fluid that you bleed out?
I have been burned before, dumping freshly bled fluid back into the reservoir.

All that bleeding activity can force air into the fluid, which you just reintroduced back into the system your trying to get it out of.
You can let it settle out on the bench but it has to be kept clean and airtight, I find it easier just to use fresh stuff all the time and ignore the extra cost.

from the very last line of page CL-3

"Note- do not reuse the fluid that was bled, it contains air"
Always nice when the manual agrees with actual experience!

BB

[saucymonkey]

I too am having major headaches just trying to do what should be a simple clutch line bleed. This project started when my reservoir went dry from a leaking wheel cylinder. I replaced that and got my brakes bled but the clutch is not pumping at all. I tried gravity bleeding for a few days but no change. I removed the line from the master to bench bleed it in place but obviously fluid started gushing out when I took it off so I just put it back on immediately. I don't really understand the concept of bench bleeding I must confess. I got a Mityvac and put it to use today. At first I thought it was working because when I opened the slve cylinder bleeder valve and started squeezing the handle all this air and fluid started gushing through the tube, but after filling the vacuum cup a half dozen times like this I realized I was just wasting fluid. I suspect I have an air leak but is it possible to leak air somewhere and not fluid. I checked the lines and they seem dry. I should add that I have van level with all 4 wheels off the ground. Please help if you have suggestions on what to try next because I'm out of ideas.

[gushaman]

When i did my clutch slave, the master started leaking. It took forever pumping it. I got a vacuum bleeder. But you really need to bench bleed it
Ot sucks taking it all back out and losing the fluid, and sometimes you can finagle doing it on the van, if you dont mind ruining your carpet with brake fluid. Or just put a pan or bunch of towels.

Basically you want to know that the master is full of fluid, so it doesnt take 500million brake pedal pumps

[gushaman]

By the way, it will still take 250million pedal pumps

[saucymonkey]

Update: I think i got it, I "bench bled" the clutch master cylinder on the vehicle. Not sure what I did or why it worked but I decided I didn't care that I was going to get brake fluid everywhere and just went for it. I gave it a few pedal strokes and fluid sprayed past my finger and then I quickly put the line back on. I think there may still be some air in the system but the clutch is working again. Unfortunately I have no one to pump the pedal for me to try to get the rest of the air out so I'll just have to wait until I do.

[Ian R.]

Not sure if this is your problem. But, Make sure the res is full to the tip top. Like ,after every time you open the bleeder valve. There are seperate reservoirs within the reservoir itself. One for clutch and one for brake.. So you can drain out the clutch res while the brake reservoir looks full.
Don't be fouled! I have spent 30 minutes pumping and bleeding. Haha

[pinkgrips236]

In keeping with the clutch bleeding theme, I'm having tangentially related issues.

I'm nearing the end of a 5speed swap that included making a new clutch line from the clutch master, through the floor, to a union underneath. I had a few issues getting (what I thought) was a decent double flare on copper tube, but I think I got close. Installed my new copper line, and definitely cross threaded the tube nut going into the clutch master.

I'm not having too much luck finding M12 x 1 double flare fittings for 1/4 tube. It looks like a few of the auto stores have them for 3/16 tube, but not 1/4. So, anyone have any leads on M12 x 1 fittings? Or, if I ran with the 3/16 tube instead, would I still get enough movement to push the clutch fork?

[Burntboot]

In my world copper tube and cars never. ever go together.

Copper can become work hardened very easily, far more importantly though, it has a tendency to crack, especially when doing things like a double flair.
Steel line is the way to go and the stuff that has a copper-like coating (I forget the trade name) is the best bet as it bends easily, resists kinking and flares well.

As for metric fittings, they can be very hard to find.
-While it seems incredibly wasteful, I have been known to go out and purchase a short pre-made metric brake-line and harvest the new fittings for the line I am making.
Or if you can get a pre-made line close to the length you need....
The other option would be a fastener or hydraulics store that does a lot of Metric stuff or an assortment from your local jobber?

[pinkgrips236]

I used the Copper Nickel e-z bend line sold at the auto parts store. My first couple attempts at flaring didn't go too well as I cranked the tool to high hell and split the tubing. After backing off a bit, I was able to get some decent looking crack-free flares, but definitely not as good looking as factory.

I also jumped around to all the parts stores yesterday with almost no success finding an M12 x 1 inverted flare fitting. Finally, one of the guys just brought me into the back and let me look through all the fittings. The M12 x 1 bubble fittings looked almost identical to the original fitting. So I guess the actual fitting isn't too big of a concern as long as you're not trying to put a bubble flare on a tube to an inverted flare on the clutch master.

I'm still a little wary of the copper, and I'll probably try to have some local hydraulic place make me a new section of line, but I'll leave the copper in there for now.

[Burntboot]

If its the CN ez-bend then your fine, no need to swap out.
The flair you have made should be fine, as long as it doesn't leak.
When doing brake lines I always aim for as near perfection as I can attain but on a clutch line I wouldn't give it a second though.