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 :wnk:. 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.

[AnotherUser]

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.



What all do you have to remove to gain access to the clutch master cylinder? Why would the whole dash come off to access the part that's just below and to the left of the steering wheel?

[Flecker]

What all do you have to remove to gain access to the clutch master cylinder? Why would the whole dash come off to access the part that's just below and to the left of the steering wheel?


:rol:

You'll know why when you do it man... it's a tight spot. At the bare minimum you will have t take out the gauge cluster and the surround to access it more easily. Theres air ducting to remove also... it's just plain easier to remove the whole dash, unless you curse like a sailor (you will anyways with the dash off too)…


Best video I have seen is Amorell's youtube vid.

https://www.youtube.com/watch?v=nYmHK_KdiF8

[AnotherUser]

:rol:

You'll know why when you do it man... it's a tight spot. At the bare minimum you will have t take out the gauge cluster and the surround to access it more easily. Theres air ducting to remove also... it's just plain easier to remove the whole dash, unless you curse like a sailor (you will anyways with the dash off too)…



Were you able to do it by just removing the gauge cluster, or did you end up having to remove the entire dash like in the video?

[Flecker]

Were you able to do it by just removing the gauge cluster, or did you end up having to remove the entire dash like in the video?

I was going through the whole thing after it sat for a coupl years and pulled it in the garage. I already had the entire dash ripped apart and it made it far easier, I know that much. Looking at where it sits, theres literally stuff over the top of it that would make it really tough to get at otherwise.

Pic for reference.

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[Burntboot]

It's been forever since I was in there, but I did not pull the entire dash.
Cluster for sure, can't remember if the side panel at the filler neck comes off then or not, but you'll see once you dive in.
Its mostly about taking your time and don't get frustrated,
(oh and have a bucket ready, for the inevitable spills.)

[Flecker]

don't get frustrated


:rol:

[toyotatimemachine]

Has anyone tried a reverse bleed using an oil can pump to force air up and out?:wave2:

[Burntboot]

I cannot imagine why anyone would want to do such a thing, perhaps I am missing something???

[boogieman]

ive done it before on motos with difficult to bleed brake systems..where air pockets could develop and you could run a whole quart of brake fluid thru a system and not get it to bleed..you do run the risk of pushing contaminants up into the master and smaller orifices..the vans clutch system has never been hard to bleed so i wouldnt see the need..

[oldvanguy]

i have a slow leak in my hydraulic brake and/or clutch system. is does not (yet) affect braking or gear selecting/changing. is there any chance that it's just the plastic reservoir leaking? the leak is indicated by just a small amount of fluid running down onto the floor mat on the clutch pedal side. when the fluid reservoir runs down to just above minimum, the brake warning light comes on when going around corners or when accelerating/braking and i am also notice that my cruise control only works intermittently (mostly not). when i top up the reservoir, the issue resolves (except the leaking on the floor mat. upon reviewing threads here on TVT, i realize that it will require the removal of the entire dashboard - especially if i want to lubricate the heat/ventilation control cable "spyder" (which i need to do). if i'm going in there, should i just figure on replacing both the brake and clutch master cylinders (the van has 277k miles on it)? how far in will i have to go to positively visually identify which master cylinder is leaking? any/all responses are appreciated.

[boogieman]

you dont have to remove the 'whole' dash, just the cluster hood and instrument cluster itself..pretty easy actually once youve done it..theres multiple threads on this i believe. id probably just do both while your there...also while the cluster is out i recommend checking the speed sensor built into speedo, its one of the components of the cruise control...

[vanwagoncowboy]

I just replaced my clutch cylinder last week and decided to go ahead and replace my brake master cylinder since it was the original and my van has 215k on it. I also decided to do my brake master cylinder for a couple other reasons as well;

a)The biggest chore is the dash removal and re-assembly. I already had to do it once to clean my climate spider and replace the heater blower motor so the following week when I had to do it again for the clutch I broke down and added a brake master cylinder to my rockauto purchase.

b) There is a youtube video by fellow member Aaron under his Grae Skye studio handle that documents the clutch and brake master cylinder swap and in it he does both clutch and brake and if you do the same it makes it extremely easy to follow along.

I may have interpreted this part wrong because I do not have a facebook account where the discussion took place but in the comments of Aaron's video, there is mention of not needing to bench bleed the clutch cylinder after the brake master if you did not depress the cylinder at all while handling. I went with this advice because I like taking unnecessary risks to save a couple minutes and it actually worked fine.

Also I was fiddling with the hairpin cotter pin that attaches the clutch cylinder to the clutch pedal in the dark on a dirt driveway and lost it to the abyss. I ended up going to auto zone and buying an assorted pack of them and used one that looked the right size. In hindsight, it had taken me a half hour to try and get the rusty old cotter pin back into the slot and I was getting pretty frustrated. The new one took a few minutes of finessing but as soon it was lined up it locked in pretty fast and made that step much easier than others have expressed.

[Burntboot]

Well, not bench bleeding the master prior to install will indeed save you like 5 or even 10 mins!

But here's the rub.
When a master is built (or rebuilt) there will be air trapped in the assembly, bench bleeding will get all that out so that when you install the part you're not trying to get all those little air bubbles out and all the way to the slave.
It is actually WAY quicker to waste those first few minutes in the vice.

Today's reality is that most masters are going to be rebuilt units, by a person getting paid by the part, not the hour.
Needless to say, rebuilds are not always 100%

Bench bleeding will identify a bad rebuild, BEFORE it gets installed.
Installing a bad master will cause hours and hours of frustration.
YMMV

[HappyCamper]

I just replaced my clutch and brake master cylinders last week. As mentioned above, unless you're a yoga master, you have much better view and access to clutch and brake master cylinders if you remove the instrument cluster unit. You may not need to remove the whole dash. I did and paid huge price to unscrew/putting back all screws. I ended up with 4 screws still left in my part dish :dizzy:

Removal of the cluster is straightforward, after removing steering column covers/shroud, just few screws holding the cluster to dash (I have a CM65 frame '94 Liteace). Unhook speedo cable, and few electrical connectors behind the cluster and pull the cluster out. In my case, I had to remove four bolts holding the dash to the frame in order to give some wriggle room for the brake master cylinder to be pulled out.

If you see brake fluid puddle next to clutch pedal, you may have leaks at the hose connector from the reservoir. Tube is connected with spring clamp. Good luck!

[oldvanguy]

thanks for your response to my post. you mention in the last line that i may have leaks at the hose connector from the reservoir - as i do have a small leak showing on the floor mat beneath the clutch pedal pivot. is it possible that i do not in fact need to replace my clutch & brake master cylinders? from what i can see (which isn't much!) i would still have to remove the cluster above the steering wheel to even visualize the reservoir connection. is it possible that the hose spring clamp is the only thing needing attention and that the plastic reservoir is not cracked?does anyone know where i might find a close-up photo of the reservoir/tubes/cylinder connection assembly? thanks again for any/all responses. (and may everyone have a happy solstice week!)

[timsrv]

Here's a couple of helpful threads:

https://www.toyotavantech.com/forum/showthread.php?63-How-to-Remove-the-Dashboard

https://www.toyotavantech.com/forum/showthread.php?1550-Installing-a-New-Brake-Master-Cylinder

These are automatic vans (no clutch master), but you get the idea. Clutch and brakes use the same reservoir, so if yours is a manual, the clutch master and the extra supply tubes would be up under there too. Tim

[HappyCamper]

Before you open up the dash/instrument cluster, I would crawl under the steering wheel section and tried to touch and feel any signs of leaks near the connections. There are two connectors in clutch master cylinder: one coming from the fluid reservoir, which is spring clamped, and the other is the clutch line going to slave cylinder, which is connected with a flair nut. Since you have puddles on the clutch pivot area, I suspect it is the case. How is your clutch working? If the master cylinder leaks, you would have tough time to shift. If the leak is at the fluid supply line, you'd probably don't have any issues with shifting.

If the brake master cylinder is leaking, you'll see puddles near brake pedal. Please see if any leak signs on brake booster drum. Mine was bad so I had to replace the brake master cylinder. Reservoir is at near door opening so it would not leak to near the clutch pedal.

Here is the picture of hoses going to clutch master cylinder (left) and brake master cylinder (right side). My van is RHD so brake fluid reservoir is on the right side of the image.

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