Clutch Master Cylinder Replacement

[ZombieResponseUnit]

I agree, It does seem like I still have air in the system. I have only ever gravity bled clutches, just put a new master on the 4-runner w/o any trouble (I don't have a vacuum pump). I've replaced both the slave/master, but not the lines. I agree they are very rough looking, but no signs of leaks or loss of fluid. It worked fine when I got the truck, but the cold temps of WV seem to have added air/froze and busted the slave. I'm really wondering if the slave/master are H specific. SOR.com list them separately, but I found the cheapest Aisin online and it looked exactly like what I took off.

 

[ZombieResponseUnit]

I might try replacing the flex line. I know outer appearances can be deceptive.

 

[dirtycruiser00]

Does the HJ have a hard line from the master to the firewall then a flexible hose from there to the slave? Thats how my 73 FJ40 is and I found that a brake hose from a toyota pickup is very close to the clutch hose on my fj40 I will know today I am goin gto pick up the new hose or like some have said you can hve a new hose made locally if thats an option

 

[mjanderle]

I've always been a fan of the back-bleed myself. Here is a vid of a guy doing it on his 325i, but the principle is the same. I used a big syringe when I did mine :

 

[ludwig]

Really shouldnt make a difference because its a closed system. Sounds like you still have air in the system or a leak. so you replaced both slave and master? did you replace the lines also?

10/4 the lines. Always replace the lines when replacing everything else in the system. Lines are famous for stress/fatigue that never shows its ugly face.

 

[sggoat]

Not sure how the hose(s) could be leaking(taking in air) and causing this as they are always under pressure--if not from pushing the clutch, at least from atmospheric and gravity--you would see a fluid leak if so. Agree this may still be air in the lines(master), and may not be completely bled.
Could there be a small leak on the master that is taking in air when you let off the clutch?

 

[dirtycruiser00]

ok I got my clutch master/slave and lines installed tonight. Craked the bleeder and closed it. Whola! instant pressure no hassle working perfect and no leaks. For those that are curious here is the replacement for the line and hose from Oreilly's

1. Hard line from Master to firewall (used an off the shelf "Japanese" 12" line from Oreilly's) I put two bends in it to get over to the firewall. Do not
bend 90 dgree angles they are about a 60 degree angle

2. Black Flexible Hose from firewall to slave cylinder (used oreilly's part # BH27301) This is a rear brake hose for a 1978 Toyota Pickup.
you can look it up on thier website. The only modification needed was I had to slightly reem the hole larger in the firewall tab so that the
new hose could be placed through tab and clipped. ***Note*** keep your old clip as the new hose does not come with one. Also I used a little
black gasket maker on the threads of the hose going into the slave cylinder. I probably didn't need to but I did anyway.

Overall Cost for line and hose $28 I know I could have done one continuous line and had it made for the same price but I wanted to keep the OEM look to the lines.

 

[ZombieResponseUnit]

Wish I had seen this before I got #H380538 flex hose from Advance for $27.99. It fits, but did not change my pumping issues at all. I noticed that there was play betewn the slave and the fork/leaver. the rod was adjusted all the way out, but the slave had to extend ~1/2" before it pushed the fork. I fabricated a new rod out of some all-thread to tighten that up. Bingo, that was all the problum was all a long. Why this suddenly came about, and how I drove for over a year like that, I don't know.

 

[taro]

Fyi-when I replaced my slave cylinder with an aftermarket one, I had to use my original rod to make it work.

 

[Fast Eddy]

You just need to adjust the clutch. The slave rod is having to travel more than one push to reach the clutch arm. If you adjust the nut properly, it will work.

 

[Rainman]

In my experience, gravity bleed takes a lot more time but is practically fool proof. In both cases, put a rubber tube the fits snugly on the bleeder valve. Place the other end in a small jar with brake fluid in it to cover up the bottom of the tube. Open up the valve and let the system drain into the bottle. Make sure the reservoir is maintaining fluid. For the brake system, the same principle works just put a rubber line on all four corner's bleeders and all into one or more bottles with fluid. Just sit and watch the fluid levels and drink a beer. Two if the first one goes down too fast.

Done. No air in the lines.

 

[Fast Eddy]

Air in the lines won't cause it to need to be pumped up, nor will pumping it up fix air in the lines.

Air in the lines will cause it to be squishy or soft. It may or may not engage the clutch. Pushing the pedal twice will not have any different effect than pushing the pedal twice.

Needing to push twice to pump it up is in indication that the amount of fluid pushed by the master is not enough to push the slave rod out of the slave cylinder far enough to engage the clutch or brakes if that's what we were talking about.

 

[sggoat]

FE is exactly correct. If you move 2 ccs of fluid with the master, it will move 2 ccs of fluid in the slave; the relative physical movement of the slave vs MC depends only on the size of the bores of each. The relative smaller bore of the slave should move it's piston more than the distance the MC piston moved.

 

[ZombieResponseUnit]

I believe the rod I had was factory (it may have been the last thing on the truck) There just wasn't much adjustment. It was already maxed out. I had to do the same thing on my Ford Diesel.