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Discussion Starter · #1 ·
I tried many ways to find the answer to my question, but I failed to locate one. I believe I had asked a similar question a while back, but I have no luck finding it.

I replaced my clutch slave cylinder on my 85 Spider. I let the fluid gravity drip for a few minutes from the slave cylinder bleeder. Then I had an assistant push the clutch pedal down and hold it while I opened the bleeder. Then I closed it and my assistant let the pedal return (which it did fine). We did that many times but I am noticing when he holds the pedal down, the clutch fork slowly pushes the slave cylinder rod back into the slave cylinder. This is while the bleeder is still closed, before I open it to bleed it. I do not see any drips or leaks anywhere.

The question: is the slave cylinder supposed to do that until I bleed all the air out, or am I having an issue I need to contend with before I spend the day (and a 12 pack) under the car trying to bleed it for no reason?

I ask a lot on here, and I truly appreciate the help. I will be under the cat finishing off the beer while I await for responses..haha.
 

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you are doing this the wrong way. Follow these steps
1. Orient the slave so that the bleeder is topmost
2. Get your assistant in the car, a 7mm box wrench on the bleeder, and a piece of hose on the bleeder
3. tell the assistant 'down' and open the bleeder simultaneously, have assistant push down, taking about 3-4 seconds to go completely to the floor. Upon reaching the floor, assistant yells 'DOWN" and holds it there. When you hear DOWN you tighten the bleeder
4. You yell 'UP' (bleeder is closed) and assistant lets pedal up and assistant yells UP when its all the way up
5. You yell DOWN and simultaneouly open the bleeder, and close it when assistant yells DOWN (the pedal to the floor)
lather, rinse, repeat
make sure you dont run low on fluid in the reservoir !!!
 
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No, it should not be doing that. Either there is a seal not holding pressure or there is still air in the system. The rubber boot at the slave can hold quite a bit of fluid if the slave's seal is leaking. Peek inside there. It should be 99% dry. If the seal at the master is leaking fluid can go right back to the reservoir so you may not see an external leak.

It is often difficult to fill the system. When you fill the master cylinder and try to bleed it out the slave* you're trying to push air down - the opposite of what it naturally wants to do. To fill the system I use a 60 ml syringe filled with brake fluid and attach it to the bleed screw with a short length of hose. Open the bleeder and use the syringe to push fluid (and thus air) up to the master cylinder. Be sure there is room in the reservoir for this fluid - spilled brake fluid will adversely affect painted surfaces. Once thus filled a few pedal strokes will get the last bits of trapped air out.

* note that the bleed screw should be positioned uppermost "12 O'clock". The slave can rotate in its mount so check it is where it belongs.
 

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Discussion Starter · #4 ·
you are doing this the wrong way. Follow these steps
1. Orient the slave so that the bleeder is topmost
2. Get your assistant in the car, a 7mm box wrench on the bleeder, and a piece of hose on the bleeder
3. tell the assistant 'down' and open the bleeder simultaneously, have assistant push down, taking about 3-4 seconds to go completely to the floor. Upon reaching the floor, assistant yells 'DOWN" and holds it there. When you hear DOWN you tighten the bleeder
4. You yell 'UP' (bleeder is closed) and assistant lets pedal up and assistant yells UP when its all the way up
5. You yell DOWN and simultaneouly open the bleeder, and close it when assistant yells DOWN (the pedal to the floor)
lather, rinse, repeat
I apologize if I wrote my message incorrectly. Your steps is the way we were doing it. I was wondering why the clutch fork slowly pushes the slave cylinder rod back into the slave cylinder while the clutch pedal is held to the floor? I get fluid out of the bleeder while the assistant is pressing the clutch pedal, but if he just presses the clutch pedal and holds it while the bleeder is closed, the fork pushes the slave cylinder rod back in. Is this normal until the air is bled out or is this a separate issue? Thank you for the quick response by the way.
 

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no, this is not normal. Sounds like you have a failing master cylinder or leaking slave. Is there fluid collecting in the boot, or leaking out anywhere?
 

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Discussion Starter · #6 ·
no, this is not normal. Sounds like you have a failing master cylinder or leaking slave. Is there fluid collecting in the boot, or leaking out anywhere?
I do not see any fluid under the boot on the slave cylinder. Could it be just air still in the system? I forgot to mention when I started this replacement of a brand new slave cylinder, the master cylinder was bone dry. I filled it and loosed the slave cylinder bleeder a little to let it gravity bleed a little before we started bleeding it together. It dripped fine out of the bleeder.
 

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After half a dozen pedal cycles, there should be no air left in the system. I suspect the master has gone, when they dry out the seals can get displaced / leaky. I always avoid allowing the master to go dry. You could removing the master, bench bleed it (do a search for that) and try again.
 

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Bad m/c's don't aways leak fluid. the seals get worn inside and the fluid will leak past them when under pressure.
 
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Air is compressible, the fluid is not, so you may be seeing the compression of air bubbles still hanging around in your tubing and hose line. I suggest before you go after the master cylinder, try progressive bleeding starting AT the master cylinder outlet fitting. Then work your way down to the hose fitting there on the crossmember, and finally, to the slave cylinder bleed fitting (oriented at the 12:00 position). Don't let the master run dry!
Put shop rags under the master cylinder, and around the fitting to catch any fluid that spews out. Have your assistant pump the pedal several times, and hold it to the floor. Then just barely crack open the fitting at the master cylinder, and you will likely see air spew out with fluid. Then snug up the fitting again. Repeat the pedal pumping as before and check for air. Do this until air no longer escapes. Retighten your fitting.
Then, go under the car to the hose fitting on the crossmember, that connects to the steel tubing. This connection can often be difficult to break, so I suggest using flare nut wrenches so you don't round off the hex. A bit of penetrating oil always helps, too. Do the same process at this connection you did at the master cylinder, to remove any trapped air. Finally, bleed at the slave cylinder bleed fitting as described previously. Safety glasses will keep brake fluid out of your eyes! Believe me-- it stings.
Don't be discouraged-- you're not the only one who sometimes has this problem bleeding the clutch hydraulics!
 

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Discussion Starter · #10 ·
I did the reverse bleeding on the slave cylinder. I used a 60ml syringe with a hose connected to the slave bleeder. I cracked open the bleeder and pushed fluid up into the master, which it seemed to do fine. I pushed almost all of it up until the syringe was almost empty. Then we bled it many times with the assistant on the pedal and me opening and closing the bleeder. I never got any spray of fluid out of the bleeder, just steady drips or a slow stream if I open the bleeder more. The slave doesn't come back by itself very well or even at all sometimes. The assistant has to pump the clutch a few times for it to come back out to where it sits tightly back on the fork.
The fork barely moves while the assistant pumps the clutch. Not really enough to even measure it.

We tried the bleeding process by starting from the master then where the hard line connects to the braided line. When we bled there, a nice steady stream came out. We know fluid will come out the braided line where it attaches to the slave because before we did all these steps, we wanted to clear all the old fluid out due to what looked like water mixed into the fluid (the white goo type stuff). When we pumped the fluid out, it all sprayed out fine from the braided line where it would normally been attached to the cylinder. Then we did all those other steps.

We also looked in the bell housing with a lighted flex camera we rented from a local parts store. From what we could tell, it all seemed attached in there. But I can easily move the fork around in the bell housing. Front to back, up.and down, and even pushed in out some. Then when the assistant pumps the clutch a few times, the rod extends out causing the fork to then be tight.. But the fork seems attached from what I can tell. I wanted to add a video of me moving through fork around so easily, but I can't seem to figure out how to format it to attach it here.

Any thoughts or suggestions is more than appreciated. I know you guys have been a tremendous help already, and I wish I had a way to share a few beers or do something besides saying just thank you.

This all started because I wanted to take a drive (at that time it had been driven often with no issues). I put it in reverse with no issue but when I put it in 1st, it jerked hard and died. From then on it would lurch as soon as I barely let off the clutch, no matter what gear I tried. Then it would immediately die to the quick learch. I can't start it and switch it into any gear. That was only if I started it while in gear.

Thank you to everyone again. I really just want to drive the car and show my dad (God rest his sole) that I am fixing it up for him. Stressed but have faith. Sorry for the long text. I just wanted to get it all out..
 

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If you haven’t changed the slave hose, do that and try again. Otherwise you have a bad master cylinder and you need to replace it.
 
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I know when I did my slave cylinder I had a heck of a time getting the air out. I tried everything and ended up pulling it part way out of the mount so I could push the piston in all the way. With it assembled I couldn't push the piston in far enough to clear the air pocket.

Good luck and I know what you mean, my dad bought my '85 Spider when it was new and he's with me every time I drive it (and occasionally when I'm wrenching).
 

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Discussion Starter · #13 ·
If you haven’t changed the slave hose, do that and try again. Otherwise you have a bad master cylinder and you need to replace it.
I replaced the slave hose a couple years ago with a braided one. I know when I press on the clutch with the slave hose disconnected from the slave cylinder, brake fluid shoots out. Can my master cylinder still be an issue even so? Thank you again.
 

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Discussion Starter · #14 ·
I know when I did my slave cylinder I had a heck of a time getting the air out. I tried everything and ended up pulling it part way out of the mount so I could push the piston in all the way. With it assembled I couldn't push the piston in far enough to clear the air pocket.

Good luck and I know what you mean, my dad bought my '85 Spider when it was new and he's with me every time I drive it (and occasionally when I'm wrenching).
I will try that. Thank you for the advice. I happy to hear you have your father with you on your drives. Mine is waiting for that ride with me driving.
 

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Yes, the hose can still be an issue since when you remove the slave, there is no backpressure at all. I think its unlikely, but possible that the hose can be at fault. I would suggest you replace the master and the hose, and rebleed everything. This will set you up for years of trouble-free clutching, and the master isnt terribly expensive either == about 100 bucks +/-.

The way I bleed the clutch hydraulics is as follows
1. Fill up the master
2. Remove the slave from the bellhouse
3. Hold the slave plunger way back in the slave, and tilt the slave so that the bleed nipple is pointing at the roof, so that any air will be at the base of the bleed nipple
4. Holding the plunger back with my left thumb, and the slave in my left hand, loosen the bleed nipple and have someone gently press the clutch pedal. Any air should be pushed up and out
5. Tighten bleed nipple; put slave back in bellhouse with antiseize on it. and install c-clips to secure

That is the method that for me, works the fastest, and eliminates multiple attempts!
 
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Goats makes the good point-- just because the master cylinder will squirt fluid out of the hose, doesn't mean it seals well enough internally to develop the pressure needed to stroke the clutch arm. And BTW that slave cylinder pushrod only moves about 1/2" to disengage the clutch.
 

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See post #8.

If you push the pedal halfway and hold it there. You will slowly feel the pedal pressure drop. This means the master cylinder is going bad.
 
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Discussion Starter · #18 ·
If you haven’t changed the slave hose, do that and try again. Otherwise you have a bad master cylinder and you need to replace it.
Could this problem be my pivot arm? I disconnected the clutch arm from the pivot arm by way of the cotter pin. I then removed enough stuff to easily pull the brake box away from the firewall. If my pivot arm is broken, would it just come out without having to remove the tapered pivot arm pin? Is there a way of knowing if the pivot arm is broken before I go through the process of removing the tapered pin? Before I did all this, my clutch pedal was higher than my brake pedal. From what I read on here, the pivot arm most likely isn't the cause of my problem. But since I removed the clutch master cylinder to replace it along with the flex hose, I thought maybe I should check the pivot arm just in case. I just do not want to remove the arm if i am able to see if it's broken or the cause of my problem.

Just seems strange the clutch did what it did all of the sudden. Like something broke or came apart. The clutch seemed to be working fine right before the bad lurch when I let go of the clutch pedal.

Thanks you once again.
 

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could be. Have someone press the clutch while you watch the pivot arm --with the hydraulics all in place. pivot arm should move about 3/4 towards the clutch master. When the pivot arm weld breaks, pressing the clutch doesnt correspond to pivot arm movement.
 

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Discussion Starter · #20 ·
could be. Have someone press the clutch while you watch the pivot arm --with the hydraulics all in place. pivot arm should move about 3/4 towards the clutch master. When the pivot arm weld breaks, pressing the clutch doesnt correspond to pivot arm movement.
Ok. Thanks. My clutch pedal has never been below my brake pedal. In fact, my clutch pedal sits just a bit above my brake pedal. And the clutch pedal always comes back up on its own. I will check out what you said, but I'm going to order the clutch master cylinder and flex line before putting it back together to check that out.

Besides Centerline, is there a recommendation on where to buy the clutch master cylinder and flex line? I am hoping to order them and get them failry quickly. I would love to show my dad I have it on the road. Thank you. Extremely awesome peeps on here.
 
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