Well today I installed my new clutch slave cylinder on my '75 Datsun 280z and when I went to bleed it, fluid got past the piston and cause the rubber piece to swell up and shoot the push rod out. Then fluid went EVERYWHERE when the rubber piece bursted. What would cause this to happen? I've already ordered a new slave cylinder because I have a lifetime warantee on it.
My first thought is that the rod was unable to move for some reason.
On my 4-Runner the piston froze in the bore. If there's that much rust in there, I assume there's enough rust and pitting to allow blowby.
Dan
Define NEW.
It's brand new from Advance Auto parts.
I was told that the seal around the piston probably didn't seal and that's what caused it to leak fluid profusely.
True. Bad rebuild or the rebuilder bore it too big. All moot because you're getting another one anyway.
Yup I'll fill everyone in when I get the newer one installed.
Once again the same thing has happened. I'm starting to think that it has something to do with the clutch line/master cylinder. I'm all out of ideas now, do you guys have any idea?
Are you applying pressure before connecting it to the release lever ? Seems as if there would be some sort of stop but then again it could be just like a wheel cylinder. Don't apply pressure if the shoes are not installed.
I'm talking about the slave cylinder on the transmission, not the brakes.
Right, but I think iceracer's point is to check and make sure that you're not actually spitting the piston out the end of the slave cylinder with nothing to retain it, as can happen with some wheel slave cylinders; very similar systems.
Are you applying pressure before hooking up the linkage?
Is it for certain the correct fitment? (Wondering whether the wrong fitment could spit the piston out before even engaging the linkage).
Seems like one of two things must be happening:
Bad rebuilds, repeatedly, such that the fluid's going right around the piston. Or...
Something's not installed correctly and you're driving the piston out the end of the slave cylinder.
In your initial post, you mention the pushrod getting spit out of the rubber gator/accordion/cover, which is pretty odd. Did the piston itself stay in the slave cylinder body, or did it wind up being spit out, following the pushrod out into the gator?
It stayed inside the rubber piece but I do have a feeling there needs to be something to keep the piston inside. I hooked up the cylinder and proceeded to bleed the slave cylinder.
In reply to turboHLS30:
The piston stayed inside the rubber gator, but was it spit out of the metal slave cylinder body? If so, it sounds like either the slave cylinder is incorrect, the pushrod is incorrect, or the clutch linkage is off its rocker, so to speak. Like the pushrod isn't being pushed back after each pump.
I'm still puzzled that the piston isn't retained somehow.
If this is blowing apart during the bleeding process, we could probably use a careful, step-by-step explanation of the specific bleed process you are using.
I didn't do any prior preparation to the slave cylinder, I just bolted it up and put fluid in the resevoir. I had the helper pump the clutch pedal 10 times and then hold it down. Then I would open up the bleeder screw and drain, then repeat. I did that about 5 times and then that's when it shot the stud out.
It sounds like the "stud" is too short. The rubber gasket gets stretched to where it burst, shooting the stud out. Are you sure this is the correct slave?? It sounds like it's for a different vehicle, or there was a running change in the cylinder you're not aware of. By any chance do you have the OE, or one you took off so you can measure the rod's length?
By any chance is this part of a complete clutch replacement, including the throwout bearing ?
OR somehow you are creating a HUGE amount of pressure in the slave cylinder, blowing it apart internally.
Well, I still think you have a linkage problem (for serious; is the helper feeling the force of depressing the clutch?), but I would see about doing the version of the bleed where the helper doesn't pre-pump.
You open the valve and say "down" and he depresses the pedal (smoothly). You close the valve and say "up" and he lets the pedal up (smoothly).
Do this all smoothly and slowly. If you see the pushrod extendeing, tell your helper to slow down on the rate of pedal depression. If you're down there paying attention, you should be able to see what's going wrong with the linkage (and stop your helper before you spit out another piston).
Sure the pressure plate or slave isn't frozen?
+5 for what Ransom says; that's the normally accepted way of bleeding when that car was built. (Yes, I know about pressure bleeders, pumps, ....., but in this case, following this proceedure would go a long way to determining what's going on. Has your helper ever done this before? If not, tell them to follow that procedure. Stomping on the pedal like it's the brake pedal is NOT the way to bleed the cylinder.
I've seen pistons retained in master cylinders but not ever slaves, not that they aren't in some apps, I'm sure. I would think the pedal hitting the floor is the stop. Not sure what the "stud" is. Do you mean the piston?
As others have said, if the piston is being pushed out far enough for fluid to leak out the problem is not with the cylinder. The push rod is too short or the linkage is not working properly.
How old is the clutch plate and disk? The disk might be worn paper thin and alowing the slave cyls piston/push rod to "hyper-extend" out side of its normal operating range causing the piston to come out of the cyl bore. Also, make shure the clutch fork is properly seated on the T/O bearing and that its not bent. what is the reason for the slave cyl replcement in the firs place? If it was because of a leak, that leak may have been a symptom of the problem that you are dealing with now. OTOH, some times aftermarket parts just don't fit, maybe you should make a trip to the local Datsun dealer(nissan still carries nearly all the mechanical parts for these)
Post a picture. Sounds like either the wrong part or the fork is not engaged somehow.
Ok here's the problem, my clutch fork is supposed to look like this
Instead of having the little indent in the fork for the pushrod, mine has a hole. So I'm thinking someone swapped the tranny before I came in possesion of this motor/trans.
Is the pushrod even moving the fork then?? Sounds like the pushrod is going through the hole, at least after some force is applied.
You need to keep the pushrod in the same location, relative to the fork. If the rod is not threaded and you don't have welding skills, drill a hole in the pushrod right before the fork, slip a large washer on there and use the hole to put a circlip in to keep the washer from moving. This should keep the pushrod from pushing through the hole for a few pumps.
Keep in mind, this fix is just a diagnostic tool to determine if the problem is the pushrod moving too far, ie, through the fork.
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