Slave Cylinder Question

mthomas58 · 05-12-2009, 11:36 AM

Just comleted an engine drop (my first!), swap and re-install this weekend!

Failed to re-install the slave prior to bolting up the engine and tranny mounts so I had to do it the hard way. Question is the slave push rod was fully extended and I had a hell of a time getting it on. I could not get it to collapse not matter how I tried it would immediatley fully extend. What did I do wrong or is that normal? I had to use a small prybar to push slave on far enough to catch a couple of threads on the lower bolt. I tried bleeding off some fuid which only served to allow some air to enter the line.......hence no clutch and could not test drive the new engine after start-up.....(the horror!) I tried bleeding off a little fluid but succeeded only in sucking some air into the line and now I need to bleed the line. I can hardly wait!

The slave is good (replaced 2 years ago).

rnln · 05-12-2009, 03:40 PM

when I installed my, engine in the car, the system was empty and I still had very hard to time push it in. Becareful, it's very easy to miss the track, push rod went out of the little spot.

mthomas58 · 05-12-2009, 08:52 PM

Quote:

Originally Posted by mthomas58

Just comleted an engine drop (my first!), swap and re-install this weekend!

Failed to re-install the slave prior to bolting up the engine and tranny mounts so I had to do it the hard way. Question is the slave push rod was fully extended and I had a hell of a time getting it on. I could not get it to collapse not matter how I tried it would immediatley fully extend. What did I do wrong or is that normal? I had to use a small prybar to push slave on far enough to catch a couple of threads on the lower bolt. I tried bleeding off some fuid which only served to allow some air to enter the line.......hence no clutch and could not test drive the new engine after start-up.....(the horror!) I tried bleeding off a little fluid but succeeded only in sucking some air into the line and now I need to bleed the line. I can hardly wait!

The slave is good (replaced 2 years ago).

Well, maybe the slave is not so good after all. Bled it twice tonight and still no love. At one point last night the slave was out and my helper pushed the pedal which blew the boot and retaining spring off......this may have damaged it. Tomorrow I'm going to pick up a new slave. Before installing the new one I'll try the old one one last time by disconnecting the line, intalling the slave and they re-attaching the line and bleeding. If this doesn't work, I'll try the new one.

I think my mistake was trying to intstall a pressurized & fully extended slave push rod. I think the rod was properly insterted into the clutch fork but the visibility is so poor, I can't be sure.

KTL · 05-12-2009, 10:48 PM

You did nothing wrong trying to install the slave atop the trans in its fully extended position. You just have to use some muscle and shove the slave into it's mounting point so you can get a nut started.

As you saw, you did do a bad thing by operating the clutch pedal with the slave free from the trans. There was no fault with your slave when it came apart- a new slave will do that too. If you want to bleed the slave while not connected to the trans, don't "pedal" bleed it, but instead pressure bleed it like you do with your brakes. The pressure bleeder won't blow off the slave pushrod. Pedal bleeding doesn't work well, even with the slave attached to the trans. You should pressure bleed it. Actually the factory Porsche repair manuals even say to pressure bleed the clutch hydraulics.

mthomas58 · 05-13-2009, 06:13 PM

Quote:

Originally Posted by rnln

when I installed my, engine in the car, the system was empty and I still had very hard to time push it in. Becareful, it's very easy to miss the track, push rod went out of the little spot.

You called it! I bled the slave a couple more times tonight and knew I got all the air out and the pedal still fell to the floorboard. I got a mirror out to check if the push rod was properly seated and it was not so it was not engaging the clutch fork at all. Pulled the slave, the guts fell out and brake fluid spewed everywhere.

Installed new slave, bled and all is good now. Finally - I was able to test drive my new engine

mthomas58 · 05-13-2009, 06:16 PM

Quote:

Originally Posted by KTL

You did nothing wrong trying to install the slave atop the trans in its fully extended position. You just have to use some muscle and shove the slave into it's mounting point so you can get a nut started.

As you saw, you did do a bad thing by operating the clutch pedal with the slave free from the trans. There was no fault with your slave when it came apart- a new slave will do that too. If you want to bleed the slave while not connected to the trans, don't "pedal" bleed it, but instead pressure bleed it like you do with your brakes. The pressure bleeder won't blow off the slave pushrod. Pedal bleeding doesn't work well, even with the slave attached to the trans. You should pressure bleed it. Actually the factory Porsche repair manuals even say to pressure bleed the clutch hydraulics.

Pressure bleeding worked like a charm. Pedal bleeding is a major PITA. Thanks for the advise!!!!

bcheney · 08-25-2014, 12:30 PM

Ok I have read a bit on this and can't get the slave installed...I understand leverage and have plenty of strength...however, this PITA is not going on and I am a bit frustrated at this point. The engine is bolted in place...Need suggestions Here is a pic...As much as I love these cars...at moments like this I want to shove it you know where!!!

KTL · 08-25-2014, 12:54 PM

Can you push the slave pushrod into the cylinder by hand? It should be no more difficult than pushing a brake caliper piston back into the caliper.

It does take a little bit of leaning and you need to have a nut ready to spin on quick once you've gotten the slave to compress a bit. Once you get one nut on, the rest of the work is done by tightening the nuts with your wrench.

bcheney · 08-25-2014, 01:05 PM

Kevin, I held the slave cylinder in my hand and tried to push in the rod and it was a no go. I put a small block of wood in my palm and tried to push it in and still it was a no go...

KTL · 08-25-2014, 01:08 PM

I think something is up with the master cylinder if it won't let fluid back into itself. You should be able to push the slave pushrod back into the slave with not a ton of effort.

bcheney · 08-25-2014, 01:17 PM

The slave has sat idle for about 8 months in my garage in the car. The had the engine rebuilt and just now gettin around to putting it back together. Any advice on next step? I think I met you in Mount Dora this year at Zonefest. I had a yellow 914/6 conversion and my wife and I followed you out to Yalaha!

steely · 08-25-2014, 03:23 PM

I did it lying on my back to compress it while having a helper push a block of wood in there. it wasn't that easy IIRC.

KTL · 08-26-2014, 11:44 AM

Well i'd put the slave rod against a block of wood and lean on it with your body weight. If you can't get it to retreat into the slave body, something's wrong upstream.

I would look at the flexible hose section just ahead of the slave. Maybe that's swelled shut? I recently had a friend's '98 F150 truck giving him a pulling problem under braking. Turns out one side had a faulty flex hose that was not allowing fluid pressure to reduce when the brakes were released.

If not a problem with the flex hose, the only other problem can be the clutch master cylinder in the pedal cluster!

bcheney · 08-26-2014, 02:01 PM

Will check all of that to be sure. I am picking up a new slave tomorrow anyways...the car has 200K on the clock so a fresh one in good to have!