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30.2 Clutch Slave Cylinder

Replacing the Slave Cylinder
Year(s):  1980-1991
Model/Type:  Vanagon, All
Bentley Page(s):  30.2

From:  Jeffrey Earl

Symptom(s):  Clutch won't engage

* Suitable Clutch Slave Cylinder
* DOT-4 Brake Fluid, about a quart

* Assorted Metric Combination Wrenches
* Assorted Metric Sockets and Ratchet Wrench, with
* Torque Wrench: 0 to 25 ft./lbs
* Phillips Screwdriver
* Vaccuum-pump brake-bleeding kit
* Penetrating oil: squirt some PB Blaster, Marvel
Mystery Oil, or similar on exterior nuts, bolts, and
bleeder screws a few days before tackling this job, to
ease their subsequent removal. Even so, I needed to
resort to the judicious application of a ...
* Small propane torch, to carefully heat stubborn
threaded fasteners.

Here's a simple homemade alternative to a store-bought
hose-clamping tool: cut a 1"-long section from a 3/8"-
or 1/2"-diameter wooden dowel, then split it down the
middle to form two half-round pieces. Tape these to
the jaws of your locking pliers and use this to
carefully pinch-off rubber hoses while you work on
related components. Not too hard though, or you'll
damage the rubber.

1) Back in the left-forward corner of the engine compartment, just ahead of the edge of the deck-lid opening, you will find the clutch slave cylinder mounted to the clutch housing. Start by using some WD-40 and a shop rag to clean loose crud from the area, especially around the union nut on the steel high-pressure line entering the front of the slave cylinder. The introduction of dirt or other crud into your hydraulic system here or anywhere else will soon mean trouble. When clean, loosen but do not completely remove the union nut.

2) Loosen the two retaining bolts attaching the slave cylinder to its mounting bracket. If yours are rusted and seized, and the penetrating oil hasn't worked, you may need to use the propane torch to carefully apply some heat to them. NOTE: be very careful to not damage nearby wires or coolant hoses. Use an open-end wrench to hold the bolt heads from beneath the bracket, while using a socket and ratchet to loosen the nuts from above. Alternatively, you may find you have better access while lying beneath the van. Completely detach the high-pressure line from the slave cylinder, and withdraw the entire slave cylinder from its bracket.

3) If your old mounting bolts are rusty and corroded, replace them with new M8x25 bolts and nuts. Before dropping the new slave cylinder into place, you'll want to be sure the rearmost (closest to you) mounting bolt is safely installed in its hole, as it will be impossible to get it in once the slave cylinder is in place. If necessary, prevent the bolt from falling out by temporarily threading its nut onto it.

4) Put a dab of general-purpose grease into the small cup at the end of the slave cylinder actuator, to lubricate the ball on the clutch-engagement lever to which it will connect. Set the slave cylinder into place, making sure the cup engages the ball (it doesn't need to 'snap' into place, but simply engage), and slip the slave cylinder over its mounting bolts (having previously removed the temporary nut from the rearmost mounting bolt). Loosely thread the nuts onto the mounting bolts but do not tighten yet.

5) Start threading the pressure fitting into the slave cylinder by hand, then finish by wrench-tightening to 12 ft./lbs.. Tighten the mounting nuts to to 18 ft./lbs..

See: Bleeding the Clutch Hydraulic System
Also see the next article below the comment box for Syncro and other fine tips

See Comments on this entry (F.W.I.W.)

R & R clutch slave
Year(s):  80 - 91
Model/Type:  All Manual Transmission
Bentley Page(s):  30.2

From:  Brent Christensen and others

Symptom(s):  soft clutch, leaking cluch slave

Date: Fri, 23 Nov 2001 15:54:54 -0800
Reply-To: Brent Christensen
Sender: Vanagon Mailing List
From: Brent Christensen
Subject: Re: Clutch Slave Cylinder Bleed problem (How to replace your
slave cylinder)

I recently replaced my slave cyl (I posted details on the Syncro list, the end result of which I have attached to this e-mail) and bleeding it took a bit more than a pint, I would say. (My master had become empty as a result of the same sort of leakage).

Included in this e-mail (in order of appearance): 1. My suggested modifications to Dr. Rainer Woitok method 2. Dr. Rainer's method, as posted to the Syncro List 3. A great tip from Tim King (originally from Daryl at AAA Transaxle)

Not sure if these tips are unique to Syncros, but should be helpful nonetheless.
Editors note: Bentley shows identical configuration for all manual trans. vanagons.

Brent Christensen '89 GL Syncro Westy Santa Barbara, CA

Well, I did the nasty deed and replaced the slave cylinder yesterday morning. Not all that bad, really. Dr. Rainer's tip sheet (which I have left attached to this e-mail) was very helpful as a road map, but I would offer the following additional advice to anyone planning this job:

First, having a pressure bleeder made bleeding the system a 5-minute one person job. If you don't have one already, run out and get one. I have a unit called an "Eezi-bleed" that I bought years ago for an Austin Healey - about $30 and it is pressurized by a tire (I use a wheelbarrow tire with about 25 psi in it). A quick search turned them up at
Editors note: Bentley says "bleed system only with pressure bleeder.

Secondly, a 13 mm "Crows foot" at the end of a long 3/8" extension worked WONDERS for removing the pesky rear bolt (the one towards the reat of the van). Forget trying to do it with box wrenches, unless you have a "super stubby" like Snap-On makes, or you are willing to make your own by cutting it in half and grinding the stub smooth. Another ideal tool would be a 13 mm "distributor wrench" but I was not able to find one, and don't even know if they are made in 13 mm.

Removing the Slave cylinder entirely from the topside is possible, and I would submit, easier. In fact, if you are lucky, you could do it without ever crawling under the van at all. The trick is to undo the banjo fitting at the slave cylinder, which is a bit tricky if you have thick fingers. You have to force the short coolant hose back far enough so that you can back the bolt out from the banjo nut. Be prepared, as all the fluid will then leak out from the system, which for me was nothing, since the slave had failed and dumped all its fluid already. (Also, having a pressure bleeder, I was not worried about introducing air into the system).

The most difficult thing about reinstalling the new unit (which I did as an entire assembly - shaft, boot and cylinder) is getting the nuts started. When you drop the slave in place, the rod rests against the clutch's throw-out arm (or whatever you want to call it). This means that the unit wants to sit about 5 mm above its mating surface unless you apply some force, which then compresses the spring inside the cylinder (which is still empty of fluid). Once the rear nut is started by hand (I used a 13 mm combination wrench slipped in underneath the bolt head to hold it in place, which is tricky) you can crank it down about 1/2 way by pushing the slave down against its mating surface and rotating the nut with your forefinger and middle finger.

Once the slave is secured like this, you can start the forward bolt from underneath (you have to do the rear bolt first, since the only way to put it into position from underneath is to use the hole that the slave cylinder fits into). Start the nut by hand, then reach in with a long extension and "wobble socket" or 13mm socket on a 3/8" knuckle. With a wobble socket, there is sufficient clearance - with a knuckle + socket it could be pretty tight. I was able to completely tighten the forward bolt this way after reaching underneath and placing a box wrench around the head of the bolt and resting against something. A couple more turns on the rear bolt head with the crow's foot and the cylinder was in nice and snug.

Next comes the banjo fitting, which was surprisingly easy to get back on. I pulled back the aforementioned hose and gently started the bolt with a couple of fingers twiddling at it until the threads caught, then tightened it down with a 17mm open end wrench. Tightened it up and then fit a small plastic tube to the bleeder screw, running it down to an empty brake fluid can propped in the engine bay.

Next, I fitted the pressure bleeder, attached the wheel barrow tire, and then went back and opened the bleeder screw. I stood and watched the bubbled dribble out of the system while I opened my first beer (when was the last time you did *that* while bleeding a hydraulic system?). After a couple minutes and no more bubbles, I checked the pedal. No pedal, so I pumped it slowly about 10 times and turned the bleeder on again by reapplying the air pressure from the tire. About 30 seconds later another batch of bubbles came out, so I shut everything down, cleaned up, and tool it out for a test drive, everything working beautifully.

Total time for job: About 2 hours start to finish, not including setup and cleanup.

Brent Christensen Santa Barbara, CA

Rainer M Woitok
Mail: Woitok@RRZE.Uni-Erlangen.DE
Removing the Clutch Slave Cylinder

1. Even though the clutch slave cylinder is held by only two bolts, it's a bear to remove. First thing you should do is to apply generous doses of WD40 or similar to the two bolts. And since, if mounted correctly, the bolts are sitting there with their heads down and their shafts up, the best way to apply the WD40 is from the engine compartment. And while you are there, also remove the tiny rubber cap on top of the bleeding valve of the slave cylinder before it might get lost in the process of the removal.

2. The flexible hose leading to the clutch slave cylinder is attached to the frame of the van by two clamps. Remove both these clamps from the van.

3. The front bolt holding the clutch slave cylinder is best removed from below the van with a 13mm socket on top of a long extension while at the same time holding the nut with a 13mm wrench. The shorter that wrench, the better. The real problem, however, is the rear bolt. Push up the rubber boot protecting the push rod for the clutch lever as much as possible. This way you are then able to access both ends of the rear bolt from the engine bay. Sneak in a 13mm wrench in order to hold the head of the rear bolt and remove the nut using another 13mm wrench. Again, the shorter this wrench the better, and a flat box wrench is probably suited best, because it will fit every 30 degrees.

4. When the two bolts are removed dive under the van again, pull the push rod out of the rubber boot at the lower end of the slave cylinder and also gently pull the rubber boot from the slave cylinder. If necessary use a small screw driver to convince the boot of letting go. Finally carefully find a path between tranny, fuel tank, slave cylinder mounting bracket, half axle, coolant and exhaust piping, and maybe some other things to bring the slave cylinder down, so it will hang on its hose right below the tranny.

5. In order to minimize the loss of brake fluid you should now remove as much brake fluid from the reservoir in the instrument cluster on the dash as is necessary to lower the brake fluid level below the hose entering the reservoir from the right. This way opening the hose at the slave cylinder will not drain the reservoir any more.

6. To disconnect the hydraulic fitting at the end of the hose from the slave cylinder you need something to catch the hydraulic fluid still in the hose, as well as a 17mm box wrench, a piece of wood, and a hammer. Put the box wrench on the head of the hyraulic fitting in such a way that wrench and slave cylinder form a rather flat triangle, cylinder to the left, wrench to the right, and the head of the hydraulic bolt pointing towards you. Place this triangle on the piece of wood and then carefully hammer on the eye of the wrench, flattening the triangle even more and thus loosening the bolt of the hydraulic fitting. Be prepared to catch the brake fluid which now starts oozing out. Remove the hydraulic fitting altogether and make sure not to lose the two copper washers sitting on the hydraulic bolt on either side of the hydraulic eye. Drain the rest of the brake fluid from both, the hose and the slave cylinder (push the piston back manually).

The Slave Cylinder Repair Kit -----------------------------

The slave cylinder repair kit contains

- a boot for the push rod

- a main seal for the piston

- a cap for the bleeding valve

Repairing the Clutch Slave Cylinder -----------------------------------

1. Place the slave cylinder in a vise, bleeding valve down. As you can see now, the piston is retained by a circular clip sitting in a grove in the slave cylinder. However, that's not the regular C-clip you can remove with the corresponding pliers. Rather use a small screw driver and a hammer and drive the screw driver between circlip and slave cylinder at the side oposite the gap in the circlip, at the same time pushing the piston slightly back with one finger of the hand holding the screw driver. This will push one side of the circlip down while the other end will go up allowing you now to easily remove the circlip.

2. Next push the piston down the slave cylinder, close the opening for the hydraulic fitting with your thumb, and then suddenly remove the thumb so the piston will shoot up and half way out of the slave cylinder, where you now can easily pull it out altogether. Remove the spring from the rear end of the piston and then remove the old seal by simply using a srew driver and pulling the seal over the rear end of the piston (it's elastic enough).

3. Dry the piston as well as the inside of the slave cylinder and then use finest emery-cloth to remove any residues from both, cylinder and piston.

4. Next, pull the new seal over the rear end of the piston. Mind that the upper and lower edges of the seal have different outer diameters. The greater outer diameter points to the rear end of the piston, where the spring is attached. Put spring and piston back into the slave cylinder, push the piston down a little, and insert the circlip.

5. Now turn the slave cylinder in the vise upside down, so that the bleeding valve is pointing upwards. Again apply some WD40, then use a 7mm wrench to screw the valve entirely out of the slave cylinder. Clean the valve, in particular the little hole near the pointed end, then reassemble the valve and close it tightly.

Installing the Clutch Slave Cylinder ------------------------------------

Basically undo all the steps you did before to remove the slave cylinder in reverse order. However, mind a few things:

- Put one of the copper washers on the hydraulic bolt, then the hydraulic eye, then the other copper washer. Then screw the hydraulic fitting into the slave cylinder. To tighten the bolt, again form a flat triangle with the slave cylinder and a 17mm box wrench. This time, however, the box wrench is at the left side, the slave cylinder at the right, and the head of the hydraulic bolt is again facing you. The rubber boot should not yet be installed. Before you fasten the bolt by placing this triangle on a piece of wood and striking the eye of the wrench more or less gently with a hammer, make sure the orientaion of the hydraulic hose is roughly perpendicular to the slave cylinder and downward.

- Top off the brake fluid reservoir in the instrument cluster and bleed the system. The bleeding valve is easily accessible now with the slave cylinder just hanging below the tranny, and you can also easily check for any leaks (if the slave cylinder is leaking at the hydraulic fitting you probably forgot to insert one of the two copper washers).

- Install the rubber boot (but not yet the push rod) at the lower end of the slave cylinder and -- folding the rubber boot against the slave cylinder -- persuade the slave cylinder to go up above its mounting bracket again. Insert the rear bolt from below and screw on the nut a few turns only. Then insert the push rod between the clutch operating lever and the slave cylinder piston, press the slave cylinder down against its mounting bracket, insert the front bolt with its shaft pointing up, and screw on the nut. Fasten the front bolt from below using a 13mm socket on a long extension and a 13mm wrench to fix the bolt, then fasten the rear bolt from the engine bay using two 13mm wrenches. Place the rubber cap on the bleeding valve.

- Pull the lower end of the rubber boot down the push rod until it sits in the small grove at the lower end of the rod. Attach the two clamps to the frame that are holding the flexible clutch hose.

- Test the operation of the clutch: pull parking brake, put the tranny into first gear, step on both, the brake and the clutch pedal, and then start the engine.

Some other input:

Tim King wrote:
Hey Folks, I've got a slave tip that will save you some time on this. I got a tip from Daryl at AA transaxle that makes removing the slave on a syncro a snap. Basically, you just remove the slave bracket from the tranny by removing ONE snap ring then the clutch lever.

1. Move slave shaft/boot off clutch lever ball. If your >slave is totally shot, you can usually just push the slave cylinder shaft/boot off the ball on the clutch lever. If it's a good slave (say you are just R and Ring the tranny), you may need to open the bleeder to make it easy to remove. Just lever it free, then let it hang free.

2. Wiggle the clutch lever off the shaft. If it's been there for a while, you may need some liquid wrench or something, but it should come off by hand.

3. Pull the bracket and slave off as one unit.

4. Pull the unit down under the van (you put it on ramps, right?) and work on it where you have access to it from both ends and room for standard wrenches. You may need to remove a couple of the hose clamps holding the hose to your tranny to give you more slack.

5. Bolt on new unit and install in reverse.

6. Pressure bleed system and hit the road.

Using this method takes about 30-40 minutes total,>assuming you are using a pressure bleeder like Brent recommends.
Note: I'm not sure if it's syncro specific -- I think it requires the flexible plastic fluid lines of the syncro, something my 83 vanagon was lacking. Have fun. This tip from trannyman extraordinaire Daryll>at AA transaxle makes a drag of a job a LOT easier. Tim King Seattle, WA 87 Syncro Westy


From: Malcolm Stebbins
Organization: Mount Saint Vincent University
Subject: Clutch slave cylinder bleed/replacement - my (syncro) story
Content-type: text/plain; charset=US-ASCII

As I had no clutch, I had the van towed to my PO trusted mechanic and with my vanagon emails in hand I asked if he wanted the collective wisdom/advice of the vanagon list. "Not really, we do these all the time" he said. Now, I have carbs on my syncro so what happened next may not be a good idea on your van.

The bolts for the slave cylinder are very awkward to "get at" (See Brent's email). So my mechanic took out the coolant hose that goes from the thermostat housing to the top cross-over pipe. He now had VERY good access to that hard to reach bolt and changing the cylinder was not so bad.

With the new slave cylinder in, we tried to bleed the clutch (also brake) fluid to purge any air. Well my clutch had NO! resistance. We pumped and pumped the clutch pedal - got some air out, but NO! resistance on the pedal. So, my smart mechanic new what the problem was - the plunger thingy in the master cylinder had "collapsed" (or whatever) and was not doing its thing. So he went to the rear and pushed up hard on the slave cylinder plunger and that forced the fluid back through the system and freed the plunger in the master cylinder. Worked first time, I had pressure on the clutch pedal and then we were able to bleed the system. (bled the brakes while we were at it).

I hope that this post helps somebody. If it does, please drop me a line, I may need a shot of vanagon that day. malcolm


Reply-To: Timothy Hannink
Sender: Vanagon Mailing List
From: Timothy Hannink
Subject: Re: Clutch Question and confirm suspisions
Content-Type: text/plain; charset="Windows-1252"

It could be that the clutch pedal itself is wearing where it connects to the slave cylinder shaft clevis. Unfortunately, the only way to check it is to remove the pedal assembly and dashboard. I have a description of the problem and how I fixed it on my website at: , then scroll to the bottom of the page. NOTE: PAGE NOT FOUND

Tim Hannink Goldibox -
1987 Westfalia Camper,
Wolfsburg Edition
Winter Park, Florida


From: Jere Hawn
Subject: Slave Cylinder Fix
Content-Type: text/plain; charset="Windows-1252"

Hi All,
Remember a number of weeks ago I was complaining about German engineering on the way they designed the slave cylinder bracket and how difficult they made it to put the slave cylinder in.... well I replace the slave on my other van this week end in about 20 minutes. I found the trick is

1. do not try to change it from underneath (as I did on my other van last month)

2. the first step is to move the hydraulic line from the old to the new.

3. When installing the new, put the one bolt (the one closest to the engine) in first, accessed through the center of the bracket where the cylinder goes and hold it in place while you drop the new cylinder in.

4. get a bleeder hose about 5 ft long makes it very easy.
Jere 90 GL 88 GL


Subject: Re: Clutch Got Soft
Comments: To: abusguy2@SPRINGMAIL.COM
Content-Type: text/plain; format=flowed

John, Pull the top off your instrument cluster. You will se a hydraulic resevior there. Make sure it is filled. If not, the first thing that goes is the clutch circuit. It pulls fluid out of the top part of the resevior. Brakes come out of the bottom. Get some Dot3 or DOT4 and top it up. You may need to bleed the line, not a hard job, just messy. I would look to see if your slave cylinder is leaking. This is located right in board of the front side of your drivers side rear wheel.
tim o'brien (been there, done that recently)


Maynard, Mine did something similar when the clutch master cylinder went out. Do you see anything leaking ont the carpet under the pedals? If it just needs to be bled and you are working alone, here is what i did. get about 10 feet of aquarium tubing (1/8 or so flexible rubber tube), slip one end over the bleeder valve on the slave cylinder, put the other end in a jar or cup or whatever you have on the ground by the driver's door. open the valve, pump the pedal, watch for air bubbles. when all bubbles are gone, tighten the valve. you don't have to worry about air getting back into the line, there will be enough air-free fluid in the tubing, so you don't have to hurry. Good luck, Don

See Comments on this entry (F.W.I.W.)

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