Audi Parts Catalog Audi Accessories Catalog Audi Technical Articles VW-Audi Tech Forums
 
  Search our site:    
View Recent Cars  |   Cart  | Project List | Order Status | Help    
 >  >
Clutch Slave Cylinder Replacement
 
Bookmark and Share

Pelican Technical Article:

Clutch Slave Cylinder Replacement

Peter Bodensteiner

Time:

2 hours2 hrs

Tab:

$75 to $150

Talent:

***

Tools:

5mm Allen socket, ratchet, extension, flathead screwdriver, drain pan and rags, fluid bleed kit

Applicable Models:

Audi A4 (1997-01)
Audi A4 Quattro (1997-01)

Parts Required:

New slave cylinder, fresh brake fluid

Hot Tip:

Might as well install a new one anytime you replace your clutch

Performance Gain:

Will help the clutch operate properly, which can save gearbox parts in the long term

Complementary Modification:

Transmission fluid replacement

The clutch slave cylinder serves as the interface between the hydraulic clutch system and the mechanical parts that actually disengage the clutch. When you push on the clutch pedal, brake fluid translates that pedal movement into hydraulic pressure, the end result of which is the extension of a plunger within the clutch slave cylinder. When the plunger extends in your Audi A4, it pushes on the clutch release lever within the transmission. When the clutch is disengaged, it separates the engine and the transmission for a moment so that you can change gears.

When the clutch slave cylinder fails, it may leak hydraulic fluid (the clutch system uses brake fluid just as the brake system does), but you may first notice a problem when you seem to be grinding gears, or having trouble getting your car in or out of gear.

The clutch slave cylinder, and the clutch hydraulic system as a whole, is easier and cheaper to fix than the clutch, and certainly the transmission. Take a look at your clutch engagement system at the first sign of trouble, before you do any damage to these more expensive parts. Start by bleeding the hydraulic system (use the bleed nipple on the slave cylinder just as you would when bleeding the brake system), and if the problem is not resolved, consider replacing the slave cylinder.

Also, if you are replacing the clutch or doing other transmission related work, you might as well replace the clutch slave cylinder. This little device does a lot of important work, and it's not too expensive, so it won't hurt to have a fresh unit in place.

It's hard to get a good straight look at the clutch slave cylinder on the A4.
Figure 1

It's hard to get a good straight look at the clutch slave cylinder on the A4. In my case I had already removed a few items that were in the way, but even then, it is difficult to get a good picture. This photo was taken from the left (driver's) side of the engine bay, looking back behind the engine toward the transmission. The red arrow points to the slave cylinder, more specifically to the bleed nipple, which is covered with a rubber cap. The blue arrow points to the hard line that delivers clutch fluid to the slave cylinder from the master cylinder. Just downstream from the arrow you can see where the hard line enters the slave cylinder.

Here's the view from underneath the car, looking up.
Figure 2

Here's the view from underneath the car, looking up. A 5mm Allen socket is attached to the ratchet handle, ready to remove the small bolt that secures the slave cylinder to the transmission via a sheet metal bracket.

Remove this bolt in order to free the slave cylinder.
Figure 3

Remove this bolt in order to free the slave cylinder. Torque this bolt to 18 ft-lbs upon reinstallation.

Once the bolt is removed, remove the slave cylinder plunger and bellows from the transmission by wiggling it back and forth while pulling in the direction of the blue arrow (straight back to the rear of the car).
Figure 4

Once the bolt is removed, remove the slave cylinder plunger and bellows from the transmission by wiggling it back and forth while pulling in the direction of the blue arrow (straight back to the rear of the car). Inside the blue circle is the part of the bracket that attaches to the transmission using the Allen head bolt. Once you have the slave cylinder free, slide the thin metal clip in the direction of the red arrow in order to disconnect the hard line from the slave cylinder. Pull the hard line out in the direction of the green arrow. Make sure to have some rags and a drain pan handy, as brake fluid will escape from the clutch line.

Here's a good look at the plunger and rubber bellows of the slave cylinder after its removal from its home in the transmission case (indicated by the blue arrow).
Figure 5

Here's a good look at the plunger and rubber bellows of the slave cylinder after its removal from its home in the transmission case (indicated by the blue arrow). To remove the slave cylinder from the car, remove the hard line from the mounting bracket (orange circle). In the background is the threaded hole for the bolt that we removed in picture 3.

The sheet metal mounting bracket has been removed from the old slave cylinder and attached to the new one (note the clean white rubber bellows).
Figure 6

The sheet metal mounting bracket has been removed from the old slave cylinder and attached to the new one (note the clean white rubber bellows). The bracket simply slides onto a plastic mounting tab on the slave cylinder (red circle). The blue arrow indicates where the clutch fluid hard line inserts into the slave cylinder. Note the protective plug that needs to be removed before reinstallation (blue circle). Installation is the reverse of removal, with a couple notes. First, if you are performing this swap as part of a clutch or other transmission-out job, reinstall the clutch slave cylinder while the transmission is just below its installed position. This gives more room to work, but the transmission can't be too far away or the clutch line won't reach. Second, put some copper grease on the end of the plunger before you work it back into the hole in the transmission, where it meets the end of the clutch fork. Last, you will need to bleed the clutch line to ensure its proper operation. The procedure is the same as the brake bleeding procedure, except you're only dealing with one bleed nipple. The clutch system uses the same fluid-and fluid reservoir--as the brake system.

Bookmark and Share

  Search our site:    

View Cart & CheckOut | Project List | Order Status |  Help    

 

[Home] [Customer Service] [Shopping Cart] [Project/Wish List]
  [Privacy Statement]  [Contact Us] [About Us] [Shipping] [Careers]

Copyright © Pelican Parts Inc. -    DMCA Registered Agent Contact Page

Page last updated: Wed 12/7/2016 02:44:25 AM