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Clutch Hydraulic System Overview
The Vanagon's hydraulic clutch system is fairly straightforward, and is
clearly depicted in the Bentley manual, Page 30.2. Essentially, the
clutch pedal actuates a hydraulic piston-and-cylinder
assembly—hereafter referred to as the "master cylinder"—tucked away
just above the base of the steering column. This master cylinder then
pushes hydraulic fluid through a 10-foot-long pipe running to the
engine compartment, where it is connected to a similar
piston-and-cylinder assembly known as the "slave cylinder". This slave
cylinder in turn actuates a lever on the side of the clutch bellhousing
to engage/disengage the clutch.
Hydraulic
fluid for the entire system is supplied by the same reservoir as
supplies the brake system; this reservoir is hidden behind the
instrument cluster on the dash, and is accessed by removing the
instrument-cluster cover.
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Typically,
the first sign of trouble in the clutch system is hydraulic fluid
dripping from the master cylinder onto your shoe, carpet, steering
column, etc.. Or perhaps a leak surrounding the slave cylinder back in
the engine compartment, accompanied by the increasing consumption of
fluid.
Vanagon lore suggests that replacement of the clutch master cylinder
will soon be followed by failure of the clutch slave cylinder, the
theory being that the original cylinders wear-out at about the same
rate—neither being stronger than the other—so they continue to function
together for quite some time. But a new, strong master cylinder will
easily overpower the worn seals in a tired old slave cylinder, blowing
it out. On a purely speculative note, I suppose the opposite could be
equally true: a new slave could be too much for an old master to
handle, causing an imminent failure of the master cylinder.
When the seals in the slave cylinder fail, it stubbornly declares to
the master "You're not the boss of me now. I ain't actuatin' nothin'!"
Failure of either will cause the inability to use the clutch to
disengage the transmission, making it difficult or impossible to shift.
Insistent pumping of the clutch pedal will result only in the loss of
your precious brake/clutch fluid.
My Westy is not used as a daily driver, but instead racks up nearly all
her miles on roadtrips and camping forays, so by definition any
mechanical failures will occur far from home. Preferring to perform
this task in the relative comfort of my own driveway, rather than a
lonely interstate or a distant logging trail in the woods, I opted to
replace both cylinders in one fell swoop.
Parts
- Suitable Clutch Master Cylinder
- Suitable Clutch Slave Cylinder
- DOT-4 Brake Fluid, about a quart
Tools
- Assorted Metric Combination Wrenches
- Assorted Metric Sockets and Ratchet Wrench, with extensions
- Torque Wrench: 0 to 25 ft./lbs
- Phillips Screwdriver
- Vaccuum-pump brake-bleeding kit
- 3-foot-square piece of plastic sheeting and some
ever-helpful duct tape: lay this down on your carpeting to catch the
inevitable spills
- A small inspection mirror and flashlight may help in seeing
what you're doing
in the tight confines above the steering column
- 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. |

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