Date:         Sat, 12 Feb 2005 10:27:11 -0600
Reply-To:     Jim Felder <felder@KNOLOGY.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Jim Felder <felder@KNOLOGY.NET>
Subject:      The second bleeding: Clutch master/slave failure observation
Content-Type: text/plain; charset=US-ASCII; format=flowed

I recently replaced my clutch master cylinder on a hunch. Neither
cylinder was leaking, and I had replaced the slave cylinder just over a
year ago, so I had to guess and was right.

In reading up on the how-to, I repeatedly ran across this bit of
conventional wisdom: if the clutch master cylinder fails in a vanagon,
the slave is often not far behind.

I am writing this to suggest that that may not always be the case.

Here's why: I also ran across a piece of advice that suggested that
bleeding the vanagon clutch system, which apparently cannot be done
with the two-person close-up-open-down method, would need to be done
again in several hundred miles and only with a pressure (per Bentley)
or vacuum (per almost everyone else) bleeding tool.

I replaced my master cylinder the night before leaving on a recent 2000
mile trip. The car shifted well for the first thousand miles, balking a
few times into all gears after than, and really started giving me
trouble about forty miles from home. It was as if one of the cylinders
wasn't working again, and since I had just replaced the master, I
figured it may be the slave that had gone bad, just as vanagon lore
said it would.

But I remembered the advice about the second bleeding, and I did that.
Problem fixed.

I wonder if some of the slave cylinder failures reported after master
cylinder replacement are due to the fact that after master cylinder
replacement, some time in the next 2000 miles air bubbles are going to
cause a problem that make the slave cylinder seem inoperative when it
really isn't. Since master cylinder replacement puts in a big slug of
air at the front of the system that has to travel to the back, it only
shows up after so many brake applications. If the slave cylinder is
replaced to correct the problem, air that enters at the back end of the
system is now easily bled out, making it seem that the slave cylinder
replacement was necessary--when in fact it was only the bleeding that
was necessary.

Just a theory and will maybe save somebody fifty bucks and some trouble.

THE SECOND BLEEDING

Turning and turning the wrong size flare wrench,
The mechanic cannot reach the rag in time.
Things fall apart, the repair will not hold.
The new parts lack cleanliness while the
floor is filled with brake fluid,
And everywhere the front upholstery is drowned.
Surely some revelation is at hand;
Surely the second bleeding is at hand.
The second bleeding! No sooner are those words out of my mouth
Than my mind is trouble by a page out of Bentley.
...
The darkness drops again, but now I know
That twenty years of dependability were vexed to nightmare
By a dripping fitting.
...
And what rough beast, its hour come round at last,
Is slouching toward Wolfsburg to be born?

Apologies to W. B Yeats.

Jim