non-quattro question - truck brakes

TEX TERRY, II texactii at
Fri Aug 23 17:52:45 EDT 2002

From: Rocky Mullin <caliban at>
i've got use of a dodge truck, with a cummins diesel power plant.
it's a nice big truck.  the brakes though, wow!  it's like stepping on a
sponge.  eventually in the pedal travel, the brakes work fine.  the guy
who owns the truck says no problem, he just hauled 4000 pounds into
over a 60 miles of washboarded switchback roads.  we're towing a very small
travel trailer with it, and i was just looking for opinions.

Brakes generally will feel spongy for one of these four reasons:
1) Air in the brake lines (the air is giving the spongy feeling) - use the
manufacture's bleeding procedure to get rid of the air;
2) Brake hoses that are internally faulty (usually due to age but also
incorrect fluid use or fluid boiling), which will swell when under pressure
(the swelling is giving the spongy feeling) - replace the hoses, all if you
can't determine which is the faulty hose;
3) Brake fluid boiling (the high temperature is causingthe loss of the
pressure capability rating, so you get the spongy feeling) - replace the
fluid, as it probably has contamination due to water condensation;
4) Pads, or shoes, getting hot during downhill use (a gaseous condition
will exist between the pad and the rotor, or the shoe and the drum, from
the excessive friction heat, causing the spongy feeling) - when driving
down a hill, it is best to apply the brake quickly, to slow down about five
miles per hour slower, then keep off the brakes until you are back up to
the starting speed, then reapply the brakes quickly for the five mph
slow-down, and keep repeating this down the hill.  This method will give
the brakes a better ratio of "apply" time to "cooling" time, which will
help keep the breaks from getting hot and giving the spongy feeling.

Tex Terry, II
83 5kt sedan (non-quattro)
Franklin, PA  USA

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