Locking Tag Axle Tire

[Jeff Miller]

That's funny Randy, you knew he'd bite didn't you?

The laws of physics haven't changed Tom, you've obviously just never
understood them.

The length of air-line doesn't affect ultimate pressure, but it does
affect timing which is important in air-brake design. If one brake is
supplied pressure before another brake you can get pulling or lockup.

As far as one brake locking without the other, several factors can
cause asymmetrical braking and traction:

Check shock absorbers and suspension links, a binding or broken link
can cause asymmetrical downforce and thus traction. A pinched air-bag
supply line can cause the pressure to vary between air-bags, a
SEVERELY out-of-level condition can cause asymmetrical
pressure/traction, brake supply lines can affect braking and cause
asymmetrical brake pressure, possibly even a restriction in the tag-
axle's R-12 brake relay valve.

Mechanical brake problems can cause asymmetrical braking as one brake
might have a bad cam or rollers, contaminated brake shoes or
incorrect friction material (FF is original, softer can cause
locking), incorrectly installed (wrong angle) slack adjusters.

Coach loading shouldn't affect tag-axle braking as the tag-axle
airbags are tied together and supplied by/at the same pressure, same
pressure between airbags will mean same downforce/weight on both
sides (or very close). Coach loading affects the side-side weight of
the drive axle mostly.

If betting, I'd start with: contaminated brakes, wrong brake friction
material, incorrectly adjusted or assembled slack adjuster,
suspension problem, and move on if those are not the problems.

An air pressure gauge comparing brake application pressure between
the two sides might also be an interesting test.

- Jeff Miller


--- In WanderlodgeForum@yahoogroups.com, Tom Warner
wrote:
> Randy unless the law of physics has changed since I retired 10
years ago a
> difference in 1/4" air line lengths of a few feet will not make a
> difference in the force that the brake chamber applies to the slack
> adjuster.. I would suspect that if one tire is locking up then I
would
> suspect contaminated brake shoes on that axel or a misadjusted
slack adjuster.
>
> Tom
> 1982 FC35
> Vernon Center,NY
>
> At 12:02 PM 6/9/2005 -0400, you wrote:
> >check to make sure that both air lines are the same length.if one
has been
> >replaced it may be shorter or longer.it does matter..Tom?
randydupree93wb