Pokeys air leak

[Gardner Yeaw]

Jeff,
Thank you for the explanation. Now I think understand why I had
problems with the front brakes grabbing when the rear brakes were
way out of adjustment. Since I had the rears set properly the whole
braking experience is significantly better.

Gardner
78FC33


--- In WanderlodgeForum@yahoogroups.com, "Jeff Miller"
wrote:
>
> It's been a while, I'll dig into the memory banks.
>
> Two things are at work here:
>
> First, the front brakes on FCs and PTs are 20"sq and the rears are
> 30"sq, so the rear brakes will use air at 150% of the rate of the
> fronts (both tanks are the same size) even with the same
application
> pressure.
>
> Second, the '78 I believe has a valve (can't remember the name of
> the valve) which delays front brake application until the
main/rear
> brakes exceed a set psi (memory tells me it something like 30psi).
> Not sure when it changed, but this was to avoid front wheel lockup
> in slippery conditions, common on older trucks. In later designs
> ratio valves replaced these valves.
>
> - Jeff Miller
> in Holland, MI
>
>
> --- In WanderlodgeForum@yahoogroups.com, "Gardner Yeaw"
> wrote:
> >
> >
> > Jeff,
> > Are you saying that the rear brakes are applied first and not
> at
> > the same time as the front brakes?
> >
> > Gardner
> > 78FC33
> > --- In WanderlodgeForum@yahoogroups.com, "Jeff Miller"
> > wrote:
> > >
> > > The front tank on the driver-side is the front brake tank
(also
> > > called secondary), the front tank on the passenger/curb side
is
> > > the "wet tank", the tank in the rear is the rear brake tank or
> > > primary.
> > >
> > > Pump the brakes very lightly, only the rear gauge should drop.
> > >
> > > - Jeff Miller
> > > in Holland, MI
> > >
> > >
> > > --- In WanderlodgeForum@yahoogroups.com, "doug_ngl"

> > > wrote:
> > > >
> > > > OK, As I understand it, The 2 air gauges on the dash only
> > monitor
> > > brake
> > > > air pressure (not suspension pressure). Under the bus, about
> in
> > > line (F
> > > > to R speaking) there are 2 air tanks, one for the front
brakes
> > and
> > > one
> > > > for the rear...I assume. I think there is also a "wet" tank
> > > somewhere,
> > > > further toward the compressor I would guess. My LH dash
gauge
> > > bleeds
> > > > down many times faster than the RH one (when I shut the rig
> > down).
> > > Now
> > > > the questions:
> > > > Does the LH gauge monitor the air in the LH tank (sounds
> > logical)?
> > > > Which tank is for which end brakes? (LH for front? LH for
> rear?)
> > > > Where is the wet tank located?
> > > > Thanks as always, still cold here in Gunnison, Doug
> > > > Doug Engel, Gunnison, CO, 1981 FC35SB "Pokey"
> > > >
> > >
> >
>