Air leaking from front when brakes applied

[gregory O]

could be "double check valve" ? anyway I dont believe it is designed to
continualy release air while service brake is applied. I think it directs the
service psi to the spring psi.
90 psi + 90 psi = 90 psi
but mechanical force of 1,000 psi and another mechanical source of 1,000 psi =
2,000 psi which is where the shoes crack.

My higheel is done and on the bus. folds up to 14 foot high then lifts
automaticaly to 19.5 foot tall
I will post pict later, parade is Sunday
Greg
94ptca


--- In WanderlodgeForum@yahoogroups.com, Curt Sprenger wrote:
>
> Greg,
> Good information for sure, thanks! Do you know the BlueBird name for that
> compounding valve?
>
> Curt Sprenger
> 1987 PT38 8V92 "MacAttack Racing"
> Anaheim Hills, CA
>
>
>
> On Sun, Nov 1, 2009 at 7:21 PM, gregory O wrote:
>
> >
> >
> > it is the anti compouning valve blowing air ?? when the spring brake is
> > left pushing (park brake on) and someone pushes on the service brakes, the
> > valve proportions the pressure working the cams on the axle that hold the
> > spring brakes so there is not too much pressure on the shoes. if the valve
> > is crapped out you get broken shoes with no sign of heat that made the
> > cracks .
> >
> >
> > to keep from giving a lecture then getting a lecture from the mods, check
> > out page 27 of Bendix
handbook<http://www.wsafc.org/WSFMA/Shared%20Docu...e%20H\
andbook.pdf>
> >
> >
> >
> >
> >
http://www.wsafc.org/WSFMA/Shared%20Docu...ook.p\
df
> >
> > here is a good video of the principles of
AB<http://www.youtube.com/watch?v=qJa5-_ExsBE>
> > without much of the new safety crap confusing the process it is from 1967
> >
> > http://www.youtube.com/watch?v=qJa5-_ExsBE
> >
> > Greg
> > 94ptca
> >
> >
> >
> > --- In WanderlodgeForum@yahoogroups.com, Curt Sprenger
> > wrote:
> > >
> > > Paul,
> > >
> > > What you found and determined does not seem right. Post pictures if you
> > can.
> > > I looked under our coach this afternoon. I see a 1/8" plastic air line to
> > > the cylinder that rotates down the driving light. Above that area on the
> > > bottom of the frame rail there are some copper and plastic air lines.
> > None
> > > are open as you describe.
> > >
> > > Curt Sprenger
> > > 1987 PT38 8V92 "MacAttack Racing"
> > > Anaheim Hills, CA
> > >
> > >
> > >
> > > On Sat, Oct 31, 2009 at 2:35 PM, P & D audvid1@ wrote:
> > >
> > > >
> > > >
> > > > Thanks you all for the assistance. Got some help today and we climbed
> > > > under coach and found a ¼ air line on the driver side front right
> > behind the
> >
> > > > fog lights that when you step on the brakes air comes out of that line
> > and
> > > > as soon as let off it stops. After looking at drawings and trying to
> > figure
> > > > out where the other end should be connected, by accident we discovered
> > that
> > > > if you plug the hose, the coach emergency brake released. (Good thing
> > we
> > > > are on a level lot) and if you un plug it, the emergency brakes stay
> > > > locked. Then we tried it with the emergency brake released and no air
> > came
> > > > out, so I think it is releasing the air bypassing the emergency brake
> > so as
> > > > to not release the emergency brake.
> > > >
> > > >
> > > >
> > > > Hope all that made sense, but it appears that is normal operation,
> > although
> > > > I never recall hearing that noise before when I stepped on the brake.
> > > >
> > > >
> > > >
> > > > Thanks again for all the help
> > > >
> > > >
> > > >
> > > > Paul & Debbie Potter
> > > >
> > > > Hesperia CA
> > > >
> > > > 1987 PT 38
> > > >
> > > > Hotel California II
> > > >
> > > >
> > > >
> > > > *From:* WanderlodgeForum@yahoogroups.com [mailto:
> > > > WanderlodgeForum@yahoogroups.com] *On Behalf Of *Wayne Kotila
> > > > *Sent:* Monday, October 26, 2009 1:56 PM
> > > > *To:* WanderlodgeForum@yahoogroups.com
> > > > *Subject:* Re: [WanderlodgeForum] Air leaking from front when brakes
> > > > applied
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Did you check the rubber hoses to the front brakes? When you step on
> > the
> > > > brake pedal air pressure applies your front brakes so you will have air
> > > > pressure in the supply hoses to until you take your foot off the brake
> > > > pedal. Sometimes from age those hoses will start leaking where the end
> > is
> > > > crimped on the hose and if you need to replace them, a farm supply
> > store
> > > > will carry high pressure hydraulic hose in different diameters and
> > lengths
> > > > and have different end adapters to convert the end connector to what
> > you
> > > > need. You should be able to get a new hose and adapters if needed for
> > under
> > > > $20.00.
> > > >
> > > > Wayne
> > > >
> > > > 1996 WB42
> > > >
> > > >
> > > > ------------------------------
> > > >
> > > > *From:* ppotter14950 audvid1@
> > > > *To:* WanderlodgeForum@yahoogroups.com
> >
> > > > *Sent:* Sun, October 25, 2009 9:38:25 PM
> > > > *Subject:* [WanderlodgeForum] Air leaking from front when brakes
> > applied
> > > >
> > > >
> > > >
> > > > Hi there
> > > >
> > > > Today while finishing up Air Force One supplemental braking install for
> > > > towed vehicle, had engine off and when applied brakes to test Air Force
> > One
> > > > and while pedal was depressed there was a constant air leak up front
> > around
> > > > the left front area, but could not find it. Any suggestions on where it
> > > > might be, will work on taking front driver side panel open and looking
> > in
> > > > there, but it is so tight in there and i dont know what i am looking
> > for so
> > > > any suggestions would be appreciated.
> > > >
> > > > Thanks
> > > >
> > > > Paul & Debbie Potter
> > > > 87PT40 - Hotel California II
> > > > Hesperia CA
> > > >
> > > >
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