Someone familiar with an auto parking brake on a Chevy/Workhorse chassis?
Steve Wolf
brake on a Workhorse or Chevy chassis.
I have learned that a flashing light leak down is most often traced to
either the pressure maintenance switch or solenoid valve. I really
don't want to throw $1000 in parts at the thing with the hope that maybe
one or the other will fix it. Neither is leaking. My luck is that I'd
then need to replace the pump and actuator and be into the thing for
$2500. I probably should flush the Dextron anyway.
Wait.
The pedal should still work, right?
Most of those working on these systems have fried their propeller shafts
and their pedals aren't working. It appears from these people that they
end up with no parking brake at all.
Help me out here. I should be able to pull the clevis pin on the auto
brake and still have the parking brake pedal, right?
Again, looking for actual experience, the kind you get when you get all
greasy.
Thanks,
Steve
www.wolfswords.com under the motorhome link
Kenn Smith
Chevvy P30 chasis with a GM 4 speed automatic transmission with the
Autopark feature.
If we are the same you probably don't want to pull the cleavis pin. My
Autopark locked up and I had the pin pulled so I could get home from
uproad a ways. I discovered that I had neither a parking gear nor a
parking brake once that pin was pulled - that was adventuresome. I ran
it about 200 miles that way and according to my transmission guy -
"didn't do my transmission any favor by doing that."
Squire
Steve, Go over to RV.NET and check for parking brake
at:
http://www.rv.net/forum/index.cfm/fuseaction/search/parms/sw%7Bparking%20brake%7D%7Ckm%7Bexact%7D%7Ckl%7Bm%7D%7Cfm%7B%7D%7Cpd%7B365%7D%7Cma%7B%7D/sr/1.cfm
A guy named "Old Used Bear" there can tell you all you want to know
about the dreaded parking brake.
On a P-30 Chevy, you can pull the pin and use the E.brake to park.
Eddy
Steve Wolf
I'm looking at the service manual schematics of the cabling and it looks
to me like the parking brake pedal cable and the auto park cable come
together at the relay lever. It looks like either the parking brake
pedal cable or the auto park cable would engage the brake. I was under
there today with an incomplete understanding of the propeller shaft. I
need to crawl under there again. It is apparent from your report
pulling one clevis disconnects both.
Then perhaps there is a modification which would allow the continued use
of the parking brake pedal cable while the auto park cable is
disconnected. That makes so much sense. Even if I were to throw the
money into the auto park, I'd still want to modify to allow for the
eventuality of another failure. I'd still want independent operation so
if ... wait ... excuse me ... so WHEN the auto park fails again I still
have a parking brake.
Thanks again,
Steve
www.wolfswords.com under the motorhome link
Steve Wolf
Right? Anyone?
Steve
www.wolfswords.com under the motorhome link
Hunter Hampton
<eww...@sbcglobal.net> wrote:
>
>A guy named "Old Used Bear" there can tell you all you want to know
>about the dreaded parking brake.
Say, any relation to "Grizzled Bear"???
Kenn???
Hunter
Steve Wolf
pin, was that a pain in the butt due to it being under pressure? I'm
expecting that was a royal PITA. And especially on the side of the
road, the thing on a jack (?), maybe no jack stands (?). The pucker
factor would be between high and ultra high, no? I don't fit under my
box unless it's up on ramps.
For someone sort-of following: The parking brakes are applied by an
automatic device whenever the motorhome is in park. The brake is off
when a pump overcomes the pressure of a large spring. When the
hydraulics fail, they fail in the "on" position. You come to an abrupt
stop as brake pads are applied to a propeller brake off the
transmission. A propeller brake looks all the world like a little drum
brake. In order to relieve the parking brake, one must pull a cotter
pin and push a clevis out. That releases the cable that is applying the
brakes. That pin must be under a lot of pressure. It is going to snap
out. Then the motorhome has no parking brake. There is nothing holding
it in place. It will roll in whatever direction gravity dictates. As
you have packed yourself under the center of the motorhome, that rolling
will become a huge and immediate problem significantly more problematic
that when the motorhome was stopped with the brake on. Something tells
me the emergency room will understand all the injuries except the gravel
embedded in the crack of your butt. That's the "pucker factor".
Steve
www.wolfswords.com under the motorhome link
Lone Haranguer
I knew but I've forgotten.
LZ
RVer Don
"Steve Wolf" <ne...@w8iz.com> wrote in message
news:5HaAm.13199$Lw1....@newsfe03.iad...
> Thanks, Kenn.
>
> I'm looking at the service manual schematics of the cabling and it looks
> to me like the parking brake pedal cable and the auto park cable come
> together at the relay lever. It looks like either the parking brake pedal
> cable or the auto park cable would engage the brake. I was under there
> today with an incomplete understanding of the propeller shaft. I need to
> crawl under there again. It is apparent from your report pulling one
> clevis disconnects both.
I had the parking brake lock up on my 95 Bounder on the Chevy chassis. A
pin had to be driven out which released the brake in order to drive. I had
no parking brake of any kind and had to have my wife get out and chock the
wheels if not on level ground. The problem with the brake turned out to be
a solenoid valve on the bottom of the brake unit on the driveshaft.
Don in Tracy, Calif.
anne watson
"...
> Steve Wolf wrote:
>> I am searching for someone who has actually wrenched on a auto parking
>> brake on a Workhorse or Chevy chassis.
Take a look at this guy's page.
Anne
Kenn Smith
had it towed to a transmission shop and they pulled it. I found the
instructions for doing so in my Chevvy owners manual and they don't have
any hazard warnings with them.
I put my front jack down to raise the unit a bit and make it easier for
the mechanic to get under there which is probably why mine didn't start
rolling when the pin was pulled. Plus, it was on a pretty flat shop
floor.
JerryD(upstateNY)
pin, was that a pain in the butt due to it being under pressure? I'm
expecting that was a royal PITA. And especially on the side of the
road, the thing on a jack (?), maybe no jack stands (?). The pucker
factor would be between high and ultra high, no? I don't fit under my
box unless it's up on ramps.<<<<<<<<<<<<<<<<<<
Up on ramps or on the ground......I wouldn't go under it without have the
wheels chocked...real good !!
--
JerryD(upstateNY)
JerryD(upstateNY)
Something else to remember..........NEVER put jackstands under your RV on a
ashphalt driveway without putting �"-�" plywood under them.
I know a guy who was killed because a jackstand sank into the driveway and
the bus fell on him.
--
JerryD(upstateNY)
Mike Hendrix
>I am searching for someone who has actually wrenched on a auto parking
>brake on a Workhorse or Chevy chassis.
>
>I have learned that a flashing light leak down is most often traced to
>either the pressure maintenance switch or solenoid valve.
Steve, let me start this by saying that I am NOT a mechanic. However,
I owned a motorhome (for 5-miserable years) mounted on a P-30 chassis.
Piece of shit is what the P stands for in P-30.
With that behind us, let me say that the "pressure maintenance switch"
was definitely the weak link in that system. I suspect I had that
damned leaking switch replaced at least 4-times in 5-years. It might
have been 5-times. ------- Did I say piece of shit?
Always, the indication was that light (mine did not flash) it just
indicated that the brake was engaged ----- yellow it was.
That always indicated I was low on the fluid (power steering fluid if
I remember correctly). But the fluid was low because of that SLOW
leak in that screw in pressure sensing valve. The pressure sensing
valve was not expensive ---- (after the 2nd experience I started
carrying a spare). The installation was a bitch but not that
expensive. Most every mechanic has replaced that switch ---- it is
famous for leaking ----- but you need to carry a spare if you own a
P-30 chassis. It was always easy for me to find a mechanic to crawl
under the motorhome and replace the switch and fill up the reservoir.
To get the motorhome to the mechanic I always had to put chocks under
the wheels -----Good NO JOKE chocks ---- then crawled under that
diesel pusher and pulled the clevis pin. Once that clevis pin was out
there was NO brake of ANY kind. I have had to travel for several days
like that ------- not fun --- in order to get to a mechanic. Every
time we stopped the MH for any reason I would hold the brake petal
down while my wife went outside and put chocks under the tires.
Seriously, the thing would roll away if the chocks were not in place.
Everything that I discussed above was with my Parking Brake on a P-30
chassis.
HTH
mike
--
Steve Wolf
pleased. I guess it all depends on what card you draw.
I believe the "ugly green switch" is my problem, too. I am going to
order two once I figure out where to get it from.
Steve Wolf
remove the clevis pin.
I am apparently more valuable alive than dead as I required my
son-in-law to apply the wheel brakes and toggle the parking brake pump
while I was under the coach watching the mechanisms work. He didn't
crush me. Good kid.
Examination of the clevis pin on the relay lever shows that you can't
remove it if you tried. Both with the brake engaged and with the brake
disengaged the relay lever is positioned behind the structures. These
structures prohibit the removal of the pin. So the mechanics that do
this must do something else first.
Has anyone removed the auto park parking brake cable clevis pin to
release the parking brake on a P-30 with their own hands? How did you
do it?
Luckily my auto park still works. But when it fails I want to know what
to do.
Hunter Hampton
<jer...@somewhere.com> wrote:
>Something else to remember..........NEVER put jackstands under your RV on a
>ashphalt driveway without putting �"-�" plywood under them.
>I know a guy who was killed because a jackstand sank into the driveway and
>the bus fell on him.
I was almost killed... woke up in the hospital ER.
After that I dyed my hair blonde and never had to change another tire
myself.
Hunter
Mike Hendrix
I have always been able to get mine from Napa or a Chevy dealer.
HTH
mike
--
nothermark
maybe a silly response as I never saw the setup. From what I read two
cables come down to a common connector. Can one cable be cut leaving
the parking brake active? Can the other end of the cable at the shift
mechanism be uncoupled?
RVer Don
on the Chevy chassis drove it out with a center punch I gave him in a couple
of minutes so apparently it isn't that hard to do.
Don in Tracy, Calif.
Steve Wolf
MotorhomesP-30GM, I've learned that you can drive the pin out but only
after you pry the relay lever toward the drum brake.
Steve
www.wolfswords.com under the motorhome link