Community Forums

mythplaced · 08-12-2010, 06:14 PM

I too have had to perform the "Mobile Parking Brake Maneuver"..And that brake works excelently!

How do I know???

I got myself in a sticky situation at a fuel stop and had to hurredly unhook the TOAD so I could back my self out of the aforementioned sticky situation...(I was blocking at least 20 customers)

Just as the pins came out of the towbar the MH started moving forward as if by magic, U suppose that the MH still being in gear might have had something to do with it?

Dropping everything, I "sprinted" into the MH,
rushed to the front,
and punched that parking brake button like I was the President launching a nuclear attack!

That brake stopped the MH INSTANTLY, I mean "INSTANTLY", and I was catapulted headfirst into the windshield, mere inches from hitting a car (you should have seen the face of the woman inside)

Yea, kinda like that, but with more panic!

So I am here to "Testify", that parking brake does its job quite well!

SteveS · 08-12-2010, 06:58 PM

Jim&MaryJo - I'm not sure about the new Alpines but the older ones (and I thing the new ones) use a driveshaft brake rather than drum or disk parking brake like most other air ride RVs and trucks. The driveshaft brake will burn out quite rapidly and I suspect would not be very useful to bringing an Alpine to an emergency stop from highway speeds. It is designed as a parking brake to hold the RV once it is stopped, not to bring it to a stop from highway speeds.

Jim&MaryJo · 08-13-2010, 07:49 AM

Got me thinking about the old Life cereal ad that goes something like:
"Let's get Mikey to try it"

Thank you Mikes' for sharing those experiences and everyone else for guidance.

Sounds as though a brake failure strategy might include:
--engage exhaust brake (if not already on)
--hit emergency blinkers
--look far ahead for clear areas
--swerve and honk as necessary
--deploy parking brake at slowest speed possible
--keep trying brakes thru this process
--stay focused while DW is screaming

--try not to burden yourself with guilt for ignoring advice to bleed brake system periodically

EngineerMike · 08-13-2010, 11:23 AM

Mikey's wife had a few choice words to say about the experiment. I don't recall the exact wording, but the sentiment lingers still. Suffice it to say, I enjoyed the comfort of knowing the results of the drill more than EngineerAnnie.

Renipladlo · 08-14-2010, 12:24 AM

EM - are they adjustable? Know this is a stupid question, but since I actually have not seen the thing under there, thought I would ask. If it is, can you post the "how to" on this thread, or on the ACA Tech Library Page somplace. I have not looked so it may be there, but it will have to wait until I get home.

Old Scout · 08-14-2010, 08:24 AM

Never attempted it but it looks like a simple cable adjustment from the air actuated release piston to the internal brake shoe [on drive shaft]. When activated, the brake shoe is held against the drum by a large spring. Suppose there is a "sweet spot" for adjustment [ie not too long and not too short] but the adjustment would seem to be the min. space needed to keep the shoe from dragging on the drum when the brake is off.

Accordingly, normal wear and tear would tend to "lengthen" the cable requiring it to be tightened to prevent dragging. Guess repeated "practice" stops could wear the shoe thus requiring the cable to be lengthened.

Renipladlo · 08-14-2010, 10:16 PM

Thank you Old Scout. Will look it over next time I'm under it. Which I don't like to do as often as I should.

EngineerMike · 08-15-2010, 11:07 AM

"Adjustment" doesn't come in to play in actuation, as in variable stopping power, nor would that be a good thing to attempt. It is on, or it is off.
Likewise, you'll decide pretty quick that the rearrangement of your coach contents isn't where you want to invest your time after multiple tests. One test so you know what to expect is pretty close to the max I cared to try. It was one more than needed according to the wife's kindly advice and sage counsel.

The brake shoes are not true wear parts like ordinary drum brake shoes, since they are almost never engaged while the coach is moving. Just on or off, no wear periods to speak of. Haven't looked closely at the cable to see if there is an adjuster.

It could be that in rare cases of extreme rust, special maintenance would be advisable, since there is no scrubbing of the drum surface to remove heavy oxidation. If I was in that situation, I'd take the rig to a big rig brake specialist that does high volume work and see what they'd have to say. E.g. there is an enormous truck brake place in West Sacramento (truckers come from all over for brake work by Capitol Clutch & Brake) w/a reputation for everything brake; that type of place; gotta be one in most large cities.

Lindenberg · 08-19-2010, 10:46 PM

I took a length of 3/4" pvc pipe that would just slide under the flat top of the parking brake switch then cut out a strip from the pipe so it would fit snugly around the parking brake switch. Once the brake is applied I can slide this under the switch and prevent it from being pressed.

mythplaced · 08-20-2010, 08:08 AM

Personally I can not understand why anyone would purposely defeat a safety switch..

JMO

SteveS · 08-20-2010, 01:10 PM

Mythplaced - I'm not sure what you are in reference to but I think you may have misunderstood Tom about his PVC tool. I believe it is a tool made for safety purposes, not to bypass a safety switch. When it is inserted, it will prevent accidental release of the parking brake.

Thanks for the tip Tom, I think I will build one also.

Dave Stanley · 08-21-2010, 02:43 PM

Does anybody know where I'd get a new screen door rubber seal for our 2005 38TP ?
Ours is ripped at the top. Also, it appears that our exterior door swing bars at the top of the door [ the ones that fold and hold the door open ] is sagging which caused the seal to rip. Thanks in advance. Dave Stanley

takepride · 08-21-2010, 09:17 PM

PTL Engineering made the door. They are referenced repeatedly on the forum. Just search their name, or click here for their website Welcome to the Official Site of PTL Engineering

Dave Stanley · 08-24-2010, 12:54 PM

Thank You ImagineIF....

Just ordered the SOS Air Brake Safety Clip from Smith on Safety. Debra was so helpful and as my knob is in an indentation on the dash board with 1 1/4 inch stem, but being indented I was not sure which to order, the 1 1/4 inch or the 7/8 inch stem model. She is sending me both and I'll send back the one that does not fit. Ordered on line after talking to her.

How's that for customer service ?? Fantastic, NO ?

Smith on Safety is a good thing !! www.smithonsafety.com

Thanks again.

Dave Stanley
05 38TP
Vacaville. CA