1985 PT40 Cruise Problems, better than a roller coaster ride

Gary,

Wow - that doesn't sound like fun! Thanks for the heads up here. Can

you tell us where to find the board in question, and provide a quick

explanation of how to clean the valves? A runaway coach is my worst

nightmare.

Here's a story:

My previous RV (1966 Travco) had the throttle linkage jam on the

freeway due to a loose air cleaner cover. At freeway speeds, I was

still having to apply throttle to maintain speed and thus had no idea

this was going on until I came across a helicopter logging crew, on a

steep downgrade, with a flagger standing in the middle of the road

holding a big read "STOP" sign. I had just picked the vehicle up not

half an hour earlier. I got her down to 40mph and she wouldn't slow

any further! Pulled the e-brake, didn't help, and the poor woman with

the stop sign was getting closer and closer. Unbuckled my seat belt

and STOOD on the brake with all my weight... got the speed down to

~30mph but still moving and about to hit this lady. Laid on the horn;

it didn't make a sound! Hit the aftermarket air horns - they didn't

work, either! My passenger stood up and made "get out of the way"

motions with his arms. She scooted over, but not enough to avoid

hitting her with the driver's side mirror... with seconds to spare I

stuck my head out the window and threaded the coach between her and

her brother's old pickup parked on the shoulder immediately opposite

of her. Missed her by mere inches but my awning bracket took out the

pickup's side mirror. Well, better that than her.

We flew past her and down into the logging zone with a large,

log-laden chopper hovering overhead... couldn't get the bus any slower

and still didn't know the throttle was jammed open because RPMs were

low, but I had the bright idea to pop it into neutral as we continued

down the grade, just to be sure and take the engine out of the

equation. While I was still standing on the brake. Boy, she stopped

fast! Almost sent me through the windshield. Then I heard the engine

perk up and RPMs climbed high. Turned the engine off, brakes smelled

like liquid rubber but she stayed put, so we trekked the couple

hundred feet back up the grade to have the discussion. All the above

happened in about a 30 second time frame... real quick.

We were on an Indian reservation and the Indian brother was torqued

off to no end about his pickup's mirror. Demanding police come, etc.

Didn't care it wasn't my fault, he wanted me jailed. Only after I got

in his face about his sister not moving out of the way in time, and

made him understand that my choice was either his truck or his sister,

did he calm down enough to have a rational discussion. A $200 bribe

for a $20 mirror and he called off the reservation police. Opened up

the engine compartment, found the problem, secured the air cleaner and

we were on our way.

Lesson learned... never drive a vehicle without a thorough inspection.

The non-functional horns and the loose air cleaner would have been

discovered had I paid more attention when I bought it.

-Ryan

'86 PT-40 8V92

On Mon, Dec 22, 2008 at 3:33 AM, GARY MINKER <"garym33407%40yahoo.com"> wrote:

> If you have a pre 1988 Bendix Cruise and you are driving along and suddenly

> notice that your cruise is stuck at full throttle, you are not alone. Your

> seat will pucker when you realize the on/off switch will not disengage your

> cruise throttle body and you are hurtling down the highway.

>

> In the 5 times it happened I was able to diagnose that when you apply the

> brakes, the pressure over rides a safety valve dump on the cruise throttle

> body and you can bring the coach to a stop and shut down the engine. Once

> the air pressure is alleviated, the valve snaps back to place for another

> scare at an unknown interval.

>

> It is pretty exciting to let go of the brake and see the engine come back to

> full 20 pound boost pressure.

>

> The culprit turned out to be sticking valves on the Bendix back board. The

> maintenance manual states that these valves should be cleaned at regular

> intervals. They are not kidding. I recommend at least every 20 years or

> 100,000 miles. Florida Detroit Diesel in Fort Pierce, Florida is the place

> to go. Mike the Svc Mgr and Gordy the Tech are kings.

>

> If anyone knows who is re-habbing the Bendix Controllers, please let me

> know.

> Thanks

> Gary

>