Bus Won't Go

[bowmaga]

Well our Super Betty is sold, and the gentleman is coming Saturday to get her.  I jumped in her today and fired her up and was going to move her into a more idea position for the new owner to check her out and look things over.....and she won't go.  She'll start, air up, high idle kick on, and i push the air brake switch off, put her in gear....and it doesn't go.  Could the brakes be froze up or something.  Its been in the mid 20's here for about 3 weeks.  some colder some warmer days.  I don;t get it.  the last time we drove her was in October and she was good to go.  I need some brainstorming on "what could be's" the problems.  Please Help!!

[Sammy]

What kind of bus is it?

[Kwajdiver]

What transmission?  What is the fluid level in the tranny?

Bill

[bobofthenorth]

Could have ice in an air line, could be the shoes are frozen to the drums, could have a stuck relay valve.  Try stomping hard on the brake pedal with the brakes released. 

[Blacksheep]

Build up the air pressure and do as Bob says. Push hard on the brake pedal and hold it it for a few seconds and then release the pedal. See if that works! I had to do that quite often here in Florida where it isn't cold when I had my Eagle.
Also tell us what type bus it is and what engine/trans you have!

Ace

[RJ]

Sammy, Bill & Ace -

It say's right at the bottom of Greg's post, in the signature area, that he's got a '79  MC-9. . .


Greg -

Chances are, especially if you've had some wet weather, that your drive axle brakes may be stuck to the drums.  Try this:

1.  Build air pressure in system to the governor pop-off, about 120 psi.

2.  With foot just resting on service brake, release parking brake.

3.  Make a full service brake application (right to the floor) and hold it for 3 - 5 seconds, then release.

4.  Put coach in reverse, and using you left foot to cover the service brake, add throttle with your right.

5.  If coach "breaks free" and starts moving backwards, immediately come off the throttle, wait a couple of seconds, then shift into Drive.

6.  Once back in Drive, you should be able to move the coach normally.  If so, suggest you take it for a 5 - 10 mile run, to get everything happy again.


If the above doesn't work, you may need to get some kind of heat to the drive axle, to thaw the interface between the linings and the drums.

FWIW & HTH. . .

[Blacksheep]

RJ although it states in his signature line "A Bus", I have found that not all that is written is true! Not necessarily in THIS post but speaking in General!

Ace

[ArtGill]

Try pulling up on the brake pedal.  I have had mine stick before after sitting for awhile.

Art

[bowmaga]

My bad on the lack of info......Super Betty is a 1979 MCI 9 w/ 740 auto Allison and 8V71 Detroit.  We did just have a tranny line replaced on the girl, the one that went from the back of the filter to the top of the tranny.  Might it be the fluid just isn't full enough?  Would that make her not go?  Not enough pressure?  Dang mechanics.....IS the only place to fill tranny fluid, where I check it, which is on the drivers side?  Hell i worried about starting this girl in 20 degree weather....one push of the button she fired right up....but she just doesn't want to roll!!  I think she secretly doesn't want to leave me.......I don't blame her.  I'll give the brake trick a go and hopefully that's all she is and she'll be a roller again.

[white-eagle]

greg, see tenor's post previously.  or you can do a search on my post last year.
http://www.busconversions.com/bbs/index.php?topic=10362.0

it happened to me a couple weeks ago.  took about an hour with heaters on high before whatever finally let up and we rolled out the driveway.

the bus was 60 inside, so i know wasn't pedal.  could have been park brake switch which is just inside the nose and it was 20 deg outside.  felt like front brakes.  we had tried the full 120# application 4 or 5 times, then tried putting it in gear, release brakes, stop, put in reverse, stop, put in drive, etc.  didn't do that until it felt like most wheels "loose", then sort of rocked it to break free the other wheel or whatever.

when i finished moving it and drove about 30 mi.  for the first time, we heard lots of water spitting from the rear tank.  for about 5 min, then stopped as pressure dropped.


i repeat this so you know how i broke loose in case that helps you.

[Sojourner]

About transmission engagement....if engine idle rpm is changing while selector move from N to Dr. If it does, chances are it is OK.

About freezing air brake system...if you don't hear air leaking, automatic purger is working normally, foot valve is exhausting after depress, parking control is exhausting normally and can get air out of all 4 air tank's drain valve (you may need to put some little heat on valve to remove ice in its passage) and no other ice blockage in air lines. Then I believe what Ace and RJ posted is your problem.

Hopeful you get it working to sell.

FWIW

Sojourn for Christ, Gerald

Safety caution:
A very important reminder to all freezing climate bus nuts driver, always check & drains wet tank first... if no water draining...then all other tanks and complete air brake system is freeze proof until after the day run. Before shut down...check wet tank for water. If it is less then a cup of water, the other tanks should be OK. However if this is your first time during freezing times...you need to be in a above freezing temperature or in warmed shop for 2 hours so all ice is thawed to fully drain all tanks.

[bowmaga]

The bus airs up, i can get it up to 120, and the relief valve blows and it appears to be ready to go....but it didn;t go.  I will try these suggestions today, during my lunch and see if this old girl will move.  I sure hope.  I try to post something this afternoon.  Everyone, say a little prayer to the bus gods for me.

[Kwajdiver]

Happen to me once,,, the tranny was to low, the MCI-9 would not go.  Added fluid and all was fine.

Just one of many things that can say "no go"

Bill


PS... I saw the model and the year,,,, I only ask for the transmission....    lol

[Don4107]

Still can't tell if you have a tranny problem or brake problem.  When you put it in gear and step on the throttle does the engine sound like it is loaded or does it rev like it is in neutral?

Don 4107

[buswarrior]

We need to take care with our terms, in order to not confuse our newer busnuts.

If the bus hasn't moved since October, the brake shoes may be rusted to the drums.

Let's reserve the word "frozen" to use when below 32 degrees F is a suspected culprit.

I'm thinking that if this bus has started and aired up as normal, that there will be no "freezing" involved in this lack of motion problem.

You need to introduce water into the brake shoe/drum and have it a lot colder for frozen brake mechanicals to seize the motion of the vehicle. The drive axle shoes have been pressed hard against the drum for months, no way for water to get in there, they have rusted in place.

RJ has it right, take that bus for a drive and use the brakes a lot to get the rust off.

To prevent this, busnuts who live where it isn't dry need to air up the coach, using shop air if necessary, and releasing the parking brakes monthly. A little move forward and back is good too, if the coach is mobile. For a coach that is planned to be stationary for really extended periods, loosening off the adjustment of the brakes so that the shoes are away from the drum when parked, and blocking the wheels to keep it from rolling away solves the problem.

happy coaching!
buswarrior