Help - broke down, air problem

Tikvah · July 12, 2015, 10:56:43 AM

Driving along I suddenly heard air from below the floor. I got worse quickly, so I fortunately found a nearby rest area. When I stopped and set the parking brake the air stopped. When I released the air it started again.

I crawled into the spare tire compartment and found the source. See picture. The air is rushing from the bottom port of this unit. This is not a threaded port, it looks more like an air vent.

My guess is that something upstream is causing this. I'm afraid I'm loosing more air than my pump can maintain if I travel the rest of the way home....about 20 miles.

Ideas?

gumpy · July 12, 2015, 11:07:38 AM

yeah, that's your quick release valve for the parking brake. The diaphragm is broke. There's a rubber disk in it. It's serviceable.

Don't travel on with it leaking as your parking brake can engage.

For now, shove a wine cork in the hole to stop the leak. Hold it in with a tie wrap or belt or anything suitable. This will stop the leak.

HOWEVER, BE VERY CAREFUL WHEN YOU APPLY THE PARKING BRAKE BECAUSE IT WILL TAKE SEVERAL SECONDS TO ENGAGE. MAYBE LIKE 30 SECONDS OR MORE.
DON'T SET THE BRAKE AND JUMP OUT OF THE BUS UNTIL YOU'RE SURE IT'S SET.

BTW, been there, done that, used the wine cork to fix my bus, and that's how I know it will work.

On mine, I was able to replace the cork with a fine threaded bolt that I got at a tractor repair shop in Nebraska. Odd size, and fine thread. You're may be slightly
different if it's not threaded, but a cork should work.

luvrbus · July 12, 2015, 11:54:00 AM

The QR-1 cost less than 20 bucks at my NAPA store here just replace it or bypass it

Tikvah · July 12, 2015, 12:59:40 PM

Grumpy,
What a day to have an empty wine cabinet. That will now become standard safety equipment in the bus.
Note: always have at least one wine bottle in stock.

But, your suggestion worked perfectly. Wife found one of those cheap tension rods that we occasionally use inside a cabinet to keep stuff from moving. I removed the rubber tip, wrapped it a few times with duct tape, to make it tighter, stuffed it in the hole, and used two zip ties. It worked perfect until we got back on the highway....then poof!

Yup - the parking brakes will stop the bus!

The little zip ties couldn't hold the strain. Now I have to work in traffic. Well, I had some really wide, thick, long zip ties. So I tightened the first two, then snugged the big one around...that did the trick.

We're back in our driveway and the bus (and wife) are happy.

Now time for repair...

What is a QR-1 ?
I assume that is the rubber diaphragm? I assume I remove the four screws and I'll see a rubber flap and maybe a spring ? ? ?
Can I walk into NAPA and ask for a QR-1 or do I need to know more than a fifth grader?
How or why would I bypass this? I assume to work the parking brake, I need the pressure to unload sometime

Again, thanks for the help...ya'll got me home

luvrbus · July 12, 2015, 01:51:36 PM

Lets the air escape out faster you can live with out the QR-1 buses and trucks did it for years it is more for convenience than safety. Just ask for QR-1 if the guy behind the counter has anything between his ears he will know what you are asking for, when you plugged it was bypassed, the newer stuff don't use the QR-1 anymore it's made into the relay

gumpy · July 12, 2015, 02:09:14 PM

So now I'm gonna solve two more of your problems. I figure you owe me for keeping your wife happy, and you need a wine cork in your tool box. You send me a nice
Cabernet or Pinot Noir, and I'll send the cork back!

Glad you got it home. That one had me fooled when it happened to me. Glad my bus mechanic took my call when I indicated I was stranded and needed advice. :-)

I think the QR-1 Cliff is talking about is the actual valve itself; the whole assembly. Might be easiest to just put a new one in. When I put the diaphragm in, I tried to do it
without taking the valve out. Pinched it, and had to remove the valve to get it in properly anyway.

Jim Eh. · July 12, 2015, 08:17:47 PM

It speeds up release of the front brakes to help re-gain steering control in a panic situation ... if you have your wits about you to actually release your brakes to re-gain your steering control ....

The application air doesn't have to travel all the way back up the lines to the treadle valve to be released to atmosphere ... not that it is a great distance from your QR1 to the treadle valve in the first place but that's what it is there for. Just an engineering thing I guess. So it saves that .000684 seconds to release the front brakes after lifting your foot.

Tikvah · July 13, 2015, 03:39:51 AM

Grumpy,
If we cross paths I'll buy you that bottle...I might even share it with you 😀

I notice when I plug the exhaust port I no longer hear the parking brake set.

I might try replacing the rubber. Replacing the valve seems tricky in that space, but the four screws are easy access. However, if I bypass would I remove the QR-1 and plug the line? A permanent plug for the exhaust port won't be easy without threads.

Scott & Heather · July 13, 2015, 07:52:30 AM

Why are we calling him grumpy? Haha. Craig, are you grumpy?

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Tikvah · July 13, 2015, 10:03:17 AM

Thanks Scott, I just went back to look to see its Gumpy.... I didn't know his real name.

I just thought Grumpy sounded like a fun handle.

Gary Hatt - Publisher BCM · July 13, 2015, 10:46:54 AM

I can't even afford Two-Buck Chuck on my budget so I always carry a pack of Bubble Gum. Works for fuel leaks too.

Scott & Heather · July 13, 2015, 11:33:08 AM

Lol. I've never met Craig yet so I thought it was a thing to call him grumpy

I'm corrected

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gumpy · July 13, 2015, 07:03:56 PM

Quote from: Scott Bennett on July 13, 2015, 07:52:30 AM
Why are we calling him grumpy? Haha. Craig, are you grumpy?

I only get grumpy when people call me the wrong name!

gumpy · July 13, 2015, 07:08:30 PM

Quote from: Tikvah on July 13, 2015, 03:39:51 AM
I notice when I plug the exhaust port I no longer hear the parking brake set.

I might try replacing the rubber. Replacing the valve seems tricky in that space, but the four screws are easy access. However, if I bypass would I remove the QR-1 and plug the line? A permanent plug for the exhaust port won't be easy without threads.

Do your research before you bypass it. As indicated before, with the port plugged, your parking brake will take much longer to set. Like several seconds to maybe a minute. The air
that keeps it off has to equalize back into the system. If you pull the parking brake handle and then leave the coach thinking your brake is set, you might get a surprise when you
turn around and find your bus has rolled away.

I don't believe this is connected to the front brakes, either.