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Author Topic: Won't air  (Read 2010 times)
Tikvah
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« on: October 11, 2013, 05:57:27 AM »

Started my bus this morning and it wouldn't build air.
I know what it is but at the same time I don't....

Under the driver seat, behind the bumper is a air device thar is bleeding a lot of air through a rubber seal on the bottom.  It seems to be related to the brakes.

It won't close

What is it? What do I do?
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I couldn't repair my brakes, so I made my horn louder.
1989 MCI-102 A3
DD 6V92 Turbo, Alison
Tons of stuff to learn!
Started in Cheboygan, Michigan (near the Mackinaw Bridge).  Now home is anywhere we park
Tikvah
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« Reply #1 on: October 11, 2013, 06:01:48 AM »

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I couldn't repair my brakes, so I made my horn louder.
1989 MCI-102 A3
DD 6V92 Turbo, Alison
Tons of stuff to learn!
Started in Cheboygan, Michigan (near the Mackinaw Bridge).  Now home is anywhere we park
luvrbus
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« Reply #2 on: October 11, 2013, 06:07:16 AM »

I would say it is brake related that looks like the bottom of the brake treadle ( pedal)
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Dave5Cs
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« Reply #3 on: October 11, 2013, 06:54:38 AM »

Dave try taping it on the bottom. There probably  something stuck in the exhaust end. That like Clifford said is your brake valve from your peddle. It is stuck in the open position

Dave5Cs from Galaxy S III
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Lin
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« Reply #4 on: October 11, 2013, 09:05:53 AM »

You could also try reaching down and pulling the pedal up.
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Tikvah
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« Reply #5 on: October 11, 2013, 09:20:17 AM »

In the garage now.  Brake peddle is right, but still don't know if it needs replaced or cleaned, or rebuilt.  Either way, I think it's been leaking for awhile.  
I'll keep you up to date.

Could it be a back-feed from something else?
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I couldn't repair my brakes, so I made my horn louder.
1989 MCI-102 A3
DD 6V92 Turbo, Alison
Tons of stuff to learn!
Started in Cheboygan, Michigan (near the Mackinaw Bridge).  Now home is anywhere we park
Tikvah
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« Reply #6 on: October 11, 2013, 12:51:08 PM »

The problem:


And the solution:
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I couldn't repair my brakes, so I made my horn louder.
1989 MCI-102 A3
DD 6V92 Turbo, Alison
Tons of stuff to learn!
Started in Cheboygan, Michigan (near the Mackinaw Bridge).  Now home is anywhere we park
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« Reply #7 on: October 11, 2013, 03:15:41 PM »

Okay, that's not the solution.  Something is backfeeding through the valve system in the pictures above.  We don't know what.  Any ideas?
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I couldn't repair my brakes, so I made my horn louder.
1989 MCI-102 A3
DD 6V92 Turbo, Alison
Tons of stuff to learn!
Started in Cheboygan, Michigan (near the Mackinaw Bridge).  Now home is anywhere we park
luvrbus
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« Reply #8 on: October 11, 2013, 03:25:48 PM »

Crimp the hoses off to the D3 brakes one side at a time if that checks out then check the quick release valve your being a dual air system there is a check valve between the 2 systems also
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Tikvah
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« Reply #9 on: October 12, 2013, 10:39:51 AM »

Could I get you or someone good with air brake system on the phone please?

Dave
231-330-3615
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I couldn't repair my brakes, so I made my horn louder.
1989 MCI-102 A3
DD 6V92 Turbo, Alison
Tons of stuff to learn!
Started in Cheboygan, Michigan (near the Mackinaw Bridge).  Now home is anywhere we park
bevans6
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« Reply #10 on: October 12, 2013, 12:18:59 PM »

The exhaust port on the bottom of the valve is what lets air out of the piping after the brake application is released.  If air is there when it shouldn't be, it could be because the foot pedal isn't letting off all the way, but it's probably coming from the R-8 relay valve at the rear of the bus.  The upper section of the E valve is the primary section and works the rear brakes by sending air through a small line to the R-8 valve.  If you disconnect and cap off the small line at the R-8 end, the exhausting air may stop - if so that tells you it's the rear brakes.  The relay valve gets it's main air supply from the primary service tank to feed the rear brake cannisters, but it's remote-controlled by the treadle valve through the small relay line. Air could be feeding back from the relay valve, is what I am thinking.

Just noodling the issue, I'm not that familiar with dual brake systems.

Brian
« Last Edit: October 12, 2013, 12:22:34 PM by bevans6 » Logged

1980 MCI MC-5C, 8V-71T from a M-110 self propelled howitzer
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Tikvah
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« Reply #11 on: October 13, 2013, 05:57:19 AM »

Friday we replaced the treadle valve under the driver seat, then we found feedback through the push/pull valve while in park.  We replaced the push/pull valve without success.  Now we spent all day Saturday removing the inverter valve in the back.  With stuck bolts and broken lines it took most of the day.  We cleaned the inverter valve and hope to re-install that today with hopes that the problem is fixed.

If anyone has ideas I'm all ears....very frustrating day yesterday.  Not knowing if we're even doing the right thing.

Dave
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I couldn't repair my brakes, so I made my horn louder.
1989 MCI-102 A3
DD 6V92 Turbo, Alison
Tons of stuff to learn!
Started in Cheboygan, Michigan (near the Mackinaw Bridge).  Now home is anywhere we park
Oonrahnjay
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« Reply #12 on: October 13, 2013, 06:10:27 AM »

  Friday we replaced the treadle valve under the driver seat, then we found feedback through the push/pull valve while in park.  We replaced the push/pull valve without success.  Now we spent all day Saturday removing the inverter valve in the back.  With stuck bolts and broken lines it took most of the day.  We cleaned the inverter valve and hope to re-install that today with hopes that the problem is fixed.

If anyone has ideas I'm all ears....very frustrating day yesterday.  Not knowing if we're even doing the right thing.    Dave 

      OK, I wouldn't know a DD3 if you hit me over the head with one, but if you've got feedback through the push/pull parking/emergency valve, that would make me look more and more a leakage between "service" and parking chambers on one or more wheel cylinders.  Did you get a GOOD clamp off of air through the braided brake hoses running to each of the chambers when you did the test that Clifford described above?
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Bruce H; Wallace (near Wilmington) NC
1976 Daimler (British) Double-Decker Bus; 34' long
6-cyl, 4-stroke, Leyland O-680 engine

(New Email -- brucebearnc@ (theGoogle gmail place) .com)
Ralph7
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« Reply #13 on: October 13, 2013, 06:20:52 AM »

          You did not pinch off the air supply to the park brake at the rear brakes!!   That is the first thing to do. A bad diaphragm on one/both will allow air to escape through the R-8.
     Got mine from Luke, while in there one of the big ones was chafing so changed it.
     717-582-78three 3
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luvrbus
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« Reply #14 on: October 13, 2013, 06:52:54 AM »

Inversion valves are in the parking brake system they are open till it get a air from another source to close very seldom do they have a problem,there should be a shuttle valve not far from the pedal 

They function just like the name implies it shuttles air to different ports It would sure help if we knew what foot valve is in that bus a E what ?,I still think it is a DD3 problem
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Life is short drink the good wine first
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