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Message |
Buddy Tennison (Buddyten)
Registered Member
Username: Buddyten
Post Number: 97
Registered: 7-2005
Posted From: 24.233.243.30
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 22, 2011 - 2:25 pm: | |
OK guys: Changed out the park valve assy on my 80 Eagle (got it from Ed at Jefferson). When it started building air, it was still blowing out the bottom of the park valve assy. While trying to figure out what was happening, I was messing with the park brake release button. Found out the just moving it and jiggling it a hair would stop the park valve assy from blowing by. Also, when you move the park release button a little, I can hear some air releasing from underneath (I think in the spare tire area).
Do I need to replace the park release valve? Or is there an adjustment on those? What do you suggest. I can hold my finger over the bottom of the park valve assy until I hear the air compressor cut off, and it quits blowing by.
Any suggestions? Just had a new air compressor, governor, and drier unit put on last week. Been having problems with the park valve assy and went ahead and replaced it as well. |
larry currier (Larryc)
Registered Member
Username: Larryc
Post Number: 377
Registered: 2-2007
Posted From: 66.87.113.79
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 22, 2011 - 4:09 pm: | |
If you have spring brakes, you have a blown emergency diaphragm. Put in a new service pack and put her back in the wind.
The escaping air is letting the spring brake drag the brake shoes instead of releasing the shoes from the drum. If you must drive it, just have a fire truck follow you because when that 125 lb brake drum gets cherry red the fire truck will be your only chance to save your coach. |
Buddy Tennison (Buddyten)
Registered Member
Username: Buddyten
Post Number: 98
Registered: 7-2005
Posted From: 24.233.243.30
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 22, 2011 - 4:18 pm: | |
Larryc:
Not sure if what I have is spring brakes. Do know they are DD3. Anyway, if I stop the park valve assy from blowing by, I can release the brakes with no problem, and they do not heat up, drag, etc. Think what you describe is the problem, and are the service packs available at Truck Pro Parts, or will I need a special order from someone |
George M. Todd (George_todd)
Registered Member
Username: George_todd
Post Number: 1306
Registered: 8-2006
Posted From: 99.29.79.160
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 23, 2011 - 12:33 pm: | |
Buddy,
There is a lot of confusion here, and lets try and clear some of it up.
First off Larry is trying to apply spring brake logic to a DD3 parking diaphragm failure. If a DD3 parking/emergency diaphragm fails, air will blow from the exhaust port on the rear brake relay valve, when the parking brake is APPLIED.
The park/emergency diaphragm on spring brakes is pressurized when the parking brake is RELEASED.
The inversion valve will not let the park/emergency brakes release until the brake reservoir pressure reaches at least 80 psi. Then when you push the knob in, the inversion valve should release the pressure from the park diaphragms, and apply pressure to the lock roller assembly to mechanically release the parking application. The locking rollers keep the brakes mechanically applied when/if the parking pressure leaks off.
So, please start your bus and air it up without trying to push the park knob. With full air pressure, shut the engine off, and listen for air blowing. There shouldn't be any, if there is, tell us where. Then block the wheels, and push the release knob. If air was exhausting due to a bad park diaphragm, it will stop, the rest of the air in the park system will exhaust at the same time, and the brakes should release.
Trying to get a release before full air pressure will cause confusion, as the inversion valve will not allow a release with low pressure even if you hold the release button down.
G |
Luvrbus (Luvrbus)
Registered Member
Username: Luvrbus
Post Number: 1315
Registered: 8-2006
Posted From: 24.251.184.12
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 23, 2011 - 7:40 pm: | |
Larry may not be wrong Buddy owns a 1980 model 10 Eagle I believe and it should be spring brakes not DD3's
good luck |
George M. Todd (George_todd)
Registered Member
Username: George_todd
Post Number: 1307
Registered: 8-2006
Posted From: 99.29.79.160
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 23, 2011 - 9:55 pm: | |
First line of Buddy's 2nd post, second sentence:
"Do know they are DD3."
Aside from that, a blown emergency diaphragm on a spring brake system will not cause air to blow out of a relay valve with the parking brakes APPLIED.
G |
Luvrbus (Luvrbus)
Registered Member
Username: Luvrbus
Post Number: 1316
Registered: 8-2006
Posted From: 24.251.184.12
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, November 23, 2011 - 10:24 pm: | |
George before we get to deep here Eagles are plumbed to act like DD3 even the release part you have to apply brake pressure to make it release.
Most spring brakes just fill the chamber Eagles are plumbed to keep pressure on the parking chambers on spring brakes at all times not just the quick charge of air for release If Buddy has DD3s it will be the only 1980 model Eagle I ever saw with DD3's Eagle went to spring brakes in late 1978 the same time they went to the wider brake shoes
good luck
(Message edited by luvrbus on November 23, 2011) |
Buddy Tennison (Buddyten)
Registered Member
Username: Buddyten
Post Number: 99
Registered: 7-2005
Posted From: 24.233.243.30
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 24, 2011 - 12:18 am: | |
Guys:
I say I have DD3's. I had a rear can to fail last year. They had to replace the can with DD3's, as that was what was on it. Had to get one from Jefferson, as the local Truck Pro didn't have one. Even went on this board to find out how to convert it over, but at the time, it was too time consuming and had to get the coach back on the road. |
Buddy Tennison (Buddyten)
Registered Member
Username: Buddyten
Post Number: 100
Registered: 7-2005
Posted From: 24.233.243.30
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 24, 2011 - 12:24 am: | |
Guys:
I say I have DD3's. I had a rear can to fail last year. They had to replace the can with DD3's, as that was what was on it. Had to get one from Jefferson, as the local Truck Pro didn't have one. Even went on this board to find out how to convert it over, but at the time, it was too time consuming and had to get the coach back on the road. |
George M. Todd (George_todd)
Registered Member
Username: George_todd
Post Number: 1308
Registered: 8-2006
Posted From: 99.29.79.160
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 24, 2011 - 11:16 am: | |
Buddy,
Thanks for clearing things up here. Trying to continue in a helpful manner, you may have an earlier shell that was converted and re-titled in 1980.
What we really need to make a proper diagnosis, is how the system behaves while it is fully aired up. So, please block the wheels, and air it up. With full air pressure and the parking brake applied, there should be no air blowing. If air is blowing from the rear brake relay valve exhaust port, it sounds like your other DD3 can has a leaking park/emergency diaphragm. If the blow stops when the parking brake is released, this will confirm it. Also, if this is the case, your parking brake application will not be very strong, as much of the air is leaking off.
The parking knob controls the inversion valve, and from what you say, it could be worn. DD3s exhaust most of their air from the rear when the parking brakes are released, while spring brakes exhaust air when they are applied.
G |
Luvrbus (Luvrbus)
Registered Member
Username: Luvrbus
Post Number: 1317
Registered: 8-2006
Posted From: 24.251.184.12
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 24, 2011 - 12:21 pm: | |
1980 was the change over from the 05 to 10 you see both the 05 and 10 in 1980 he probably has a 05 chassis, the can location is a giveaway the 05 is mounted on the back of the axle the 10 with springs on the front side a 05 could have either Eagle never wasted`spare parts lol.
Takes about 4 hours to change DD3's to springs on a Eagle without buying any different hardware takes a little re plumbing
(Message edited by luvrbus on November 24, 2011)
(Message edited by luvrbus on November 24, 2011) |
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