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For 1991 # 277 : Took coach to mechanic to have engine temperature sensor and antifreeze changed. Temp gauge works now, but now supply air will not activate or come up.
Am planning to call Newell on Monday, but looking for answers before then. It seems through trouble shooting there is no power to the solenoids to allow the brake air to connect to supply air. Any ideas?
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Any chance mechanic accidentally unplugged a connection?
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Danny,
Can you be more specific about the problem? Do you have brake air, but not supply air?
There are no electrically actuated solenoids that bleed brake air to supply air. There are PPV, pressure protection valves that protect the brake air tanks from losing all air to the supply tanks, but they are not electrical.
Not trying to be wise guy, but can you hear air hissing?
Richard and Rhonda Entrekin
99 Newell, 512
Maverick Hybrid Toad
Inverness, FL (when we're home
)
(This post was last modified: 09-26-2015, 07:23 PM by
Richard.)
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(09-26-2015, 06:50 PM)ccjohnson Wrote: Any chance mechanic accidentally unplugged a connection?
Well, anything is possible, but all he did was drain the coolant, and remove engine temperature sensor on passenger side that drives gauge in dash.
Brake air builds up just fine. Usually over 70 psi, it would begin pressurizing the supply air system. That connection is not happening now. We do not hear any leaks of air.
I did have him drain and refill genset coolant as well, so it did work. Now the genset will not extend because of a lack of air pressure, so the gauge
appears to be correct.
A diagram or schematic of supply system would be most helpful! Thanks for looking!
Danny
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Does the pressure in the brake tank increase went the engine is running? Have you plugged in to AC power or started the generator and turned on the 120 volt air pump to see if the pressure comes up with the 120 pump?
If it does, your engine mounted air compressor may not be coming cycling on.
Michael Day
1992 Newell 43.5' #281
NewellOwner.com
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I think Richard may be on the right track. Perhaps a stuck PPV is not letting air into the supply system. Not exactly sure where it is located though.
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i believe that valve is on top of the round big tanks in the front.
i had leo put a new one in mine. it was not fun to get at if that is the one.
it is just a check valve and usually they stick open, not closed. sounds like a very strange failure
tom
2002 45'8" Newell Coach 608 Series 60 DDEC4/Allison World 6 Speed HD4000MH
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On my 93 coach the ppv is located on the bulkhead in front of the rear axle near a pair of quarter turn ball valves and the pressue switch that triggers the the low air pressure light. Unless someone got under the coach and shut the ball valves the ppv is the only restrictor of air to the gauge. Since the brakes are pressuring the supply tank itself is pressurizing. One final check would be to check the pressure gauge at the rear six pack. If it is low then the ppv is likely stuck closed, it seems to happen at the weirdest time.
Basically, the dash gauge is fed from a distributor block adjacent to the front six pack. The supply to that block comes from one of the two ball valves I mentioned above, the supply to the rear of the coach comes through the other ball valve. A T after the ppv supplies the two ball valves. The ppv is supplied by the rear air tank known as the service tank. This is the arrangement on my 93 coach. The ppv is quite cheap, changing isn't hard but will cost you some skin.
Jon Kabbe
1993 coach 337 with Civic towed
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A ha!
Jon has again provided a great clue. I forgot about the isolation valves. The mechanic could have intentionally or inadvertently closed the quarter turn valve(s).
Richard and Rhonda Entrekin
99 Newell, 512
Maverick Hybrid Toad
Inverness, FL (when we're home
)
Posts: 90
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Joined: Aug 2015
(09-26-2015, 07:55 PM)Fulltiming Wrote: Does the pressure in the brake tank increase went the engine is running? Have you plugged in to AC power or started the generator and turned on the 120 volt air pump to see if the pressure comes up with the 120 pump?
If it does, your engine mounted air compressor may not be coming cycling on.
Brake pressure is zero until engine is started. Then brake pressure begins to build. At some point (around 70-80 psi) the supply system would begin to
pressurize. Brake pressure is building to 120 or so, but supply pressure never builds.
I just bought the coach 08-25-15 and didn't verify the operation of the electric compressor. I found the switch, but don't have a clue as to what it actually operates
and can't find it mentioned in any of the books.
I'm suspecting there is a solenoid or regulator which 'guards' the air pressure for the brakes and only allows flow to the supply system above a required minimum
for safe brake operation. There has to be something malfunctioning in there or maybe a switched valve?
Where are the isolation valves?
Thanks!
Danny
