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1983 coach leveling issues. Pneumatic control and power schematic.
#1

Control overview.
panel at the drivers position. At the top,4 bat handled center return momentary contact switches, forward=fill, back=dump. bottom left switch 2 position bat handled toggle, forward= manual, back= automatic (road). bottom left switch 2 position bat handled toggle. forward=on for the auxiliary air compressor, back =off
KIP relay's, Bendix hardware
2 sets of "six pack" 12vdc EP's (manual and automatic fill and dump relay's. one fore and one aft.
4 newer bags all around. 4 in back 2 in front.

Current issues.
1. air leaks off overnight while in manual.
2. uneven fill performance of air bags. drivers back takes a very long time and never reaches maximum height. All dump operations work at the same speed.

Current repairs
1. I installed new plunger's/seats and springs in the KIP solenoid six packs.
2. Replace the air/moisture bleeder on the main air tank.

Current request for help.
I would like to find, a parts list (Bendix) for the air leveling system. Bag fill relay.. various other leveling related controls and parts. I would also like to find a power and control schematic diagram for the manual and automatic leveling system, electrical and pneumatic.

I realize this coach is dated. Still I would like to have these parts and drawings so I can complete repairs.

Thank You Brion Cool


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1983 Single Axle. Detroit 6v92.
Retired Refrigeration Mechanic
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#2

Some questions.

Air leaks off overnight:
Supply air gauge?
Air bags/coach settles?
Air brake gauge?

On coach slow to raise on one corner………How much pressure does the system build?


Can you post a pic of what you are calling six packs? Here is why, the coach did not originally come with six packs. It originally came with the raise, lower, and travel air solenoids hard piped in the appropriate way. Before we go further, it would be great to understand which setup you know have. Comments on one style system are not transferable to the other.

Richard and Rhonda Entrekin
95 Newell, 390  Ex caretaker
99 Newell, 512  Ex caretaker
07 Prevost Marathon, 1025
Maverick Hybrid Toad
Inverness, FL (when we're home Cool )
Reply
#3

(05-30-2025, 12:10 PM)Richard Wrote:  Some questions.

Air leaks off overnight:
Supply air gauge? 118 PSI
Air bags/coach settles? Yes, starting with the drivers back. Then eventually all the others
Air brake gauge? 118 PSI

On coach slow to raise on one corner………How much pressure does the system build? 123 psi on first build from flat. Then 118

The picture of the relay indicates an general area leak.

Thank You for the reply.


Can you post a pic of what you are calling six packs? Here is why, the coach did not originally come with six packs. It originally came with the raise, lower, and travel air solenoids hard piped in the appropriate way. Before we go further, it would be great to understand which setup you know have. Comments on one style system are not transferable to the other.

1983 Single Axle. Detroit 6v92.
Retired Refrigeration Mechanic
Reply
#4

Thanks for the follow up. Those are indeed six packs. Someone has retrofitted the six packs to the coach. It came with a different style manifold originally. I can see the old screw holes where the original was mounted.

I notice that one of your brake tank gauges is also dropping. That could be because of the leak at the relay valve.

I am sort of guessing this is a new to you coach, and you are on the journey to making it roadworthy. So I am going to give you a few links providing the fundamentals of how the system works. With your background you will be able translate the fundamentals into how the switches should be wired.

https://www.hwhcorp.com/ml20635.pdf

http://www.newellowner.com/newell-air-system/

Your situation is actually easier to troubleshoot because you have toggle switches instead of the HWH control panels.

Here are some key takeaways;
The Height Control Valve is BEFORE the six pack. The travel solenoids must be open for the HCV to automatically control the height.
When the key is OFF, the air bags should be isolated from the rest of the system. Translation, a leaking supply gauge and a dropping corner are NOT the same leak(s).
When checking the actuation of a solenoid, a steel washer should stick when actuated.
You are going to need to fabricate an air system isolator to temporarily install between the six pack and an air bag to understand what is leaking. https://newellgurus.com/showthread.php?t...D+isolator

Don’t hestitate to ask specific questions. We are here to help. The above reading should get you started.


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Richard and Rhonda Entrekin
95 Newell, 390  Ex caretaker
99 Newell, 512  Ex caretaker
07 Prevost Marathon, 1025
Maverick Hybrid Toad
Inverness, FL (when we're home Cool )
Reply
#5

Thank You for your follow up. I will read, watch and assimilate the knowledge you have provided and then test components.

1983 Single Axle. Detroit 6v92.
Retired Refrigeration Mechanic
Reply
#6

I watched the video link set. I found the leak on one of the drive axle brake relays. A 3/4" plug had been installed without thread sealant.

Drivers back (left) bags never fully inflate or deflate. This set of bags is receiving air from an unknown source. The kip solenoids have brand new plungers/seat, o rings and springs. The closest drawing I could find on hwh's website is mp75.2108 23sep04. For the drive axle manifold it seems to show the raise valves supplied in parallel with compressor air. The enclosed pic seems to show right side supplied with compressor air and the left side from another source. The travel solenoids are supplied by the HCV's. I can't access cad drawings of the manifold. I have emailed HWH, they indicate a wait time of 4 weeks.
Thank You Brion



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1983 Single Axle. Detroit 6v92.
Retired Refrigeration Mechanic
Reply
#7

The picture is very helpful.   HWH will be no help, because that is NOT an HWH manifold. There was a short period where Newell was making their own. I believe you have one of those.

Let’s confirm some things before disconnecting air lines. 

Using your picture, I think the travel solenoids are the two on the far right. I think that because they are wired together. Please confirm by key on, travel on, and checking the solenoids to see if they are magnetized. A small steel washer is your friend. 

Keeping this one counterintuitive concept in mind, the six pack is BETWEEN the height control valve and the air bag. That throws many a truck mechanic for a loop. 

In order to approach the problem systematically, the air lines must be identified. The two adjacent to the travel solenoids will originate at the HCV. One top and one bottom. The left side is normally on the top. 

It’s the other four lines that I don’t know about. One pair, top and bottom, should have supply pressure. They would be used to raise the coach when in Level mode. The other pair, top and bottom will go to the air bags. 

This is how I would approach it. You will need an external air compressor and some fitting arrangement to connect to the tubing that you disconnect from the manifold. I would start with the tubing on the upper left. Disconnect from the manifold and pressurize that tubing with the air compressor. If this is indeed the line to the left air bag, then the left rear should start to raise when you pressurize the line. 

I think, and that’s a SWAG, the middle lines, top and bottom are from the supply side. That would be confirmed by disconnecting them and seeing if they air up when you turn on the coach compressor.

Richard and Rhonda Entrekin
95 Newell, 390  Ex caretaker
99 Newell, 512  Ex caretaker
07 Prevost Marathon, 1025
Maverick Hybrid Toad
Inverness, FL (when we're home Cool )
Reply
#8

Thank you. I'll purchase the appropriate fittings and pressurize.

1983 Single Axle. Detroit 6v92.
Retired Refrigeration Mechanic
Reply
#9

Somewhere in my corrupted memory chip is the idea that the raise and dump positions for the Newell manifold and the HWH manifold were reversed.

It’s kind of how Tom, Michael Day, and I got to know one another some 20 years ago. We were trying to figure out how the six pack worked. Tom made a diagram, and I compared it to my coach and swore it could not be right. He triple checked his. I triple checked mine. We were both convinced the other had it wrong. We were both right. We were looking at two different manifolds. Michael had two six packs in the rear.

Richard and Rhonda Entrekin
95 Newell, 390  Ex caretaker
99 Newell, 512  Ex caretaker
07 Prevost Marathon, 1025
Maverick Hybrid Toad
Inverness, FL (when we're home Cool )
Reply


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