Hadley system 450LXi

[dentmac]

Trying to learn what changes Hadley did to the Active Air system when they changed the tie rods, etc.
Obviously they added a solenoid to plumb the right and left front airbags together. This appears to be "Normally closed". When leaving the coach without power, you should leave it with the levelling system (SAMS) on as the solenoid is then off. With SAMS off, the solenoid is drawing enough power to be quite hot.
ie The solenoid is active in Drive Mode.
I understand that the levelling is done by the twist from the back like a 3 point system but what is used for the height of the front? Just one side? The wouldn't work well - In a corner when the outside suspension compresses--the leveller would raise the entire coach.
I'm trying to get a response from Hadley .
Ross

[dentmac]

A little more info.
It appears that changes were made to the ECU. The Drive :tag ratio was changed to 65:35 from 60:40 to take some of the load off the front axle.
When the genset was moved , the total net effect was to lighten the right front by 500#( and add 500# to the left rear.) In order to equalise the front side to side loads, the front airbags were plumbed together and the ECU was altered to take the average height of the 2 front level sensors. One side can be 3 inches and the other 5--BUT the average is perfect at 4. If the average is low, then air is increased to both sides via the manifold (and the air line between keeps the pressures exactly the same.) The side to side level is maintained only by the drive axle height sensors. In a corner , the right side may compress, but the left side will increase-- the average height does not change. If the brakes were applied at the same time, the average height would decrease so air would go to both sides, raising the coach.
It appears that separating the right and left airbags (by de-activating the solenoid) has no useful effect.

To weigh individual corners on the 450, one would have to drop all air or put the coach in SLS (level ) mode on level ground. Drive mode masks the discrepancies in the front.

[davidbrady]

Great info Ross. Any chance of getting help from Hadley to restore the system to its original pre-recall operation? I wonder if there are any Hadley ECU's available on the used market with original flash programming...

[dentmac]

As for used, I don't think any used would be available as they are custom for the 450. Hadley will want proof of certified side to side weights and front weights before they would consider a change. Changing to the larger tires/wheels is good for the tire consideration. I doubt that Hadley would ever allow the change -liability -why would they? Whats in it for them?
They made the change at BB request in 2008 before BB removed other steel from the front end.
BB won on this one-- did it without telling owners.
As for de activating the solenoid joining the right and left airbags-- No purpose and may be dangerous. The air pressures in each front bag is controlled only by the need to hold the average level. If the flow rate from the Hadley manifold to each bag is uneven or if one side has a small leak then the other side will increase pressure. The system remains happy because the "Average level" is satisfied. The discrepancy is masked by the rear twisting the coach to maintain basic level.
Outcome is one side overloaded, front end un-level in drive mode- which screws up alignment and tire wear in a IFS .

(10-18-2013 10:59)davidbrady Wrote:  Great info Ross. Any chance of getting help from Hadley to restore the system to its original pre-recall operation? I wonder if there are any Hadley ECU's available on the used market with original flash programming...

[davidbrady]

Ross,

Is this it:
  Spartan Hadley SAMs ECU.pdf (Size: 183.5 KB / Downloads: 1943)

[dentmac]

No,but great try. If figure 3 is the ECU, the appearance is significantly different. The part number is close however. ECU part Number H00701-03, Model H00700J

(10-18-2013 13:43)davidbrady Wrote:  Ross,

Is this it:

[Hisham Amaral]

Ross
All you have to do is to restore the system to original configuration is remove the ground wire to the solenoid you will be able to look in the first bay and you see what was changed to the Hadley ECU. I thing the solenoid is installed on number one height control.

[dentmac]

Hi Hish,
Who told you that?
I think that is too easy.

(10-18-2013 20:47)Hisham Amaral Wrote:  Ross
All you have to do is to restore the system to original configuration is remove the ground wire to the solenoid you will be able to look in the first bay and you see what was changed to the Hadley ECU. I thing the solenoid is installed on number one height control.

[Hisham Amaral]

(10-18-2013 21:37)dentmac Wrote:  Hi Hish,
Who told you that?
I think that is too easy.

(10-18-2013 20:47)Hisham Amaral Wrote:  Ross
All you have to do is to restore the system to original configuration is remove the ground wire to the solenoid you will be able to look in the first bay and you see what was changed to the Hadley ECU. I thing the solenoid is installed on number one height control.

Ross
You can look at the system you will find what changed. BB added a solenoid to the Hadley ECU. You can look up in bay one street side and you will find the change, it is very much an after thought, wire are rigged to that solenoid, you can't miss the change.
Hish

[dentmac]

RE: Hadley system 450LXi
Hi Hish,
The solenoid and the wires are the only visible change but it is not correct that de-activating the solenoid will restore the system to pre-modification. The ECU (computer) was changed and the individual height sensors are used in a different way. De-activating the solenoid is possibly dangerous and affects sway minimally.
The ECU is at the rear of the Hadley manifold and accessible by removing 4 screws. It is labled "For use only with the Hadley crossover solenoid" and has a software change date and number-- Apr 2008)

Consider for example that the airbags have 100 psi each side-- when driving in a corner, the outside wheel will compress.
1. with the solenoid working and the sides plumbed together, the airbag pressures stay at 100 on each side and the body tips
2. cutting the wire and therefore separate airbag pressure-- the outside airbag compresses and the pressure rises some-because the sides are no longer kept equal pressure.- the body tips but not as much as in 1.
3. In original system-- outside wheel compresses and air is ADDED to the outside airbag and removed from the other wheel-- body stays flat. There is no need of anti sway bars in this type of Active air systems. (As David has indicated, the exhausting of the inside wheel can be faster then the adding air so the front of the coach may go down a little temporarily. (similar to HWH system)

There is a risk of significant side to side airbag pressure (and therefore wheel load) discrepancy by de-activating the solenoid without flashing the ECU.(discussed in previous post)

The Hadley was changed to keep the front side loads equal since moving the genset lightened only the RIGHT front by 500#. And with the "Active Air" in a corner, the opposite side tire ,wheel and suspension was overloaded.
The other 350# of steel removed in front of the axle was structural/protective and for towing and had no imbalance effect

Ross

quote='Hisham Amaral' pid='50407' dateline='1382140034']
Ross
All you have to do is to restore the system to original configuration is remove the ground wire to the solenoid you will be able to look in the first bay and you see what was changed to the Hadley ECU. I thing the solenoid is installed on number one height control.
[/quote]
[/quote]
Ross
You can look at the system you will find what changed. BB added a solenoid to the Hadley ECU. You can look up in bay one street side and you will find the change, it is very much an after thought, wire are rigged to that solenoid, you can't miss the change.
Hish
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