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ZF Suspension-RL-85/E and RL85/A Steerable Tag Diagram/Steering Gearbox 8098
#71

(08-13-2024, 04:28 AM)jdkskyking Wrote:  During the week of August 18, 2024, Newell will replace all four steering axle control arms and bushings (we have been waiting on ZF parts). We’re replacing rotors and pads as well on the steer and tag, drives were replaced earlier this year. 

The coach is driving fantastic as a result of the changes I personally made to the tag tire alignment to the drive axle and the change I made to the steer tire toe-in. Hands off driving has been achieved…. 
I’m looking forward to the alignment process in Columbia Missouri. 
JK
Looking forward to the report!  I'm trying to digest what you said about lowering the pressure to allow steering if the pump quits.

(08-13-2024, 04:28 AM)jdkskyking Wrote:  During the week of August 18, 2024, Newell will replace all four steering axle control arms and bushings (we have been waiting on ZF parts). We’re replacing rotors and pads as well on the steer and tag, drives were replaced earlier this year. 

The coach is driving fantastic as a result of the changes I personally made to the tag tire alignment to the drive axle and the change I made to the steer tire toe-in. Hands off driving has been achieved…. 
I’m looking forward to the alignment process in Columbia Missouri. 
JK
Looking forward to the report!  I'm trying to digest what you said about lowering the pressure to allow steering if the pump quits.

Jim
2014 Newell Coach 1482 Mid Entry 45'8" Valid Slides and Valid Levelling
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#72

I lost my power steering in 712, 2004 steerable tag, Fan motor got damaged probably when it run low on oil from a leak at the solenoid valve,oil tank has low oil level float switch  installed, but never hooked up by Newell,  I drove it 1400 mi home from Ocala Florida to Toronto Ontario Canada, pulling a 30' stacker that was loaded, It was EXTREMELY  difficult to turn the steering wheel it wanted to go straight, Richard said that the pressure in the steerable tag was trying to make it go straight so less pressure would make it easier to turn, gentle curves on the interstate required a LOT of pressure trying to get out of the truck stop is something that I hope I never have to do again, I don't know what my accumulator pressure is, but I have bought the gauges and a pump that I have to modify to do the hydraulic side,  I have been busy with other things, when I find out what my pleasures are i will post them. Just checked my tag axle hydraulic pressure, only had 50 psi, coach drove fine, could back up no problem.

John Kosir
712 2004  45-8
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#73

Good to know steering may still be accomplished.

Jim
2014 Newell Coach 1482 Mid Entry 45'8" Valid Slides and Valid Levelling
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#74

I removed the accumulator, the diaphragm had failed so there is a lot of fizzy nitrogen infused hydraulic fluid.  There is a 6" muffler type clamp that retains the accumulator.  Removing one nut allowed the accumulator to slide out.  I installed the new accumulator and started to bleed the system but need to get another fitting to finish that tomorrow.

Nice to know that even with a failed accumulator the tag steered OK, perhaps it will track better now??  I couldn't tell any difference.  The Tag Steering Pressure low pressure light didn't work, discovered one wire on the sensor plug connector was on the wrong terminal.  I did replace the pressure sensor.

Jeff, how did the Newell visit go?

Jim
2014 Newell Coach 1482 Mid Entry 45'8" Valid Slides and Valid Levelling
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#75

Well… since you asked… 

#744 officially has a completely refurbished undercarriage, radiator, and CAC. All rotors and brake pads are new. All Drive tires are new and Steers and Tags are relatively new. 

The compound turbo system now produces 50 psi of boost. Lots of get up and go… Cooling system is performing better as well. 

With new steer axle control arms and bushings, front end stability has greatly improved. 

Last I knew my TAG accumulator pressure is set to 15 bar per ZF specifications, the TAG works great. 

HERE’S THE BEST NEWS OF ALL!!! 
My most recent service for the coach is a fantastic all axle alignment that has transformed how the coach drives. I’ve only put a couple hundred of mikes in the seat but I’m blown away. 

I literally found the “Alignment Whisperer” Bill Rajewski at Perry Legend Collision and Repair Center, Columbia Missouri. Bill is a wonderfully knowledgeable person. I really enjoyed our conversations about my bus and his ability to explain the “Why” is fabulous. 

Bill had never aligned a Newell. I put together a collection of my ZF Service Manuals in a binder and sent them to him. He took it from there. 

Bill and his expert technician Paul quickly identified why I was not happy how my coach handled. Long story short, the tag axle was heading right, the drive axle was headed left, and the steer axle was just not right. 

I’m just blown away how it drove. I left Columbia Tuesday heading down to Springfield Missouri for more service work. The route is hilly and lots of turns. Four lane and winding two lanes. The coach handled it all wonderfully. I’m a happy camper! 

As I continue to drive the coach I’ll provide updates. I make minor corrections, the bus just drives down the road. I’m tickled to death… 

Thanks for asking!!!
JK

Kristi & Jeff King
Bentonville, Arkansas
#744 2005 45’ Newell Coach 
ZF Suspension/Active Steering Tag Axle
CAT-13 ACERT KCB Engine 525HP 1642 ftlbs Torque Cat Compound Turbocharger 43.5 psi
Allison HD4000MH Transmission with PTO drive.
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#76

Wow, let me know if you can go for some coffee on a long straightaway! Can you fill us in on the alignment numbers?

Jim
2014 Newell Coach 1482 Mid Entry 45'8" Valid Slides and Valid Levelling
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#77

As I said before… I had a tug of war happening in the back of the bus. The Drive axle and Tag axle were fighting each other. 
Before 
   


After 
   


Bill and Paul knew exactly what’s needed to set up all three axles. 
They disconnected the “Hydraulics” to properly set up the “Mechanicals”. When they had the mechanics of the suspension set up to roll down the road, they connected the ZF RAS system again. 

Bill and Paul could have made additional adjustments in Caster and Camber however they were limited by the steer control arm mounting stud length. They estimated if studs were 1.25” longer, they could have continued to shim the A Arms to achieve the values they wanted to make the bus drive optimal. 

Unfortunately it doesn’t appear we can replace the steer axle studs. 

My next drive will be from Springfield Missouri back home to Bentonville Arkansas. I’ll continue to update the blog and will likely add a summary of my journey. 

The last modification I’ll make to my ZF RAS will be in an attempt to bleed the hydraulic system more effectively. I have a plan but right now I don’t have the time to execute. 

JK

Kristi & Jeff King
Bentonville, Arkansas
#744 2005 45’ Newell Coach 
ZF Suspension/Active Steering Tag Axle
CAT-13 ACERT KCB Engine 525HP 1642 ftlbs Torque Cat Compound Turbocharger 43.5 psi
Allison HD4000MH Transmission with PTO drive.
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#78

I replaced the RAS (rear axle steering) accumulator and bled the system.  The diaphragm in the accumulator had ruptured so there was some nitrogen charged fizzy fluid.  It's a fairly easy repair except for getting the new accumulator back into the 6" exhaust clamp.  The flange is welded to the frame and the U bolt wouldn't come out enough to put a nut on it.  I gave up on that and instead used another 6" flange along with 8" bolts to clamp the two flanges together with the accumulator in between.  Pressurized the system, ops checks good.

FWIW, the ruptured accumulator wasn't noticeable, it steered fine.

During the cleanup I noticed a "muffler" hangar that had come apart on the generator/AquaHot exhaust.  The bracket was welded to the frame so I cut a piece of thick mudflap, drilled holes in it and used that to replace the broken piece.

Jim
2014 Newell Coach 1482 Mid Entry 45'8" Valid Slides and Valid Levelling
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#79

When my accumulator failed my tag tires would not remain straight backing up. 
I drove it to Newell, they determined the TAG system had no pressure and could not find any signs of a hydraulic leak. They charged the system and sent me home. I was back at the factory in a few days. This was the beginning of the discovery of the life limited pressure accumulator bladder …. The rest is hi$tory…

Kristi & Jeff King
Bentonville, Arkansas
#744 2005 45’ Newell Coach 
ZF Suspension/Active Steering Tag Axle
CAT-13 ACERT KCB Engine 525HP 1642 ftlbs Torque Cat Compound Turbocharger 43.5 psi
Allison HD4000MH Transmission with PTO drive.
Reply
#80

(09-21-2024, 05:59 PM)jdkskyking Wrote:  When my accumulator failed my tag tires would not remain straight backing up. 
I drove it to Newell, they determined the TAG system had no pressure and could not find any signs of a hydraulic leak. They charged the system and sent me home. I was back at the factory in a few days. This was the beginning of the discovery of the life limited pressure accumulator bladder …. The rest is hi$tory…
It's interesting that you lost pressure.  I suppose I should add the pressure gauge with the Minimus fitting to a spare parts box.  Pretty soon I'll have to add a trailer for all of the spare parts.

Jim
2014 Newell Coach 1482 Mid Entry 45'8" Valid Slides and Valid Levelling
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