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ZF Suspension-RL-85/E and RL85/A Steerable Tag Diagram/Steering Gearbox 8098
#81

Yep, I just verified accumulator pressure. Still holding steady at 15 bar.

There are several steps we can take to improve our ability to bleed the system of air by adding bleed valves in certain locations. I stand by my concern that the master cylinder can’t be bled unless the hydraulic connection ports are as close to 12 o’clock as possible. ZF specifically states that if the cylinder can’t be oriented properly then the cylinder must be bled properly then installed in its operating location.

I have both cylinders internal pieces and don’t believe that flowing fluid through the system using the MINIMESS fittings will rid the system of all air unless bleed valves are installed at key locations such as at the accumulator top, rear cylinder side that centers the tags, and the front cylinder’s ports. By adding additional MINIMESS and using a multi step process of bleeding, there is a better likelihood of ridding the system of air. 

My front cylinder was re-oriented and the system has been serviced so many times that it might have less air in the system than before. I’m happy with the current performance but the game changer was getting all three axles working together. 
All the accumulator does is ensure there is ample pressure in the system to keep the TAG straight going down the road. That a simplistic statement but and yes there’s benefits when the rear tires work in concert with steers while maneuvering but if you don’t have a good straight ahead rolling bus… the rest is useless.  

We’ve figured out the ZF RAS mysteries and now the mission will be improving our system.

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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#82

(04-16-2024, 11:40 AM)hypoxia Wrote:  I see the nitrogen pressure should be 10 bar, 145 PSI and hydraulic pressure should be 15 bar, 217 PSI according to page 11 of the attached ZF Servocom RAS manual.  Is this the wrong manual?

(Eventually I had Newell set my hydraulic pressure to 15 BAR per ZF. The system has been working perfectly. I was told the 275 psi was a mistake. I was also told the 250 psi is used because of leak down. I disagree otherwise the pressure sensor would not be 230 psi. I will eventually need to install a pressure sensor of around 200-210 psi. I believe there are failed pressure sensors because there is not an isolation valve to protect the sensor during the process used to pressurize and bleed the system.)

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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#83

(09-22-2024, 02:11 PM)jdkskyking Wrote:  
(04-16-2024, 11:40 AM)hypoxia Wrote:  I see the nitrogen pressure should be 10 bar, 145 PSI and hydraulic pressure should be 15 bar, 217 PSI according to page 11 of the attached ZF Servocom RAS manual.  Is this the wrong manual?

(Eventually I had Newell set my hydraulic pressure to 15 BAR per ZF. The system has been working perfectly. I was told the 275 psi was a mistake. I was also told the 250 psi is used because of leak down. I disagree otherwise the pressure sensor would not be 230 psi. I will eventually need to install a pressure sensor of around 200-210 psi. I believe there are failed pressure sensors because there is not an isolation valve to protect the sensor during the process used to pressurize and bleed the system.)
I pressurized to 16 bar 232 PSI (ZF Specifies 15 +1/-3 bar) and adjusted the Noshok 300L pressure switch to around 170 PSI.  The dash light did not come on when I depressurized the system.  It turned out  the wires on the DIN plug were connected to terminal 2 & 3 which is Normally Open.  I changed it to terminal 1 & 3 Normally Closed, now the dash light illuminates below ~170 PSI ~12 bar.

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