R Model Cab Air Ride

[Mr Black]

Hi,

I hope you can help with a question.

I am having a sleeper installed on my R Model and the installers need to know how the cab will sit with the cab air bag pumped up. Unfortunately I have no tanks or fuel lines attached to the truck as it has been stripped for painting so I can't start it.

I don’t own a stand-alone compressor but could bring another truck on site and attach its air outlet to the R Model’s air tank.

Do you think that will work to pump up the air bag or is it likely that a valve somewhere along the line will prevent the air from reaching the bag without the truck on?

Otherwise I will have to just put a bottle jack under the cab and lift it to what I believe to be the operating height.

Any other ideas?

Thanks

[gearhead204]

if you plumb into the wet tank it will work just fine! mine levels at just over 60psi. The wet tank is the one behind the cab, facing front to back of the truck if you plumb into the tanks under the battery box one side or the other will level the cab. I think the cab is plumbed off of the secondary tank. if you get the wrong tank the check valves wont let it work.

[Mr Black]

if you plumb into the wet tank it will work just fine! mine levels at just over 60psi. The wet tank is the one behind the cab, facing front to back of the truck if you plumb into the tanks under the battery box one side or the other will level the cab. I think the cab is plumbed off of the secondary tank. if you get the wrong tank the check valves wont let it work.

Awesome - thanks

[phildirt]

Here is a scan of the Mack Service Bulletin (SB-668-008)

It shows the height and method.

cab height adjustment.pdf

[Mr Black]

Here is a scan of the Mack Service Bulletin (SB-668-008)

It shows the height and method.

This is very helpful - thanks.

[Lmackattack]

when you mount the sleeper do give proper clearance to the front of sleeper for the cab movement. the top of the cab will tip backwards over large bumps and overnight if the cab leveling valve leaks down. Make sure the membrane around the sleeper opening has proper flex to take up the cab movement.

if you want to get really trick. I have seen photos of a guy and his R model that mounted a sleeper on long beams that extended and connected it to the cab floor. Then he added air bags to the back of the beams under the sleeper so that both the cab and sleeper was air suspended as one unit...

[brett windsor]

1987 ultraliner rear cab airbag height 229mm Any know exactly where to measure from to Thanks in advance

 

[mrsmackpaul]

Nope sorry 

Most times the link bends slowly overtime

As long as the bag is fairly pumped with no wrinkles they work okay

 

Paul