4104 air ride problem

[Bob & Tracey]

We are having a problem with the right front of the bus not rising up. I have read the manual and understand there should be one height adjustment valve for the front of the bus so where do I start? Are there any common problems I should look for? Also the manual states that the bus air pressure should be between 100 and 105 psi, we are running at 125 to 130 psi. Any thoughts on this?

Thanks in advance for any help,
Bob

[Dallas]

Bob, I think if I were you I would look at the rear leveling valves... unless you can physically hear air leaking from the front, that would be the place to start.

The bus air pressure of 100-105 psi is the median level.. depending on temperature, you maximum should be 120 to 130 psi before the air compressor governor kicks out, and it should kick back in about 80 to 90 psi.

[Bob & Tracey]

Hi Dallas,

I understand why I should start at the rear however if I dump the air to the front the bus will sit with the front down and the rear up and level.

Bob

[TomC]

That's because you are squaring out the load, and the left rear spring is still doing the work.  You need to look at the rear air bags and air leveling valves since a stock 4104 has two leveling valves in back to control left to right, and the front has just one that only controls the front axle up or down.  I'll bet you have a faulty right rear leveling valve.  Good Luck, TomC

[Bob & Tracey]

OK, it makes sense. How do I determain the valve is bad? Is this something I can find through a truck parts department?

Thanks for the help,
Bob

[TomC]

Hendrickson, Neway, etc makes universal valves that should work.  Best just to take the old one off and try to match it up.  Remember to drive up on blocks high enough that will allow the bus to settle down onto the axle bumpers and still give you enough room to crawl under the bus.  Good Luck, TomC

[Bob & Tracey]

Thanks for all the help, tomorrow the fun starts.

Bob