Air ride suspension ride height suddenly increases by 4 to 6 inches

Hello, I am interested in hearing if anyone has experienced a 'sudden' increase in the ride height of 4 to 6 inches at low speed rush-hour traffic (intermediate 20 to 30 MPH with lots of breaking) of a loaded 50 ton 20" ride height lowboy tri-axle with air ride suspension. Load was 70,500 pounds.

Can anyone tell me what might cause this to happen. Could a flat or leaking tire on axle with ride height valve connected cause it, or a plugged ride height valve exhaust line? Or or ???

My thoughts on this are could the heavy braking acceleration braking cause the load height valve to actuate (increase pressure) because of brake lock and roll back , but if the adjustment and/or exhaust line was blocked there could be no bleed-off??

Thank you

 

Thank you for your inputs

I do not have pressure gauge reading.

Your scenario is interesting; however, with the arm flipped, from braking and air pressure not being able to vent, would it be possible that air could go in with arm flipped?

The trailer is driven on a daily basis, and right after this ‘ride height elevation situation’ just trying to understand if there is anyway that the ride height could change 4 to 6 higher in say 10’ of travel in rush hour bumper to bumper 30 MPH average speed traffic.

Unfortunately right under a bridge with low clearance after clearing all 11 out of 12 beams of bridge.

Well you get the picture.

 

Thank you very much. Will be able to test as suggested in next three weeks


By suddenly, I mean within 10’ of travel distance at bumper to bumper max speed 30 MPH, but lots of stop/go/stop

 

Thank you. I have had replies.

 

So if brake applied because traffic stopped the brakes cause a suspension rotation making the axle center go lower (or better said distance between trailer deck and axle center would decrease), linkage would push valve up in picture and air goes in, but the axle is ‘rigidly held’ so axle can not react to increased air bag pressure , and air continues in - maybe until either brake is released or slips, etc. but result is a ,jump,

Are jounce and rebound typically enough to allow 4 to 6” rise under the increased air bag pressure - assuming the scenario led to over normal air pressure, owing to stop-go-stop low speed bumper to bumper


Got graphic from Hendrickson web site as example. Not saying it is Hendrickson - do not know, just want to be sure I understand your inputs.

Thank you again