Hi all, hit some rough road in SC and the ride height went crazy all the sudden causing some very bad vibrations (I assume because of the effect on the drive line). I just replaced the dryer because it was a mess (carboned up bad) when I went to change the canister, the leveling valve seems to work ok when I operate it by hand with the rod disconnected but when its hooked up it doesn't seem to shut the air off to the bags. anyone have any ideas of what to look at next? have any of you ever ran into this before? I haven't seen anything damaged or anything else like that. Also, what would be a normal average bag pressure reading, this one was as high as 117 when I noticed it and seems to be currently around mid to high 80s to low 90s (front) and 20-40s (rear) (rear was also over a hundred when it happened) according to the truck info on the dash readout. Appreciate any help very much.
06' 780, rear air bags keep inflating sending ride height way too high.
Discussion in 'Volvo Forum' started by tomar, Mar 26, 2017.
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I would change the leveling valve.
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A lot of trucks I've had run about 58-62 psi in the rear air bags with a full load. I had a levelling valve go once, it only let air into the bags, it never let it out.
So if you started out by dumping the rear air. Filled it back up, it would settle in at the correct pressure. But as the day wore on, every time you hit a bump, a bit more air would go into the bags, but never out. Eventually there was so much air, the ride height went up and I got a noise in the drive line.
Usually I dumped the air when I dropped a trailer, but to confirm it was the levelling valve: when I dropped the trailer I left the air in the suspension. Then when I pulled out from under the trailer, I noticed that my rear suspension pressure did not drop, I went outside and confirmed that the levelling valve was not exhausting the air.
$150 and hour later after changing the valve myself, all was good. -
The Leveling Valve is defective, remove and replace.
Problem solved.CoyoteExpress, KB3MMX and tomar Thank this. -
Thanks all for the input, big help, leveling valve is now 1st on the todo list in the morning.
I have another question though; while I was doing the dryer replacement I notice 4 what look like valves on the cross member behind the transmission (they have 2 wire twist lock plugs going into them at the bottom and 1 airline each coming from the tops with a main supply line on the right side) I can't seem to find any information on these, any ideas what these are and do? they look like maybe some kind of check valve or solenoid. -
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[GALL[GALLERY=][GALLERY=][/GALLERY][/GALLERY]ERY=][/GALLERY]
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Best I could do for a pic., guess I'm not as smart as my phone.
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