What would symptoms of worn bushings be in a volvo 780? I'm assuming these are actually the suspension bushings rather than axle, they are in the leaf springs on the drive axles. Anyway when I loose my air at night the truck I guess moves a couple inches when the bags lose their air. The front drive axle bags look rolled forward when no air in them. Will move a trailer about 3 inches from dock stops if air runs out of bags then too. Would this cause the truck to feel like its jetking when driving or maybe make ubolts on axle shift around?
Axle bushings
Discussion in 'Volvo Forum' started by Metalicious, Jan 18, 2023.
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What you describe is normal. When the air is depleted and the bags deflate, your truck doesn’t lower in a perfectly straight up and down line. Think of it more like a triangle (I’m being grossly over exaggerated to explain the point) where one of the 3 sides is your air bags. As it deflates your truck lowers at an angle which causes the truck to move a bit.
Think if it like the airbags on the back of your sleeper. When they deflate your sleeper moves back while the pivot is in the front. The entire sleeper doesn’t lower, just the back.
Signs of bad bushings are tire shoulder wears in steers, irregular tire wear, lose alignment rapidly, and if really bad can hear almost like a pop as it moves on the front axle during hard slow speed turns.
It also depends on the suspension. I remember stoughton trailers would move like 6” from the dock and I was always frustrated. Wabash actually has 2 arms that come down and keep the trailer from creeping or lowering to prevent this. Other suspensions and trailer manufacturers have their own designs (most use the same couple types of suspension such as Hendrickson).Last edited: Jan 18, 2023
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Not sure what would give you the jerking feeling going down the road.
Let us know when you find out.
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I'll keep looking into the jerking. It isn't all the time, kind of hard to explain could be steers maybe or something off center. I'll let you all know when I figure it out though.Rideandrepair and xsetra Thank this. -
When I had my Ubolts replaced, I retorqued them after a couple weeks. Same with motor mounts and spring hanger bolts.
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A jerking motion is definitely something like a loose u bolt or loose or cracked leaf spring hangar. I just did the bushings on my truck and the front leaf spring hanger where the bolt goes through was oval shape from bad wear when the bolt loosened up and I never caught it. Perhaps a really bad kingpin as well. Maybe a cracked leaf spring. Who knows, just inspect and retorque everything.
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A lot of my issues with the uncomfortable ride and really bad jerking was believe it or not the freakin cab bushings. They replaced those and it rides a hell of a lot better. The cab use to bottom out, a lot driving down the road. Especially on that rough spot on 30 heading east toward Little Rock. Now I know I need new cab shocks even, and it still doesn't bottom out with the new cab bushings being put in. Other than these nuance issues I am having to chase down its not a bad truck. Definitely wouldn't have paid what I did for it though had I either a.) gotten to pull even an empty trailer behind it when I test drove it, or b.) was given the opportunity to have it thoroughly looked over by a well qualified mechanic, not a mecca-nic like he was taking it to for all his work to be done. He got screwed on a lot of things with that mobile repair service guy he was using.
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