2014 Volvo 730 suspension problem.

Cab bushings are shot.(sloppy loose sensation when driving ,sway)

Probably torsion springs too. They should be done at the same time with cab shocks.

48psi is also low. Max load should be around 58-60..... Where's your fifth wheel set at?

How many miles?

 

They all pull to the right, so I wouldn’t bother about that part.
What exactly did they do these 3 times in the shops so far?

 

Company truck or owner operator?

 

My 780 was a 2013..at 80k it was just over 60 psi on the drives. 48 seems real low. Have your ride height checked?

 

Has anyone checked your suspension bushings? That could explain some of your crappy ride and poor handling. I’d check the ride height again too.

 

Things like this can be very frustrating but I'm sure there's someone that's a member here that's had a similar problem that can help you.

But in the meantime here's a few things that I would do anyway.

First thing is I would check that that leveling valve is the right valve. The actual correct authentic valve for that truck not a generic valve.

Next I would get what the actual reading should be from Volvo and I would set the ride height myself. I would put the truck on a level concrete floor and I would measure the frame all the way around to make sure from side-to-side the truck is sitting level meaning that you don't have a broken spring or a bent frame or something of that nature.

I would also pay attention to how quickly you lose air and how quickly you build air. I would get a spray bottle with soapy water and I would go back to the airbags and I would spray them the fittings and all the lines straight up to wherever they go to I would spray all around that leveling valve and see if there is any leakage. It's also possible that you have a bad air bag or bad air bags. Remember it's not just air there are Springs inside the airbags and they do wear out. You also could spray the line that feeds the leveling valve and I would probably even take it off and put a gauge on it to make sure there's no restriction. Visually check to make sure that you do not have any pinched lines.

I would try the truck also without the trailer and see if that makes any difference in how you ride or your air pressure etcetera etcetera.

There are a lot of things that could make the truck ride sloppy and pull to the right, but since you know that you're having a problem with the air pressure I would concentrate on the ride height the leveling valve and the airbags and any other air valves associated with it until you have that situation straightened out.

You also could put a separate gauge outside the truck instead of the gauges inside the truck for your axles just to test that those gauges are working right.

If those gauges are not working right it'll send you on a crazy goose chase when it could be something else.

Anyway I wish you good luck and I'm sure someone that knows more about it will be able to help you.

 

How far forward is the fifth wheel?

 

If the suspension pressure gauge is reading low either you've got a gauge issue, you are lighter on the drive axles than you think, or your ride height is too low. If this only started right after they replaced the leveling valve I'm willing to bet its one of the following:

Did they replace the leveling valve with the exact same one that came off it?

Is the ride height being measured correctly? Was ride height checked both bobtail and with full legal weight on the drives?