Community Forums

mystere900 · 01-14-2007, 09:22 PM

I have a 2005 Expedition that looses all of it's suspension air in less than a day of sitting. Freightliner says it should hold longer but didn't sound to sure. Can any one else help to give me an idea of how long it should take to go flat. The guys at the local Peterbilt store say they have had trucks stay inflated for a month. Don't know if that's much of a bench mark for my coach though.

On a different note, since this coach was new it has always had a lot of nose dive during brake application. So much so that I think most all of the braking is being done by the front wheels due to the increased weight transfer. While in Phoenix last month I had my brother install a set of the new Koni FSD shocks. Nose dive is gone and handling is very much improved but the ride has suffered a lot. These shocks were supposed to be the answer for ride and handling due to the new valving design. Anyone else had experience with the Koni's?

mystere900 · 01-14-2007, 09:22 PM

I have a 2005 Expedition that looses all of it's suspension air in less than a day of sitting. Freightliner says it should hold longer but didn't sound to sure. Can any one else help to give me an idea of how long it should take to go flat. The guys at the local Peterbilt store say they have had trucks stay inflated for a month. Don't know if that's much of a bench mark for my coach though.

On a different note, since this coach was new it has always had a lot of nose dive during brake application. So much so that I think most all of the braking is being done by the front wheels due to the increased weight transfer. While in Phoenix last month I had my brother install a set of the new Koni FSD shocks. Nose dive is gone and handling is very much improved but the ride has suffered a lot. These shocks were supposed to be the answer for ride and handling due to the new valving design. Anyone else had experience with the Koni's?

Cruzer · 01-15-2007, 04:04 AM

Let me be the first to welcome you to iRV2.

As to the leaking air bags - it depends. RVs self-adjust the ride height with height sensing valves. If that position is riding too low, it addds air to the bag to lift the coach at that corner. If that area is riding too high it drains air from the bag at that location. On my 2004 40' Bus (Freightliner) I lost air within 1 day when parked in my driveway. But, my driveway is pitched and the weight shift caused my height sensing valves to try to compensate, which drained the bags. When I parked on a level surface it would stay pumped up.

This "may" be your situation. If it isn't, then I'd check for leaks. Sometimes a few leaky hose connections here and there can add up. Also, the height sensing valves can also leak and may need rebuilding.

So, it could be a mechanical issue or it might just be an operational condition.

Don in E Texas · 01-15-2007, 05:12 AM

Air bags should stay inflated at least a month. We have both a Class 8 tractor (Freightliner) as well as a bus conversion (MC8). Both of these vehicles keep pressure in all air bags while parked. I run the bus once a month to keep air in the bags (we are in the bus during the Winter). Air bags have check valves between them and the tanks --- a faulty check valve will let air out of the bags. On trucks, the leveling valve can do the same thing - allow air to bleed out of the air bags. You will have no air in the air tanks, but air in the bags.

Front brakes do most of the stopping of all vehicles - but should not nose-dive. Wonder if the rear brakes are fully operational?

My $.02 worth this morning.

don

"007" · 01-15-2007, 06:55 AM

Welcome mystere900 to irv2

As you can see RVers here eager to help.
Enjoy the forums and post often.

mystere900 · 01-15-2007, 07:08 AM

Thanks for the replies and the cordial welcome.

I hadn't thought about the auto leveling just trying to do it's job but this seems to happen no mater if it's parked on a level surface or not. Suppose I should let Freightliner look at it. Hope it's covered under warranty.

Because the new shocks have minimized the nose dive, braking is much more effective because the rear brakes do more work due to less weight transfer forward. I'm really happy about this and the better roll stability. The thing I don't like is the rough ride. The Koni FSD (Frequency Selective Dampening) shocks are supposed to relax on small displacement high frequency bumps like tar strips and stiffen up on low frequency large displacement like roll and braking. Great idea if they worked as advertised but it seems the dampening doesn't relax fast enough form a large displacement resulting in a rough ride all the time. Stability is good thing but if the ride is causing the coach to shed parts, not good. The wife says go back to the OEM shocks but I'm torn on what to do.

URL to Koni's web site explaining how they work.
http://www.koni.com/

mystere900 · 01-15-2007, 08:02 AM

Hey don, good point about the rear brakes working properly.

Last summer I was getting a loud clunk noise in the front brakes when I made a moderate to heavy brake application. Turned out to be the S cam rollers lack of lubrication causing them to jump on the S cam. The chassis book says to lube them at 6000 mile intervals. After spending $400 to accomplish this, I think I'll wait for the noise to return then re-lube. After having them lubed the clunk went away and brakes seemed to be more effective. Wonder if the rear brakes would benefit from the same procedure?

Cruzer · 01-15-2007, 09:03 AM

Freightliner has a 3 year warranty on the chassis. They should cover it as long as they can find something wrong. If they can't, and use the old "that's normal" excuse, then they won't get reimbursed under warranty. I'd do a little preliminary checking myself to see if you can hear an audible leak. Then you know where to direct them.

mystere900 · 01-15-2007, 09:16 AM

Thanks Mark, good advice, I'll do that as soon as the snow melts, got 4" on the Il./Ws. border last night. (don't laugh, I'm not quite retired yet)

Pusherman · 01-15-2007, 10:39 AM

Mystere900 --

On my '00 Journey this past spring I had my s-cam rollers replaced at Freightliner in Gaffney. Parts = $20.42, Labor to clean & lube S-cams and install new = $180 (2.5 hrs). This was for both front wheels. Same symptoms as yours.

mystere900 · 01-15-2007, 11:26 AM

Thanks Mark. I thought it was a bit much just to lube the rollers. Going to check if there was any other service done on the same invoice. If not will protest and try to get a partial refund.

Garbageman · 01-15-2007, 01:47 PM

Hello Roger. Regarding your Koni shocks, have you contacted Koni about how the coach is riding? I know the Konis on my coach are adjustable so you may be able to adjust some of the "shock" out of the shock.

Paul

mystere900 · 01-15-2007, 05:16 PM

Hi Paul, I haven't talked to Koni directly but my brother, who put them on, is a dealer for Koni has talked to them. They said I could return them for a refund if I wanted. The shocks I have are the FSD model painted gold and are supposed to make internal adjustments automatically, no manual external adjustment available. I'll bet your shocks are red in color, right?

Garbageman · 01-16-2007, 12:49 PM

The Koni's on my '91 Hawkins are original to the coach and I think, after cleaning some dirt away, they are black or dark blue. They are adjusted by removing the lower mounting bolt and compressing the shock and twisting it to the counter clockwise (firmer). They have been a great shock but now need replacing.
Good luck with your.
Paul