Community Forums

gator67 · 04-23-2009, 06:17 PM

It seems that on SOBs (not Alpine), when the jacks are lowered, the coach itself raises (similar to when the air bags are inflated) and the tires stay on the ground until they are finally drawn up with everything else.

It appears that when I dump the air bags on ours, then lower, say, the rear jacks, the body comes up a little bit, then the tires start to come up. So, now I am up on 4" of wood, and even raising the coach a little more with the jacks, the tires start to come off the wood.

Is the Alpine made different from other coaches? Are the jacks set up so it raises both the axles and the body? We seem to have to use wood more often to level the coach than other brands we've been around.

Any explanation? Or, is my coach broke

Old Scout · 04-23-2009, 07:46 PM

Nope--the jacks are mounted to the frame. IF your wheels are being lifted while extending the jacks, this means the coach was enough off level that the entire travel of the shocks has been taken up. At this point, the wheels/axles are hanging from the fully extended shocks--generally speaking, not good for the shocks. Dont think the travel on these shocks is more than 5-6 inches--havent heard of a situation where the travel on a shock[s] has gone bad--unless the wrong size shocks were put on at some point. If the shocks are wrong, it seems you'd of bottomed-out/hung-up on a bump or dip before now.

Jeff and Cheryl · 04-23-2009, 10:50 PM

Gator,

I've noticed the same issue. I think perhaps it has to do with lhe longer wheelbase of our coaches. My 36' with a 252" wheelbase has the same wheelbase as the typical 40' of the other guys. I figure that since the wheelbase is longer, the the distance between front and rear jacks is longer as well. NOW, I could be out in left field on this, perhaps someone with greater knowledge has another idea. In my case, it's likely not the shocks as this has happened with both the Bilsteins and the Koni's. I put more blocks under the tires to keep them supported, sometimes it is really a stack.

dgerstel · 04-24-2009, 10:08 AM

Jerry,

Is your coach fairly level side to side when this is happening, or if not, it is only the tires on one side of the coach lifting? The rear suspension arms on our coaches are VERY stout and will not allow the rear axel to twist in reference to the frame. If one side of the coach has to lift very much more than the other, the side requiring more lift will raise the tire off of the ground.

Also how high are you trying to raise the coach? If I try to get my rear wheels off of the ground, and it is level side to side, I might have to add blocks under the jacks to get that much lift.

Old Scout · 04-24-2009, 01:02 PM

Not sure what wheel base has to do with it--Alpines or SOBs. The fact remains--if you are raising your tires are off the ground via yr jacks, it means yr axles are hanging from the shocks. True, the back and front axles are ridged but the suspension allows for modest movement [tilt] over uneven ground--eg, the Walmart wobble. If you crawl under yr coach [not with it lifted] you will see how shock travel ultimately dictates tire lift at some point.

powerboatr · 04-24-2009, 02:54 PM

may i add a dime here

our coach puts enough lift on the frame to make the tires seem like they are just about to lift off.

yesterday i moved her over a foot under the port to better align with my big ol sun screen out front.
i manually dumped the air bags and let the coach sink low
then selected auto level, it screwed up the process big time, it ran two jacks down and left the other two about 1" off the ground.
so i had to turn it off and waited a few minutes and selected auto and this time all was normal.

can we use the manual mode and and dump the bags then select manual to level her and not lift it so high in the air?

dgerstel · 04-24-2009, 05:04 PM

Powerboatr,

Assuming that you have the HWH system, the auto mode should dump all of the air and then set the jacks. A manual dump first should not be required. Having air suspension and being able to dump the coach is a big advantage over springs when leveling. It allows the leveling process to start with the coach much lower.

EngineerMike · 04-24-2009, 10:09 PM

With the HWH 625 system, the auto level initiates a timed air dump (30 sec IIRC) then levels jacks in pairs. If the rear and right sides are low, it raises the rear first till it is even w/the front, then raises the right till it is even w/the left. Now the coach is level, but the FL jack hasn't extended, so it extends the FL till the feedback sensor on the head of the jack reads back pressure (~1000# again IIRC).

All of the above assumes the system is fully operational. I have a part time pressure sensor on the FR; when it isn't working, the final step is to raise the FR till the jack is fully or nearly fully extended, then report Excessive Slope. This is one of many errors you can diagnose using HWH's excellent documentation (or their 800# help line) by reading the LEDs on the mother board. Here is a link to the HWH 625 LED & Fuse Key.

Here is a link to an interesting HWH diagnosis incl. fuses with a twist I won't spoil.

Ted III · 04-29-2009, 06:38 AM

Just keep in mind that the emergency brake holds the rear tires. If per chance you got them both off the ground the coach could roll even with the brake on.

Just a safety thought.

Renipladlo · 04-29-2009, 09:13 PM

My front air bags have never dumped except twice.

However, I have only put the front wheels off the ground once and did not like that so I put wood under them to support the assembly. I guess I am lucky in finding mostly level spots. This past trip we did have to put wood under the LR wheels since they would be off the ground a little. The front bags did not seem to dump. I think I have a loose wire or something, and was hoping to go to the Rally in Lebanon, OR, but our schedule has changed, and we won't make it. I also know my LF air bag (most likely a fitting needs to be tightened) has a leak, because it is the first one to loose air over time, none of the others do. Just my 2 cents.