hi fellow barth owners,i recently purchased a 1977 barth 30t. it needs new front air suspention cushions. mechanic is having trouble locating the front air bags. asked if i knew where to locate them. any help would be greatly appreciated.have been following this website since i found it. excited about owning this vehicle since i first saw it. i know it is a p-30 chevy chassis. havent checked with local rv place yet. would like to go in prepared with the right info on what i need. always helps. im sure i will have many questions in the future. as this unit needs just about everything. nice to meet all of you fellow barth owners.any and all advice welcome.

Use the SEARCH feature above and ask for "asir bags" and you will find a wealth of infor mation. I just replaced the air bags on my P-30 with bags from Camper's Choice (about $70). Camping World has the same. Relative easy job; big improvement.

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Gary & Edie
North Idaho
1988 28' P-30 454

The air bags are located inside of the springs. There are "urethane donuts" which are located at the top and bottom of each air bag.

Am I wrong in that most air bags are not within springs? I was under the impression that they replace springs. When I DUMP my a air the coach lowers, and if they were within springs how would they lower? I am confused. Is it that the springs just help hold the shape of the bag, and that the springs are very weak thus allowing the coach to settle?

Dale, if you have a P30, especially with a tag axle, you're probably not dumping air from your front suspension.

On mine, the front air bags are serviced separately, as are the Firestone Ride-Rites that are on my main rear axle.

The only air I have controllable from the cockpit, is the air for the tag axle, which has air suspension only, no springs. It's handy to have in order to set your rear ride height for varying loads, but most of us, myself included, are not sophisticated, or caring enough, to reset things everytime we add fuel ,or water or dump holding tanks.

My load for traveling doesn't vary a whole lot, and the amount of fuel and water, fresh, gray, or black, is the only thing that varies significantly when we travel.

[This message has been edited by olroy (edited September 30, 2004).]

Dale,

There is a a big difference between the air suspension on a P30 type chassis and the air suspension on a diesel chassis. The air bags on your coach are of the commercial type and their pressure is actively maintained by the system compressor that also provides pressure for braking and shifting of your transmission.

Air suspension on a P30 chassis is not standard operating procedure, rather an upgrade or after market addition. It can be managed either manually of automatically and comes in a few different configurations.

I'm sure That many others could add more to this as I do not have direct experience with the P30 chassis.

Bill G

I have the 78-34ft. with the tag on the rear axle. The tag has two bags, one on each side that controlled from the dash with a guage and valve for each bag. Your front end on the P-30 will have a bag inside each coil spring which most likely will have a tire type valve out the bottom of each spring. They can have extensions on them so you don't have to crawl under to check the pressure. I think if your mechanic is having trouble finding these bags I would be considering a new place of service as this system is not uncommon.

The P-30 air bags are standard GM. Airlift makes replacement bags, separate electric pump, gauge, and solenoid which automatically inflates and maintains the pressure at 60 psi. You can apply more pressure for windy conditions. As I understand GM's engineering, the P-30 chassis was used for many different things from bread truck to RV, so GM used air bags with a standard set of springs to cover this wide range of load variations. You can buy a set of springs from Helwig or IPD and eliminate the air bags. The front end needs to be weighed with the amount of weight that you travel with included and then buy the proper springs. I think Bill H. has done this and added a thicker sway bar.

The front air bags are absolutely necessary with the standard P30 springs. I test drove a SOB with blown bags, and scared myself badly. The funny thing is, the owner was oblivious to how bad it was. I bought the coach anyway, but put in new bags immediately.

I bought my springs from Supersteer, and I believe Rusty bought his from a place in Marysville Kansas. Hellwig makes a transverse leaf helper spring that I have used on a previous SOB. Both Hellwig and IPD make stiffer anti roll bars. I use the IPD, but have since learned that the Hellwig one is stiffer, so it might be better for the taller coaches.

My Euro has tire type valves in each wheelwell that control the airbags.[P30] I run 75 pounds and it still seems I could stiffen the ride with a tad more for better highway control, but I don't really know what it's supposed to feel like yet being rather new to box RV's. I'm running the stock 8r19.5 fronts and wonder if a wider tire wheel combo would keep her straighter.

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Dan & Suzy Z
'81 Euro 28

Tire pressure is the first thing to consider, coupled to making sure all are at the same pressure. The wider the tire the more the road is going to move the coach from side to side. A lot of roads are cupped from heavy traffic and wide tires do not like such. With that said I doubt though that you can put a wide enough tire on your rims to cause such to be a problem. I would keep a good watch on tire pressure, shocks, and sway bar size. Running at or near the pressure that is stamped on the tire is step number one. Side winds are always going to be present so there is only so much you can do.

quote:

Originally posted by Danny Zeeff:
I'm running the stock 8r19.5 fronts and wonder if a wider tire wheel combo would keep her straighter.

Danny, Dale is right on tire pressures. Weigh your rig and adjust per the manufacturer's chart, maybe adding 5 or 10 lbs.

I went from Michelins to Bridgestones and got an improvement in stability.

You can go to 225 width and get a small improvement at the expense of less ground clearance. And a lower effective ratio if used in the rear. According to the charts, you will need wider rims to go to a 245, although some do it without any reported problems.

Do a search here on "ride height" and "alignment"

The P30 really responds to front end adjustments and improvements

I've got all brand new Bridgestones so I'm not going to get anything just yet. I started the trip with 90 in all of them and the heat brought them up about 5 or 6. Should I cut it back to 84 so they come up to 90 [stamped recommend] or keep them at 90 cold? My biggest complaint [just a little whine actually] was when a big rig passed going faster than us. I have to steer into them for a second, then away at the last second. It's a tiny motion on the wheel, but very necessary.

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Dan & Suzy Z
'81 Euro 28

Danny, FWIW, my former s.o.b. was not on a P30, but the steering lashup underneath was a dead ringer for the P30 system. I danced on eggs every time a big rig pased.

My current P30 tag axle Barth has the "SuperSteer" bellcranks, and the difference in handling & stability from the s.o.b. is the difference between night and day.

My s.o.b. had a single rear axle and single tires on the rear as well. I had my local 4x4 shop fabricate a track bar (panhard rod) that prevented any side-to-side movement in the rear axle. That changed my handling from scary, to merely exciting.

The same people who make the SuperSteer, make a bolt-on track bar for the P30, but it's more expensive than the welded-on setup my local shop made.

Per Bill H., the bar helps with single rear axles, but not with a tag.

quote:

Originally posted by olroy:
Per Bill H., the bar helps with single rear axles, but not with a tag.

Roy, when I posted that, I was quoting the guy from Supersteer. The owner, I think. He said that the big spring chassis did not benefit from the Panhard bar.

Since then, I have had other input that a Panhard bar does indeed improve the heavier P30, at least a non-tag coach. I see nothing in the design of the Neway tag axle suspension that would obviate the need for a Panhard rod back there, so I suspect that a tag axle chassis would also benefit.

So,in the best tradition of Overengineering LLC, I am gathering the parts to make my own bar.

Heck, if a Panhard bar is good, a Watts link should be better, huh?

It's on my list.