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Chev P30 Drive axle air bags
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Supporting Member of Barthmobile.com 7/17
Picture of Steve VW
posted
My rear springs are getting tired. I will eventually get them rebuilt but in the meantime I decided to restore the ride height with some additional air bags on the drive axle.

My Regal has a tag axle with air bags but if I use them to level the coach they are running higher pressures and loads than they should.

Firestone Ride-Rite #2080 air bags are made for the drive axle. They are fairly easy to install.

Pass side from front:



From the rear:



To make it easier to check and adjust their pressures, I installed a pressure gauge and Schrader valve on each air line and ran them into the side compartment.





The proper ride height is restored. It will also be adjustable for different loads, etc.

I will make a mounting bracket to attach them to the top of the compartment soon. Haven't driven anywhere yet, still working on other stuff.

I'm in the process of dropping the oil pan to change the rear main seal. Found some other stuff..

Here's one of my motor mounts:



Here's the new one:



I've got everything out but the pan. Engine is up on blocks. I'll post that job when I'm done!


8607-3346-33TFPOB------9708-M0037-37MM-01
86 Regal SE 33 Tag axle--"98" Monarch 37
Chev P3(7) 454TBI--------Cummins 8.3 300 hp
400 hp fuel injected-------6 spd Allison, Spartan MM
 
Posts: 3231 | Location: Kalkaska, MI | Member Since: 02-04-2011Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 3/12
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Subscribed. I dunno, but had the front coils replaced and rear leafs re-arched for about $1100. I like that set-up though. Thanks for posting.
 
Posts: 161 | Location: Nanaimo, B.C. | Member Since: 04-12-2007Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 7/17
Picture of Steve VW
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New springs are the best/final fix. I'm planning to replace front coils and rebuild rear leafs next summer. Even with good springs the bags will help to compensate for varying loads, trailer/toad, etc. I'm neck deep in my rear main seal project for now. (see thread in tech talk forum!)


8607-3346-33TFPOB------9708-M0037-37MM-01
86 Regal SE 33 Tag axle--"98" Monarch 37
Chev P3(7) 454TBI--------Cummins 8.3 300 hp
400 hp fuel injected-------6 spd Allison, Spartan MM
 
Posts: 3231 | Location: Kalkaska, MI | Member Since: 02-04-2011Reply With QuoteReport This Post
"Host" of Barthmobile.com
Supporting Member of Barthmobile.com 8/16
Picture of Bill N.Y.
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Nice... I like this setup too. Thumbs Up

I have a few questions.

~How far away is the brake line from the bolts?

~Is the airbag straight or is it slightly cocked on the bottom towards the spring?

~Is the bag touching the spring?

~Can you slide the lower mount towards the rear axle housing anymore?

- Suggestion -

Perhaps installing a washer and additional nut under the top plate might prevent the bracket from bending - it would act as a shoulder point to support the brace.

Here's what I was thinking.



˙ʎ˙u ןןıq- „ǝןƃuɐ ʇuǝɹǝɟɟıp ɐ ɯoɹɟ pןɹoʍ ǝɥʇ ʇɐ ʞooן ɐ ƃuıʞɐʇ sı ǝɟıן oʇ ʇǝɹɔǝs ǝɥʇ„

Regis Widebody1990 Barth Regis Widebody
8908 0128 40RDS-C1
L-10 Cummins
Allison MT647 Transmission
Spartan Chassis
Regal Conversion1991 Medical Lab Conversion
9102 3709 33S-12
Ford 460 MPFI
C6 Transmission
Oshkosh Chassis



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Posts: 7289 | Location: Newburgh, New York | Member Since: 05-10-2003Reply With QuoteReport This Post
First Month Member
Supporting Member of Barthmobile.com 11/13
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quote:
Originally posted by Steve VW:
New springs are the best/final fix.


A new spring will never be right for your coach and the load of the day.

I use Hellwig adjustable helpers and air bags. The Hellwigs are set for an almost empty coach, and the air bags are set at minimum when empty. Then, as water, boat, motorcycle, etc is added, the air bags keep my ride height just right.

The P30 caster is sensitive to rear ride height. The P30 is sensitive to caster.

BTW, It might be good to tack weld the air bag saddle or the U brackets to the axle saddle. Extreme torque application, such as getting in and out of really difficult campsites can cause the axle to twist and the air bag can fail. A torque arm would obviate that, of course. Or Traction Masters.


.

84 30T PeeThirty-Something, 502 powered
 
Posts: 7397 | Location: AZ Central Highlands | Member Since: 01-09-2001Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 7/17
Picture of Steve VW
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As usual good questions. There is about 1/2 inch clearance to leaf spring. Should be OK. Also, the clearance to brake lines is better than it looks, no pinching, (unless the axle torques around and bag mount slips around axle!) No offroad racing is scheduled for now.

You noticed the two design flaws: straddle clamp holes are slightly oversize and bracket ends bend slightly. (The washer/nut fix would be ideal, how do you do those cool photoshop tricks?) Thumbs Up
The brackets are pretty tight now but if they loosen I will do this fix.

The right side bag is slightly cocked toward spring. (It looks worse in the picture, I had the other side jacked up at the time, doing the other bag) The axle vent tube and shock mount give little leeway to move bracket toward center. The predrilled holes in the base bracket are not perfect for this. I would have drilled them about 1/4 inch over, but this would keyhole the existing holes. Once I get this thing roadworthy I'll recheck how they are sitting.

Meanwhile I'm doing the rear main job... confusion


8607-3346-33TFPOB------9708-M0037-37MM-01
86 Regal SE 33 Tag axle--"98" Monarch 37
Chev P3(7) 454TBI--------Cummins 8.3 300 hp
400 hp fuel injected-------6 spd Allison, Spartan MM
 
Posts: 3231 | Location: Kalkaska, MI | Member Since: 02-04-2011Reply With QuoteReport This Post
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Supporting Member of Barthmobile.com 8/16
Picture of Bill N.Y.
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Perhaps, the problem can be fixed by turning the lower plate 180° - or, if that can't be done, maybe swapping the left lower plate to the right side and vice-a-verse?



It looks like the lower plate has offset holes for the airbag mounting. This might place the bag far enough over. It also looks like the ear is slightly longer on that side too.

It would make the base plate closer to the spring but should put the airbag closer to a straight line with the upper plate and farther away from the spring.
quote:
Originally posted by Steve VW:
BTW, It might be good to tack weld the air bag saddle or the U brackets to the axle saddle.
I would just tack weld the lower saddles.

BTW: All the games I play with images are done with the PAINT program found on most pc's.


˙ʎ˙u ןןıq- „ǝןƃuɐ ʇuǝɹǝɟɟıp ɐ ɯoɹɟ pןɹoʍ ǝɥʇ ʇɐ ʞooן ɐ ƃuıʞɐʇ sı ǝɟıן oʇ ʇǝɹɔǝs ǝɥʇ„

Regis Widebody1990 Barth Regis Widebody
8908 0128 40RDS-C1
L-10 Cummins
Allison MT647 Transmission
Spartan Chassis
Regal Conversion1991 Medical Lab Conversion
9102 3709 33S-12
Ford 460 MPFI
C6 Transmission
Oshkosh Chassis



Quick Link: Members Only Link To Send Me A Private Message
 
Posts: 7289 | Location: Newburgh, New York | Member Since: 05-10-2003Reply With QuoteReport This Post
"Host" of Barthmobile.com
Supporting Member of Barthmobile.com 8/16
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quote:
It looks worse in the picture, I had the other side jacked up at the time, doing the other bag) The axle vent tube and shock mount give little leeway to move bracket toward center. Once I get this thing roadworthy I'll recheck how they are sitting.
Because your image isn't seen from a straight angle, I used the lines from the airbag bellows (red oval - red line) and found them to be 13px offset @ 161px long. Using that as my base, I drew an orange and yellow line that are representative of the angles you would have for the bolts, studs and nuts. That also gets me closer to a 90° angle off the base and upper mounting plates.



I want to thank you for taking the time out to post these images - it really helps our members see what they should be looking for when doing this type of repair or upgrade. Thumbs Up


˙ʎ˙u ןןıq- „ǝןƃuɐ ʇuǝɹǝɟɟıp ɐ ɯoɹɟ pןɹoʍ ǝɥʇ ʇɐ ʞooן ɐ ƃuıʞɐʇ sı ǝɟıן oʇ ʇǝɹɔǝs ǝɥʇ„

Regis Widebody1990 Barth Regis Widebody
8908 0128 40RDS-C1
L-10 Cummins
Allison MT647 Transmission
Spartan Chassis
Regal Conversion1991 Medical Lab Conversion
9102 3709 33S-12
Ford 460 MPFI
C6 Transmission
Oshkosh Chassis



Quick Link: Members Only Link To Send Me A Private Message
 
Posts: 7289 | Location: Newburgh, New York | Member Since: 05-10-2003Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 7/17
Picture of Steve VW
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When I installed these, this one wouldn't line up with either set of factory holes. I think the problem is the location of the vent tube on this Dana axle, other axles have vents in other locations. I tried every combination and the one shown was the best but not quite right. The other side is no issue, the bracket can straddle the shock mount on center and the bag is perfectly straight.

When I get back to this project, I'll pull that bottom plate and swap it around (again!) and drill new holes in the right place, even if I have to weld the old ones over.

Good idea to tack the straps, not the base. Not quite as sturdy bit allows removal of the base if needed.

Thanks for the feedback on the photos! I try to get them close enough and in focus so they are useful. Hopefully other Chebby owners can use em. They seem to provoke good discussions, too.

(Actually I only do it for selfish reasons... with all the documentation on my coach I'm sure if I ever sell it I'll have a bidding war between buyers for all this documented cool stuff I've shown, raising the price and rewarding me for all my work... yeah right!) ROTFLMAO


8607-3346-33TFPOB------9708-M0037-37MM-01
86 Regal SE 33 Tag axle--"98" Monarch 37
Chev P3(7) 454TBI--------Cummins 8.3 300 hp
400 hp fuel injected-------6 spd Allison, Spartan MM
 
Posts: 3231 | Location: Kalkaska, MI | Member Since: 02-04-2011Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 7/17
Picture of Steve VW
posted Hide Post
Final update:

I removed the lower bracket on the right side and drilled 2 more holes about 1/2 inch over from the original holes. The bottom bracket lines up properly now. There is also more clearance from bag to spring.

The problem is the location of the rear axle vent hose. Evidently this varies depending on axle type. My Dana 70 vent interferes with the axle bracket on that side. Be prepared to drill 2 holes if you have this axle!

I put about 60 psi in the bags to start. This seems to put the ride height where it should be. Road testing confirms numerous improvements.

Less body roll on corners, more stability in crosswinds, better ride. Still a typical P30 stiff ride but there is less harshness to the bumps, less rattling and banging on rough stretches. Tooling Along

I tried a few psi more or less but 60 seems about right.

I ran to Milford II and back (about 500 miles) I ran 85 psi in the tires (had been 90) and the ride was the best it has ever been. Thumbs Up

These bags work well on my Barth. Now to make it more quiet... Sleeping


8607-3346-33TFPOB------9708-M0037-37MM-01
86 Regal SE 33 Tag axle--"98" Monarch 37
Chev P3(7) 454TBI--------Cummins 8.3 300 hp
400 hp fuel injected-------6 spd Allison, Spartan MM
 
Posts: 3231 | Location: Kalkaska, MI | Member Since: 02-04-2011Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 8/10
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What do you mean by noisy? In the rear of the coach or up front near the cowling? I've got mine where my wife and I can easily converse going down road...
 
Posts: 438 | Location: The Great Midwest | Member Since: 12-04-2009Reply With QuoteReport This Post
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