Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×


Reply
 
Thread Tools Display Modes
 
Old 02-13-2017, 06:47 AM   #1
Skoolie
 
ourmefa's Avatar
 
Join Date: Dec 2016
Location: Nashville, TN
Posts: 208
Conversion of spring to air ride suspension

Has anyone every heard of someone converting the spring suspension in a school bus to an air suspension?

I know nothing about large vehicle suspension systems, so any thoughts or suggestions would be great. Thanks!

__________________
Family of 4 - Jamie, Mel, Jensen and Maddie (+3 cats) - less than 60 days out from ditching suburbia in a converted school bus.
Find us on Facebook-Affiliate Link Disclaimer
ourmefa is offline   Reply With Quote
Old 02-13-2017, 07:12 AM   #2
Skoolie
 
Join Date: Dec 2016
Posts: 164
I haven't. What would be the purpose of doing such a thing? It sounds like a pain, but that's usually my reaction to stuff involving large, heavy objects like leaf springs.

If you're just looking to even out the ride, a set of "helper" air springs, in addition to the leaves, might be what you're looking for. Many RVs use that configuration. The air bags are just there to provide softness to the upper range and let the driver level the vehicle better.
lucasd is offline   Reply With Quote
Old 02-13-2017, 07:20 AM   #3
Bus Geek
 
EastCoastCB's Avatar
 
Join Date: Sep 2014
Location: Eustis FLORIDA
Posts: 23,764
Year: 1999
Coachwork: Thomas
Chassis: Freighliner FS65
Engine: Cat 3126
Rated Cap: 15
Quote:
Originally Posted by ourmefa View Post
Has anyone every heard of someone converting the spring suspension in a school bus to an air suspension?

I know nothing about large vehicle suspension systems, so any thoughts or suggestions would be great. Thanks!
It can be done, but you'll spend a lot.
Lots of school buses out there are equipped with air ride. Its totally worth it to find one that is. I've gotten lucky on both mine and they ride great. The shorty even has an air seat.
Kubla's BB has air ride on all four corners. That's gotta ride real nice!
EastCoastCB is offline   Reply With Quote
Old 02-13-2017, 07:21 AM   #4
Skoolie
 
ourmefa's Avatar
 
Join Date: Dec 2016
Location: Nashville, TN
Posts: 208
Quote:
Originally Posted by lucasd View Post
I haven't. What would be the purpose of doing such a thing? It sounds like a pain, but that's usually my reaction to stuff involving large, heavy objects like leaf springs.

If you're just looking to even out the ride, a set of "helper" air springs, in addition to the leaves, might be what you're looking for. Many RVs use that configuration. The air bags are just there to provide softness to the upper range and let the driver level the vehicle better.
Yes, the idea would be to help avoid some of the bounce that happens with spring suspension and also help with leveling the bus when needed. I have not heard about "helper" air springs - I will have to look into this.

My thought is that for some bus manufactures, the rear suspension seems to be an option. Once we have purchased our bus, I considered that maybe robbing the air suspension from a salvage bus and installing it on our bus might be a possible solution?

Thanks for the assist!
__________________
Family of 4 - Jamie, Mel, Jensen and Maddie (+3 cats) - less than 60 days out from ditching suburbia in a converted school bus.
Find us on Facebook-Affiliate Link Disclaimer
ourmefa is offline   Reply With Quote
Old 02-13-2017, 07:24 AM   #5
Traveling
 
Join Date: Nov 2015
Location: Midwest
Posts: 2,573
Year: 2003
Coachwork: BlueBird
Chassis: TC2000
Engine: 5.9L Cummins
Rated Cap: '00
Quote:
Originally Posted by ourmefa View Post
Has anyone every heard of someone converting the spring suspension in a school bus to an air suspension?

I know nothing about large vehicle suspension systems, so any thoughts or suggestions would be great. Thanks!
It is possible, some work, but doable. Leaf springs do 2 things- they absorb the bumps, of course, but they also locate the axle. That means, they keep the axle right where it needs to be.

Air bags handle the bumps great, but they are just rubber bags of air- your axle would wrap on acceleration or shear on braking. You would have to add control arms to keep the forward/rear placement of the axle. Then you need to be concerned about the side to side movement of the axle, you'd need all this to be able to move without impingement. You'd need a small air compressor.




Hepler bags are much simpler.
Rusty is offline   Reply With Quote
Old 02-13-2017, 11:29 AM   #6
Bus Geek
 
Join Date: May 2016
Location: Eastern WA
Posts: 6,401
Year: 2002
Coachwork: Bluebird
Chassis: All American RE (A3RE)
Engine: Cummins ISC (8.3)
Rated Cap: 72
I have no real knowledge in the area but I can share something that I have observed others do with success trying to smooth the ride of heavily sprung trucks.

They installed GOOD shocks all of the way around. Removed one or two leaves from each leaf spring and added air bags between the axle and frame at each corner.

I am sure that there is some math to be figured out as far as how many pieces to remove and what size airbags to add. Do we have an engineer in the house???
PNW_Steve is offline   Reply With Quote
Old 02-13-2017, 11:32 AM   #7
Skoolie
 
ourmefa's Avatar
 
Join Date: Dec 2016
Location: Nashville, TN
Posts: 208
Quote:
Originally Posted by Rusty View Post
It is possible, some work, but doable. Leaf springs do 2 things- they absorb the bumps, of course, but they also locate the axle. That means, they keep the axle right where it needs to be.

Air bags handle the bumps great, but they are just rubber bags of air- your axle would wrap on acceleration or shear on braking. You would have to add control arms to keep the forward/rear placement of the axle. Then you need to be concerned about the side to side movement of the axle, you'd need all this to be able to move without impingement. You'd need a small air compressor.

Hepler bags are much simpler.
Great information! I just learned something about axles that I did not know. I guess I should take some time to investigate this more. Thank you!
__________________
Family of 4 - Jamie, Mel, Jensen and Maddie (+3 cats) - less than 60 days out from ditching suburbia in a converted school bus.
Find us on Facebook-Affiliate Link Disclaimer
ourmefa is offline   Reply With Quote
Old 02-13-2017, 11:33 AM   #8
Skoolie
 
ourmefa's Avatar
 
Join Date: Dec 2016
Location: Nashville, TN
Posts: 208
Quote:
Originally Posted by PNW_Steve View Post
I have no real knowledge in the area but I can share something that I have observed others do with success trying to smooth the ride of heavily sprung trucks.

They installed GOOD shocks all of the way around. Removed one or two leaves from each leaf spring and added air bags between the axle and frame at each corner.

I am sure that there is some math to be figured out as far as how many pieces to remove and what size airbags to add. Do we have an engineer in the house???
This sounds like the best of both worlds! I will definitely look at this! I like the idea of shocks, as they are what will help the bus the most when we are not up on jacks!
__________________
Family of 4 - Jamie, Mel, Jensen and Maddie (+3 cats) - less than 60 days out from ditching suburbia in a converted school bus.
Find us on Facebook-Affiliate Link Disclaimer
ourmefa is offline   Reply With Quote
Old 02-13-2017, 01:41 PM   #9
Bus Geek
 
Tango's Avatar
 
Join Date: Mar 2011
Location: Houston, Texas
Posts: 8,462
Year: 1946
Coachwork: Chevrolet/Wayne
Chassis: 1- 1/2 ton
Engine: Cummins 4BT
Rated Cap: 15
Can't give you a formula, but skoolies are sprung for their max gross with a full load of passengers and are typically WAY too stiff for any RV type build.

I can tell you I cut the rear spring rate in half on my 1.5 ton shorty and it is fine. I did add good shocks in back as the original chassis had none.

Any competent spring company can tell you what spring rate you need if you can give them the final front & rear axle weights. Talk to Eaton Detroit. They have been in the biz for over a hundred years and are great to work with.
Tango is offline   Reply With Quote
Old 02-13-2017, 01:57 PM   #10
Bus Crazy
 
Stu & Filo. T's Avatar
 
Join Date: Sep 2013
Location: Vacaville, Ca
Posts: 1,634
Year: 1988
Coachwork: Crown / Pusher
Engine: 8.3 Cummins
Actually a fellow Skoolie who lives just a few miles from me just had his converted, I'll text him later to find out what kind of cost was involved.
Stu & Filo. T is offline   Reply With Quote
Old 02-13-2017, 03:34 PM   #11
Bus Geek
 
Elliot Naess's Avatar
 
Join Date: Oct 2005
Location: Clearlake, Northern California
Posts: 2,505
Year: 1992
Coachwork: Blue Bird
Chassis: TC-2000 Frt Eng, Tranny:MT643
Engine: 5,9 Cummins
Rated Cap: 84
This has been discussed around here before.

You would need the axle (the housing, anyway) with the suspension, since the brackets are suspension-specific and welded to the housing.

Way to go might be to cut the frame on the donor and bring the whole thing home. Then you could accurately drill the new holes to match the old frame.

The donor would likely be a single-axle highway tractor, since these are readily available.

I would love to do it, having driven air ride cross country for 27 years.
__________________

Elliot Naess is offline   Reply With Quote
Old 02-13-2017, 03:43 PM   #12
Bus Nut
 
Join Date: Dec 2015
Location: Utah
Posts: 266
Year: 1990
Coachwork: BB
Chassis: TC2000
Engine: Cummins
Rated Cap: 25.999K
Hi. I am also considering adding a HELPER air pack to the front of my TC1000. It has rear bags already, and an air seat. Id like to smooth out the front a bit, and maybe raise it a little. Also, I know they are not as Heavy Duty as the bags, but has anyone been known to add Air SHOCKS instead. I know some add 1500 or so lbs of capacity, and handle 150 psi..
SDR76 is offline   Reply With Quote
Old 02-13-2017, 08:53 PM   #13
Bus Crazy
 
Stu & Filo. T's Avatar
 
Join Date: Sep 2013
Location: Vacaville, Ca
Posts: 1,634
Year: 1988
Coachwork: Crown / Pusher
Engine: 8.3 Cummins
Ok he got back to me,, $10,000.00

That included everything , housing axles ring & piñon, bags
Stu & Filo. T is offline   Reply With Quote
Old 02-13-2017, 09:14 PM   #14
Skoolie
 
Join Date: Oct 2016
Location: Motor City
Posts: 146
It's not done a lot, but people do swap air suspensions onto medium duty trucks. Junkyard parts and lots of DIY seems to be the norm.

Here's one:

$300 rear air suspension - Diesel Forum - TheDieselStop.com
ennonne is offline   Reply With Quote
Old 02-13-2017, 10:08 PM   #15
Bus Geek
 
Elliot Naess's Avatar
 
Join Date: Oct 2005
Location: Clearlake, Northern California
Posts: 2,505
Year: 1992
Coachwork: Blue Bird
Chassis: TC-2000 Frt Eng, Tranny:MT643
Engine: 5,9 Cummins
Rated Cap: 84
Quote:
Originally Posted by Stu & Filo. T View Post
Ok he got back to me,, $10,000.00

That included everything , housing axles ring & piñon, bags
"Everything"? Now I'm puzzled. Because…



…For Ten Grand, you can buy THIS complete air ride suspension, and he’ll throw in the rest of the 1995 Freightliner with Cummins M11 and 10-speed and you can drive it home. And you can do that almost THREE TIMES for Ten Grand. Price: $3,400. Los Angeles.






And if that one is not shiny enough, you can drive your choice of THESE air ride suspensions home with the rest of the 2005 Volvo attached, 365 horsepower humming, and still have $500 left over for the celebration. Price: $9,500. Dallas.
__________________

Elliot Naess is offline   Reply With Quote
Old 02-13-2017, 10:27 PM   #16
Bus Crazy
 
Stu & Filo. T's Avatar
 
Join Date: Sep 2013
Location: Vacaville, Ca
Posts: 1,634
Year: 1988
Coachwork: Crown / Pusher
Engine: 8.3 Cummins
There's labor in there too he paid a shop to install it. I'm just repeating what I was told
Stu & Filo. T is offline   Reply With Quote
Old 02-13-2017, 10:51 PM   #17
Bus Geek
 
Elliot Naess's Avatar
 
Join Date: Oct 2005
Location: Clearlake, Northern California
Posts: 2,505
Year: 1992
Coachwork: Blue Bird
Chassis: TC-2000 Frt Eng, Tranny:MT643
Engine: 5,9 Cummins
Rated Cap: 84
Yes, of course. Maybe 30 or 40 man-hours at $180 or some such -- wild guess example.

I do understand that not everyone considers it a pleasant hobby to transplant major assemblies from one frame to another.

It just "hurts" to see it, when some of us would drive that Freightliner home for $3,400 and have the M11, RTO 10, and complete air suspension installed in the bus over a few weekends.
__________________

Elliot Naess is offline   Reply With Quote
Old 02-13-2017, 11:04 PM   #18
Traveling
 
Join Date: Nov 2015
Location: Midwest
Posts: 2,573
Year: 2003
Coachwork: BlueBird
Chassis: TC2000
Engine: 5.9L Cummins
Rated Cap: '00
You could get away with the existing axle. If you look, most of the suspension components are bolted on w/ U bolts. May have to torch a flat here or there, but is doable.

This company is supposed to be the cat's pajamas. Looks bolt-on, few mag drill holes in the side of frame. NEVER drill on top or bottom ledge of frame, nor weld to frame.

Hendrickson Comfort Aire


Rusty is offline   Reply With Quote
Old 02-13-2017, 11:26 PM   #19
Bus Geek
 
Elliot Naess's Avatar
 
Join Date: Oct 2005
Location: Clearlake, Northern California
Posts: 2,505
Year: 1992
Coachwork: Blue Bird
Chassis: TC-2000 Frt Eng, Tranny:MT643
Engine: 5,9 Cummins
Rated Cap: 84
As in the video of the "little" Ford, the track rod must be attached to a bracket that is welded to the housing.

And I like the idea of having the donor frame (or section thereof) as a template for drilling all the new holes correctly.

I used to drive Kenworths with "8 bag" suspension. That would be "4 bag" for a single drive axle. With that arrangement, ALL the truck's weight rides on air bags. The rods that hold the axles in correct position carry no weight.

Rode wonderfully. A few drivers opined that the locator rods were a tad inadequate and allowed the axles to shift around a bit. I suspect that was only runaway opinionism -- voicing an opinion for the sake of sounding wise and important.

8-bags also have two height valves -- one on each side, not connected. That completely eliminates leaning to one side in a long curve and in crosswind. No reason not to use two on any suspension.
__________________

Elliot Naess is offline   Reply With Quote
Old 02-13-2017, 11:47 PM   #20
Traveling
 
Join Date: Nov 2015
Location: Midwest
Posts: 2,573
Year: 2003
Coachwork: BlueBird
Chassis: TC2000
Engine: 5.9L Cummins
Rated Cap: '00
Quote:
Originally Posted by Elliot Naess View Post
... the track rod must be attached to a bracket that is welded to the housing.

And I like the idea of having the donor frame (or section thereof) as a template for drilling all the new holes correctly.
The track rod in the picture above is attached to the cantilever, that is bolted to axle. other end goes inside frame rail. No weld needed.

2nd leveler might be nice, easy diy addition.
Rusty is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 07:56 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.