I'll chime in a bit here... I have air springs on my EcoDiesel and concerned about failures on long trips to Mexico, Baja, etc. I installed heavy duty springs so the air springs don't do a lot but I still use them more as a levelling tool. My camper is on full time so it's a bit easier for me to dial in the psi, etc.
Blown airbag
- Thread starter daverave
- Start date
RONR
R³
Kevin: Great minds think alike. I had the airbags for quite awhile but always concerned about failure while out in the middle of nowhere on rough terrain. I finally added more leaf springs. My camper is on full time as well. The beefed up springs really work well. I’m very happy I got them. Now the airbags are just used to fine tune (since they are there anyway).kmcintyre said:
daverave
Senior Member
Hey all! Hope everyone is having a fulfilling holiday weekend!
Lest you thought that this topic will ever go away, here is the latest in our saga:
We have deduced from the original installation work order that there are adjustable shocks and leveling blocks on the front end of the truck. The truck was never "lifted" in the traditional sense of the term, it has just had the standard slight factory rake leveled out.
So we took the truck up to a third party for evaluation of the air spring install by Four Wheel Parts because I frankly do not trust their work anymore. This new shop came highly recommended by a friend and neighbor. They put the truck on a lift and four different sets of eyes at different times, with us looking on, gave us answers from "it seems okay to me" to "I'm not sure" to "did you know that both of your rear shocks are blown?" Surprisingly this assembled opinion has cost us nothing, yet.
The crux question to me is whether the 2" spacer that FWP added below the air spring makes any sense at all. The alleged justification from FWP is that the spacers will prevent the over-extended spring that caused the bracket failure. I also don't like the obvious pinching on the inside of the bag suggesting that the wear there will be greater. (See reply #34 photo above.)
My thinking now, especially after talking to the tech at Firestone, is to have the 2" spacers removed, replace the shocks, keep the air springs more fully inflated and get back to traveling while keeping more of an eye on things than we have in the past. I'm also wishing/hoping that taking out the spacer will reduce the pinching on the bag.
So my question to the wisdom of this crowd is this:
Have any of you that have air springs EVER simultaneously installed an additional spacer for any reason???
Thanks for any and all opinions.
Lest you thought that this topic will ever go away, here is the latest in our saga:
We have deduced from the original installation work order that there are adjustable shocks and leveling blocks on the front end of the truck. The truck was never "lifted" in the traditional sense of the term, it has just had the standard slight factory rake leveled out.
So we took the truck up to a third party for evaluation of the air spring install by Four Wheel Parts because I frankly do not trust their work anymore. This new shop came highly recommended by a friend and neighbor. They put the truck on a lift and four different sets of eyes at different times, with us looking on, gave us answers from "it seems okay to me" to "I'm not sure" to "did you know that both of your rear shocks are blown?" Surprisingly this assembled opinion has cost us nothing, yet.
The crux question to me is whether the 2" spacer that FWP added below the air spring makes any sense at all. The alleged justification from FWP is that the spacers will prevent the over-extended spring that caused the bracket failure. I also don't like the obvious pinching on the inside of the bag suggesting that the wear there will be greater. (See reply #34 photo above.)
My thinking now, especially after talking to the tech at Firestone, is to have the 2" spacers removed, replace the shocks, keep the air springs more fully inflated and get back to traveling while keeping more of an eye on things than we have in the past. I'm also wishing/hoping that taking out the spacer will reduce the pinching on the bag.
So my question to the wisdom of this crowd is this:
Have any of you that have air springs EVER simultaneously installed an additional spacer for any reason???
Thanks for any and all opinions.
daverave
Senior Member
Bump....
Sorry for my overworked persistence but I'm really hoping to get some answers to the question posed just above before getting new shocks installed. I like kmcintyre's idea above to use heavier duty springs to help share the load.
Dave
Sorry for my overworked persistence but I'm really hoping to get some answers to the question posed just above before getting new shocks installed. I like kmcintyre's idea above to use heavier duty springs to help share the load.
Dave
ntsqd
Custom User Title
Springs with the correct rate for the loading are the best solution.
I've never seen such a spacer, but FWP's reasoning aligns with the little that I do know about air spring management. You do NOT want to over-extend them as they will be pulled apart. This problem is why Daystar makes a cradle for air springs, so that the axle can droop beyond the max extension of the air spring.
I've never seen such a spacer, but FWP's reasoning aligns with the little that I do know about air spring management. You do NOT want to over-extend them as they will be pulled apart. This problem is why Daystar makes a cradle for air springs, so that the axle can droop beyond the max extension of the air spring.
daverave
Senior Member
Thanks for some input Thom. I'm trying to avoid adding any leaf springs.... too many variables for my non-mechanical mind to process!
ckent323
Senior Member
Daverave, et al,
The following may have been written previously, if so I apologize for being redundant.
The springs (or airbags if there are no springs or even if used in combination with springs) are the primary suspension component and support the weight of the vehicle (not the shocks). They also determine the ride height above the axle (I am including any riser blocks and/or spacers in this).
Shocks are used in conjunction with springs and airbags. The purpose of shocks are to damp out the bounces. The shock valving affects how fast or slow the shock recovers from compression (how fast or slow it damps or responds to bouncing). Ideally you would like a critically damped set up that after a bump or bounce completely damps out in one bounce (rather than several successively smaller bounces)
The appropriate shock length and travel depends on the spring (or airbag) and the length and travel must be determined with the springs fully unloaded (extended) and if possible fully loaded (compressed) to the point the bump stops are contacted. Typically, however, the travel and length is calculated by measurement from the fully unloaded position to the bump stop because loading the springs to the point of full compression at the bump stop is not feasible.
In all events you do not want a shock to have less travel than the spring (or airbag) will allow if you go over a bump and the spring (or airbag) unloads. It can pull the shock apart. Similarly you do not want a shock to have less travel than the springs (or airbag) which would cause it to bottom out when it gets compressed going over a hard bump, as it will produce a hard jolt and it can damage the shock.
So getting to the spacers. If they are added or removed there needs to be an understanding of the shock length and travel range before making a change as it may cause you to need to replace the shocks.
Based on the discussion above it seems that the spacers were a bandaid to remedy shocks that were not the correct length. It seems to me appropriate (if you do not already have the measurements) to have the shock length and travel measurements made on your vehicle and make sure you have the appropriate shock length and range before deciding to remove (or keep) the spacers.
Relative to thee failed brackets. It seems like the mechanics argument for failure is similar to having the wrong size shock (not enough travel or length). The loads on that bracket in compression can be quite high but it seems to me that the loads in extension would be significantly less (the axle and suspension are a lot lighter than the truck with camper). This makes me wonder if the bracket design is insufficient to handle the loads produced by your vehicle/camper combination. The cracking is a sign of fatigue which suggests to me the bracket is bending and working that 90 degree bend. If that is true then it seems to me that the bracket is not stiff enough (too thin or perhaps not mounted appropriately or ?).
Spacers and other additions may not be addressing the root problem.
If you have not done so (apologies again if I missed this in previous discussion) it seems to me it would be appropriate to contact the manufacturer of the bracket and provide them with the weight of the truck (rear axle weight loaded) along with photos of the installation and failure (both sides) and get their opinion.
I hope this is of some help.
Edit:
This link might also be helpful
https://www.motortrend.com/how-to/1001mt-shock-absorbers-air-springs/
The following may have been written previously, if so I apologize for being redundant.
The springs (or airbags if there are no springs or even if used in combination with springs) are the primary suspension component and support the weight of the vehicle (not the shocks). They also determine the ride height above the axle (I am including any riser blocks and/or spacers in this).
Shocks are used in conjunction with springs and airbags. The purpose of shocks are to damp out the bounces. The shock valving affects how fast or slow the shock recovers from compression (how fast or slow it damps or responds to bouncing). Ideally you would like a critically damped set up that after a bump or bounce completely damps out in one bounce (rather than several successively smaller bounces)
The appropriate shock length and travel depends on the spring (or airbag) and the length and travel must be determined with the springs fully unloaded (extended) and if possible fully loaded (compressed) to the point the bump stops are contacted. Typically, however, the travel and length is calculated by measurement from the fully unloaded position to the bump stop because loading the springs to the point of full compression at the bump stop is not feasible.
In all events you do not want a shock to have less travel than the spring (or airbag) will allow if you go over a bump and the spring (or airbag) unloads. It can pull the shock apart. Similarly you do not want a shock to have less travel than the springs (or airbag) which would cause it to bottom out when it gets compressed going over a hard bump, as it will produce a hard jolt and it can damage the shock.
So getting to the spacers. If they are added or removed there needs to be an understanding of the shock length and travel range before making a change as it may cause you to need to replace the shocks.
Based on the discussion above it seems that the spacers were a bandaid to remedy shocks that were not the correct length. It seems to me appropriate (if you do not already have the measurements) to have the shock length and travel measurements made on your vehicle and make sure you have the appropriate shock length and range before deciding to remove (or keep) the spacers.
Relative to thee failed brackets. It seems like the mechanics argument for failure is similar to having the wrong size shock (not enough travel or length). The loads on that bracket in compression can be quite high but it seems to me that the loads in extension would be significantly less (the axle and suspension are a lot lighter than the truck with camper). This makes me wonder if the bracket design is insufficient to handle the loads produced by your vehicle/camper combination. The cracking is a sign of fatigue which suggests to me the bracket is bending and working that 90 degree bend. If that is true then it seems to me that the bracket is not stiff enough (too thin or perhaps not mounted appropriately or ?).
Spacers and other additions may not be addressing the root problem.
If you have not done so (apologies again if I missed this in previous discussion) it seems to me it would be appropriate to contact the manufacturer of the bracket and provide them with the weight of the truck (rear axle weight loaded) along with photos of the installation and failure (both sides) and get their opinion.
I hope this is of some help.
Edit:
This link might also be helpful
https://www.motortrend.com/how-to/1001mt-shock-absorbers-air-springs/
daverave
Senior Member
That is an impressive treatise on the intricacies of suspension Mr Kent! I may share it with whomever ends up doing the work to make sure the shock and airbag travel concerns are addressed.
Many thanks to you for taking the time to write that.
Cheers
Dave
Many thanks to you for taking the time to write that.
Cheers
Dave
fuzzymarindave
Senior Member
What he said...ntsqd said:
daverave- If you replace the spring pack with a set designed for the load then there are actually fewer variables and no need for air bags! If you want to keep the airbags then take a look at Daystar cradles which would eliminate your concern for over extension. I have fussed around with airbags, then additional leafs into the pack with airbags, then added daystar cradles; and now ditched all that for a custom new leaf pack and I wish I had done that at the outset.daverave said:
ntsqd
Custom User Title
One thing about shock length and travel, ideally you set the minimum compressed length of the shock to be slightly less than the minimum distance between the mounts. This is to allow for frame etc. distortion.
If the dampers are mounted outside of the springs then the minimum distance measurement is made with one side is fully compressed to metal to metal and the other side is fully extended.
If the dampers are mounted inside of the springs then the measurement is made with both sides at full compression (metal to metal)
.
This is the important part: take these measurements WITHOUT the bump-stops being in place. Bump-stops do disappear now and again, and the loss of one should not cause the damper to fail.
If the dampers are mounted outside of the springs then the minimum distance measurement is made with one side is fully compressed to metal to metal and the other side is fully extended.
If the dampers are mounted inside of the springs then the measurement is made with both sides at full compression (metal to metal)
.
This is the important part: take these measurements WITHOUT the bump-stops being in place. Bump-stops do disappear now and again, and the loss of one should not cause the damper to fail.
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