Koni Shocks/Airbag Replacement

[0533]

I am considering replacing my shocks. I called Prevost Car in Jacksonville Fl. to discuss the replacement.

The first part of my question is: I am considering changing out the original shocks with Koni shocks. have any of you made this transition and did it make a difference??? I do not have many actual miles on the coach, but it has been on the road for 9 years driving and sitting on these shocks. Plus the possible improvements in the Koni Shocks. Do these Koni's really make a difference??

Second part: If I do replace the shocks, why not the Air Bags as I will have all drive wheels off. Have there been any improvements in Airbags in 9 or 10 years??? The Airbags do not leak. How do they degrade over time, elasticity etc???

Third part: While doing these upgrades and having the wheels off the coach, what else would make sense to inspect and upgrade if this were your coach.

I have a need for speed and good handling and figured that if I started fresh I would be ahead of the power curve. Am I on the right track.

Thanks,

Bruce

[Jon Wehrenberg]

The Prevost position on air bag replacement as expressed by Bill Jensen at the Branson rally is replace them when they leak or fail.

My position is at 10 years, regardless of condition they will be replaced. I choose to do that because if the leak or failure is greater than the compressor can handle, your bus is parked, or on the back of a trailer. It cannot be driven with a failed air bag.

My position on shocks is if they show any signs of leakage they need to come off. These shocks are not like the ones we used to have 40 or 50 years ago that became useless after a few years.

If you do intend to replace both, the timing is perfect because you access the air bag and the shocks the same way so it saves money. I haven't checked on the price of shocks, but they literally come off and go on within minutes. I would allow 15 or 20 minutes with an air gun. The air bags (8) will average an hour apiece. These times for air bags include removing wheels or the front fender liner ahead of the drive axle. So if you are taking it to a service center I would plan on no more than 12 hours labor, and around $140 per air bag. Maybe someone can post the price of shocks.

[0533]

The Prevost position on air bag replacement as expressed by Bill Jensen at the Branson rally is replace them when they leak or fail.

My position is at 10 years, regardless of condition they will be replaced. I choose to do that because if the leak or failure is greater than the compressor can handle, your bus is parked, or on the back of a trailer. It cannot be driven with a failed air bag.

My position on shocks is if they show any signs of leakage they need to come off. These shocks are not like the ones we used to have 40 or 50 years ago that became useless after a few years.

If you do intend to replace both, the timing is perfect because you access the air bag and the shocks the same way so it saves money. I haven't checked on the price of shocks, but they literally come off and go on within minutes. I would allow 15 or 20 minutes with an air gun. The air bags (8) will average an hour apiece. These times for air bags include removing wheels or the front fender liner ahead of the drive axle. So if you are taking it to a service center I would plan on no more than 12 hours labor, and around $140 per air bag. Maybe someone can post the price of shocks.
Is there any info on the merits of the Koni Shock's verses any other brand?? The Koni shocks cost about twice as much as standard shocks.

Also if you use the 10 year rule of thumb on air bags why not do the same with the shocks??

[dalej]

Bruce,

It is to bad you can't come thru Nebraska, I'm in the zone, I just replaced mine (air springs/shocks). After you do one bus, you want to do another.

My air springs had a date of 95, so they were replaced before I had aquired the bus in 98. I inspected them last year and seen the date on them and thought I had better replace them. I contacted Jim Malcome, my favorite Prevost service rep. and he said that if I wasn't having trouble, just let them go.

On our last trip to Phoenix (February 6th or so) the front spring for the right drive axle started leaking around the bottom rim. I thought it might be time to do them all, so I did along with shocks.

When you buy a set of 8 springs they run around $128 and the shocks are around $40 with the grommets from Prevost.

[BrianE]

Bruce,

I replaced our shocks, airbags, brake chambers, and rubber brake lines in January. It's a very easy job with the wheels removed. Jon's estimate of time is very close to what I experienced also. From my Prevost Invoice, replacement shocks were $39.23 and air springs were $129.90. I purchased the brake parts from a local truck parts outlet. The service chambers were about $30.00 ea, the spring brakes were $135.00 ea and the brake lines averaged about $7.00. I checked with the Prevost Service Manager in Calif regarding Konis and his advice was they're not worth the expense but they would be glad to sell them to me if I wanted them. We experienced a significant ride improvement with the new replacement shocks. So far on our trip the leveling system has been tight as a ...............:rolleyes:

It was a fun project and I learned a lot about the bottom side. Would highly recommend you purchase a PAIR of air jacks from Harbor Freight or Northern Tool and a set of Jon's jack-stands if you haven't done so already.

[0533]

Bruce,

I replaced our shocks, airbags, brake chambers, and rubber brake lines in January. It's a very easy job with the wheels removed. Jon's estimate of time is very close to what I experienced also. From my Prevost Invoice, replacement shocks were $39.23 and air springs were $129.90. I purchased the brake parts from a local truck parts outlet. The service chambers were about $30.00 ea, the spring brakes were $135.00 ea and the brake lines averaged about $7.00. I checked with the Prevost Service Manager in Calif regarding Konis and his advice was they're not worth the expense but they would be glad to sell them to me if I wanted them. We experienced a significant ride improvement with the new replacement shocks. So far on our trip the leveling system has been tight as a ...............:rolleyes:

It was a fun project and I learned a lot about the bottom side. Would highly recommend you purchase a PAIR of air jacks from Harbor Freight or Northern Tool and a set of Jon's jack-stands if you haven't done so already.
Thanks Brian. The parts look about right, the labor is the real cost on my quotes, but seems fair based on my boating experiences. I would like to enjoy a firmer more responsive ride if possible.

[Orren Zook]

Part of the price difference is that Koni offers a lifetime replacement warranty. You can also buy adjustable gas shocks made by Monroe or Gabriel at slightly more than standard OEM shocks.

[0533]

Part of the price difference is that Koni offers a lifetime replacement warranty. You can also buy adjustable gas shocks made by Monroe or Gabriel at slightly more than standard OEM shocks.
Hello Orren,

Is there any performance or field reports on the three shocks, Monroe, Gabriel and Koni.

[Jon Wehrenberg]

I should mention that air bag part numbers are different depending on the coach.

The prices we all gave are correct for the coaches we all have. A forty foot coach takes different air bags from a 45 footer. There are also different size air bags for the fronts on some 40 foot coaches. I do not know what the air bags might be for an IFS coach or an XLII or an H3.

For anybody contemplating changing their own air bags be very detailed and specific when ordering them, especially if you have an early nineties coach. Some have been modified with larger air bags than what was originally installed.

[lloyd&pamela]

Bruce,

I just replaced the front shocks at Prevost Mira Loma and asked about the Koni shocks. They said customers could not tell any difference except for price. They recommended the Prevost shocks even though the Koni were more than twice as expensive and I was willing to have them installed.

The new Prevost shocks seem to work fine. Though I am not an expert.

[Orren Zook]

Is there any performance or field reports on the three shocks, Monroe, Gabriel and Koni.

I'll have to get this information for you in the morning. Koni, as I mentioned has a lifetime warranty, Gabriel and Monroe offer 250,000 miles on their gas shocks and 100,000 miles on their heavy duty lines. I don't know that it would be cost effective to opt for the gas shocks over conventional ones unless you were going to really put some miles on your coach. You would have the option to adjust the dampening for a different ride with any of the gas shocks and it might be a nice suspension upgrade.

[dale farley]

Bruce, I replaced mine last year on my 93 Marathon just because I wasn't sure how old they were. I called Marathon and they wanted $234 each. I called Prevost and bought the shocks for less than $37 each. None of my old ones were leaking, and I am not sure I really saw any significant difference in the ride after the replacement of all of them. I will wait until I see a problem or leakage before I change shocks again.

[0533]

Bruce, I replaced mine last year on my 93 Marathon just because I wasn't sure how old they were. I called Marathon and they wanted $234 each. I called Prevost and bought the shocks for less than $37 each. None of my old ones were leaking, and I am not sure I really saw any significant difference in the ride after the replacement of all of them. I will wait until I see a problem or leakage before I change shocks again.
Hi Dale, What type of shocks did you install. I have heard that the Koni really make a difference. I am looking for a Silver bullet I guess.

[0533]

I'll have to get this information for you in the morning. Koni, as I mentioned has a lifetime warranty, Gabriel and Monroe offer 250,000 miles on their gas shocks and 100,000 miles on their heavy duty lines. I don't know that it would be cost effective to opt for the gas shocks over conventional ones unless you were going to really put some miles on your coach. You would have the option to adjust the dampening for a different ride with any of the gas shocks and it might be a nice suspension upgrade.
Good morning Orren,

I found that on some roads, especially when there were large uneven stretches that the front end would rise and fall too many times on the shocks and bags for my taste. I would prefer to be able to adjust this if possible. It sounds like the gas shocks might help in the situation?

[dalej]

I ordered all the parts from Prevost, give them the last four of your vin # and they send you what you need.

[dale farley]

Bruce, I really don't remember what brand of shocks I used. They were the one's that Prevost sells. I would hope there would be some noticeable difference in the performance of the standard shock and the high-end gas shocks.

[0533]

Bruce, I really don't remember what brand of shocks I used. They were the one's that Prevost sells. I would hope there would be some noticeable difference in the performance of the standard shock and the high-end gas shocks.
I will report back. I have decided to go ahead with the Koni's and see what they can offer. I'll ask the Prevost car folks to recommend a setting as well for each.

[0533]

I ordered all the parts from Prevost, give them the last four of your vin # and they send you what you need.
Hi Dale,

When I think about ordering the parts from Prevost I then think about installing them, and two things come to mind, skill and safety. I am not sure that I have the skill, and am sure that if I did the install there would pictures of me on the POG site looking like the Wicked Witch of the West in the Wizard Of Oz, with only my feet sticking out from under the bus that squashed me like a grape.

[Jon Wehrenberg]

One of the problems you might be experiencing Bruce is related more to front end weight and that affects your air bags more than your shocks.

To give you an example, my front will rise when the air bags reach about 100 to 105 PSI.

I know some early coaches that had batteries and generators located near the front, marble floors, and other heavy weight on the front axle requiring as much as 120 PSI to raise the front. There are some coaches whose front is so heavy that when leveling in a campground the owner has to lift the tag in order to get the maximum extention on the front air bags. Once they are fully inflated then the tag can be lowered.

That means that the force to compress the air bag and the resultant rebound is greater than lightly loaded air springs. A shock is calibrated to dampen a certain force or rebound. It may be if you air bags have considerable pressure you may wish to consider the dual front shock set up some coaches once had. However, I think you have IFS and I do not know whether your coach would be set up to accomodate that change, or if you have to have higher air spring pressures because your axle weight may already have components sized to deal with the loads.

[Toy Box]

I know this is the wrong place to post, but I can't find the one about the jack stands. Jon, I received the super fantastic jack stands today!!!! how cool. the color is terrific and the height is spot on. Since the above posts are dealing with replacing air bags, everyone should have a set of these stands. Please don't send any money for the overage, rather, use it for some refreshments at your upcoming get together. signed, A VERY HAPPY JACK STAND OWNER.

[0533]

One of the problems you might be experiencing Bruce is related more to front end weight and that affects your air bags more than your shocks.

To give you an example, my front will rise when the air bags reach about 100 to 105 PSI.

I know some early coaches that had batteries and generators located near the front, marble floors, and other heavy weight on the front axle requiring as much as 120 PSI to raise the front. There are some coaches whose front is so heavy that when leveling in a campground the owner has to lift the tag in order to get the maximum extention on the front air bags. Once they are fully inflated then the tag can be lowered.

That means that the force to compress the air bag and the resultant rebound is greater than lightly loaded air springs. A shock is calibrated to dampen a certain force or rebound. It may be if you air bags have considerable pressure you may wish to consider the dual front shock set up some coaches once had. However, I think you have IFS and I do not know whether your coach would be set up to accomodate that change, or if you have to have higher air spring pressures because your axle weight may already have components sized to deal with the loads.
My real problem Jon is that I expect every vehicle that I drive to handle like a Porsche. I always want to drive too fast, corner to fast and stop too quickly, and seem to expect that 50K LBS will handle like its 3K.

The facts about the coaches front end weight are this: We have no extra weight issues up front that jump out at me. Cork floors, there is a slideout tray under the front bumper with a stainless storage box in it, this has weight, the Howard active steering system a spray unit for the windows, not much else.

I am simply banking on the hope that with some new rubber and some new gas up front that I will at least have the best chance of getting a better ride over some of these uneven roads that our tax dollars are repairing.

[Jon Wehrenberg]

Bruce,

You do not know if you do not have a weight problem until you scale the coach and each axle, comparing the results with the Prevost limits.

If you think you can make a sports car out of it, before you mess with anything else, work on the brakes. Our stopping power, especially at higher speeds truly sucks. We have about 2.5 to 3 times the stopping distance of the average car, and if that doesn't make your butt pucker I don't know what will. We can all drive fast. But none of us can stop.

[0533]

Bruce,

You do not know if you do not have a weight problem until you scale the coach and each axle, comparing the results with the Prevost limits.

If you think you can make a sports car out of it, before you mess with anything else, work on the brakes. Our stopping power, especially at higher speeds truly sucks. We have about 2.5 to 3 times the stopping distance of the average car, and if that doesn't make your butt pucker I don't know what will. We can all drive fast. But none of us can stop.
So your thought is to weigh the beast first to see were it is on the Prevost limits. I can do this. I would think though that Marathon would have considered this in the original build process. I have an electric shade over the drivers seat (assume you all do) that says the weight overall is like 49K?? plus or minus. Will check the front axle and report.

Three times the distance is about right I would guess. Not bad considering that the coach is almost 3x's long and 12x's as heavy as the average vehicle. I actually am a defensive driver, don't trust anyone to do the right thing. Just live in Florida in the winter when all of our retired friends are visiting and you would never drive any other way, and never ever ride a motorcycle down here in sunny so. Fl in the winter time, it suicide.

[Jon Wehrenberg]

Yes, check the weights. If for nothing else you need them to know the tire inflation pressures. The pressures vary depending on the weights at each location.

There are a number of coaches here on POG whose axle limits have been exceeded so while the converter may have delivered it with the weight limits in conformance, the new owners may have exceeded the limits when they brought their tooth brushes on board.

[truk4u]

Bruce,

You'll find your Marathon steer axle right at gross and possibly over. My 97 was within 200 lbs of gross with very little in the front bay. The generator and battery placement are the cause.

Real important to weigh it, so you know what your dealing with.

[0533]

Bruce,

You'll find your Marathon steer axle right at gross and possibly over. My 97 was within 200 lbs of gross with very little in the front bay. The generator and battery placement are the cause.

Real important to weigh it, so you know what your dealing with.
Where is the genset in a country coach?, same as a Marathon, in the C/S #1 bay. I also thought that some coaches had cruise air units up front as well under the front bumper??

Jon mentioned tire pressure based on axle weight, what should the tire pressure be??

[Jon Wehrenberg]

If we knew your weights we could answer your tire pressure question Bruce.

http://www.michelintruck.com/michelintruck/tires-retreads/load-inflation-tables.jsp

Scroll down to your tire size to see what pressures are required when you weight the bus. Weigh it with full fuel, water, and all that you normally carry when departing on a trip.

[dale farley]

Burce, My Marathon had the batteries and generator in 1st bays and the cruise airs behind the front bumper, so I was very close to max in front end weight.

My CC has roof airs, the generator is in the 2nd bay and I think the batteries are are in the 3rd bay, so the weight is more evenly distributed.

[dale farley]

Bruce, My Marathon had the batteries and generator in 1st bays and the cruise airs behind the front bumper, so I was very close to max in front end weight.

My CC has roof airs, the generator is in the 2nd bay and I think the batteries are are in one of the 3rd bays, so the weight is more evenly distributed.