Koni Shocks

[jack14r]

I was visiting a friend recently and he had a problem with his coach and Bill Jensen was helping him out over the phone so I asked him to ask Bill about shocks and Bill said that the OEM shocks were only good for 35-40,000 miles and that the adjustable Konis were the best.I have just over 35,000 miles on my coach and I just replacer all 8 shocks with Koni adjustable shocks,2 were totally junk and the other 6 had almost zero resistance in compression.The end result is astounding,my coach has never driven so well and there has always been a noise in the front whenever I went over expansion joints or over any other small bumps,the noise is gone.The coach always seemed to wander due to(I think)swaying,now there is not any swaying or wander.I now go over a large dip at speed and there is only 1 oscillation instead of 2-3.The Konis are very easy to install except for the ones behind the tag which you really need to take the tag tire off to install them.I adjusted these to the firmest setting because from the charts it really only changes the resistance near the limit of the extension.I am so surprised in how much better the coach drives that I would put these shocks a new coach immediately.I know that the factory has to watch every nickel but a 1,000,000 shell with 35,000 mile junk shocks makes no sense.

[Ray Davis]

Was there any evidence of leaking. I have asked several times about shocks and have been told if there is no leaking, they are fine. Also what was the cost to do your coach. I've been considering new shocks for awhile now.

[jack14r]

There was no leaking,fronts were $142 each,rears were $180 each.

[Lawrence M.]

Ray,
I replaced my shocks with Konis early this year. There were no leaks, however, the change in ride and handling was fantastic. Medium setting.

[grross]

jack,
where did you find them at that price??? Koni online store has a price of $197 for each shock whether front, tog, drive.
Thanks in advance.

[jack14r]

I purchased them from Prevost parts.

[Ray Davis]

Have you a part number. I assume all XL2 are same?

[jack14r]

I think that all IFS Prevost are the same,the Koni # for the front is 90-2574 and the rear is 90-2573,Prevost has their own number but they can cross reference to the Koni number.

[PLSNTVLE2]

Ray
Those are the correct part numbers. I know the front shock part number from Prevost is, 630235. And they are $137.10 ea.

[Gary & Peggy Stevens]

So how many shocks are on an XLII if I was considering replacing all of them with these Koni's ?

[grross]

This morning I ordered koni shocks from Prevost parts...there are 2 on the frt axle($148), 2 on the tag and 4 on the drive($180)
for a total of $1,374.

[jack14r]

Once you installed them let us know if it is as unbelievable as my coach is now.

[tpr]

Jack14r

What's the noise you mentioned in the front end. When I hit an expansion joint I hear the regular tire bump and then a secondary boom on my X L II's front axle.

[jack14r]

I think that would describe the noise my coach had before the Koni shocks.

[pwf252]

Ordered a set (2 steer/4drive/2tag) installed at Prevost Fort Worth for $1700.00 out the door. Had to work on Rodney abit to get them to that number but he finally caved. Now I have to hope when its complete that the bill is actually for 1700.00, as in the past their final bills tend to be higher then their quotes which leads to consternation-indignation-aggravation followed by frustration and then finally to compromise. Which inevitably has me walking to the bus talking to myself about not spending anymore money here. UNTIL NEXT TIME!!!! OH, also I was told by them that Koni doesn't make shocks for the tag so they were going to use OEM. Does that sound right? Why would Koni not have them for the tags?

[Gary & Peggy Stevens]

Patrick, the Koni web site might help everyone with this shock problem and part numbers.

http://www.konirv.com/nextstep.cfm?Model=H3%2C+XL%2C+XLII+w%2F+IFS

The Rear / Tag shocks are the same #'s 902573.

The Front Shock is # 902574.

Maybe Prevost was out of them? I would make Rodney check again for Koni, NOT OEM Shocks. Just my 2 cents worth.

Gary S.

[pwf252]

Earlier today I called Fort Worth Prevost (FWP) to confirm that as Gary states above the Koni shocks for the tag are in fact the same as the ones for the rear axle. Apparently after they (FWP) done a little research on their end they discovered and reported to me that Prevost no longer offers the Koni shocks for either the rear nor tag. They explained to me that there appears to be a clearance issue and that they are speaking to Koni about the problem but for now there is no Koni alternative. Can anyone else shed any light on this? The use of these shocks sure sounded good here on the thread, enough so that I jumped right on trying to put them on my bus, However at this point I don't know!!!!!!!!!!!!!!

[grross]

Patrick,

When I ordered my koni shocks directly from Prevost parts in Elgin, IL they had no problem looking up the part number using either the Koni website part numbers or
going directly to the Prevost part number. Apparantly parts are warehoused at the Prevost service centers. The Konis for my chassis were inventoried in
Jacksonville, FL and were being shipped to me at my FL residence. I will be returning to FL on Fri. and will install them on Sat. If there is a problem with the
fit I will post the problem on this site.

[jack14r]

I installed mine myself and I did not have any clearance issues,the factory OEM and the Koni are almost the same size,I did not measure them but I don't see any real difference.There have been others that have installed the Konis and no one has reported a problem on this board.

[pwf252]

grross/jack,
Its really hard to say with these guys at Fort Worth Prevost I've heard things from them before that turned out not to be quite as they presented. Anyway its good that we have people on this site that can give us first hand knowledge. I will wait to install the rear ones until I can look into it further. I will report back on what if anything I discover. Thanks for the input.

[Jon Wehrenberg]

$1700 to buy and install 8 shocks???????????

Wow!

[Gary & Peggy Stevens]

I am talking to the Jim Koni Shock Rep about the issue of their shocks not working on the rear of a Prevost's ? :confused:

I explained what some of you had found out, but he had heard of ONLY ONE instance where the dust cover of the shock was hitting the frame and needed to be notched out.

He is calling Prevost to find out what the story is, cause he said if there is a PROBLEM with their shocks he wants to get it fixed so we can contnue to use their products. Makes sense to me.

I hope I didn't stir up some s*** up with Prevost Ft. Worth, but I am just trying to get to the bottom of this before I replace all my shocks.

Gary S.

Gary S.

[Gary & Peggy Stevens]

Just an Update to the Koni Shock issue.

Jim from Koni called me back after talking with Prevost. Apparently there can be an issue with ONLY the Tag Shock Dust Cover hitting the frame. But it has about as good a chance of not hitting the frame when installed as it does hitting your frame. Some guys have replaced and had no issues.

So I asked Koni, if he would suggest another mfg for at least the Tag axle and he said, possibly Monroe, but to check the clearance on that shock as well.

Koni will be taking down the web site listing their Tag shocks as working on Prevosts.

NOW what say you guys about the best possible shocks to replace all around on our bus? Oh, I also called Monroe to see if they had a listing for the correct shocks for my bus, but they have to have the OEM's part number or at the very least all of the dimensions of the shocks I am trying to replace.

Anybody out there have all those numbers for an XLII? :rolleyes:

I like to have uniformity of equipment if at all possible. Same Tires, Same Shocks, same Wine Glasses, etc.etc.

Gary S.

[jack14r]

I am surprised that there are some problems because Prevost builds these coaches in a jig that they claim is within thousands of an inch from coach to coach.

[Jon Wehrenberg]

The problem may be that the shocks are attached to the chassis frame (which is precise), but the other end of the shock is attached to the floating suspension assembly. There is a great deal of compliance in the moving structure that carries the wheels and that structure not only goes up and down, but on warped surfaces one side of the structure can have the shock compressed while the other side has the shock extended and is moving in an arc in up and down directions in two planes. I would guess that is where the interference comes about.

Superficially it might seem an easy fix, but I suspect when the CAD analysis of the location of the shocks is made the computers do not factor in movement in bushings and the slight deflection of the structural members due to side forces. Whenever I change a hose or a part such as a fitting I run my bus all the way up and all the way down through full range of motion to insure I have not changed clearances between parts, but I cannot duplicate the relationship of parts that might exist when the coach is exposed to side forces such as a tight turn.

[michaeldterry]

So Jon or somebody - bottom line it for me - what is the current consensus conventional wisdom if one wants to replace all the shocks on a 1995 XLV chassis? I was really liking what I was reading about the the improved (stiffer) ride afforded by the Koni adjustable shocks, but now am confused as to which shocks to choose given the recent disclosures about possible clearance issues....:confused:

[pwf252]

Jon, Are you saying WOW good price or WOW bad price??? That quote was for 6 Koni's and 2 OEM. Well that quote was actually rescinded since they claim they can't install Koni on the rear. Anyway I was talking to one of the techs at Fort Worth that apparently came from Tennessee Prevost and he stated that he has put the Konis on quite a few buses and has never heard of any problems . I decided to put them on the front for now and wait on the rear until there is a clear consenses on whether they foul or not.
You know these buses are hard enough to afford and maintain without all this darn confusion.
Now let me get this straight extended life or more frequent changes of the antifreeze??????? JEEEEZ!!!!!!!!!!!!!!

[Jon Wehrenberg]

I don't remember the exact price I paid for the standard shocks, but it was under $50 apiece.

Add $100 to the price of six Konis and you get about $1150, leaving $550 for labor. First, at the price of Koni shocks they have to be so good anybody can tell the difference, something I doubt. If they were that good, Prevost would spend an additional $1000 (on a $450,000 bus or 0.2%) to make them standard. Apparently Prevost does not think they are worth it. As to the cost of labor I think that is a little high, especially considering the Prevost techs should possess the expertise and efficiency to do the remove and replace far more efficiently than anyone else.

I am changing to extended life after the Kerrville rally. I have no clue what my cost differential will be to go from 2 year changes to 6 year changes, but my reasoning is changing coolant is a pain and takes a lot of time so I want to make my life easier.

[Steve Bennett]

I have driven coaches with both (XL's, XLII's & H3's) the difference is noticeable on the front end. The shocks on our busses provide most of their resistance in rebound, with very little compression dampening. My feeling is that the Konis (depending on the setting) will settle the front end of the coach, and eliminate the tendency to pitch. This is most evident on large undulations, particularly when they are of a frequency that amplifies the size of the bumps because of the distance between the bumps matching the wheelbase, etc. My personal feeling is most people will not notice the difference in the rear, but the Konis are likely built to a better standard than the OEM shocks, and may offer a longer service life.

[Jon Wehrenberg]

Don't forget Steve that the weight distribution and the combination air bags and shocks plays a role.

In the early 90's there were two converters who were exceeding Prevost axle weight limits and a pair of shocks and the size air bags used were inadequate. The excessive front axle weight was in excess of the capacity of the shocks and air bags to control jounce and bottoming over the very road conditions you describe. I am sure you are aware that brought about the use of the Mae West airbags and in some conversions the modification to a 4 shock setup.

My point is that while the difference may in fact be noticeable to the average driver on some coaches, other coaches with different weight distribution and air bags it may not be discernable.

For those owners who are looking for direction from owners as to which shock is best I really believe the decision has to be made in the context of the age of the coach, the converter and the axle weights. I have standard shocks (Monroe I think, I would have to confirm) and I have not experienced rebound or jounce issues.

There is no doubt the Konis have a good reputation and installing them to get a better (presumed) quality may be good enough reason to install them. FWIW I have driven my coach and an IFS coach on the highway and secondary roads for several hundred miles and would be hard pressed to identify which was which if I were blindfolded and in the passenger seat. I did not detect a measurable difference as a driver. Maybe my seat of the pants senses are not as good as others.

[jack14r]

My first post stated that Bill Jensen stated that the original shocks are worn out at 35-40000 miles,I believe that this is accurate.I have a friend that installed Konis on his 1997 Vantari and he feels the same way that I do and that is that the original shocks are not any good.The original shocks have almost zero compression just as Steve stated,the difference in the Koni is the lack of roll or you might call it bounce,the coach is now almost flat in the corners and does not wander any more.

[Jon Wehrenberg]

Steve is a racer so I know he will agree that the biggest influence on cornering flat is the sway bars. The shocks will definitely resist the lean in a corner but only for a very short period of time (seconds) as the bus tends to lean due to centrifugal force. Once the shocks are compressed they then resist the bus returning to the level condition because that is what shocks do. Depending on how they are valved their greatest resistance to movement might be compression or extension, my guess being these are biased towards resisting extension.

The biggest single difference between a later model coach and a 97 is the use of fast reacting ride height valves in the newer coaches and the time delay ride height valves in older models.

As soon as we put our coaches into a hard turn the body is going to lean (regardless of what shocks are in place). The rate at which it leans now depends upon the forces in the lean and the ability of the sway bar to resist the lean. As the coach leans the ride height valves in the rear begin doing their job. On the older time delay valves for a few seconds they don't do any thing. But the outer air bags compress while the air bags inside the turn extend. On newer coaches such as Jack's as soon as the air bags compress or extend the ride height valves are instantly dumping air from the inside bags and adding air to the outside bags to restore the coach to the level position. As soon as the bus exits the turn the forces on the air bags are removed and the ride height valves must again react to change the amount of air in the air bags so the coach continues to ride level. All the time however the sway bar is attempting to restore the coach to a level (side to side) position.

[LA-HODAG]

Prevost Mira Loma quoted me $817.50 for replacement of all OEM shocks on my XL 40 today. The OEMs are from Gabrielle. Service tech Luis, whom I really trust, says it is not worth the $$ to put Konis on the older buses. I was experiencing a lot of porpoise-ing and side to side sway on the old ones. Not sure how old they are as they were on there when I bought the bus. Will report results when I get it back.

[grross]

Update: Today I installed Koni shocks set on Max on all axles. Took 3 1/2 hours and had to remove wheels on tag axle. Drove approx 60 miles on I-75 between summerfield and san antonio, fl. Moderate improvement in ride and handling. After 43,000 miles exterior of rubber bushings had deteriated but inside was still solid...coud have replaced just the bushings since the origional shocks still had acceptable resistence. However with everything apart I went forward with the installation of the Konis. There was no clearance problems with the tag axle shocks.

[Jeff Bayley]

I put OEM shocks on our bus about 20,000 miles ago and it was the single best bang for the buck i've ever spent. My old ones evidently were spent. Had I known about the Koni's I would have put those. I will put those next. Regarding the price difference it's a no brainer. For less than the price of one tank of fuel you can justify the better shocks.

[jack14r]

I drove my coach to Road Atlanta(500 miles)this past weekend to a vintage race,I now have more seat time with the Konis and they are as reported earlier Superior to the OEM shocks in ride,roll and in all other aspects of handling.My coach is much easier to drive in crosswinds and undulating road conditions,I am not chasing the wheel any more.

[Ray Davis]

Was able to wangle 2 Koni's from Prevost Mira Loma. Man those puppies are hard to come by, if you're in a hurry. Installed today, but bus still at service center awaiting new dryer cartridge. Will see soon if it improves. Put Koni's on the front, and 6 new stiff Prevost black shocks on all others.

Ray

[GDeen]

I replaced the front I am sure original OEMs with more of the same when the sway bar bushings were replaced. Amazing difference in ride and handling. Wonder how much more improvement the Koni's would make (if any) with my vintage coach, which is much lighter on the front end than some of the slide models and other XLII's.

[Gary Carmichael]

Is the installation and clearance the same for a H3-45 as a XL1, 2 ? have 50,000 on my bus and was wondering, you know you get used to the ride and don't think about it. have not had any issues, such as swaying or up and down. but as a comparison I thought the old out house was fine till I tried an indoor facility!

[pwf252]

I had Koni's installed on the front and left the old OEM's on the drive and tag for now. Drove it back to where I store it, maybe 30 miles and I can't say I noticed an appreciable difference in the feel, at best maybe a little firmer. We'll see how it feels on the way to Kerrville in a couple weeks.

[Bill1170]

I did not read about how the shocks were adjusted when put on the coach. Any info on this?
Bill

[campers]

Bill,


Rebound Adjustment Procedure
Some shocks can be adjusted while still on the vehicle by removing the lower nut and compressing the shock fully from underneath. If you can do this, follow the instructions below, bearing in mind that clockwise turns will increase the force in the shock, and counterclockwise turns will decrease it. If there is insufficient room under the vehicle, remove the shock and hold it vertically with the dust cover on top. You may use a vice to hold the bottom attachment. If you do mount the shock in a vice, we recommend you use soft jaws to minimize damage to the shock.

Fully collapse the shock absorber while turning shock slowly counterclockwise until you feel the adjustment nut engage in the recesses of the foot valve assembly. Once the adjustment nut has engaged, it is a good idea to make a mark with a black felt on the dust cover and shock body (to make it easier to keep track of adjustment turns).

The damper may have already been adjusted so gently turn it further to the left counting the half turns until you feel a stop.

DO NOT USE FORCE.

If you want to increase the forces, keep the shock absorber collapsed and make a minimum of 1 half-turn (180 degrees) clockwise. In case of prior adjustment add the number of half-turns previously found. The total range is about 5 half-turns.

Pull the shock absorber out vertically without turning for at least 1 cm to disengage the adjusting mechanism. The shock may now be turned freely and reinstalled on the vehicle.

ADJUSTING DIRECTION
Clockwise = Firmer Counter Clockwise = Softer