ACR Shock Rattle
- Thread starter John ACR
- Start date
ACR Joe
Enthusiast
You might want to check two recent strings on this topic. Lot's of information and a few technical suggestions. I regret that none of the suggestions have proven to be effective; at least based upon my efforts and research to date.
As I previously indicated, I decided to conduct an investigation on my own in an attempt to get to the bottom of this issue. I strongly believe that the noise has nothing whatsoever to do with the internal shock valves. The noise is just too heavy a metallic rattling sound for that.
I removed and disassembled the r/s shock/spring assembly from my 99 ACR and carefully inspected each component. I though for sure I would find some evidence of what was causing the rattle, but no such luck. Well that may not be entirely true. The inside of one of the conical bushings appeared to have light thread marks on the inside. This made me think about why the upper retaining bolt would have threads in that location in the first place. The answer is simple; an "off-the-shelf" "that's good enough" part was used. I measured the diameter of the bolt both on the shoulder (where one bushing rests) as well as on the threads (where the other bushing rests. I found the former dimension to be ~0.436" and the latter to be ~0.431". That means that the clearance between one bushing and the retaining bolt (again in the threaded area) is 0.005" greater than the opposite side.
The key question is whether or not this added clearance could cause such a severe rattle. To answer that question I have communicated with several people from the Viper community (thanks Dean, Bob, John, Kevin, John B. and whoever else I missed). While there are differing opinions, most agree that we MAY be on the right track. I also spoke with George at MGW who has the metals fabrication experience and resources to support the fabrication requirements. I am in the process of laying out the design of a new upper shock support retaining bolt. The bolt will be a "Flange/Hex Head Shoulder Bolt" style with dimensions specifically intended to eliminate the aforementioned clearance.
Since my car is already apart, I'll be the gineau pig. I plan on speaking with George at MGW before the end of the week and having him custom fabricate the bolts ASAP. If the fix is effective, MGW will be able to supply the parts as necessary.
Which gets to the bottom line - will this modification be successful? I've vacillated on this a bit and concluded that it is absolutely an excellent first attempt. Besides, I said before that I just couldn't stand on the sidelines any longer; some constructive action needed to be initiated. Needless to say, I would be absolutely thrilled if this modification proved effective. Of course I'll share the results with the entire Viper community as soon as possible.
Wish me luck ....
PS - As far as a class action law suit is concerned - forget about it; total waste of time and energy! At least as far as I'm concerned.
As I previously indicated, I decided to conduct an investigation on my own in an attempt to get to the bottom of this issue. I strongly believe that the noise has nothing whatsoever to do with the internal shock valves. The noise is just too heavy a metallic rattling sound for that.
I removed and disassembled the r/s shock/spring assembly from my 99 ACR and carefully inspected each component. I though for sure I would find some evidence of what was causing the rattle, but no such luck. Well that may not be entirely true. The inside of one of the conical bushings appeared to have light thread marks on the inside. This made me think about why the upper retaining bolt would have threads in that location in the first place. The answer is simple; an "off-the-shelf" "that's good enough" part was used. I measured the diameter of the bolt both on the shoulder (where one bushing rests) as well as on the threads (where the other bushing rests. I found the former dimension to be ~0.436" and the latter to be ~0.431". That means that the clearance between one bushing and the retaining bolt (again in the threaded area) is 0.005" greater than the opposite side.
The key question is whether or not this added clearance could cause such a severe rattle. To answer that question I have communicated with several people from the Viper community (thanks Dean, Bob, John, Kevin, John B. and whoever else I missed). While there are differing opinions, most agree that we MAY be on the right track. I also spoke with George at MGW who has the metals fabrication experience and resources to support the fabrication requirements. I am in the process of laying out the design of a new upper shock support retaining bolt. The bolt will be a "Flange/Hex Head Shoulder Bolt" style with dimensions specifically intended to eliminate the aforementioned clearance.
Since my car is already apart, I'll be the gineau pig. I plan on speaking with George at MGW before the end of the week and having him custom fabricate the bolts ASAP. If the fix is effective, MGW will be able to supply the parts as necessary.
Which gets to the bottom line - will this modification be successful? I've vacillated on this a bit and concluded that it is absolutely an excellent first attempt. Besides, I said before that I just couldn't stand on the sidelines any longer; some constructive action needed to be initiated. Needless to say, I would be absolutely thrilled if this modification proved effective. Of course I'll share the results with the entire Viper community as soon as possible.
Wish me luck ....
PS - As far as a class action law suit is concerned - forget about it; total waste of time and energy! At least as far as I'm concerned.
As Joe says, we have been talking a great deal about this a lot lately. I am assembling a list of affected ACR owners in order to submit a letter to Dodge to dramatize our aggravation with this persistant problem. I would appreciate it if you could E me your name,address,and Vin # so I could add you to our list. I expect to close the information gathering effort within the next two weeks. In the meantime, Joe is going ahead with his own inquiry and he may be on to something. What is especially gratifying is the teamwork that is being demonstrated by the Viper community to get a fix for this annoying problem. Thanks and we will all continue our efforts.
DonMc
Enthusiast
i have a '00 acr and have notice a bad rattle only on bumps. it seems to be more concentrated on the passenger side rear wheel area. is this similar to the acr shock rattle y'all have experienced??
ACR Joe
Enthusiast
Hey Don:
In a word yep! For some reason the noise seems to prevail on the passenger side more so than the driver's side. As indicated in this and other recent strings, we are pursuing a technical solution independent of Dodge since they are apparently unwilling or unable to lend any form of support. That is to say support beyond the "swap for GTS parts" or "replace the rears only" with the newer and quieter version. Neither scenario has been well received by the ACR community at large, present company included.
I will post the results of my personal efforts asap so stay tuned.
In a word yep! For some reason the noise seems to prevail on the passenger side more so than the driver's side. As indicated in this and other recent strings, we are pursuing a technical solution independent of Dodge since they are apparently unwilling or unable to lend any form of support. That is to say support beyond the "swap for GTS parts" or "replace the rears only" with the newer and quieter version. Neither scenario has been well received by the ACR community at large, present company included.
I will post the results of my personal efforts asap so stay tuned.
Hey Joe,
I am making progress with that local NJ dealer and viper tech about a possible DSP (Vs. Koni) swap for all 4 shocks and springs. I will keep you and all other ACR owners posted. The last word I heard is that Dodge is involved and informed to some extent. Lets keep our fingers crossed.
I am making progress with that local NJ dealer and viper tech about a possible DSP (Vs. Koni) swap for all 4 shocks and springs. I will keep you and all other ACR owners posted. The last word I heard is that Dodge is involved and informed to some extent. Lets keep our fingers crossed.
ACR Joe
Enthusiast
Hey John ACR:
I read your message with great interest and I am eager to learn much more about what Dodge's actual involvement and ultimate intentions may be.
On the "hands-on side", I drafted the upper shock/spring retaining bolt using dimensions that MAY prove effective in negating the shock rattle. This drawing was faxed to George Ciamillo at MGW yesterday and I plan on following up with George today. I still believe that this is a prudent first attempt. If successful, MGW should be able to manufacture and supply production quantities to the ACR community at large. George is a great person to work with and I have all the confidence that MGW will produce a quality part within very tight tolerances.
What if this first step proves unsuccessful you ask? Well, I will focus my attention on the upper spring saddle (hat) which is somewhat suspicious as well. Without getting into too much detail (and please use your imagination as I may not be using proper Detroit parlance), the hat fits over a retainer that is secured to the shock. The gap between the hat and the retainer is very excessive and represents another potential source of the rattle. Correcting this will likewise require that a better engineered component be fabricated.
While I am approaching this matter with an open mind and total objectivity, I find it humorous that a sales guy from Philadelphia is (perceptively) at the forefront of this technical initiative.
I read your message with great interest and I am eager to learn much more about what Dodge's actual involvement and ultimate intentions may be.
On the "hands-on side", I drafted the upper shock/spring retaining bolt using dimensions that MAY prove effective in negating the shock rattle. This drawing was faxed to George Ciamillo at MGW yesterday and I plan on following up with George today. I still believe that this is a prudent first attempt. If successful, MGW should be able to manufacture and supply production quantities to the ACR community at large. George is a great person to work with and I have all the confidence that MGW will produce a quality part within very tight tolerances.
What if this first step proves unsuccessful you ask? Well, I will focus my attention on the upper spring saddle (hat) which is somewhat suspicious as well. Without getting into too much detail (and please use your imagination as I may not be using proper Detroit parlance), the hat fits over a retainer that is secured to the shock. The gap between the hat and the retainer is very excessive and represents another potential source of the rattle. Correcting this will likewise require that a better engineered component be fabricated.
While I am approaching this matter with an open mind and total objectivity, I find it humorous that a sales guy from Philadelphia is (perceptively) at the forefront of this technical initiative.
WHY Passenger side?:
Remember, the rattle is while "unloaded or unloading" in most cases. If you have yet to corner-weight your Viper, there is likley MORE WEIGHT on the Driver's side! (in my case 230 lbs more) and so the passsenger side gets "light" sooner/faster.
This race-car-rattle is THAT sensitive an issue. ACR Joe is on the right track......
JonB
Remember, the rattle is while "unloaded or unloading" in most cases. If you have yet to corner-weight your Viper, there is likley MORE WEIGHT on the Driver's side! (in my case 230 lbs more) and so the passsenger side gets "light" sooner/faster.
This race-car-rattle is THAT sensitive an issue. ACR Joe is on the right track......
JonB
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