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Discussion Starter #1
Has this happened to anyone else? I had a front Bilstein shock (24-011044) lower mounting bar pin shear off on one side. I did not notice this and apparently drove long enough with only one side connected which lead to fatiguing the single remaining mounting point to the point of failure. The A- arm through-hole failed, allowing the shock to fully extend, and (eventually) contact the ground under suspension compression...

I'll hopefully be replacing the shock under warranty, I was just concerned that this might repeat itself, if it's a common occurrence?

Also, does anyone have any suggestions for repairing the damage to the A-arm, short of replacement? I'm thinking I might weld a reinforcement panel (with captive nut?) where the torn mount hole remains.
 

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I'm not sure if that sheered off or the captive nut gave way on that side. It probably sheered off when it hit the ground.


I've been changing front springs on mine and notice that the captive nuts are pretty week after being taken on and off a couple times.


They should be replaced with bolts and lock washers or lock nuts.
 

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That shock is toast, hopefully they give you a replacement under warranty. Can't say for sure on the A-arm since there is no picture but think it's time for a new arm based on your description of the damage.

Not sure you really have any options other than the stock Speed/Spring Nuts used to slide into the a-arm. I just don't think you have access to hold a nut on the opposite side that the bolt goes thru. Maybe tack weld them in if your against the stock style nuts. On all the cars I've had with this type of suspension, never have seen a shock shear off like that from the bolt backing out. I suspect something hit it and ripped it off.
 

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Discussion Starter #4
I'm not sure if that sheered off or the captive nut gave way on that side. It probably sheered off when it hit the ground.
I should have mentioned that the sheared off side was still attached to the A-arm, nice and snug, but perfectly sheared off...

They should be replaced with bolts and lock washers or lock nuts.
I will definitely be doing this, on both sides, while I'm sorting out this broken shock. Still won't help if the pin decides to give up though... 👎

That shock is toast, hopefully they give you a replacement under warranty.
I contacted Summit, they're sending me a replacement under warranty, though they aren't offering any help regarding the A-arm.
 

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One of the ak1195? (the crown vic shocks) i had failed maybe like yours. Notice one day that pushing down on the bumper, one side abruptly stopped. Thought it was something else at the time. But later when i undid the bottoms, the suspension moved freely. Taking them out, the bad one works fine to about 1/2 compression, then stops cold like it's hitting something inside. Some hard pot holes would have probably ended up breaking something like your did.

Not to bash them, as this might be the only two instances of it ever happening. One day, with some free time, plan to open up that shock and see what's going on. Nothing I can see in internal view pictures that could cause it.
 

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Discussion Starter #7
Not to bash them, as this might be the only two instances of it ever happening. One day, with some free time, plan to open up that shock and see what's going on. Nothing I can see in internal view pictures that could cause it.
Unfortunately, they've asked that I send the damaged unit in exchange as part of the warranty. Good thought though, I suspect an internal failure could have caused enough force on the pin to shear it.
 

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be nice if they could follow up. did you send it already? Going directly to bilstein might have gotten us more information. But probably take longer to get a replacement.
 

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Discussion Starter #9
be nice if they could follow up. did you send it already? Going directly to bilstein might have gotten us more information. But probably take longer to get a replacement.
No, I haven't sent it yet. They've asked I send it in the 'return' for the replacement they're sending me, so it'll be a few days.
 

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Yeah, the AK shock is the non warranty version hence me pulling it apart for curiosity. But they are quite a bit cheaper too. Trade offs..
 

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Here's a pic of the damage to the arm, I think it can be repaired with a plate welded in, and a captive nut.
I would replace the arm since they are cheap and available....but that does require some extra labor. Can you weld the "plate" while the arm is still on the car or are you planning to remove the arm for repairs anyway? If pulling the arm, I would just replace it.

This assumes you have the standard 9/16" ball joints in those arms. If it was the 5/8" arms which are a tougher find, I may look to see if it could be saved as you described. Just not crazy about the idea of trying to save a Stamped Steel Suspension piece that obviously took one heck of a shot. Good luck.
 

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This assumes you have the standard 9/16" ball joints in those arms. If it was the 5/8" arms which are a tougher find, I may look to see if it could be saved as you described. Just not crazy about the idea of trying to save a Stamped Steel Suspension piece that obviously took one heck of a shot. Good luck.
New fully assembled arms are easy to source in both sizes. The 9/16" are listed as regular B-Body replacements. The 5/8"s arms are RWD Astro van units.
 

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Discussion Starter #13
I would replace the arm since they are cheap and available....but that does require some extra labor. Can you weld the "plate" while the arm is still on the car or are you planning to remove the arm for repairs anyway? If pulling the arm, I would just replace it.
I'm going to get a better look at it this weekend. I agree with you though, If the arm has to come off for repair, I'll just replace it entirely.
 

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Get tubular arms for coil-overs, and the shock will not have the skimpy piece of metal to hold onto. You will also be able to adjust your ride height.
 

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One of the ak1195? (the crown vic shocks) i had failed maybe like yours. Notice one day that pushing down on the bumper, one side abruptly stopped. Thought it was something else at the time. But later when i undid the bottoms, the suspension moved freely. Taking them out, the bad one works fine to about 1/2 compression, then stops cold like it's hitting something inside. Some hard pot holes would have probably ended up breaking something like your did.

Not to bash them, as this might be the only two instances of it ever happening. One day, with some free time, plan to open up that shock and see what's going on. Nothing I can see in internal view pictures that could cause it.
You're getting close to an explanation of what happens....Bilstein "high pressure" gas shocks have a divider piston. On the end opposite the shaft extending out, gas (nitrogen, typically) is contained at up to 360 PSI.

The divider piston keeps pressure on the shock fluid/oil, which is why the shock shaft, with the working piston, extends when not mounted--it's possible to push it in, but it comes right back out to full extension.

When the shaft seal fails on a Bilstein shock (and they do) the loss of shock oil allows the divider piston to travel toward the working piston on the shaft. At some point in the fluid loss/seal failure, the divider piston will begin to act as a travel limiter (just as you described above), and as the suspension moves up & down, the working piston begins to "crash" into the divider piston--NOT GOOD--with the result that the shock shaft can bend and much higher than normal load is placed on the ears of the lower control arm that secure the lower end of the shock....and your failure is described in the process.

Why does the seal fail? More often than not, something happens to the normally EXTREMELY smooth shaft surface--it gets a nick in it from road debris, but more often I think when people work on their cars, they'll use something like vise-grip pliers to grab the shock shaft during suspension R&R, damaging the shaft surface, which will quickly damage the shaft seal, which leads to shock oil loss and the scenario described above.

So, ask yourselves...when installing that set of lowering springs or doing other front end work, did (you) doom your Bilstein shocks to failure inadvertantly by POSSIBLY grabbing the shock shaft to hold it when removing or re-installing the nut at the top end of the shaft????

And be VERY careful trying to open a Bilstein HP gas shock....not much volume of gas, but that divider piston still is holding back a lot of pressure, and it could hurt you.

Get tubular arms for coil-overs, and the shock will not have the skimpy piece of metal to hold onto. You will also be able to adjust your ride height.
Nice of you to spend his money for him like that....the millions of front suspensions out there with the OE design win. A 4000# car isn't a candidate for aftermarket coil-overs, IMO. The coil-over LCA is stronger because it HAS to be, since all of the front-end weight is on the lower shock mount--that's also hard on the shock lower bushing and cross-pin. Stock LCA's can be modified/reinforced in the mount area if need be, but the LCA is meant to be sacrificial, as it's relatively inexpensive and easy to replace compared to doing damage to the frame, etc.
 

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Forgot about the divider piston. Here's a pic from Bilstein's catalog for those interested:
I don't recall any signs of fluid loss. But I could see that the divider piston might have gotten skewed somehow and wedged itself.

There was definitely no abuse of the shaft on install. This was the around the 4th set of shock I tried trying to find the best compromise for our roads here. It was the winner until the failure. Familiar with issues taking them apart. Was going to pick up one of their revalving kits to play around with some changes. The 1195 wanted a little more low speed rebound control. For those interested, there some good youtubes out there showing how to mod the shocks and adapt them for refilling. Seems big in the import tuner crowd.

Why does the seal fail? More often than not, something happens to the normally EXTREMELY smooth shaft surface--it gets a nick in it from road debris, but more often I think when people work on their cars, they'll use something like vise-grip pliers to grab the shock shaft during suspension R&R, damaging the shaft surface, which will quickly damage the shaft seal, which leads to shock oil loss and the scenario described above.

So, ask yourselves...when installing that set of lowering springs or doing other front end work, did (you) doom your Bilstein shocks to failure inadvertantly by POSSIBLY grabbing the shock shaft to hold it when removing or re-installing the nut at the top end of the shaft????

And be VERY careful trying to open a Bilstein HP gas shock....not much volume of gas, but that divider piston still is holding back a lot of pressure, and it could hurt you.



Nice of you to spend his money for him like that....the millions of front suspensions out there with the OE design win. A 4000# car isn't a candidate for aftermarket coil-overs, IMO. The coil-over LCA is stronger because it HAS to be, since all of the front-end weight is on the lower shock mount--that's also hard on the shock lower bushing and cross-pin. Stock LCA's can be modified/reinforced in the mount area if need be, but the LCA is meant to be sacrificial, as it's relatively inexpensive and easy to replace compared to doing damage to the frame, etc.
 

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Discussion Starter #17
Get tubular arms for coil-overs, and the shock will not have the skimpy piece of metal to hold onto. You will also be able to adjust your ride height.
Nice of you to spend his money for him like that....the millions of front suspensions out there with the OE design win. A 4000# car isn't a candidate for aftermarket coil-overs, IMO. The coil-over LCA is stronger because it HAS to be, since all of the front-end weight is on the lower shock mount--that's also hard on the shock lower bushing and cross-pin. Stock LCA's can be modified/reinforced in the mount area if need be, but the LCA is meant to be sacrificial, as it's relatively inexpensive and easy to replace compared to doing damage to the frame, etc.
Ha, Bill, I was kind of thinking the same thing! While I did briefly consider tubular LCAs, when I saw how expensive they were for in all likelihood minimal performance improvement, they were quickly ruled out.

Thank you (and 91SS) for all the great information and explanations. While I can also assure that I did not damage the shaft during installation or other service, I suppose it is still possible that an internal failure to the divider piston could have caused a 'bind' which lead to the damage. Unfortunately now with the shaft all bent to hell, there's not really any way for me to test the travel in the shock to check the theory.

Oh, and 91ss, your attachment...
 

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While I can also assure that I did not damage the shaft during installation or other service, I suppose it is still possible that an internal failure to the divider piston could have caused a 'bind' which lead to the damage. Unfortunately now with the shaft all bent to hell, there's not really any way for me to test the travel in the shock to check the theory.
Whether the shaft seal failed or not, the other possibility is the shock tube itself could be hit and cause the working piston to be unable to travel normally. It is quite unlikely (more like impossible) for the divider piston to become pushed out of position--as long as the shaft seal is intact and shock is full of oil, the divider piston isn't moving. When/if the seal fails, as oil leaks out, the gas pressure will cause the divider piston to move toward the working piston, unless the shock tube is deformed enough to prevent it's movement--and that deformation could also allow the gas to escape to the oil side.
 

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I have had 2 failures now.

Last year, passenger side broke - shaft completely snapped. There wasn't a mark on the control arm at all, but the mounting tab was bent over. I'm fairly certain the shock seized up and had nowhere to go.

Just last week, 2nd failure. This time I think the control arm itself was the cause. Part of the mounting tab is just gone, and yet, the bolt and U-nut were still attached to the shock! With only 1 side holding, the cross bolt eventually gave way and out went the shock. With the tab missing, I'm replacing the control arms.

This on a car with only 48,000 miles on it and purportedly always garaged by the 2 previous owners.

And I haven't tried going after warranty (yet). I'm not about to spend that kind of $ again, so cheaper shocks going back on.
 
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