Protech front shocks failure

[BABIS]

Hello guys,

I am reporting this issue on behalf of a D. owner friend of mine who prefers to remain anonymous.

a little background on his car: complete suspension rebuild less than 2 years ago including new bushings, new DMCEU lower control arms and outriggers, lowered front springs, protech shocks all around, front end alignment.

With this setup he drove about 4000 miles and he is not a spirited driver.

a couple of weeks ago he noticed some noise coming from the front suspension and he discovered this:

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that's what I call a major failure!

the passenger side looked better, but the shock was definitely next to broke like the other:

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it appears that they both broke at the lower end of the shock, which is threaded in the shock main body (usually our shocks are welded in that area).
what do you think? are there some other sensible reasons behind the obvious manufacturer defect?

Thanks

[dn010]

It looks like they were not able to cope with the angle of the suspension, maybe the bottom eyelet seized and stressed the bottom of the stock with the inability to rotate?

[Joe Kuchan]

The bump stop on the top of whatever shocks are installed up front is what limits ultimate suspension travel. If these shocks did not have something to appropriately limit travel they would either have the piston rammed through the bottom of the shock and/or be bent by contact with the LCA when it's allowed to travel too far.

[BABIS]

The bump stop on the top of whatever shocks are installed up front is what limits ultimate suspension travel. If these shocks did not have something to appropriately limit travel they would either have the piston rammed through the bottom of the shock and/or be bent by contact with the LCA when it's allowed to travel too far.

do you mean the shocks upper bushings?

[Bitsyncmaster]

I think even with the stock shocks limit the travel via the shock length limit. I would not think you ever hit that limit unless you do off road racing. Maybe those shocks did have to short of an extended length.

I did have a strut break apart on an old Dodge car I had with 250 K miles on it. That looked like rust made it fail.

[David T]

I think even with the stock shocks limit the travel via the shock length limit. I would not think you ever hit that limit unless you do off road racing. Maybe those shocks did have to short of an extended length.

I did have a strut break apart on an old Dodge car I had with 250 K miles on it. That looked like rust made it fail.

You need to get in touch with the vendor that provided this kit. If this problem is happening to all of their kits something is very wrong. One possibility is somehow something was not installed correctly. That could explain your particular problem and why all of the kits are not failing. The shock mounts must be allowed to swivel a little as the shock extends and retracts. If the shock mounts were tightened so much that it could not move then it would bend the shock till it breaks. Just a possibility I am suggesting. The shock looks like it broke from a bending motion, not a pulling motion.

[chris williams]

I'm sure it's an isolated incident, but will check my own ones shortly. Lots have them fitted in the UK.
Chris

[BABIS]

I helped my friend to remove the broken shocks, and the stem nuts were properly torqued, even the lower bolts on lcas were torqued by factory specs. I suggested him to measure the distance on his new lcas between the shocks mounting bolt and the main bolt to the frame. (it turned out the lcas had a very poor paint job since they are rusted worse than his original lcas, but that's another matter lol)

[FABombjoy]

Could failure have been exacerbated by performing final torque with the car raised, keeping the bushing & shock in a constant state of torsional preload?

[Bitsyncmaster]

Could failure have been exacerbated by performing final torque with the car raised, keeping the bushing & shock in a constant state of torsional preload?

Looks like those shocks have a floating bushing. Besides, looks like the break is aligned with the bushing.

[DMCMW Dave]

do you mean the shocks upper bushings?

No. He means whatever limits the shocks travel in one direction or the other. Typically a large rubber bushing on the shock rod to limit the compression direction, or an internal bumper to limit extension. This appears to me that the shock body was hitting the opening in the lower control arm at the base of the spring. This implies that the shock is too long for the application.