Rear glass hatch solenoid broken!

I mean that in a fairly literal sense. The metal bracket actually cracked in half. I had a local shop weld it back together since the part is no longer available. I was wondering if any of you guys have seen this and what may have caused it.

My guess here is that since the body of the solenoid hangs so far over its mounting points that it's inertia when closing the tailgate causes it to flex and then crack. Or, less likely, the actuation acts like a hammer and over time causes similar stress fracturing. It cracked right through that hole that's not used as a mounting point- at least not on this car.

I dunno, I'm no structural engineer.  

Yeah, that is a disturbingly flimsy looking part, considering it's function..... looks like a functional repair, but I'm surprised the welder didn't want to weld a second thickness onto that.....

Well, you get what you pay for and all I asked was for them to put it back together. It should hold long enough for me to come across another one that I could reinforce before it breaks.

If my first theory is correct, one way to avoid the problem would be to add another mounting bolt in that unused hole. That might prevent the bracket from flexing and cracking. Another possibility would be to put a piece of structural foam between the solenoid and the inside facing sheet metal to counteract the force of closing the tailgate. Again, just theories. The weld may hold together another 20 years as it is.

GM put a stress relief radius at the corner where the flange bends, and may have left a burr on it. That could start a crack, and since the small hole makes that area the weakest, it would propagate in that direction. The parts are known to break, and that is the most frequent place. If GM had designed it without the cut out area, and made the bracket filled above the hole, it would not break. It is made to last about 5-7 years like all other car parts. Another screw with a washer would probably stop further incidents of that nature, because you are making the bracket flex less, and you are also moving the pivot for flexing toward the heavier part of the bracket. I have a few of the solenoids for sale if you are interested in one.

If you want to modify one, a triangular brace in the corner would minimize the flexing.

Fred Kiehl wrote:

I have a few of the solenoids for sale if you are interested in one.

Hi Fed, I am new here but in need of one of these solenoids if you happen to have one.

I need one of those solenoids. If you still have one, how much?