On Friday (7/10/20) I drove my 96 98 to work. A few miles from work I hit a bump. From that moment until I got to work and for the 5 miles I drove at lunch time the rear end would CLUNK severely with each bump in the road. It turns out the driver's side rear strut mount failed. The strut ripped out from the strut mount. The bump I hit wasn't so severe that it caused the damage. Unfortunately, I had just replaced the rear struts and strut mounts in January. I have no idea how the strut mount failed. I suppose it was a faulty part. The ones I installed were O'Reilly's brand with a lifetime warranty. I ordered Moogs as replacements. Too bad they'll take a week to arrive. Guess I'll be driving momma's Kia this week.

 

Wow, that seems odd. Are those air struts? (looks like the old air shocks). I'm wondering if the upper strut mounts aren't up to the task of supporting some of the weight ? Just wondering, I'm not really familiar with those cars...

 

Greg, yes they are air struts. You can buy kits to convert the air suspension to conventional struts. However, the air compressor on my car tested good when I purchased it and I decided to keep the air strut functionality.

 

So, the strut mounts failed again today (7/21/21). Those d@mn Moog strut mounts are POS. Are these parts manufactured so poorly that they aren't up to the task? I bought a special tool to install them and torqued them to the spec I found in my tech manual (not Chilton's). I was thinking, does the strut mount need to be greased? I thought a bit of wheel bearing grease where the strut goes through the mount would prevent the rubber from binding. Here's the pic:

 

That sucks, to have to repeat that job more than once. I wonder if there is some structural damage that is putting to much torque on that mount that is causing excessive failures.

I haven't had any experience with that type of repair, so I'm just throwing a random thought out there.

 

Let's see a pic from the top of the mount as installed with the hardware?

 

That really is strange, Jesse. I would think that a regular strut, like a regular shock, would need a mount with a certain amount of strength. The weight on the mount would be much less as all it does is dampen the bounce of the springs. Where the weight on a air strut or air shock would be much higher as the strut/ shock is now taking weight of the car, along with the springs. I wonder if you are getting regular mounts for regular struts, and there is a heavier mount for the air type???

 

I've done quite a bit or research today and have well over a dozen part numbers for struts and strut mounts. Thankfully, the MOOG strut mounts I bought from the auto parts store have a lifetime warranty. Interestingly, the MOOG strut mounts didn't include part # 51 from the diagram below. The strut mounts never had a gusset plate between the strut tower and the strut.




I know pics and part numbers from online sources can be misleading and downright WRONG (I even wonder if these diagram are 100% correct). Notice there is no gusset plate in the diagram below.




Many of the strut mount "kits" I found seem to include a gusset plate. The first time I swapped the strut mounts I used the parts store house brand and they didn't have a gusset plate either. I'll do some disassembly this weekend and post some more pics.

 

Here is a diagram from my tech manual (Bishko auto literature for Pontiac Bonneville, Olds 88/98 and the Buick LeSabre/Park Avenue). It doesn't include the gusset plate so I suppose it shouldn't be included. It doesn't mention using bearing grease and the suspension is to be torqued before lowering the car. Unfortunately, the Moog strut mounts are unavailable unless I order them from Parts Geek. The guys at the parts store will honor the lifetime warranty on the Moogs, get me some house brand strut mounts and pay me the difference. I already tried them once, but...



BTW, the quality of that Bishko tech manual SUCKS compared to my FSM and CSM for my 71. Even the writing in my Chilton's guide is better than the choppy English in the Bishko manual (undoubtedly written by someone in China). Were the later corporate GM manuals all so poorly written?

 

So here are some pics.





The driver's rear strut pulled out from the strut mount. I replaced the struts and strut mounts again. Interestingly, one of the strut mount kits I ordered in from O'Reilly's had two gusset plates in it. I tried to order another 3 from O'Reilly's to get another kit with gusset plates but none of them did. So, I went to NAPA and bought two kits that contained upper and lower gusset plates. I installed it all yesterday and my Olds is back on the road