Subframe weldnut failure?

Post by **cn90** » 07 Nov 2016, 05:42

Also, the thread below by Rsterns has some good photos re steering rack:

http://forums.swedespeed.com/showthread ... Volvo-Tool

info2x · Post by **info2x** » 07 Nov 2016, 07:53

cn90 wrote:Also, the thread below by Rsterns has some good photos re steering rack:

http://forums.swedespeed.com/showthread ... Volvo-Tool

Thanks for this. I have a set of bushings. Probably makes sens to swap them out if I'm going through all of this trouble. Wife will call it scope creep, but if I get it all back together I hopefully won't have to touch the subframe for a while.

info2x · Post by **info2x** » 08 Nov 2016, 16:21

Well I played with my cadaver a little bit more today. I dropped the subframe enough that I could make the following observations:
- The interior piece does not protrude through the body
- Said piece doesn't have any easily recognizable joining method - I'm thinking it is a structural adhesive

Anyone have any ideas on how this might be fastened?

I guess my next step is to go after the real car and see what I really have to deal with.

edit: no idea why my pictures are upside down. If I click on the links they are oriented correctly.

Post by **pkc303** » 08 Nov 2016, 18:22

Eric,

Is that the nut plate shown earlier? Was it initially attached/welded?

Eric

info2x · Post by **info2x** » 08 Nov 2016, 18:54

pkc303 wrote:Eric,

Is that the nut plate shown earlier? Was it initially attached/welded?

Eric

Afraid I'm not sure which item you're asking about.

info2x · Post by **info2x** » 12 Nov 2016, 14:05

Well time for some updates.

- I put my cadaver back together so I could move my engine support over to the real car, no more practice not that it required a lot. I removed the seat, carpet, and cut the foam underneath. I Was very happy to see the signs of a plug on the newer car as well, cut the plug out and peered inside. Immediately apparent that the metal underneath the threaded area gave way, particularly on one side. I Was able to remove the bolt by wedging the tab under another piece of metal allowing it to bite in. Removed the threaded piece. It was now apparent that been failing for quite sometime. Most of the surfaces were corroded except for a few clean spots which finally gave way when I tried to unbolt it a few days ago. My guess is this process started with an accident of some kind. After buying the car I found evidence that it had been involved in a small fender bender. My guess is that this area became weakened and overtime fatigued ultimately until the point of failure. I had been noticing some front end instability that I I couldn't figure out. This could have been part of it but who knows.

So what's next... Well I'm going to clean up the threaded part and see if I can understand how it is put together. I suspect that my fix for this will be to have a friend come over and weld this from the top and bottom. If it were just the threaded part that was an issue I would say that this could be "glued" back into place but this failure mode doesn't support that option.

Thoughts?

Post by **MadeInJapan** » 12 Nov 2016, 14:14

Vice Grips from above after heating!

Edit:
Actually, I answered without knowing there was a page 2 to this tread. I would get the "sleeve" off of the threaded part of the bolt and find a way to weld it back in place (even if you have to use some sheet metal for reinforcement, and then once everything is solid again...well, you know what to do at that point.

zhenya · Post by **zhenya** » 12 Nov 2016, 20:46

When I did the subframe bushings on my 850 I wondered what would happen if those inserts were ever damaged. I can't believe that Volvo provides access to them! Just one more point in Volvo's favor for this platform. Unbelievable.

Post by **theWIFES_S70** » 13 Nov 2016, 16:21

zhenya wrote:When I did the subframe bushings on my 850 I wondered what would happen if those inserts were ever damaged. I can't believe that Volvo provides access to them! Just one more point in Volvo's favor for this platform. Unbelievable.

Well, they could've just designed the car without the crazy independent subframe thing to begin with...

Is anyone else surprised by all that rust and corrosion around the bushings? I've started at bushings for far too many hours of my life, and I never saw any rust like that. I wonder if you had some water coming from above and pooling around that nut...

I can't wait to see how it gets welded back together. Thanks for keeping us updated.

info2x · Post by **info2x** » 13 Nov 2016, 23:00

theWIFES_S70 wrote: Is anyone else surprised by all that rust and corrosion around the bushings? I've started at bushings for far too many hours of my life, and I never saw any rust like that. I wonder if you had some water coming from above and pooling around that nut...

I can't wait to see how it gets welded back together. Thanks for keeping us updated.

My guess is that as the mounting point began to fail the bushing would occasionally let water into that area and slowly ate away at it. There could be something else at work, but my guess is that water came in from below. Otherwise I would have expected more rust in the access point. Just a guess though.

Speaking of bushings 3 of 4 are showing their age. I'll swap them all out while I have the subframe out. I took some time today to degrease the subframe and steering rack so that when I get leaks again I can hopefully find them quickly.

Subframe weldnut failure?

Re: Subframe weldnut failure?