E46 M3 Subframe Reinforcement Inspection

[HamedBMW]

Looking at buying this E46 M3. Seller says the RACP/subframe mounting area was previously cracked and repaired/reinforced. These are the underside reinforcement and trunk-side photos. For those of you who have professionally repaired E46 RACPs: does this appear structurally and properly repaired? I'm particularly concerned about the weld quality, the trunk-side welding, and the line/crack visible adjacent to the plate. Would you buy this as-is, or have the repair stripped and inspected? Or does this reinforcement appear questionable? He had receipts for the reinforcement however I am questioning the weld quality and was hoping our experts could chime in.

[Slideways]

That is a mediocre underside plate install at best - booger welds and not welding the complete perimeter of the plate. This looks like a DIY or rush job. Wherever they left voids, cracks can propagate out and moisture can get in forming rust, both of which seem to be happening based on those pictures. Best way to assess the job and see if those plates are salvageable is to have a shop remove the rear subframe.

Inside the trunk looks factory.

[HamedBMW]

Your awesome, thank you for this reply. Honestly if you were buying an E46 M3, and this is what you found on the list after the seller showed you an invoice for 11k that includes the RACP reinforcement. Would you walk away or try to get the subframe inspected?

[bigjae46]

The rear subframe reinforcement requires inpsecting the top side of the front mounts which requires removal of the rear seat bottom and cutting into the sheet metal. Should have a pic of that if the reinforcement was done thoroughly.

I never give credit to any seller for the big 3 - most cases the job is incomplete or incorrect. Exhibit A here. In fact, I get nervous about rod bearing jobs because it is possible they already had a rod knock, cleaned up the crank, threw rod bearings at it and then listed it for sale. Then you spin another bearing in a couple thousand miles.

Maybe a few OGs here on the forum would get that credit.

[Cubieman]

Is that body filler all over/around the plates?

Also whats up with what appears to be a hole in the reinforcement plate in the first picture?

[Slideways]

Is that body filler all over/around the plates?

Also whats up with what appears to be a hole in the reinforcement plate in the first picture?

Off the shelf spray paint lol. Least they could have done was used the SEM stuff.

[Cubieman]

Thats super unfortunate how much time was spent to drop the rear subframe just for someone to learn to weld for the first time.

As a buyer I would feel more comfortable if a shop did this.

If some shop botched one job on the car, ok, unfortunate, but it can be fixed.
But if the previous owner did this and all other work, god forbid engine work, be afraid and walk away.

[HamedBMW]

Sorry for not replying earlier. It has been a busy few days. Thank you all for chiming in so quickly and giving me the direction and advice I needed. I recognized the welds looked horrible and too many things about this vehicle seemed questionable, but I needed advice from those with the knowledge and experience that have seen what a good quality subframe reinforcement looks like. I am going to continue to hunt for a solid E46 M3.

Whats crazy is that they provided an invoice that showed the subframe reinforcement cost and that it was paid. When I did research the shop seemed like a reputable shop, but I guess I was wrong. You guys might find this interesting, check out the invoice he sent me it is attached.

[bigjae46]

Not sure if you should be posting PII of other people on the internets...

They didn't even replace the subframe bushings? That's a seriously half assed job.

[HamedBMW]

bigjae46 You are completely right and I honestly spaced that part about his personal information on there. I appreciate you calling that out, it was an accident. I will remove it and re-upload with that info redacted.

[HamedBMW]

Here is a video of the undercarriage and plate welds on a different M3 I am looking at right now. Can you all tell me what you think from what you are able to see? Dealer says they dont have any documentation on the Big 3 , but sent this video to show the obvious reinforcement job on the car. I attached a youtube link for the undercarriage.

https://youtu.be/5wPIqzD5IZ0?is=Suk6S-rnJWqkaIWn

[Cubieman]

That one looks like it would be worth your time, just really look into the rod bearings, what shop did them, what parts were used.

Preferably OEM bolts, ARP's are somewhat frowned upon on this forum, using the stretch gauge method on them I'll bet they are just fine..

I am also not so sure the ARP "hate" is so warranted as to my knowledge most of the negative opinions point to an article by Lang (despised on here) that says ARP bolts can cause the the rods to not be perfectly concentric around the crankshaft.

[fattycharged]

that first repair for $6k is just depressing that someone paid for that job.


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[02_lsb]

Booger welds.

[bigjae46]

Booger welds.

I've mastered those. Ya want big boogers? Or little cute ones?