Foam subframe reinforcement - production date question - technical

[AggieBlake]

Any time a Manufacturer starts a warranty program, they have to pay their dealerships parts and labor for the warranty work.
Maybe BMW doesn't want to pay the dealerships for the epoxy and labor when they believe the problem is resolved with the floor modifications

Now that makes some sense! Perhaps this does ultimately come down to a financial issue related to warranty repairs.

[slater]

Now that makes some sense! Perhaps this does ultimately come down to a financial issue related to warranty repairs.

that seems the most logical reason, yeah!

[AggieBlake]

I would fill them if there is no issue with cracking.

What is the cost difference just for the parts to fill vs weld? BMW still sells the material to fill I assume?

Good question. As best I can tell, I would need 2 of these kits (https://www.ecstuning.com/ES1898189/) per side, or 4 total. But I could be wrong - maybe it's one per side. Hard to tell b/c the part # and quantity of epoxy has changed over the years. Worst case, 4, would put us at ~$350, plus $100 for the gun (unless I can get one used or find a cheaper alternative), plus another $20 for supplies. So a little under $500 total. If it's just 2 tubes and I can find a used gun, it would be closer to $200.

The Reddish weld plates are only ~150, but labor for that job must be in the $800+ range. I can't weld (on the list of life goals, but ain't going to happen at the moment). So that option is at least twice the epoxy option if not more.

I haven't heard back again from Reddish, and no luck with BMW either. I still think it's likely that the plastic is meant to add stiffness to the floor. But it may still be worth doing the epoxy method. The rub is that we don't have instructions for how to do it when that plastic piece is present. What volume do we use? Where do we need to inject cavity foam to dam up the void we'll fill with epoxy? We'll be doing the repair in the dark. The good news: it's hard to imagine the epoxy hurting anything. I think it's unlikely it will react chemically with the plastic piece since it's packaged in plastic and is dispensed through a plastic nozzle (though, to be fair, there are many different variants of plastics).

[AggieBlake]

Found a camera scope. When I get home tonight I'll try to thread it into the cavity in the floor and see if I can get better pictures of that plastic piece.

[Sockethead]

I think it all depends on the expansion properties of the injected material... too much expansion and it could warp the floor

A lot of the labor cost for the welding is the removal of the subframe and gas tank. With the epoxy, obviously all you'd be doing is injecting it in couple of holes... nothing needs to be removed

I can weld the Redish plates but I don't have a lift and it would be impossible to do those welds laying under my car

[Sockethead]

Found a camera scope. When I get home tonight I'll try to thread it into the cavity in the floor and see if I can get better pictures of that plastic piece.

Awesome!

[Vas]

Looks like the cheapest place right now for the foam is from The BMW Parts Store at $74.23 per cartridge. You do need 4 of them to do both sides.

Plus this gun
http://www.grainger.com/product/COX-...3737-_-Generic

Basically comes out to right around $500 to do this.

[ELCID86]

Looks like the cheapest place right now for the foam is from The BMW Parts Store at $74.23 per cartridge. You do need 4 of them to do both sides.

Plus this gun
http://www.grainger.com/product/COX-...3737-_-Generic

Basically comes out to right around $500 to do this.

$138 caulk gun I like buying tools, but this one has Barry limited use.


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"ZHP is a garbage option anyway- just some cosmetic upgrades with a different cam and diff to claw back some of the performance lost fitting those hideous and heavy wheels. Any 330 with a 3.46 diff will smoke a ZHP every time. The whole Mafia thing reeks of childish behavior." - an e46fanatic

[slater]

I think it all depends on the expansion properties of the injected material... too much expansion and it could warp the floor

A lot of the labor cost for the welding is the removal of the subframe and gas tank. With the epoxy, obviously all you'd be doing is injecting it in couple of holes... nothing needs to be removed

exactly.

the stuff BMW uses has almost zero expansion (and a very high tensile strength), which is likely why they chose it.

[slater]

$138 caulk gun I like buying tools, but this one has Barry limited use.

perhaps a few folks could go in together and amortize the cost of the gun?