Question: Plastic Undertray

[KNS]

When you remove the plastic undertray underneath the engine there are two metal brackets/tabs that get inserted into the aluminum subframe. I bought this car BMW CPO so I'm not sure if mine is set up correctly.

When you remove the undertray do the metal brackets stay attached to the subframe or do you leave them screwed in and they come off with the tray?

I'm not sure if something might be missing or not quite right. On my car the metal brackets just insert into the subframe, they're not attached in any way, there's nothing holding them in. Once the tray is back on you can bang on the bottom of the tray and they just hang sort of loose off the subframe - that can't be right. I'm wondering if some BMW tech screwed something up before I owned the car. I checked Real OEM but it doesn't really show any means of attachment that I could see.

How is it on your car..?

[Matticus91]

Pictures? There's a lot of little clips down there

[KNS]

I didn't take any pictures, the undertray is already back on the car. It's fastened by about 15 screws.

Surely there must some people who've removed this tray..?

[Suhb]

It's supposed to be screwed to the subframe on one end and screwed to the undertray at the other.

[gjm120]

Here's a link to a thread on the undertray I started.

http://www.1addicts.com/forums/showt...2#post21167232

[KNS]

I found the answer - the brackets are held in place by plastic (of course) inserts with little tabs holding in place. Pretty cheap, actually. The plastic inserts are bound to strip out easily and need replacement.

Thanks guys.

[iminhell1]

It's not a plastic insert (rivet). It's a metal screw.
If someone used a rivet then they probably stripped out the threads and just used what was handy. It's the same plastic plug/screw combo as the rest of the undershield.

[KNS]

Originally Posted by iminhell1

It's not a plastic insert (rivet). It's a metal screw.
If someone used a rivet then they probably stripped out the threads and just used what was handy. It's the same plastic plug/screw combo as the rest of the undershield.

You're correct - on the plastic undertray side. There are screws and speed nuts just like you describe. The other end of the bracket is fastened with a plastic insert. It's not the kind of plastic rivet you see all over BMWs these days either it's just a simple stud inserted into a slot. This was confirmed by a BMW tech at the dealer when he gave me a couple of the plastic inserts.

[iminhell1]

Well that isn't how mine is attached.

[A6bullet]

Yep, its supposed be screwed to the subframe with metal screws or bolts. at least in my car thats how it is.

[gjm120]

I recall the screws (#8 on attached) fastening into a combination of the plastic inserts (#9) and metal clips (#3). The plastic inserts are in the subframe and the clips are along the bumper shielding.

http://www.realoem.com/bmw/enUS/show...diagId=51_6971

I attached the small radiator shield and the brackets to the subframe first then attached the large shield. It was difficult getting the large shield lined up with the metal brackets (#10) to attach it using the screws. Whether right or wrong it worked as I just finished a 2,500 mile road trip and it's all still there.

Here's a Pelican diy on E90 shield R&R that may help.
http://www.pelicanparts.com/BMW/tech...d_Removing.htm

[KNS]

Update:

Finally got around to solving the undertray issue. Whomever fastened it in place (most likely BMW as it was CPO and they were the only ones who had any service history on the car at 18,000 miles) screwed it up and did a half assed job fixing it place. I put everything back in place as it is supposed to be.

My apologies to a couple of you above - you guys were right. I was only looking at the botched work from previous mechanics.

Have I ever mentioned how much I hate and avoid dealers..?

Thanks all.