X-pipe Install and Reinforcement Plate

[rantarM3]

I have a follow-up question for those that did the install without removing the reinforcement plate. I looked under the car today to make sure I could access everything before attempting the install. There's no problem getting to the copper header nuts by hand or with a crows foot. Everything else is definitely easy to access with just the transmission undertray removed, except for one thing.

On the passenger side there is a heat shield for the primary O2 sensor plugs (and another plug as well). Here's a couple of photos:





There are two 10mm bolts that hold the heat shield in place and it appears that the O2 sensor cannot be disconnected without removing or at least moving the heat shield. The upper bolt goes into a hexagonal spacer while the lower bolt is held in place with a nut. The nut on the lower bolt is pretty much inaccessible with any tools or even one's hands.

How did those of you who removed your x-pipe without removing the reinforcement plate tackle that O2 sensor plug?

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ORIGINAL POST:


Quick question regarding x-pipe installations. Can anyone confirm whether the reinforcement plate has to be loosened or removed to remove and install the M3's x-pipe (i.e., is it possible to install/remove the x-pipe without loosening or removing the reinforcement plate)? I saw the EAS Akra install video and they loosened the reinforcement plate (but did not remove it).

If it has to be removed, are the bolts torque to yield bolts (per BMW)?

Thanks!

[pbonsalb]

What is the reinforcement plate? You will likely have to loosen up the engine undertray although it need not be removed. You will have to remove a bracket over the driver's side 02 Sensor if you want to disconnect it. You will have to remove the tranny undertray. You will undo the front flexi hangers. You will remove the midbrace or support with the x-pipe still attached to it.

[kitw]

I find it much much easier to remove the reinforcement plate. It's only a few more bolts and it comes right off, and you can reach the 02 sensor plugs and the nuts on the midpipe->header connection much easier.

[Moxie]

I removed it each time - Too much a PITA getting to the nuts on back. Like Kitw said, it's just a few bolts & doesn't take but a few minutes.

[edwinm3]

The reinforcement plate does not need to come off. Bolts are accessible with it on

[rantarM3]

Thanks for the replies! I suppose I'll try first with the plate on and if it turns out to be too much of a PITA, I'll loosen it.

[rantarM3]

Bump for follow-up question.

[pbonsalb]

I take the little heat shield on the driver's side off. To do that, I have to remove the rear undertray bolts and the center ones so it is just hanging from the front. That gives me several more inches. No problem then. Done this several times.

[M3amigos]

On the passenger side, i was able to just unplug the sensor then unclip the wire. I had to loosen the skid plate though to get the driver side unplugged. There are two 10mm screws that hold the bracket in place, they needed go be loosened in order to free the connector and wire. Its not too difficult.

[rantarM3]

Originally Posted by pbonsalb

I take the little heat shield on the driver's side off. To do that, I have to remove the rear undertray bolts and the center ones so it is just hanging from the front. That gives me several more inches. No problem then. Done this several times.

Originally Posted by M3amigos

On the passenger side, i was able to just unplug the sensor then unclip the wire. I had to loosen the skid plate though to get the driver side unplugged. There are two 10mm screws that hold the bracket in place, they needed go be loosened in order to free the connector and wire. Its not too difficult.

Can either of you tell me if the nut on the lower 10mm bolt is welded into place? I checked out some photos from a diy with the shield removed and the hexagonal spacer seems to be fixed in place so no risk of it falling away if I remove that 10mm bolt. But I saw that the lower bolt is held in place with a nut. I just can't imagine that nut not being welded or fixed to the bracket because there's just no space in there to hold the nut while torquing the lower bolt. I sure hope it's fixed in place.

[pbonsalb]

The nut is captive to whatever assembly is behind the bracket. You need not worry about the nut. Just remove the two 10 mm bolts.

[happos2]

I ended up partly removing the metal undertray to remove the shield. It was just a few bolts, I then pulled it down a little and it was easier to get to the nuts. An extra 5 or less minutes to the job and makes it easier to get to the nuts.

[rantarM3]

Originally Posted by pbonsalb

The nut is captive to whatever assembly is behind the bracket. You need not worry about the nut. Just remove the two 10 mm bolts.

Perfect! This is exactly what I needed to know and thanks for the correction to the terminology (re. "captive").

Originally Posted by happos2

I ended up partly removing the metal undertray to remove the shield. It was just a few bolts, I then pulled it down a little and it was easier to get to the nuts. An extra 5 or less minutes to the job and makes it easier to get to the nuts.

I know there are only 7 bolts but based on experience with my E46 M3, these are torque to yield bolts. It's not so easy to get them torqued and then get the additional 90 degrees (or whatever the correct spec is) on them while on your back under the car. If I can get away without taking it off, that's what I'd prefer to do.

[happos2]

Gotcha. I had power tools and was on a 4 point lift so I had it easy.

[pbonsalb]

Originally Posted by rantarM3

Perfect! This is exactly what I needed to know and thanks for the correction to the terminology (re. "captive").



I know there are only 7 bolts but based on experience with my E46 M3, these are torque to yield bolts. It's not so easy to get them torqued and then get the additional 90 degrees (or whatever the correct spec is) on them while on your back under the car. If I can get away without taking it off, that's what I'd prefer to do.

I certainly did not treat the undertray bolts as TTY and would not think that those bolts are TTY, but do not have an E90 shop manual.

[rantarM3]

Originally Posted by pbonsalb

I certainly did not treat the undertray bolts as TTY and would not think that those bolts are TTY, but do not have an E90 shop manual.

I checked TIS yesterday and these are TTY bolts. If I recall correctly, the spec is 56 Nm and then 90 degrees.

[pbonsalb]

Interesting. I bet a lot of people have had that off or loose and few have replaced the bolts or done the proper torque sequence.

[edwinm3]

And IIRC the bolts should be replaced

[signes]

Originally Posted by rantarM3

I checked TIS yesterday and these are TTY bolts. If I recall correctly, the spec is 56 Nm and then 90 degrees.

Great to know, thanks for posting the values.

[pbonsalb]

Could someone post the TIS? I need convincing these are really non-resuseable torque to yield bolts as opposed to bolts that just have a torque to angle spec for tightening. Not all torque to angle specs are torque to yield. I would also like the specs so I can measure to see if mine really need replacement.

[rantarM3]

Originally Posted by edwinm3

And IIRC the bolts should be replaced

You are correct. These are one-time use bolts.

Originally Posted by signes

Great to know, thanks for posting the values.

Sure.

Originally Posted by pbonsalb

Could someone post the TIS? I need convincing these are really non-resuseable torque to yield bolts as opposed to bolts that just have a torque to angle spec for tightening. Not all torque to angle specs are torque to yield. I would also like the specs so I can measure to see if mine really need replacement.

I'd like to post the TIS pages but because of copyright issues I'll have to refrain. The TIS is just two pages long and addresses the removal and reinstallation of the reinforcement plate on the M3 (the TIS is REP-REP-RAE9231-3110010M). It simply states that (1) you release the screws (3 total) for the tranny cover; (2) release the screws for the plate itself (7 total). For installation, you "replace screws" with a torque of 31 10 3AZ. If you look up that torque specification, it provides:

Replace screws
Jointing torque 56 Nm
Torque angle 90 degrees.

I suspected that these were one time TTY bolts because that's how they are on the E46 M3. When I installed headers on my E46, I researched the issue and also found that TIS indicated TTY bolts that were one-time use.

Many people don't even bother replacing the bolts but because I'm a stickler for doing things as required by the repair literature, I replace my bolts and follow the proper torque sequence. I even purchased a gauge that gives me the exact torque angle.

Hope this is useful information.

[Scharbag]

Originally Posted by pbonsalb

Could someone post the TIS? I need convincing these are really non-resuseable torque to yield bolts as opposed to bolts that just have a torque to angle spec for tightening. Not all torque to angle specs are torque to yield. I would also like the specs so I can measure to see if mine really need replacement.

I know this is an old thread, but I was wondering if you found out if the 33326768354 bolts really need to be replaced. It seems silly that these are one time use. I have had mine off a couple times now and just re-used them. Going to do it a third time soon - due to a bad oil level sensor - and now I am paranoid...

I found a post from an E46 M3 forum where a guy measure 0.015" of stretch on the similar bolts on the E46. That seems like it is not really worth worrying about. Quite a few people said they re-use the bolts and have never had an issue. This really seems like a bolt that just needs to be good-and-tight or tight-as-fuk.

They are ~$6 each in Canada. I know an extra $45 is not going to kill me, but I hate to spend money for no reason.

Cheers,