Downpipe install on 335i xDrive

ilicboris · 04-11-2016, 12:18 AM

This was probably the most insane install/modification I've ever done on a car and I've swapped engines on a BMW and Mustang before.

It was about 6 hours of work on Saturday and another 5 on Sunday from start to finish with lunch breaks and mini breaks in between those 11~ hours. I wasn't in a rush either and wanted to do everything properly because I definitely did not want to repeat any steps. I also had help from a good friend of mine so that was nice to switch off if one of us couldn't get something off or get into a tight space. There definitely was a lot of tight spaces.

The biggest pain was the front passenger axle and getting your hands and arms around it to undo the v-band clamps on the downpipe and turbo housing. The clamps were stuck on there super tight and it took a few tries to get them loose. Putting them on was a bigger pain, but overall took less than removal.

O2 sensors were also kind of a nuisance, but we got past them. Dropping the subframe was a lot easier than I thought it was going to be. Literally 3 bolts on each side and then the 2 motor mount bolts and it was down and it at first doesn't seem like it goes down much at all, but it made a huge difference in removing the factory pipes. Still not sure what is so different with the xDrive subframe than the regular RWD subframe, if there is a difference? Or does the additional components of the AWD system just make it harder which results in dropping the subframe?

One thing I did discover was I have a leak somewhere down there. Bunch of dirt and something wet is on the front diff that is somehow connected to the oil pan? Looks like a very heavy duty oil pan on this car. Something is definitely leaking and it won't be fun to replace, but I'll check it out.

After this whole install situation I literally feel like I could get through almost any car repair.

Nonecure · 04-11-2016, 06:31 AM

I normally do my own work, but I didn't feel like doing DP's and inlets on this car. I took this to my Indy that has done many RWD's in less than 3 hours. He said he would never do this work again on a AWD.

hz_diesel · 04-11-2016, 06:52 AM

The AWD does suck. I opted out and let my mechanic do it.

trixdout · 04-11-2016, 07:13 AM

Your leak that you noticed is the seal on the front diff. I too have this leak and noticed it when I did my clutch change. Do not let that diff go too low on oil or you will have to replace more than just the seal in the future.

ilicboris · 04-11-2016, 11:42 AM

Quote:

Originally Posted by trixdout

Your leak that you noticed is the seal on the front diff. I too have this leak and noticed it when I did my clutch change. Do not let that diff go too low on oil or you will have to replace more than just the seal in the future.

How big of a pain is this gonna be? Have you done it yet?

trixdout · 04-11-2016, 12:00 PM

Quote:

Originally Posted by ilicboris

How big of a pain is this gonna be? Have you done it yet?

I have not done it yet and cannot even tell you how hard it is without guessing.

My guestimate is it won't be a quick job. You gotta disconnect everything from the hub and remove the half shaft and then get to the pumpkin. Once you get to the pumpkin, you gotta replace the seal, which probably is the easy part. Getting to the pumpkin is the problem.

PrematureApex · 04-11-2016, 12:56 PM

Did mine in 3 hours. Like many other people, no dropping of the subframe required. If you remove the DP bracket entirely, with a pry-bar you are typically able to squeeze the DP out between the subframe and the unibody.

PrematureApex · 04-11-2016, 12:58 PM

Quote:

Originally Posted by trixdout

Your leak that you noticed is the seal on the front diff. I too have this leak and noticed it when I did my clutch change. Do not let that diff go too low on oil or you will have to replace more than just the seal in the future.

Quote:

Originally Posted by ilicboris

How big of a pain is this gonna be? Have you done it yet?

I too noticed a leak from somewhere. Fluid seemed pretty fresh looking, and was building up on the underside of the flex plate.

+1 on how big of a job is it?

Maybe I'll pull the DP back off and take it into the dealer.

ajsalida · 04-11-2016, 01:18 PM

Quote:

Originally Posted by PrematureApex

Did mine in 3 hours. Like many other people, no dropping of the subframe required. If you remove the DP bracket entirely, with a pry-bar you are typically able to squeeze the DP out between the subframe and the unibody.

Do you have a N54 e9x XI? If you do and did the DP's in 3 hrs without dropping the subframe that is impressive.

deadmn1337 · 04-11-2016, 01:41 PM

Quote:

Originally Posted by PrematureApex

Did mine in 3 hours. Like many other people, no dropping of the subframe required. If you remove the DP bracket entirely, with a pry-bar you are typically able to squeeze the DP out between the subframe and the unibody.

I don't know how you managed that on an xi. It takes me 3 hours with subframe drop. Only take me 2 hours to do the rwd dps.

ilicboris · 04-11-2016, 02:13 PM

I'm having a hard time believing an xdrive downpipe install was done without dropping the subframe. It literally looked impossible. There's just no room.

ajsalida · 04-11-2016, 03:43 PM

Quote:

Originally Posted by ilicboris

I'm having a hard time believing an xdrive downpipe install was done without dropping the subframe. It literally looked impossible. There's just no room.

Same here. I spent a good deal of time under there trying to figure how to do it without dropping the subframe. If there's a way to I'm all ears. I did not have a hoist or the HF engine bay support bar thing, and it was very uncomfortable under there with several jacks and so forth.

I've since got the HF hoist and dropped the subframe a number of times using it for various reasons, highly recommended. Using it + experience gained I could maybe do DP's start to finish in 3-4 hrs, but it would be pushing it. But the first time, flat on my back on cold concrete, without the HF hoist, more like better part of an entire day. Getting the O2 sensor wires right was challenging for some reason.

edit: this was on a N54 2009 e92 335XI

PrematureApex · 04-11-2016, 05:47 PM

Quote:

Originally Posted by ajsalida

Do you have a N54 e9x XI? If you do and did the DP's in 3 hrs without dropping the subframe that is impressive.

Quote:

Originally Posted by deadmn1337

I don't know how you managed that on an xi. It takes me 3 hours with subframe drop. Only take me 2 hours to do the rwd dps.

Quote:

Originally Posted by ilicboris

I'm having a hard time believing an xdrive downpipe install was done without dropping the subframe. It literally looked impossible. There's just no room.

Oh, my apologies. I didn't see what car the OP had. I'm an idiot.

N55 here (an X1, but everything is the same)

Can be done without dropping the subframe on the N55s.

http://www.e90post.com/forums/showpo...6&postcount=87

xDABSx · 04-11-2016, 08:47 PM

You could get at the v band clamps if you go thru the wheel well with a long extension.I just did my downpipes and inlets.Worst part was doing it in the cold on my back lol.

ilicboris · 04-12-2016, 10:31 AM

Does anyone know of a DIY for the front diff seal? Can't seem to find anything besides changing fluid in the front diff.

PrematureApex · 04-12-2016, 11:44 AM

Quote:

Originally Posted by ilicboris

Does anyone know of a DIY for the front diff seal? Can't seem to find anything besides changing fluid in the front diff.

From what I've read, it depends where your leak is. If it's an axle seal, it can be replaced. But if its the case seal, BMW apparently replaces the whole "sealed" unit.

ilicboris · 04-12-2016, 03:34 PM

Quote:

Originally Posted by PrematureApex

From what I've read, it depends where your leak is. If it's an axle seal, it can be replaced. But if its the case seal, BMW apparently replaces the whole "sealed" unit.

Well damn, of course they do. Guess I'm going back under and pinpointing it.

mightbaal · 04-13-2016, 07:05 AM

I had that same seal go out had a shop do the whole thing for 330 bucks was 1.5 pints low at the time. I was taking it into Valvoline while I was waiting getting it topped off with the full synthetic it needs for the time being every few weeks for free. Passenger diff seal.

04-11-2016, 12:18 AM	#1
ilicboris First Lieutenant 77 Rep 334 Posts Drives: 2009 E90 335xi Join Date: Nov 2014 Location: Nebraska, USA iTrader: (0)	Downpipe install on 335i xDrive - wow This was probably the most insane install/modification I've ever done on a car and I've swapped engines on a BMW and Mustang before. It was about 6 hours of work on Saturday and another 5 on Sunday from start to finish with lunch breaks and mini breaks in between those 11~ hours. I wasn't in a rush either and wanted to do everything properly because I definitely did not want to repeat any steps. I also had help from a good friend of mine so that was nice to switch off if one of us couldn't get something off or get into a tight space. There definitely was a lot of tight spaces. The biggest pain was the front passenger axle and getting your hands and arms around it to undo the v-band clamps on the downpipe and turbo housing. The clamps were stuck on there super tight and it took a few tries to get them loose. Putting them on was a bigger pain, but overall took less than removal. O2 sensors were also kind of a nuisance, but we got past them. Dropping the subframe was a lot easier than I thought it was going to be. Literally 3 bolts on each side and then the 2 motor mount bolts and it was down and it at first doesn't seem like it goes down much at all, but it made a huge difference in removing the factory pipes. Still not sure what is so different with the xDrive subframe than the regular RWD subframe, if there is a difference? Or does the additional components of the AWD system just make it harder which results in dropping the subframe? One thing I did discover was I have a leak somewhere down there. Bunch of dirt and something wet is on the front diff that is somehow connected to the oil pan? Looks like a very heavy duty oil pan on this car. Something is definitely leaking and it won't be fun to replace, but I'll check it out. After this whole install situation I literally feel like I could get through almost any car repair.
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04-11-2016, 06:31 AM	#2
Nonecure Lieutenant 77 Rep 466 Posts Drives: 2013 M3 Join Date: Nov 2012 Location: Cincinnati, Ohio iTrader: (1)	I normally do my own work, but I didn't feel like doing DP's and inlets on this car. I took this to my Indy that has done many RWD's in less than 3 hours. He said he would never do this work again on a AWD.
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04-11-2016, 06:52 AM	#3
hz_diesel Lieutenant Colonel 192 Rep 1,703 Posts Drives: 2012 E92 335ix Join Date: Jun 2015 Location: New England iTrader: (7)	The AWD does suck. I opted out and let my mechanic do it.
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04-11-2016, 07:13 AM	#4
trixdout Lieutenant 57 Rep 439 Posts Drives: '11 335xi 6mt Join Date: Apr 2014 Location: NNJ iTrader: (1)	Your leak that you noticed is the seal on the front diff. I too have this leak and noticed it when I did my clutch change. Do not let that diff go too low on oil or you will have to replace more than just the seal in the future. __________________ LMB , M-Sport, JB4 Stg. 2, AR catless res. dp, ETS cp
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04-11-2016, 12:56 PM	#7
PrematureApex Colonel 840 Rep 2,402 Posts Drives: N55 X1, N54 135, s54 m3 Join Date: Jan 2008 Location: Philadelphia iTrader: (0)	Did mine in 3 hours. Like many other people, no dropping of the subframe required. If you remove the DP bracket entirely, with a pry-bar you are typically able to squeeze the DP out between the subframe and the unibody. __________________ '02 S54 M3 (500/500 GC/Koni) '08 N54 135 (JB4, DCI, BMW PS/Bilstein B6s, H&R M3 FSB, Strongflex FCABs) '14 N55 X1 (JB4, BMS DP, BMS Intake, Alpina TCU reflash, H&R Sports, Bilstein B6s, E93 M3 RSB, Strongflex FCABs, baby seat) '08 N54 535xi touring (Bilstein B6s, Downpipes, MHD tune, baby seat)
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04-11-2016, 02:13 PM	#11
ilicboris First Lieutenant 77 Rep 334 Posts Drives: 2009 E90 335xi Join Date: Nov 2014 Location: Nebraska, USA iTrader: (0)	I'm having a hard time believing an xdrive downpipe install was done without dropping the subframe. It literally looked impossible. There's just no room.
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04-11-2016, 08:47 PM	#14
xDABSx Private First Class 11 Rep 136 Posts Drives: Sedona 135i,JB e92 335xi Join Date: Jun 2012 Location: 60430 - Chicago iTrader: (3)	You could get at the v band clamps if you go thru the wheel well with a long extension.I just did my downpipes and inlets.Worst part was doing it in the cold on my back lol.
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04-12-2016, 10:31 AM	#15
ilicboris First Lieutenant 77 Rep 334 Posts Drives: 2009 E90 335xi Join Date: Nov 2014 Location: Nebraska, USA iTrader: (0)	Does anyone know of a DIY for the front diff seal? Can't seem to find anything besides changing fluid in the front diff.
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04-13-2016, 07:05 AM	#18
mightbaal g35x 105 Rep 630 Posts Drives: 2008 BMW 335XI Join Date: May 2015 Location: wisconsin iTrader: (0)	I had that same seal go out had a shop do the whole thing for 330 bucks was 1.5 pints low at the time. I was taking it into Valvoline while I was waiting getting it topped off with the full synthetic it needs for the time being every few weeks for free. Passenger diff seal.
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