Front sub-frame removal? Anyone do it?

Guys,

I want to pull the front end of my car apart this spring and refresh a bunch of stuff. IN the process I want to add the subframe re-inforcement kit for the front of the car. I know my rear subframe is good now due to the recall work, but the front of my car is feeling mighty loose these days. I am going to pull my steering rack, control arms, bushings, and all the rest, is it really as easy as dropping a few bolts and the subframe comes out?

Here is the diagram

Do you want to replace the older reinforcement triangle with the newer aluminum plate?

Originally Posted by mrblorry

Do you want to replace the older reinforcement triangle with the newer aluminum plate?

No, I want to reinforce the actual subframe mounting points.

Does the subframe support the engine at all? You going to be replacing all the rubber pieces; bushings, etc?

Originally Posted by mrblorry

Does the subframe support the engine at all?

Yes - the engine mounts sit on top of the subframe. I would definitely recommend replacing the mounts if you ever have to drop the front subframe.

You'll also need to support the engine from the top before removing the subframe.

Smolck, dropping the front subframe just requires removal of your reinforcement brace #3 and once that is out, just 4 bolts to the subframe goes into the chassis. Granted before you do this you will also want to unbolt the engine mount bolts that go into the subframe and support the engine from the top. Use a jack with a 2x4 underneath the subframe to lower it.

EDIT: if you have Xenons do not forget to disconnect the level sensor. You also have to disconnect the steering guibo!

Here are some more pictures...I'm about to go in the second time to drop the front subframe after I swap out my tranny. I have a suspension refresh and also have to fix these mushroomed strut towers. I may as well take out the front subframe and reinforce it too.

EDIT: If you are replacing your engine mounts, go for the E92 M3 engine mounts. They are direct replacements and are better designed. If I knew back then I would have gone with them. Part number is 11812283798. See also: http://www.e46fanatics.com/forum/sho...d.php?t=744213

Originally Posted by genuity

Here are some more pictures...I'm about to go in the second time to drop the front subframe after I swap out my tranny. I have a suspension refresh and also have to fix these mushroomed strut towers. I may as well take out the front subframe and reinforce it too.

EDIT: If you are replacing your engine mounts, go for the E92 M3 engine mounts. They are direct replacements and are better designed. If I knew back then I would have gone with them. Part number is 11812283798. See also: http://www.e46fanatics.com/forum/sho...d.php?t=744213

THANKS! Yea, at 230k miles I am going to replace the motor mounts too. Guess with the subframe out I will do the oil pan gasket as well. Great pics! Can't wait to do this DIY!

Originally Posted by smolck

THANKS! Yea, at 230k miles I am going to replace the motor mounts too. Guess with the subframe out I will do the oil pan gasket as well. Great pics! Can't wait to do this DIY!

Is your oil pan gasket leaking? The whole reason why I had to do it was mine was leaking from the back...the gasket under the rear main seal leaked.

I also secured my oil pump nut. With your manual transmission, I would do it. However, the caveat to this is that even though your securing the oil pump nut, these M54's they have a weak oil pump shaft--so the shaft can still break; although not as common. Vac Motorsports sells and upgraded pump shaft and cog, but that thing is like $1k+. I think this little insurance is fine...just don't take it too often to redline and you should be fine.

Also, supposedly on latter E46s, BMW actually used some loctite on the nut, after realizing that it could back off; however, they never punched it. My 2001 had no loctite, but it was tight and not loose. The bolt is reverse threaded.

EDIT: Also here is what my motor mounts looked like at 98k. Supposedly this is nothing compared to some others Again, if I knew that the E92 M3 motor mounts, 11812283798, would have fit, I would have bought them instead. However, my replacements in this picture are genuine BMW replacements.

When dropping the subframe, also observe the range of motion and see if the power steering lines get in the way...I do not quite remember but I had taken out my whole power steering system to replace it since I had leaks. I guess I will find out this time around when I drop the subframe again...I'll just be swapping the steering rack though or will be attempting to put in a rack from a Z4MC aka 12.8:1 since my current stock 13.7:1 is leaking

Originally Posted by genuity

Is your oil pan gasket leaking? The whole reason why I had to do it was mine was leaking from the back...the gasket under the rear main seal leaked.

I also secured my oil pump nut. With your manual transmission, I would do it. However, the caveat to this is that even though your securing the oil pump nut, these M54's they have a weak oil pump shaft--so the shaft can still break; although not as common. Vac Motorsports sells and upgraded pump shaft and cog, but that thing is like $1k+. I think this little insurance is fine...just don't take it too often to redline and you should be fine.

Also, supposedly on latter E46s, BMW actually used some loctite on the nut, after realizing that it could back off; however, they never punched it. My 2001 had no loctite, but it was tight and not loose. The bolt is reverse threaded.

EDIT: Also here is what my motor mounts looked like at 98k. Supposedly this is nothing compared to some others Again, if I knew that the E92 M3 motor mounts, 11812283798, would have fit, I would have bought them instead. However, my replacements in this picture are genuine BMW replacements.

When dropping the subframe, also observe the range of motion and see if the power steering lines get in the way...I do not quite remember but I had taken out my whole power steering system to replace it since I had leaks. I guess I will find out this time around when I drop the subframe again...I'll just be swapping the steering rack though or will be attempting to put in a rack from a Z4MC aka 12.8:1 since my current stock 13.7:1 is leaking

I don't have any bad leaks. But with my mileage I might as well replace the oil pan gasket. I think I will also tack weld the nut to the cog and be done with it. These are great pics! Thank you!

Originally Posted by genuity

Is your oil pan gasket leaking? The whole reason why I had to do it was mine was leaking from the back...the gasket under the rear main seal leaked.

I also secured my oil pump nut. With your manual transmission, I would do it. However, the caveat to this is that even though your securing the oil pump nut, these M54's they have a weak oil pump shaft--so the shaft can still break; although not as common. Vac Motorsports sells and upgraded pump shaft and cog, but that thing is like $1k+. I think this little insurance is fine...just don't take it too often to redline and you should be fine.

Also, supposedly on latter E46s, BMW actually used some loctite on the nut, after realizing that it could back off; however, they never punched it. My 2001 had no loctite, but it was tight and not loose. The bolt is reverse threaded.

EDIT: Also here is what my motor mounts looked like at 98k. Supposedly this is nothing compared to some others Again, if I knew that the E92 M3 motor mounts, 11812283798, would have fit, I would have bought them instead. However, my replacements in this picture are genuine BMW replacements.

When dropping the subframe, also observe the range of motion and see if the power steering lines get in the way...I do not quite remember but I had taken out my whole power steering system to replace it since I had leaks. I guess I will find out this time around when I drop the subframe again...I'll just be swapping the steering rack though or will be attempting to put in a rack from a Z4MC aka 12.8:1 since my current stock 13.7:1 is leaking

Only ZHPs got the loctite on the nut (the part number points to being a ZHP-specific item). It was probably specified due to the increased redline of the ZHP. (M54s have ridiculous harmonics above 6000RPMs, so I guess BMW felt even the extra 300 would be enough to cause issues).

Originally Posted by G. P. Burdell

Yes - the engine mounts sit on top of the subframe. I would definitely recommend replacing the mounts if you ever have to drop the front subframe.

You'll also need to support the engine from the top before removing the subframe.

How do you recommend properly supporting the engine from above?

Originally Posted by catso

How do you recommend properly supporting the engine from above?

Cherry picker of course!

Originally Posted by catso

How do you recommend properly supporting the engine from above?

Buy or rent an engine support bar. They usually sit on the inner fender channels.

Originally Posted by Scott ZHP

Buy or rent an engine support bar. They usually sit on the inner fender channels.

Genius! I think I may get one of these just because. I have access to a cherry picker though.

ugh this post makes me want to replace my engine mounts :-\

Originally Posted by smolck

Genius! I think I may get one of these just because. I have access to a cherry picker though.

They've been around for a while; mainly used when wrenching on the transaxle of FWD cars. I normally use the 'piece-o-wood-under-the-oilpan' method when R+R engine mounts. I'm too cheap to buy one, I think they're about 80 bucks at Harbor Freight, supposed to be good for 1000lbs.

Smolk, don't mean to hi-jack your thread (sorry!), but I'm hoping somebody can shed some light on the whole engine mount issue. I couldn't find anything in the Wiki - are these a known/common failure item, or do they have a predictable life-span like the cooling system? I don't have any reason to suspect that mine are bad, but with 93K miles and my preference for 'pro-active' fixes, it'd be nice to know!

Originally Posted by Just_George

Smolk, don't mean to hi-jack your thread (sorry!), but I'm hoping somebody can shed some light on the whole engine mount issue. I couldn't find anything in the Wiki - are these a known/common failure item, or do they have a predictable life-span like the cooling system? I don't have any reason to suspect that mine are bad, but with 93K miles and my preference for 'pro-active' fixes, it'd be nice to know!

Did you see my pics--post number 9 above? Those are mounts at 98k and this car has been in the south her entire lifetime. Some have reported their mounts completely separated into two pieces at this mileage, so much worse off than mine.

http://www.bimmerfest.com/forums/sho...69&postcount=9

Another thing is if you see an imprint of your power steering reservoir on your hood felt, then it is time to replace.

At 93k, I bet yours are gone, especially since you live in the north.

Thanks! Yes, I saw the pics, which is what prompted my reply. My question is, is the condition of your mounts more the rule than the exception? From your post, I'd guess it's the former... Again, thanks!

^I would say this is more of a rule...granted your fine to go over 100k without replacing mounts, but knowing how the 100k mark seems to be quite a maintenance laundry list for E46s, then this is just my rationale for it being a rule. Take a look at yours and see, but judging from what I saw, I was very shocked to see the difference. One of my pics shows my old one really squashed...I cannot recall whether that was the driver or passenger side.

Here is the engine support bar Scott_ZHP mentioned in action...currently installed on my car as extra insurance as I tilted the engine for tranny removal. I originally bought it for doing my oil pan gasket but ended up using the cherry picker because it was sturdier. I will tell you though, this gadget is okay; however the feet on it can travel down the sides...I have noticed mine slipping a bit but again I never had the full engine weight.

The engine sits pretty much on its center of gravity on the mounts across the front subframe. I really do not have to support it, but am not taking any chances while I wait for my rear main seal to come in. Currently I have a floor jack with a 2x4 right under the oil pan. The hook of this engine support is just up against the front engine eye hook.

Smolck, if you use a cherry picker you will need a chain link. The eye hook is too small to fit anything through it. I bought the highest capacity stainless steel one from home depot.

I personally prefer the cherry picker, although the legs of the cherry picker will get a bit in the way, but then again so does the subframe and steering rack. If someone is thinking about using this engine support bar, I still as a word of advice, take all proper precaution that you can...if everyone looks to my first image posted with the cherry picker holding up the engine while the floor jack supports the front subframe/steering rack, I have blocks of wood on the side as extra insurance and those were four 3 ton double locking jack stands, plus the car had weight on the rear tires that were chalked. When working under your car one should take it very seriously and it is no laughing matter. It's not worth getting flattened over for saving a hundred dollars or two for buying tools to get under your car.

Right now my car sits 22 inches off the ground (measured from the factory jack point to the ground) supported by four 6 ton double locking jack stands. I have a 3.5 ton floor jack under the diff subframe carrier in the back in case the vehicle decides to tilt back. Later on when I drop the entire rear subframe, I'll have two floor jacks under the front subframe. I am saving the cherry picker to use as a crane so this is why I do not have it supporting the engine now. There is no way I am turning into a flattened pancake by this 3500# car Granted this is overkill, but better safe than sorry

Wish the weather would clear up so I can get on this project. My motor mounts probably look like pancakes!

Found this thread, fitting now isn't it.

^

Oh, Smolckie! You must have been a very bad boy, to have been blessed with a car that punishes you so. Look at the bright side: the groundwork had already been laid out in this thread for what was inevitably coming.