need tips for changing front subframe
 

hey guys, I searched, but couldn't seem to find a DIY for front subframe removal. mine is damaged, so I bought a new one, and want to change it myself. any tips, or links to a diy would be much appreciated. I intend to begin working on it Wednesday or Thursday. thanks in advance.

have the car on stands, and keep the engine supported at all times. once you have stands holding everything up, it's basically unbolt the suspension from the pickup points, unbolt the engine mounts, and unbolt the subframe from the chassis. you probably won't find a DIY thread since it really isn't something that's commonly damaged or removed. I just helped someone do it in an E88 1er. We had the luxury of using a two post lift, but even without one it's a pretty straightforward job.

good luck.

Check this document out. Way beyond my level of expertise.
Good luck and take plenty of pics!!

someone replaced one maybe a couple years ago. i cant remember if he posted a full how-to?? try searching.

I am pretty handy at wrenching, and have an engine hoist and air tools, but will be working alone. Is this a one day job, or a little more than that? To be honest, looking at it, it seems like an afternoon project, but we all know how those turn out lol!

I was looking for DIY for lowering front subframe to change passenger engine mount and upper oil pan but could not find any. I think it is doable on jack stands but would be much easier and faster if you had lift. You have to crawl a lot under the car. And someone mentions also you have to take off some steering components. If you do it please report back. Good luck!

This document pertains to replacement of aprons, baffles, and rails in the front of the car which are cold bonded and riveted together.

OP is asking about replacing the front subframe, which is nothing more than a bolt in crossmember that supports the engine and provides pickup points for the control arms. the document you attached does not apply to what OP is trying to do.

If you're mechanically inclined, have a good assortment of tools available, and have an engine hoist to help keep the engine suspended while you do this, my guess is you'll have it done in a day.

good luck.

I lowered the subframe (I did not remove it) on my 2006 530i (N52 engine) in order to change the oil pan gasket. I don't remember all of the steps, but I'll try to give you a rough idea of what to expect. The Bentley E60 service manual is a big help, or get access to TIS.

Tools and Supplies

3/8-drive E-Torx sockets
Torx bit sockets
3/8" drive ratchet, (a long-handle flex is great to have)
1/2" drive sockets
1/2" drive ratchet
3/8" and 1/2" Torque wrench
Breaker bar, 1/2" drive, 18" (or longer)
3/8" and 1/2" -drive various length extensions
U-joint extensions
Jack stands
Jack
Engine support bar or engine hoist
Digital camera for record-keeping purposes
1/2" Impact gun and sockets are nice to have
Drip pan
Oil sorbent pads
Rags

Parts

Many of the bolts removed in the process are aluminum and therefore need to be replaced during reassembly. Make sure that you have the replacement bolts on hand. Check penskeparts.com for parts diagrams, which are also helpful for seeing how things go together.

If you have a leaky oil pan gasket then now is the time to change the gasket. It will add another ~ 1.5- 2 hours to the job but it will be worth the extra time.

Now is the time to replace the engine mounts as well.

Since the power steering rack is being disconnected you might as well change the power steering fluid.

Notes/Instructions

You need to support the engine, of course. You can use the tow hook from the tool kit screwed into the threads located near the engine oil filter as one lifting point. I had an engine support bar, but it would be a lot easier with an engine hoist.

Jack the car up using the front center lifting pad. I'd recommend getting the car supported as high as you can. You'll be spending a lot of time under the car and you have to pull out the subframe so you will want as much room as possible. Remember, once the subframe is dropped there is no easy way to lift the car higher!

Remove the front wheels.

Remove the two plastic windage trays from under the car.

There is an aluminum reinforcement plate that is removed by taking out five screws.

You need to remove the screw (Torx) from the steering shaft located near where the shaft goes into the cabin.

Drain the power steering fluid and disconnect the hoses from the cooler.

Remove the engine supports.

Remove the front suspension components that are attached to the subframe. This includes the tension struts, wishbones, tie rod ends and front strut assemblies.

Remove anything else that is connected to the subframe- brackets, hoses, etc.

Put a jack under the subframe and support it. Remove the six bolts from the subframe- two are longer than the others.

Slowly lower the subframe and see if anything else is connected to it.

Move the steering rack and other components from the old subframe to the new. Re-assembly is the reverse of removal. Mind the steering shaft assembly as you lift the subframe back in place.

The subframe bolts are a bitch to torque down. You'll want a very long flex handle, or a powerful impact gun to get them started.

Again, I don't remember all of the steps so double-check my recommendations and plan accordingly.

Good luck. I didn't have to remove nearly as much stuff to lower the subframe enough to change out the oil pan, and it took me two full days to do the job. I'd budget at least three days for this job, personally, unless you are a very gifted DIY mechanic.

Thanks txag! Thats exactly the kind of info I was looking for. I will let you all know how it goes (hopefully uneventful).