Crossmember/Subframe replacement

[Heysüß]

hey guys...

got everything off (stabilizer bar links, shocks, brake lines, and diff mount), I think that's all.

and those plates by the subframe bushings that are held by allen bolts came off too. bushings are ready to start coming down but before all this...

Where the driveshaft and diff meet. Took of the 4 nuts but the bolts seem like they are permanently stuck to the driveshaft side. Am I right?

If so how do you separate these two parts so once the two bushings come out the whole rear end can come down as one?

[Heysüß]

Inner cv and driveshaft and you should be good. If you have the chance, change out he gear oil for some synthetic at the same time. Check your CSB too while you are at it as now is an easy time to put a new one in.

If you are doing RTABs in urathane at the same time ( I recomend his over the stock) cut some diagonal grooves in the OD and install then with LOTS of anti seize. This will keep them from squeeking and the copper or aluminium powder in them will imbed itself into
the urathane so there is no contact with the metal. Urathane to metal contact is what causes the squeek.

few questions since I'm a noob and this is the first time I've ever done anything like this....

A) I'm assuming you mean diff oil, and what kind would you (or anyone else) recommend.

B) yep, I am doing urathane. Where do I cut diagonal grooves? And what anti-seize product do you recommend?

The ones I got (ireland engineering) come with some silicone something or other but I'm assuming you mean something in addition to this.

Thanks again!

[Heysüß]

well, got the exhaust off and yeah I finally found a thread where I saw that the allens are the ones you want to remove.

but I just remembered that I'm changing the trailing arm bushings so I'm just gonna take it all out as one (diff, subframe, trailing arms) while keeping the drive axles connect to the diff. Seems a lot easier to do all that with everything out as one. I'm replacing the diff mount too.

[bmwmech1]

Take out the green circled ones. The red ones will do you no good until the axle is unbolted anyway, since they're behind the axle flange. Taking out the bolt at the hub and removing the axle is not necessary, but will help with the removal of the diff and the subframe, since they'll be out of your way.

Garey

[der affe]

here's what i'm talking about... the red ones are the ones i'm think might be ok to take out.

but i'm pretty sure i'm wrong. I'm just being lazy and looking to cut corners.

No! Take out the ones in green. If you take out the flanges you are making another mess.
grab a can of brake cleaner and a pick tool and clean out the allen bolts first before you try to remove them. If you can't completely seat the allen wrench, you can easily strip them out, then life really sucks.

[der affe]

Inner cv and driveshaft and you should be good. If you have the chance, change out he gear oil for some synthetic at the same time. Check your CSB too while you are at it as now is an easy time to put a new one in.

If you are doing RTABs in urathane at the same time ( I recomend his over the stock) cut some diagonal grooves in the OD and install then with LOTS of anti seize. This will keep them from squeeking and the copper or aluminium powder in them will imbed itself into
the urathane so there is no contact with the metal. Urathane to metal contact is what causes the squeek.

[Heysüß]

here's what i'm talking about... the red ones are the ones i'm think might be ok to take out.

but i'm pretty sure i'm wrong. I'm just being lazy and looking to cut corners.

[Heysüß]

any advice on removing the diff?

you think i'd be ok doing it at the inner cv?

[der affe]

I link 2 wrenches togeher for more leverage and crank the shit out of them. You could use a little red loctite, but they are in a crappy spot for leverage, so if you need to take them out to work on the diff it will take lots of luck and bad language to break the bolts free.

I have solid aluminium motor mounts, delrin trans, and an m3 diff mount ( soon to be solid aluminium ) so I do get more vibration. Even with he fact that I had to brace my leg against the car and pull like hell the last time I took the diff loose, I still check it periodically and some times find a loose bolt.

[Heysüß]

I have the same thing going on with my rear subframe. The bolts kept working loose and eventually the movement broke out a section and the bolt was still there along with a torn out section under it.

I have a spare subframe with The AKG bushings. I just need to buy and install the camber/ castor bolts before I put it in.

Yes you can break subframes.

now that you say this, is there something we could use to keep this from happening in the future?


and another question guys, it's finally nice enough outside again and we're sanding and rust-proofing the replacement and finally trying to get the broken one out but being as cautious a guy as I am (and clueless), I'm here to ask where should I disconnect the drive axles.

Bentley's telling me to take the axle nut out and all that when all I want to do is move the diff. there are 6 regular bolts and 6 who-knows-what-they're-called-bolts (hex is on the inside) both at the inner cv. This seems like it'd be easier to disconnect to free the diff and get it out.

So should I disconnect it from the 6 regular bolts, the other ones, or do the whole axle nut route which seems like added work?

Thanks again R3v!

[der affe]

I have the same thing going on with my rear subframe. The bolts kept working loose and eventually the movement broke out a section and the bolt was still there along with a torn out section under it.

I have a spare subframe with The AKG bushings. I just need to buy and install the camber/ castor bolts before I put it in.

Yes you can break subframes.

[Heysüß]

I want pics of said cracked subframe, this would be the first time hearing of anyone cracking the actual subframe - and an N/A m30 definitely isn't gonna do it. You had to have seriously hit something hard to break it, even the spots where the trailing arms connect are incredibly rugged.

I'll get a picture of it up as soon as i can. It wasn't a crack, an entire piece of it was broken off. one of the two bolts on top of the diff was not supporting the diff. the bolt was attached to the diff but the metal around it looked like it just broke off. So there's no way I hit something since this damage is on top.

[TexasTerp]

I want pics of said cracked subframe, this would be the first time hearing of anyone cracking the actual subframe - and an N/A m30 definitely isn't gonna do it. You had to have seriously hit something hard to break it, even the spots where the trailing arms connect are incredibly rugged.

[Heysüß]

Heysub

I replaced only the subframe bushings on the car with IE greens. I will take the old ones off your hands if you're parting with them.

I can't believe that subframe was cracked, damn M30s lol.

yeah, toooooo muuuuuch powah! haha

I think someone up here may have already called those bushings if they have the money by the end of this week. i'll let you know though.

[Zacm829]

Heysub

I replaced only the subframe bushings on the car with IE greens. I will take the old ones off your hands if you're parting with them.

I can't believe that subframe was cracked, damn M30s lol.