getting annoyed...

[B318M42W]

how can i take out the propshaft without removing the cat??? muffler assy is out, but the bolts on the cat/manifold flange are rusted to hell, and i don't have very good tools to deal with them. (used a lot of PB blaster already, a lot of elbow grease (the socket slips...))...
this is the first time i attempt to take out the propshaft... so i only 1/2 think that i have an idea on what i'm doing.

here's what i can saw about it: there's a guibo on the tranny side (no vibration damper), and there's a universal joint right before the CSB, and then it looks like it can be seperated at that point as i can see splines, and then there's another u-joint at the diff end with a 3 bolt/stud connection.

any ideas that don't require me to remove the darn cat is great!
thanks!

[DesktopDave]

Can you get to the a few of the bolts on the guibo?  If you can undo one at a time, then rotate the driveshaft to get them all, you should be good.

There is a big steel nut in the middle over those splines at the CSB.  If you loosen it and clean the splines a little, you can compress the driveshaft an inch or two.  Should be enough to get the diff flange nuts out.

If that doesn't work, split the driveshaft at the CSB.  Mark the two parts carefully before you do that, it's a balanced assembly.

If you're really desperate, you can also drive the studs out of the diff flange.  That should give you enough room to drop it down.

[B318M42W]

thanks! i have the 3 diff + 3 guibo + 2 CSB bolts out already, just don't know how to get it passed the cat... like do i have to "compress" it somewhere? are there splines on the guibo side? how can i compress it?? (and then how do i retract it?)

[DesktopDave]

You're going to have to cut the exhaust off to get that out IMHO.  I don't see how you can slip the driveshaft out of the diff subframe when the front end is stuck on the cat.

Just cut those studs on the cat pipe and get them replaced later.  I'll be using copper nuts when I have to do that job.  I hope a muffler shop will weld a few studs in for me, they're rusted solid just like yours are.

But if you want to take a crack at it...look in the middle of the driveshaft...close to the CSB...there should be a hex-shaped sleeve or housing covering the splined part of the shaft.  It's pretty beefy black sheetmetal, not a nut.  That spins and loosens the two parts of the shaft, then the splines can slide back & forth, allowing the shaft to come apart & replace the CSB.  I think it's #13 on this diagram:
http://www.realoem.com/bmw/showparts.do?model=AJ93&mospid=47318&btnr=26_0009&hg=26&fg=10

If you can twist it (I had to use a big channel lock wrench), and twist it, and twist it...then twist some more (you get the idea)...it'll loosen up and hopefully you should be able to compress the driveshaft enough to wiggle it around the exhaust.

[B318M42W]

yeah that part is completly loose, off the threads...  what i'm wondering is, i had my clutch replaced about 2 years ago, and my mech had to take out the tranny... so how come he can take it out, and i can't take out the drive shaft??? and do i just need to push hard on the (diff end) of the propshaft to compres it??

[tom d]

Unbolt both ends, unbolt and drop down the center support bearing, pry the shaft off the transmission, seperate the two halfs by pulling the front half forward and away, pry rear half forward off of diff.
This will work, i just did it last week with the complete exaust system still mounted. You can also put it back in the same way.

[DesktopDave]

+1...but don't forget to mark the two halves and put them back together the exact same way...otherwise you might end up with some vibration from an unbalanced assembly.

[B318M42W]

thanks! managed to get it out without seperating it! I was missing the prying part... so yeah basicly i took a large screwdriver as a lever and pried/compressed the propshaft and then i took the CSB down and then took a chisel/hammer to the rear diff u-joint for seperation. once it was all loose, i pushed the cat aside and managed to get the propshaft out on the left side (right side won't work... kinda tried...)

and then managed to get the fuel tank out... it was a PITA! first lower the front lip and then bang it a bit and it just "fell" ... have a feeling that installing it won't be a walk in the park either :rolleyes: either way, now the "fun" part really starts, cleaning out the tank! as from what i could see with the flashlight, it seems mostly like surface rust. but there's a sh*tload of it on the bottom:eek:

anyone knows if the tank walls are thick???

[DesktopDave]

What kind of sealer are you thinking of using?  I've heard great things about the POR-15 sealer.  I've used Kreem in the past, it worked well too.  Granted this is on motorcycle tanks...they're small enough that you can't get your hand in there, but you can use the "shake n flake" rust removal method with a short length of steel chain.

[B318M42W]

yeah i'm opting the the chain rattle method and i'll try to get some sealant from my local radiator shops.

[B318M42W]

seems like radiator shops don't use such product or will sell some but at a really a$$ raping price... kinda pisses me off. I acid cleaned, degreased cleaned and thoroughly rinced with water and even took the time and effort to degrease exterior and repaint it with rust stop/prevention paints. and now, it has started to rust on the inside again:( i aint going through that again in the next few months that's for sure... It amazes me that no one here holds or even knows a product that will seal the inside of the gas tank... i'm stumped...

[DesktopDave]

Don't use conventional paints, use a sealer.  POR-15 or Kreem.

http://www.por15.com/US-STANDARD-TANK-SEALER/productinfo/TSG/

Ignore the flag plastered all over eveything...it's good stuff.