Ok, How screwed am I ???

[Jeff in MN]

Tonight I started the drive shaft support bearing replacement project on the 1990 535i. Taking off the last nut from the studs that connect the exhaust manifolds to the exhaust pipe when I snapped a stud in half. There is still about an inch sticking out.

What's the best way to get the stud out? Do I need to pull the exhaust manifold or are there any slick tricks to pulling the stud? Is it reverse thread?
Even if I pull the exhaust manifold, seems like it would be a bitch to remove, nothing to grab onto. Any and all ideas would be welcome.

Thanks,

[Boom n Zoom]

Do you have a set of ViseGrips with good jaws? This would be my first attempt.

Firstly has it sheared square?

if so get a center punch and hammer (large then you only have to hit it once) Support the headers from behind with a large block of timber. Center punch the stud first.

If not get a bastard file and flatten it off as much as you can then carry out the above procedure.

Next, Soak it in WD40/CRC/Any sort of penetrating fluid. leave it for about a good half hour, then apply the ViseGrips nice and tight and try to undo it applying constant pressure it should be a stock righthand thread so anticlockwise to undo it.

Try if you can to support the flange with wedging a block of timber between the the exhaust and floorpan this will not hurt anything you just need it firm to stiop it moving so that when you apply the twisting force it is not dissipated through movement of the exhaust.

If this fails you will need to get an ezyout set/stud extractor from your local hardware and follow the included instructions. The part about the center punching will help you here as it will make it easy to drill it out to the correct size to accept the ezyout for extraction.

Failing all else drill it out carefully until it is almost the original size of the stud, this will then make it even easyer to get the remnants out.

Follow this up with a starting tap/thread cutter to clean up the thread before fitting a new stud.

Apply copper grease to the stud and the thread that the nut tightens on for all the threads, this will facilitate a much easier time later on. could I also suggest replacing the nuts with thread locking nuts.

Hope this helps :)

[bmwalfa]

your extremely screwed.

yeah i have no clue

[Jeff in MN]

Since there is a about an inch of stud sticking out from the bottom of the flange, I think I need to hit the little top of the stud that is visible when looking down from where the air filter was. Hitting it is just for the purpose of sending a shockwave thru the stud to break the rust grip right? Hope there is enough room to get a swing at it. BTW the exhaust pipes are disconnected and basically out of the way. copper grease is a great idea.
thanks.

[Blitzkrieg Bob]

as long as you don't bust the flange on the manifold you'll be okay in the end.

try to replace the stud....if it strips out...No problem, drill it and replace it with a bolt and nut.

[bsell]

Tonight I started the drive shaft support bearing replacement project on the 1990 535i. Taking off the last nut from the studs that connect the exhaust manifolds to the exhaust pipe when I snapped a stud in half. There is still about an inch sticking out.

What's the best way to get the stud out? Do I need to pull the exhaust manifold or are there any slick tricks to pulling the stud? Is it reverse thread?
Even if I pull the exhaust manifold, seems like it would be a bitch to remove, nothing to grab onto. Any and all ideas would be welcome.

Thanks,

When I was working at the dealership, I bought something like this:
http://www.asttool.com/product_images/200-5_16.jpg

At the time, there were two sizes. These things are the ticket for pulling studs as when you turn them to twist the stud out, the internal workings squeeze the stud harder. I can think of only one time where this kind of tool didn't work. Then I hack sawed the stud flush with the flange and drilled the dirty dog out and used a more common bolt remover to pull the last of the stud out.

See if you can't find something like this locally as they make a nasty job easy when they work and it's not much of a cash outlay either.

Brian

[SnakeyesTx]

I'd start simple. Get a can of PB Blaster penetrating oil, squirt it liberally on the stud where it meets the manifold. Let it sit a few minutes then tap the stud with a hammer upward IN to the manifold. Don't whack it, just tap it to give it a light impacting effect and help shake loose some of the rust in the threads and let the penetrant seep in farther. On REALLY stubborn studs, repeat this process for a DAY or TWO. Then get a really good set of vice grips or even a small pipe wrench with good sharp deep teeth on it and dig in to that stud a bit while applying constant pressure counterclockwise. One time I had to soak/tap a stud for 4 days and when I got the vice grips on, I was tapping the stud with a ball-peen hammer while trying to turn it with the vice-grips. It eventually came out with little fuss since it had plenty of the penetrant soaked in and the impacting effect while turning was jarring it loose.

[genphreak]

All good info here, but I'd be careful turning it. When you get a replacement (BMW have them) think about getting new springs also- this joint requires decent ones to stay tight and not leak. Most exhaust shops tighten the nuts too far and squash the springs down as they do badly enough over time and heat cycles anyway. I consider them a wear item...all this hardware is Stainless btw, except for the nuts which look like a copper alloy, so anti-seize goes without saying...

[Triton540i]

I would lightly spray the area with a good penetrating oil. After a few minutes, I would take a wire brush and lightly brush the area around the stud and remove any surface crusty rust. I would then soak the area down with more penetrating oil while LIGHTLY tapping with a hammer to encourage the penetrant to work it's way down the threads of the stud. Let it sit for about an hour, then soak it down again with more penetrant. Let it sit again for another few minutes and wipe the area down with a cloth. I would then gently heat the area (2" or so around the stud, but not the stud itself) and use an extractor to gently extract the broken stud from the block.

I'm not sure as to direction, I would call a local shop like ORR Automotive or one of the BMW dealerships on that one.

This is the way I would approach the situation at hand, although we all have different ways of approaching the same problem. :)


Here's a stud remover from Sears, order online.

http://www.sears.com/sr/javasr/product.do?cat=Tools+%26+Equipment&pid=00990125000&vertical=AUTO&BV_UseBVCookie=Yes



Here are 3 stud removers listed in Harbor Freight Tools... cheap!

http://da.harborfreight.com/cpisearch/web/search.do?keyword=stud&Submit=Go

Good Luck! :)
-Eric

Minneapolis Bimmer Group Founder
http://technobmw.com

[Ross]

If you have room use fire. Heat the stud with a torch, the expansion will break the bond of the corrosion.
PB Blaster is a very good penetrating oil also if that's the method you choose.
Broken studs suck. Good Luck.

[ryan roopnarine]

you don't "need" to remove your exhaust to play with the driveshaft. i do it by putting a hydraulic jack under the muffler and lowering it out of the way. works in a satisfactory manner for me. combine that with "leave the stud alone for a more convenient time", and you are good to go.

[WarrenBrown]

The hotter you can get it the better then use vise grips. I've tried PB Blaster and the like with little success. The bolts were going to come out on their own. Ideally you want to apply torque after the surrounding metal is red hot. This trick has failed only once in 30+ years. I don’t ever try to loosen an exhaust bolt that I want to reuse without heat.

Watch out for fuel lines and grease and undercoat. You don't want to set everything on fire. Have a fire extinguisher handy; I've never needed it.

Warren
88 318iX
91 318is
95 525iT

[Jeff in MN]

Thanks for the support guys. I am going to spend time on the drive shaft today as I PB blast and heat the stud off and on thru today and tomorrow. The other good news as I now have an excuse to head to Sears for more tools. Looks like Christmas is early this year.

BTW - I can believe how flimsy that center support bearing is. Why would bmw bury such a disposable part so deep.?

I'll post again when I get the stud out with details on the method.

Thanks.

[Jon K]

the bearing has to be flimsy - it's role isn't to brace the driveshaft in place... it's to provide a mounting point at the joint region and ALLOW for movement.

If we had something more solid you'd likely have bent driveshaft issues

[Alexlind123]

as long as you don't bust the flange on the manifold you'll be okay in the end.

try to replace the stud....if it strips out...No problem, drill it and replace it with a bolt and nut.

When this happened to me the stupid exhaust place i brought it too said they wore through two drill bits trying to drill it out so they cut it and welded on a new one but that broke to so they had to weld it on again and now its ok i think.

[Dash01]

Tonight I started the drive shaft support bearing replacement project on the 1990 535i. Taking off the last nut from the studs that connect the exhaust manifolds to the exhaust pipe when I snapped a stud in half. There is still about an inch sticking out.

What's the best way to get the stud out? Do I need to pull the exhaust manifold or are there any slick tricks to pulling the stud? Is it reverse thread?
Even if I pull the exhaust manifold, seems like it would be a bitch to remove, nothing to grab onto. Any and all ideas would be welcome.

Thanks,

A friend who was a machinist for 60 years told how he dealt with these problems:

1. scrape arond the intersection of stud/manifold upper and lower with a pick, to clean off the crud

2. heat the stud and surrounding manifold with a propane torch, til cherry red

3. Using a candle (jeweler's or bee's wax even better), melt the wax so it runs down into the tiny cracks/crevices. Capillary action helps draw the wax into the cracks, and the heat helps break the bond formed by the rust. When it cools, the wax acts as lubricant. (The "lost wax" method was used 2,500 years ago by Greek sculptors in the Bronze Age, which still works.)

4. Use Vicegrips to loosen the stud. Dremel tool can be used to flatten the sides of the stud for grip by small wrench, or make a slot at the stud tip for a flatblade screwdriver.

You may not even need to remove the exh. system for access to the driveshaft: My kid replaced the rubber busing in ~15 mins. on my '90 535ia, by reaching up and over the exh. and shaft with small wrenches, and the bushing just slides out. Shop manual says you must remove the exh. system for this procedure, but the shop manual is wrong. Could be, the bearing is similarly mounted, but I dunno. Think about it

[Rus]

A friend who was a machinist for 60 years told how he dealt with these problems:

1. scrape arond the intersection of stud/manifold upper and lower with a pick, to clean off the crud

2. heat the stud and surrounding manifold with a propane torch, til cherry red

3. Using a candle (jeweler's or bee's wax even better), melt the wax so it runs down into the tiny cracks/crevices. Capillary action helps draw the wax into the cracks, and the heat helps break the bond formed by the rust. When it cools, the wax acts as lubricant. (The "lost wax" method was used 2,500 years ago by Greek sculptors in the Bronze Age, which still works.)

4. Use Vicegrips to loosen the stud. Dremel tool can be used to flatten the sides of the stud for grip by small wrench, or make a slot at the stud tip for a flatblade screwdriver.

You may not even need to remove the exh. system for access to the driveshaft: My kid replaced the rubber busing in ~15 mins. on my '90 535ia, by reaching up and over the exh. and shaft with small wrenches, and the bushing just slides out. Shop manual says you must remove the exh. system for this procedure, but the shop manual is wrong. Could be, the bearing is similarly mounted, but I dunno. Think about it

The bearing requires at least one end of the driveshaft to be disconnected. Whatever the case, the exhaust has to move. I found it very difficult to unbolt the two halves of the driveshaft on my 535iA even with the driveshaft out of the car. I can only imagine what a pain that would be if it is installed and obstructed by the bulky exhaust system. Just my $.02