I cannot get this bolt out - PeachParts Mercedes-Benz Forum

okyoureabeast · #1 01-12-2010, 06:12 PM

I cannot get this bolt out of the unibody underframe.

I tried drilling in a pilot hole, but the problem is when I put the bit onto the power drill the entire bolt moves upward into the frame. Apparently on the other side of the metal frame is some sort of metal that moves upward with the other bolt listed in the picture.

I've taken a picture very poor of the offending bolt. I'm guessing the differential just hangs there.

If I put my hand through the hole there is a piece of metal block me from grabbing this thing that the bolt screws into.

Any suggestions? I've been digging through EPC for another way to attack this little son of a bolt but I can't get it.

Biodiesel300TD · #2 01-12-2010, 06:19 PM

Your pic doesn't work.

Junkman · #3 01-12-2010, 06:21 PM

Can you cut or grind the head off and push the bolt through? Where is it?

okyoureabeast · #4 01-12-2010, 06:21 PM

How about now?

I can grab it with pliers but there is a piece of metal that the bolt attaches to inside of the unibody. I'm trying to find it in EPC, but it is more complicated then Pro Tools to find anything in it.

BodhiBenz1987 · #5 01-12-2010, 06:31 PM

Is there enough of the bolt protruding that you could put vice grips or a clip on it, then drill into it? I.e., the vice grips would keep it from slipping back into the frame. Or you could put a thin nut on it. If I'm imagining the scenario right, that would hold it outward and you could drill into it, then back the entire bolt out, nut and all.

okyoureabeast · #6 01-12-2010, 06:38 PM

Quote:

Originally Posted by Maki

Get a stud extractor like the ones pictured in this link. http://www.sjdiscounttools.com/lis19250.html

I just had to drop the differential to replace the SLS lines. One of the bolts holding the mount to the floor was broken already when I started; I snapped of two more while trying to remove them. So I ended up extracting three broken studs, replacing them all with grade 10 hardware.

I got a somewhat similar set of the external-type extractors from Sears. Using a 3/8-inch rachet and 10-inch extension, I was able to press the extractor hard against the broken bolt stub. Once the extractor got some bite onto the bolt end, it was easy to crank it out.

Oops, here's a better example of the type of extractor I used: http://www.sjdiscounttools.com/han394100.html

One thing to keep in mind: the threads the bolt screws into are not in the body itself, but in a metal strip that fits inside the body channel. Screw the other bolt on that side of the mount tight to hold the strip fast so you can apply force effectively.

Maki said it completely perfectly in the other thread. I need to get me a set of one of those.

In the mean time. Is it safe for me to be driving with three fresh bolts holding the bracket in the differential up?

Maki · #7 01-12-2010, 06:39 PM

I just posted to your other thread on this topic.

Basically, you should install the other bolt on the same side of the mount and crank it down tight. That will hold the carrier in place so you can apply some force to the broken bolt.

And, again, I'd go after this with an external-type stud extractor instead of an ezy-out. No drilling required, and it should make the job a breeze if you have a quarter-inch or more of broken stud to work with.

okyoureabeast · #8 01-12-2010, 06:45 PM

Yeah I'll go and get a set now.

In the mean time is it safe to bolt everything back up and drive with only three bolts in the sub frame?

whunter · #9 01-12-2010, 06:53 PM

In EPC, section 35 (Rear Axle), 075 (Rear Axle Suspension), item 47

MB# 910106 008007
13 MM BOLT, USED TO HOLD DIFFERENTIAL MOUNT TO UNIBODY, FOUR PER CAR
http://catalog.peachparts.com/item.wws?sku=910106008007

BRACKET, DIFFERENTIAL MOUNT TO UNIBODY, TWO PER CAR
MB# 115 351 05 40
http://catalog.peachparts.com/item.wws?sku=1153510540

okyoureabeast · #10 01-12-2010, 07:06 PM

Yup that's the bolt. I found it in the EPC, but I could find the piece of metal it attaches to in the under body frame like Maki mentioned.

4x4_Welder · #11 01-12-2010, 08:08 PM

Captured metal plate that is threaded, not sure on the proper name but I know the bit you're talking about. If all else fails, you could cut the side of the "frame" section to make a piece that hinges up, and fish in the resulting hole to pull out the captured piece. Soak it at least overnight in a small tub of PB Blaster or another proper penetrant, then do as you sig suggests, and get the remaining bolt stub out or take it to a metalworking shop and have them copy it for you. That would probably only cost $25-$30 at a more expensive shop.
Once you get it fixed/re-created, slip the plate in and put the bolts in to ensure correct positioning, then bend the little flap back down and weld securely. I'd also weld a patch plate over the whole repair area, but that's at your discretion. Make sure you don't light anything on fire above the floor, or yourself laying underneath it.

whunter · #12 01-13-2010, 12:32 AM

Quote:

Originally Posted by 4x4_Welder

Captured metal plate that is threaded, not sure on the proper name but I know the bit you're talking about. If all else fails, you could cut the side of the "frame" section to make a piece that hinges up, and fish in the resulting hole to pull out the captured piece. Soak it at least overnight in a small tub of PB Blaster or another proper penetrant, then do as you sig suggests, and get the remaining bolt stub out or take it to a metalworking shop and have them copy it for you. That would probably only cost $25-$30 at a more expensive shop.
Once you get it fixed/re-created, slip the plate in and put the bolts in to ensure correct positioning, then bend the little flap back down and weld securely. I'd also weld a patch plate over the whole repair area, but that's at your discretion. Make sure you don't light anything on fire above the floor, or yourself laying underneath it.

Drill out the broken bolt, pop the rubber plug/cover from the Unibody, slide the bad bracket out.

The new bracket is $10.00

BRACKET, DIFFERENTIAL MOUNT TO UNIBODY, TWO PER CAR
MB# 115 351 05 40
http://catalog.peachparts.com/item.wws?sku=1153510540

okyoureabeast · #13 01-13-2010, 12:38 AM

Quote:

Originally Posted by whunter

Drill out the broken bolt, pop the rubber plug/cover from the Unibody, slide the bad bracket out.

The new bracket is $10.00

BRACKET, DIFFERENTIAL MOUNT TO UNIBODY, TWO PER CAR
MB# 115 351 05 40
http://catalog.peachparts.com/item.wws?sku=1153510540

That be would be the way to do it.

Thanks a bunch for the help Roy