I have this problem with my right rear brake, I want to replace the calliper what is attached with 2 bolts.
1 came out easely but the second is stuck,I tried heat but no go.
I don't want to drill it out cause ime scared I will destroy the thread.
Any ideas apreciated.

Do you have room to slip a breaker bar over the wrench?

That's what I usually find to work on stuck caliper bolts.

__________________
Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record

/8 200,

Sometimes brake hardware gets frozen due to the extreme heat they see, similar to exhaust bolts.

First try a good penetrating spray. Let it sit for a few minutes and try.

Make sure you are using the right tool. Since the bolt is stuck, I wouldn't use a ratchet to break it loose. Use a closed end wrench if space allows or even better yet, a socket with a breaker bar. You will be surprised by the additional leverage and force you will get with a breaker bar.

Hope this helps.

I've tried a breaker bar slipped over the wrench.
Even tried to lift the breakerbar with an extra jack and so use the cars weight as an force.
The only thing it got me is an bolthead that is totally gone to waste.

/8 200,

A breaker bar does not slip over a wrench. A breaker bar is a specific tool. It is basically a solid metal bar with an end that accepts a 3/8 in or 1/2 in socket.

Slipping a pipe or anything else over a wrench to increase leverage is NOT the correct way to break a bolt or nut loose.

Sorry to hear that the head of the bolt is ruined.

Good luck getting it off now.

-David

Gator Grip socket sometimes helps with rounded off bolt heads, but you still need to address the leverage issue.

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

I've had good luck using a combination wrench. With the box-end on the bolt, I smack the opposite end with a big hammer. The shock will usually overcome the initial friction and get it started. Then I switch to a 3/8 drive ratchet / socket to finish removing it.

So, with the bolt head trashed, it will be a challenge. Can you get vice-grips on it? If so, try the hammer trick. If not, you need to decide if your tool arsenal is adequate to be able to complete the job. Don't get to the point of no return and end up getting the car towed.

__________________
D.H.

04 ML500
02 E430

Experience is something you don't get until just after you need it.

A pipe wrench works good on round things.

I have a dremmel tool that I use to put a new face on bolt heads.

Sometimes tightning it first will "rock" it loose.

Or you could do what I did, move to Sunny Southern California where things don't rust

Assuming that you already spray a good penetrating oil for a while, now try to use a sharp chisel seating against the head of the bolt and hammer the chisel in the direction unscrewing the bolt. The trick works for me everytime on big bolts. I have never tried this trick on small bolts. I always use 6-point socket when the bolt is very tight so that I do not round off the head.

David

If I come across a hard to remove bolt, I make sure that I am using a 6-point socket. Sometimes it takes a breaker bar with a cheater bar (pipe) as well. If you can't get the 6-point soket over the bolt, use a file or dremel to dres up the flats. Use a hammer to tap the soket on the head if you have to.

My $0.02.

Good luck!

__________________
Michael LaFleur

'05 E320 CDI - 86,000 miles
'86 300SDL - 360,000 miles
'85 300SD - 150,000 miles (sold)
'89 190D - 120,000 miles (sold)
'85 300SD - 317,000 miles (sold)
'98 ML320 - 270,000 miles (sold)
'75 300D - 170,000 miles (sold)
'83 Harley Davidson FLTC (Broken again) :-(
'61 Plymouth Valiant - 60k mikes
2004 Papillon (Oliver)
2005 Tzitzu (Griffon)
2009 Welsh Corgi (Buba)

I finally managed to get it loose !!
I sprayed the bolt with penetrating spray after I used my Dremeltool to repair the bolthead.
I gave the spray a few days time to do it's work spraying again every day.
After that I used a new 6-point socket ( Thanks for that pointer Michael ) and a BIG hammer
I thought either it will come loose or I'll break it off.The bolt decided to come loose.
I allready bought a new bolt for the freaking price of almost 13 Euro.
MB had to order it from Köln-Germany cause it wasn't an normal stock item.
Anyway I'm very glad to have this problem solved and now I can get on with putting on new callipers and rotors.

THANKS EVERYONE FOR THE GREAT INPUT.
This board is proving its worth time and again.

I always remove bolts by first fitting them with a good box or socket wrench, then hitting the wrench with my hand rather than trying to turn the wrench. The shock is what helps breaking it loose. If that doesn't work, I apply "Liquid Wrench", wait a while, then again hit the wrench, but this time with a rubber mallet. If that doesn't work and I have room, an impact wrench, either air or electric, will 99% do the job.
The thing to remember is never try initially to turn the bolt/nut, always shock it loose.

__________________
'76 240D-Sold
'78 240D-Sold
'85 300 SD, 165K-Sold
'88 300 TE, 165K-Sold
'64 Porsche 356C Cabriolet- under restoration
'86 560SL 124K Miles-Sold
'94 320E Wagon, 74K Miles-128K Miles JUNKED
'06 E350 Wagon, 84K Miles
07 SL550, 14K Miles

Just a thought having been in similar situations before, you may want to coat threads with antiseize compound on reinstall if you haven't already to prevent reoccurrence.

__________________
2008 GL320CDI 6K
1970 280SL 112K
1982 240D 210K (Sold)
1973 220D 220K (Sold)
1967 200D 160K (Sold)
1992 400E 139K (Sold)
1988 300E 148K (Sold)
1987 300D 257K (Sold)
1991 300E 108K (Sold)
1987 300E 131K (Sold)
1978 300D TMU (Sold)
1980 300D TMU (Sold)
MBCA Member

While you're talking about it, would you use antiseize in exhaust header and other real hot part bolts? I'm doing a turbo transplant on my wifes turbo gas Peugeot this weekend and am predicting lots of fun. And is the German antiseize compatible with French cars

I would think you should use it on all fasteners subject to significant heat, but especially where joining two dissimilar types of metal (steel to aluminum etc.).

Good luck with the project, sounds fun!

__________________
2008 GL320CDI 6K
1970 280SL 112K
1982 240D 210K (Sold)
1973 220D 220K (Sold)
1967 200D 160K (Sold)
1992 400E 139K (Sold)
1988 300E 148K (Sold)
1987 300D 257K (Sold)
1991 300E 108K (Sold)
1987 300E 131K (Sold)
1978 300D TMU (Sold)
1980 300D TMU (Sold)
MBCA Member