The other day I changed the rotors on the wifes '85 300D. I had a hellova time breaking loose the bolts that hold the calipers on.

I noticed the bolts had blue stuff near the tip. I'm guessing it's Locktite. I didn't put any locktite on the bolts when I re-assembled. I didn't put any on the hub bolts either.

Do I need to? I'd rather not so they won't be so difficult to remove in the future. Although, I don't want the calipers or rotors to fall off either!

P.S. I got a used MB caliper from a bone yard for $25. It works fine.

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Mr. BILL

91 300E 120K
90 300SE 275K (sold)
92 BMW 525iM 120K
90 BMW 525iA 175K
85 300D 175K (sold)
84 300SD 245K (sold)

I usually do use a little Blue Loctite on the bolts for the calipers. It is a safety issue. They were probably tightened with an air wrench last time which is why they were so tight.

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Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS

Donnie,

Thanks for the reply. It's easy to go back and do. The Haynes manual called for a tork spec of 84. That's not real tight, do you go by that or them as tight as you can?

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Mr. BILL

91 300E 120K
90 300SE 275K (sold)
92 BMW 525iM 120K
90 BMW 525iA 175K
85 300D 175K (sold)
84 300SD 245K (sold)

Use Locktite and tighten the bolt to specification. Do not overtighten the bolt. Locktite does NOT make the bolt difficult to remove. I use it all the time.

David

blue lockitite is breakable, usually used in a vibration enviroment.

I always have locktite around, and also anti seize compound when working on my car. Use anti seize whenever steel bolts go into aluminum parts. (Most of the dang car!). Prevents galling of threads later. I learned about threads and bolts in the navy, (submarines), where it is against procedure to assemble parts without a lubricant on the threads, in critical systems. So I follow this on my car. May be overkill, but hey....

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1989 560SEL (172k)
1989 325IC (122K)
2004 Suzuki Volusia LE (3500 miles)
2005 Yamaha Road Star (20 K miles)

Technically, these bolts are supposed to be replace with new any time they are removed. They are coated with a 'microencapsulated' locking material, as are various other bolts throughout the car (caliper bolts for example). Locktite, properly applied, would probably serve the same purpose. Torque spec. listed in above post is pretty close. TDM calls for 115nm (X.72 to convert to ft#).
Dan

I almost always use anti seize compound on bolts (except if locktite is specified) and tighten to specifications. Using anti seize compound on bolts prevents them from corroding. Never had a problem with bolts working loose or fighting to get them off. The only time I had trouble getting a set screw off with locktite applied (on my lawn mower) I just heated it up with my propane torch. The locktite appeared to soften like wax and come off easily.

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Ray
1998 Mercedes E320, 200K Miles
2001 Acura 3.2TL, 178K Miles
1992 Chevy Astro, 205K Miles