It's looking like I have one, possibly two, sheared bolts in the AC mounting bracket.




Couple questions.



1.) Does anyone know what size these bolts are? They look m8, but no clue re: thread pitch or length.
#104 on the EPC

2.) Assuming I've two broken bolts, how much wiggle room do I have? I'll certainly have to loosen the AC belt, but will I need to unmount the compressor to get at these bolts?My concern is putting stress on cooling lines (a system I have little know how or experience with, other than an undying appreciation for its current integrity). Basically, how much fooling around I can do down there?

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1981 240D 4sp manual. Ivory White.

Damn. All three bolts were broken... though one I was able to remove with pliers.
That leaves two.



New territory for me.

What's next?

Left hand drill (haven't used before)? And not a lot of room to work...

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1981 240D 4sp manual. Ivory White.

Penetrating oil, center punch really good, LH drill bit. Close quarters drill if necessary. Extractor if the LH drill bit isn't enough.

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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

Take EXTRA EXTRA time when drilling to make sure you are drilling straight. An assistant watching the bit alignment is very useful.


Good luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Thank you gents. Just picked up a close quarters drill and left hand bits at harbor freight.

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1981 240D 4sp manual. Ivory White.

Man I am getting nowhere with this.

I’ve drilled about as far into the lower bolt as I feel comfortable doing.
Alternated between LH bits and extractors and it just won’t budge

Is there another technique?

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1981 240D 4sp manual. Ivory White.

Drill straight, straight, straight at a diameter slightly less than the diameter of the internal threads of the block/bracket and then collapse the remaining part of the bolt inward and remove it (visualize a thread insert).

If the threads get too damaged in this process, repair them with a Time Sert (sp?) instead of HeliCoil.

Good luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

It’s just a little too tight for me to be certain I’m drilling straight.
Never mind the top bolt… without removing the oil cooler lines, I can’t see how to get to that one.

I’m tempted to remount the bracket with one bolt but I suspect I’ll be right back where I started soon enough.

If I pay a shop to remove those bolts, is that a fairly straight forward thing?

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1981 240D 4sp manual. Ivory White.

You’re panicking and not thinking straight. The shop will do what you are doing and charge you for it. They’ll remove the cooler lines etc.

Take a break. Calm down and rest up. Think before do.

I’d set the harbor freight LH bits aside. Set the extractors aside. The bolts are obviously very stuck. You may break an extractor.

You need to use heat for any chance of that extractor to work.

I’d just set that stuff aside. The last thing you want is a broken extractor in there. Just get some good bits (Dewalt black and gold sets are on sale this week at Lowe’s 14 bit set for $9.98). Drill the bolt out at low rpm. Retap the hole for a slightly bigger bolt. I like moving up to an SAE bolt that is slightly larger than what I drilled.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles

If I was confronted with this situation as it is now, I would be using a torch to heat well the little troublemaker.
CAUTION: Please do not use heat in the presence of much lubricant!

You're right of course.

I get a little shaky drilling holes in touch tight quarters.
Especially after reading all of the 606 glowplug horror stories.

I've been fairly conservative so far... here's where it's at.



I haven't even made it to the bottom of the bolt. My concern of course was drilling into the block. Still think the upper bolt will be out of my reach unless I find a really thin 90 degree adapter for another drill.

If I'm to use heat, what kind, and what method?

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1981 240D 4sp manual. Ivory White.

Not bad progress.

Patience is key.



One never knows with these things.

An open mind is key.



I use this one from Home Depot:
Bernzomatic Trigger Start Torch Kit-TS4000KC - The Home Depot
Yellow cylinder (MAP gas) burns hotter than blue cyinder (propane).
Keep the flame focused on the hole/bolt, be sure not to burn other things such as wiring.
This process is one of some of this, then some of that, then some of this, then some of that. Rinse and repeat.

Great advice. I forgot to say be careful. Fire extinguisher handy or garden hose nearby. Clean up the area (Shern’s car is very clean BTW) of oil residue.

My experience is when the head breaks off like this it’s really stuck. The extractor isn’t nearly as strong as the old bolt unless it was held in under tension vs. corrosion. I’ve busted off enough extractors to hate them. Heat is the equalizer for this kind of thing.

Tapping with a punch can help bust up corrosion too but nothing beats a torch.

Man when I saw those photos above yesterday I was like “I’m glad thats not me.” It is very doable. Patience and focus. Low rpm. You will have to keep at it. The latest photos are right on track. Keep going. Then move up a drill size. Tap with a punch. Heat.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles

And that's how you felt. Imagine how I felt!

Thank you for the encouragement fellows.

When drilling into the bolt, I don't know this for sure, but I'm assuming there's a slight cavity behind the terminus of the bolt end? In other words, will I feel myself drilling through the bolt end, or will I move directly into block.

Oh and fyi, not sure how much difference it makes, but the head didn't snap, more like the last 75% of the shank. I suspect they loosened over the years and wiggled until they broke. I think I've been on one mount bolt (the one that recently broke and captured my attention due to the banging) since I bought the car. The one snapped bolt that I could remove, I turned fairly easily with a pair of pliers. If I had a left hand tap and a left hand bolt, I'm sure I could crank the remainder right out. But now I'm really starting to stack up on tool costs...


I digress... I can just swing a hammer in there, maybe three or four inches of wind up. Onward.

__________________
1981 240D 4sp manual. Ivory White.

I would expect space between the end of the bolt and the hole. If it was a stud vs. a bolt then maybe not.

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer