Glad this adds more info on the auxiliary fan, since US cars had a/c we would not have known that it was used on all automatic coupes as well.
Fixing that little rust spot...
- Thread starter eriknetherlands
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My 1970 2800CS appears to be a US model that never had a/c and no aux fan, but was, according to BMW, "delivered to a company named J.B.S. in Frankfurt/Main, probably for delivery to a US citizen temporarily living in Germany."
Did all US delivery cars have a/c?
I believe Hoffman ordered all with a/c but yours ordered in Germany would be different. Canada got the same VIN series as us and those cars could come without a/c and usually had vinyl seats.
Yes, my Chamonix car has blue vinyl seats as well. They are still in terrific condition.
Was busy with the subframe; it was covered in 40 years of wax oil and dirt, so started by scrapping it off as best I could.
While cleaning the remains with solvent, I noticed how annoying all the weldspatter bits are; there were about 100 little blobs scattered all over the part, from factory it seems.
But they are bloody annoying if I ever want to wipe-clean the subframe ever again. So I belt sanded them all off.
Not sure if it will ever earn those 3 hours back, ever....
Then I also noticed cracks, the famous ones near the towhook, so I had it sandblasted to see if there were more. (None luckily!)
Drilled the end of the crack, grooved it, and welded them up.
then checked with dye penetrant. My welds were good, but it's not easy to check as the dye just hides in the 1000 corners, dimples and ridges that are on and around the welds. Rest of the frame checked out fine.
But what a sh*t job did my new sandblast shop do! I was hoping it would be clean enough to send it out for rustpreventative coating, but still a cup full of grease and sand and stones were stuck in corners.
I'm sending it back for a rerun, let's see if the sandblasting shop gets the PINK clue...
While cleaning the remains with solvent, I noticed how annoying all the weldspatter bits are; there were about 100 little blobs scattered all over the part, from factory it seems.
But they are bloody annoying if I ever want to wipe-clean the subframe ever again. So I belt sanded them all off.
Not sure if it will ever earn those 3 hours back, ever....
Then I also noticed cracks, the famous ones near the towhook, so I had it sandblasted to see if there were more. (None luckily!)
Drilled the end of the crack, grooved it, and welded them up.
then checked with dye penetrant. My welds were good, but it's not easy to check as the dye just hides in the 1000 corners, dimples and ridges that are on and around the welds. Rest of the frame checked out fine.
But what a sh*t job did my new sandblast shop do! I was hoping it would be clean enough to send it out for rustpreventative coating, but still a cup full of grease and sand and stones were stuck in corners.
I'm sending it back for a rerun, let's see if the sandblasting shop gets the PINK clue...
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Buggered.
Ordered the correct Ribe bits for the front calipers, it's size 6 by the way.
Choosen an A brand (Hazet, like snap-on), and gave it a go. It lasted one bolt, and snapped at the other.
I greased them up a day before, hit them with a low temp butane gas burner, got the bolt+nut spinning (still fused together) in the caliper, but still it wasn't enough to get the nut to spin off the bolt.
Buy a new one, perhaps 2 at the same time and try again?
Ordered the correct Ribe bits for the front calipers, it's size 6 by the way.
Choosen an A brand (Hazet, like snap-on), and gave it a go. It lasted one bolt, and snapped at the other.
I greased them up a day before, hit them with a low temp butane gas burner, got the bolt+nut spinning (still fused together) in the caliper, but still it wasn't enough to get the nut to spin off the bolt.
Buy a new one, perhaps 2 at the same time and try again?
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At least the fastener did not get damaged. Maybe a touch more heat next time such that the expansion can break it free. Watching with interest!
I'm doubting if I can re-use the nuts (and bolts perhaps as well) after heating them up. In uni they tought me that heating them change their special molecular cristal-like structure that made them a high grade bolt (class in US terms). Heating them just degrades them to mild steel.
It will get them off all right, but i can't re-use em. Meaning I'd be forced to switch to allen head bolts from Walloth. Which is non-original.... but then again , it's a safety item; i should not be so stubborn
It will get them off all right, but i can't re-use em. Meaning I'd be forced to switch to allen head bolts from Walloth. Which is non-original.... but then again , it's a safety item; i should not be so stubborn
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If you dont think you can re-use the fasteners, break out the welder and weld a nut to them. The heat sink will likely break them free and give you a strong surface to put a wrench on.
Well, they did let go this time. I invested in an Oxy Acetelyne burner that reaches 3300 Celsius - enough to get them nicely cherry red. Plus a new Hazet RIBE -6 bit drive.
250 euro's worth of equipment for 8 bolts... And they just popped off.
Now I just have to think about the re-use question.
250 euro's worth of equipment for 8 bolts... And they just popped off.
Now I just have to think about the re-use question.
You can't go wrong with the oxy-acetelyne torch. You'll need to heat something else up eventually. I have used my tig torch for the same purpose. It will very precisely heat up a bolt in a hurry (if I'm not careful, it will melt it).
The oxy-acetelyne torch is also good for carbon coating sheet metal, cutting, and you might even try welding with it - old school style.
The oxy-acetelyne torch is also good for carbon coating sheet metal, cutting, and you might even try welding with it - old school style.
well, it can't be stuck if it's liquid...
)
tdgray
Well-Known Member
I am one that has a firm belief that one can never have too many tools 
Hello Erik, it’s not advisable to reuse those high strength bolts and nuts after you heated them up. It will have reduced strength. Buy new high quality (same grade).
PS for low strength bolts it isn’t so harmful to use a burner for unscrew them.
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That is exactly what he already said in post #308