Mystery beru bolts - rotor arm W124

angst

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260E 1989 2600
I've had to break and replace two beru rotor arms on my 260E because of the 3 weird allen key constructed bolts that hold the rotor arm.

The bolts have round smooth heads and the allen key fits into a hexagonal sleeve or collar placed in a circular hole drilled into their centres, rather than as in a normal allen key bolt where a hexagon hole is drilled directly into the metal.

The trouble is the sleeves flatten out so they bolts can't be removed with the same allen key used to tighten them.

Can anyone shed any light on this / recommend a decent brand that has sane bolts?
 

Alex Crow

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W169, W124, w202, W203, KTM 250 EXC, VW T25 camper and a Polo in a pear tree
angst, i am sure you are wrong. the problem is just that the hex centers are too small for the torque needed to unscrew them - the hex is just machined/stamped into the center of the bolt as normal. you could use any 4mm bolts cut to length, but may have to grind the threads away just under the head a little as they are captive to the rotor arm, have a look and this will make sense.
 
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angst

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Thanks, but doesn't that mean I'm only half wrong, or half right :)-

British engineering wouldn't come up with such a daft bolt given the torque you refer to!
I've always thought that the Germans would indeed by very good if they employed some British Common Sense Consultants.
 

Alex Crow

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W169, W124, w202, W203, KTM 250 EXC, VW T25 camper and a Polo in a pear tree
from memory the hex size is 3mm, later rotor arms had 4mm hex. then we went distributor-less.
 

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