caliper

[USA64]

LR caliper: after a rebuild I went to final mounting, 7/16 fine torque to 40lb from manual. Lower (rearward) no problem this one popped just before 40lb. Ideas what to do anyone? Would JB Weld work do you think? And what caused fail, too much torque? already present crack? It came off the same mount '69 Elan S4 off road for 30+ years.

[Mike Ostrov]

Most unusual. I would suspect a previous fracture or the "ears" were not parallel to the upright. Cast iron is brittle and easy to fracture. JB weld is not suitable. A qualified welder might be able to re construct the eye and then it must be machined with the new surface parallel to the existing eye. Check the upright threaded portions to make sure the surfaces are parallel. Cheers. Mike, in Richmond, CA 510-232-7764

[Frogelan]

That is a quite a sad case, especially given the cost of replacing a caliper!

Whilst Mike's instinct to repairing things rather than to throw them away appeals to me, on something directly involving personal safety I think you have no choice but to buy new rear calipers.

[Andy8421]

If the calipers are indeed cast iron, then welding is a skilled job. It would require pre-heating of the caliper prior to welding and then controlled cooling to avoid cracking. I have a vague recollection that because of cast iron's high carbon content, even a properly executed weld will always be a weak point as the carbon contaminates the weld pool.

Probably worth trying to weld a cracked Bugatti engine block, but given the price of a new caliper and the safety critical nature of the item I would certainly replace rather than repair.

Worth checking that nothing is out of alignment on the caliper mounting points on the upright before you tighten the new one up - they need to be clean and free of corrosion as well.

[Hawksfield]

Hi

To me it looks like it has not been pulled in square to the mounting how was the other side ? ok
I would grin and bear the cost as your safety is worth more

[david.g.chapman]

I agree. Although I am a fan of JB Weld, in this case I think you need to grit your teeth and replace it.

As mentioned, check that the mounting ears on the new caliper are lying flat and not being twisted in any way before you assemble.

Dave Chapman.

[Mike Ostrov]

I am finishing up another "for sale" posting and have a full set of rear calipers, if needed.

I have one bare caliper without any handbrake bits, but not sure which side. Will examine it when back at the shop in a day or two, if needed. Cheers. Mike.