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I bought new calipers and fasteners. The hex head is 5/8" or 0.625, the lock washer OD is 0.776 or a bit over 3/4". Seems like an odd match up to me. While snugging up the bolts with a 3/8" ratchet one acted like the hole was stripped so just in case I gave it another turn or two then stopped. You can't see without a mirror so I had no clue what was happening. after removing the bolt I was a bit shocked to see the lock washer had opened up. My first though is it's not really a grade 8 lock washer.
Looking at the caliper there is a convex depression at the bolt hole and I'm assuming that is the problem.
When I removed the old calipers one bolt had a lock washer and one had a broken lock washer.
What do you guys suggest I do? Use Nord Lock washers? Use a grade 8 flat washer?
I did install the LR caliper and got up to 40 ft. lbs. of torque and looking at the split lock washers it looked like they were starting to spread open a tiny bit so I quit. I just don't think that bolt head is big enough for the 70 ft. lbs. the service manual specifies.
When I rebuilt my calipers I simply used Grade 8 hardware on all of it. I would also use a grade 8 lock washer and a grade 8 fender washer on the joint.
Socket head Cap screws are nice and I use them on my Motorcycle as they are a more reliable fastener and are very resistant to rounding off inside. I would not use anything that "might" pull through the hole and cause a problem hence the suggestion of a fender Washer as they offer more protection being larger around.
While at Carlisle many years ago I bought a couple boxes with assortments of Grade 8 hardware. Every bolt I take out of the important parts gets grade 8 hardware to replace it. On the engine I only use ARP hardware just to avoid any hardware failures.
The same thing happened to me. Brand new grade 8 bolt and washer on the rear caliper. Split multiple lock washers before I put a flat washer underneath which solved the issue. I’m also interested in a better/more permanent solution.
When I rebuilt my calipers I simply used Grade 8 hardware on all of it. I would also use a grade 8 lock washer and a grade 8 fender washer on the joint
All the fasteners that came in the kit were Grade 8. Fender washers are large OD and usually pretty thin. Using a flat washer with a split lock washer defeats the lock washer as you are adding a smooth non locking part to the fastener.
The 7/16" Wedge Lock Washer (Nord Lock) has an OD of 0.730". I've used the Nord Lock on automation equipment I've built and it takes very little torque to lock them up and a lot more torque to remove the bolt. The spec is 70 ft. lbs. so I'm concerned about causing damage to the caliper trying to remove one down the line.
Maybe chinese grade 8 isn't what it used to be. I have two hardware stores near me. Both sell grade 8 hardware. Looking at both one is superior and twice the price.
BTW: You are using a Torque wrench and not over tightening?
Maybe chinese grade 8 isn't what it used to be. I have two hardware stores near me. Both sell grade 8 hardware. Looking at both one is superior and twice the price.
BTW: You are using a Torque wrench and not over tightening?
I do use a Snap On torque wrench but didn't get past my little 3/8" ratchet when the split lock washer spread open. So yeah it could be chinese grade 8...
I'm going to order some bellville lock washers and some Made in USA grade 8 split lock washers from McMaster Carr this morning and they will be here tomorrow.
I've seen the Nord locks. Almost is better than spit washers. I have also seen the underside of bolt heads with this design machined onto them.
I do not do it as often as I should, but I did buy everything and do it once. Any fastener that may come loose and kill me gets the head drilled and safety wired.
Also doing some research if the fasteners are lubed up with oil then you reduce the torque by 25% and if you use an anti-seize compound you reduce the torque by 40%. So for the `82 caliper fastening bolts dry the spec is 70 ft. lbs. and for lubed with oil it would be about 52 ft. lbs. now for coated with anti-seize it's only 42 ft. lbs. I tend to use anti-seize on bolts that are exposed to the weather so I gotta adjust the torque I use. When I put the LR caliper on when I got to 40 ft. lbs. it felt about right so I quit.
Caliper Fasteners
