Using a spring with the potential to exceed your perch spread when fully flat means that the car can drive a wedge between the perch bolts repeatedly until one fails. I suspect Posie's will tell you the same thing. You need a spring that matches your axle or shackles that will allow the spring to go to full spread without trying to pry the perches apart.
I think any side loading of the perch would cause variations in the tensile load. This should be true in normal use as well as the extreme in the scenario I described above. You may have fallen victim to simple fatigue. I don't think 65 ft/lbs sounds excessive, but you didn't say if new or used. Could it have been over tightened before? Then there is the roulette wheel of cast materials. Maybe you just hit the wrong color this time around.
I had one brake 25 years ago, Super bell are ductile steel,use a forged steel after market or orginial,
Super bell is owned by Pete and Jakes which is a Alliance Vendor for Hambers, i am sure they will help you out in anyway and replace it for free if it was there product that failed Rusty
Go forged! I am a blacksmith who has made a lot of suspension parts.I am amazed that someone would contemplate making cast parts, is there any test certificate on these parts? Take the part back, get your money back. The shear section should have a very fine light grey grain structure, if there is a slightly discoloured or different looking grain structure (usually near the outer edge) that will be where the fracture started. If that is the case that fracture could have started with a nick or an inclusion (foreign shit) in the casting. Also castings are stronger in compression than tension, castings are not designed to be tightened like that. If you want to test if a part is forged or cast, hold it to a grinder (on the end of the thread, never put a nick in a forging) a casting will produce red sparks, a forging yellow sparks. Drop forged parts look almost the same as cast parts in that they both have parting lines down each side of the part, so a visual inspection is not enough. Also forgings are more expensive than castings..... theres a reason for that..... they don't break. Remember the cheap thing is often the dear thing in the end, and you only get one life.. don't trade your life for a cheap part. As far as I know Hambers aren't posting from six feet under.
A friend sheared a perch right there. He was running a tube axle with split bones. I would think that if it was spring induced it would break at the top of the radius rod. Way at the bottom indicated something else.
man, this spooks me. i am trying to get all the pieces for my A rounded up, and as my usual paraniod self, i have been trying to get the heaviest duty parts i can find. i never once in a million years would have thought about a perch bolt breaking.... so would a stock forged piece be better/safer than a new cast one??
I agree--this is no place for a casting!! Betcha the cast part has cut threads, too, so it can fail multiple ways. Henry used more forgings in his car than were necessary, but this one sure wasn't unnecessary!
While everyone is taking the perch design to task the most important part of this question has been addressed by a couple posters and dismissed. That being that the length spring being used. If this is the spring designed for the original 40 front end, this spring is around 38" in overall static length and way to long. By moving the spring in over the axle and based on the manufacturer and type axle, axles have have a 34" to 38" perch span and require a spring between 29-33" long depending on this distance. The shackle length c/c is 1 1/2" plus the offset of the perch is 1", double this and you need a spring 5" shorter than the perch distance. What appears to have happened is that the longer spring has flexed during operation to a degree that it has bottomed out between the perch pins enough times to stress the pin and create a fatigue point and the part just gave up due to the stress. If you want a good answer, post a picture of your front end to help explain your setup failure and wait for the response.
It needs clarification, but he does say Posie's spring to fit that spread... Posie does make a non-standard spring length for converting later axles, but if that is what he has, proper spread does need confirmation...I don't think it would be possible (well, make that within reason...a good rodder can do anything) to stuff a front spring between top perches on the axle it was built for. Just too damn long due to spread of the perches.
as the others have said , cast perch pins have been breakin' since they were start being made , we had a wave of 'em in aussie land , just been replacing with forged units or stainless steel 18/8 heat treated your install looks right , good shackle angle
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