Welcome! Becoming a registered user of ShortWingPipers.Org is free and easy! Click the "Register" link found in the upper right hand corner of this screen. It's easy and you can then join the fun posting and learning about Short Wing Pipers!
We have the original oil cooler and hard lines mounted in the chin and the brackets keep breaking. Not sure exactly what's wrong and why they keep breaking. This has got to be the 5th or 6th time a part of the bracket has broken. We've had both the left and right side break at different times and different places. Currently the left side one with 3-legs has broken where the leg attaches to the generator. Basically the flattened part of the tube broke. It's getting kind of frustrating as it's a nuisance taking the prop, nose bowl off to get to it, repair it and put it all back together and pray you don't have a oil leak when you are all done.
I know it's a big hunk of metal hanging there but why do the mounts keep breaking? I really don't want to buy a new lighter oil cooler because we have no issues with oil temp with the existing one. We had the engine dynamically balanced a couple of years ago so there isn't any unreasonable vibrations. We're wondering if maybe we should/could switch from the hard lines to flexible lines and possibly remove a point of tension -i.e. the hard lines pushing one way while the mounts push a different way? Would it help/hurt and can it be done without an STC of some sort?
I was also looking at Univair and their replacement mounts MAN oh man are they proud of the ones they are selling -$225 for one and $450 for the other. I guess we will keep repairing ours.
Any suggestions on how to keep them from breaking again? The repaired sections are not re-breaking (so far) but I think with every repair we're just moving the weak link to another spot on the bracket. There's got to be an underlying reason why it's under abnormal (at least I think it's abnormal) stress.
“Seek advice but use your own common sense.”
― Yiddish Proverb
From my experience it is not uncommon to find them broken but sounds like you might have something in a bind or work hardened like Forrest posted. Only thing I know to do is to make sure everything is relaxed when you start tightening things up. Not sure the hard lines are stiff enough to cause a problem. I replace them with -8 Stratoflex with fire sleeve via a log book entry, common hardware and practices.
I had a generator bracket welded by a "Pro". As soon as the bead was completed he threw it in a bucket of water.
I thought well it will break again very shortly which it did. It should have been allowed to air cool slowly.
[QUOTE=It should have been allowed to air cool slowly.[/QUOTE]
I'll second Gilbert. Vermiculite is a wonderful media for slow cooling to prevent formation of martinsite crystals. Heat above and below stress effected areas....Dull red.....Tempi sticks are great tools for insuring you reach annealing temperature...say 1600 degrees https://www.amazon.com/Tempil-Surfac.../dp/B01HQ3L7IC