Not an issue - more a curiosity I hope someone can explain I'd swapped out the swing pins/bushes on my 303.5ecr, but I'm racking my brain to figure out how they are supposed to work. Every other bushing/pin setup makes sense -- There is usually a moving/rotating part where the pin is captive, whether by and end flange or through-bolt. The stationary part (where the pin rotates within) is where the consumable bushings are pressed. But the swing 'knuckle' is different... Both the upper and lower pins are fixed to that knuckle... but the bushing are also pressed into that same knuckle.. so the pins here dont actually rotate within the knuckle, but instead rotate inside the connections to the house, which aren't fitted with any bushings and are free to wear out... It would make sense if the pins were fixed to the house connection instead of the knuckle... but the way it is? No idea why. Anyone know why this is done this way?
Parts Manual for My Cat 305e2 shows bushings in the frame part as well as the fixed side like shown above. I would imagine yours is the same.
They put a replaceable sleeve on the fixed area of the pin so that when the pin slapping movement starts to wear the hole egg shaped you can replace the sleeve rather than having to repair the bore. Ther3 will be a bearing on the boom that rotates on the pin.
Wish my komatsu pc35mr also had bushings in the swing bracket. Couple mm of slop in it even with a brand new 100mm pin. Nothing to do but weld it up and line bore, or bore it bigger and sleeve it.