By the way, that pic of a stuffing box hose looks to have been caught on something and ripped..that's not what a cracked hose will look like.
Seriously, look at the picture. The angle of the tear doesn't follow the angle of the nylon wrap in the hose. Plus, if you save the pic and blow it up, you can see where the snag actually caught, came loose and caught again.. Looks like it was snagged from the middle and was twisted to the right, since the attaching clamp (hose clamp) hose protector (the dark black thing under the two hose clamps) is actually COVERING part of the tear. This is the same type of nylon hose used for exhaust
connectors for thru-hull exhausts and also for turbocharger and intercooler connections as well as for Farm Tractor radiator hoses. It has around 3 layers and is the equivelant of having weather
checks on an 8 ply mobile home tire sidewall. The first ply is cosmetic. However, if you can insert a screwdriver PAST the first layer or two..then you replace the tire. Since these have zero positive pressure (unlike when they're used in radiator and turbocharged applications where they see 30 PSI and HEAT, they rarely disintegrate unless exposed to fuel
Also, oddly enough, hoses seem to deteriorate more from the inside OUT when exposed to heat, since engine heat will hit the inside of the hose first.
How many engine hoses have you changed in your car that were torn up internally but looked decent on the outside? I race
and have for 30 years or more, and I've yet to blow a radiator hose from an outside scuff like that.
The outer nylon wrap is there just for that reason too, to protect the hose. I wouldn't say that the hose in the pic doesn't have internal damage from that scuff that happened over time, but since the area isn't pressurized much, or tremendously hot, like a radiator or heater hose is on an engine, I seriously doubt it was anywhere near failing.
That's like having your car mechanic
say you need new brake calipers because you have a weather
cracked dust cover on your caliper puck
. That dust cover has NOTHING to do with sealing the caliper..but it DOES keep dirt away from the internal seal..but you can simply wipe a coat of black RTV around the dust cover to fix any minor cracks. However, if you drive in any heavy dust, rain, snow, etc, and the dust cover is missing, then you get a new dust cover and install it, but you don't need a new caliper unless you're losing brake fluid thru the seal or the caliper puck
Oh, and if you own Michelin tires, they have a tendancy to dry out a bit faster than other brands. However, if the tire dealer tries to sell you new tires, yet your tires have nearly new tread (especially trailer tires that weren't covered) you can simply swap the tire around on the rim..the rear facing sidewall usually IS NOT cracked because it has been protected from UV exposure.
Believe it or not, I've had RV guys tell me to slather a bunch of SPF50 sunscreen on the exposed sidewalls to keep them from suffering UV related deterioration too.
Anyway, the big part of any hose is the inside of the hose..especially if it is a multi-layer hose. If the inside gets soft, THAT will allow a blowout. Just like if you have a bubble in the sidewall of a car tire..That's a BREACH of the inner surface..sort of like a hernia. THAT needs to be replaced asap.
Just my two cents from 30 plus years of auto racing