Cracking Rubber on Clutch Flexible Hose Line

Hello all, I am asking for your opinion.

My knowledge of vehicle maintenance is relatively basic, so bear with me.

I have been having trouble with what feels like air getting into the clutch hydraulic system on my 96 3.4L 5 Speed Tacoma. My clutch pedal has lots of free play and is very spongy. It doesn't feel like it has the same travel/resistance it used to. Now it lacks resistance until about half way depressed; if I bleed it, and adjust the free play in the clutch rod under the dash, I can get it to somewhat resemble “normal.” However I believe that it only feels better because I have tightened the play. I know having 0 play is a bad thing. This has led me to believe driving the truck in its current state would be detrimental.

Some background: My pedal had no resistance and fell to the floor a month or so back. I replaced only the slave cylinder, with an aisin one. It drove fine for a bit but after a while there were symptoms of more air in the clutch line. Long story short I have bled the thing a dozen times, returned/replaced the new slave cylinder I bought, put in a new master cylinder and replaced the hardline that goes from the slave cylinder to the flexible hose you see pictured below. Essentially I have almost replaced the entire clutch hydraulic system, with no success. I see no visual signs of fluid leaking anywhere from: the inside of the boot of the slave cylinder, the plunger rod that connects from master cylinder to clutch pedal, any of the hard lines or the flexible line between the master and slave cylinder.

Assuming there are no faulty parts, and that I am bleeding thoroughly, my only logical conclusion would be the flexible hose (pictured below) with rubber crumbling off is letting in air? The only other component I have not recently replaced myself would be the hardline between master cylinder and the flexible hose in question. I doubt this is causing issues because it seems shiny and new, as if it was replaced not long before I got the truck 5 years ago.

So my question is, am I missing something here? What seemed a simple fix has not been so simple. As of now I stand to order the sunsong flexible hose for 6$ on rock auto to potentially stop air from entering the system. Either that or take it into a local mechanic to have the problem diagnosed/repaired. Not my daily so I can wait the delivery time, but I am also growing impatient with throwing parts at the issue. I would like to accomplish these things on my own, but am okay with letting someone with more experience handle it.

Anyways apologies for the lengthy read, any and all help is appreciated.

Thank you!

Ps- To make sure I am not bleeding incorrectly: When bleeding I have a buddy help press and hold down clutch pedal while I crack/close bleeder valve on slave. After a few of those I tell him to pump it 10-20 times then hold it down while I crack/close the bleeder valve again. Repeat this process up to 10 times max all while ensuring fluid is topped off in reservoir.

 

I'm surprised no one has answered you on this. One look at that hose and my response would be, "Good Lord, yes. That could be a problem." Given that it is a cheap and easy thing to try, and given everything else you've done, I would replace that before giving up and taking it to a mechanic. I hate to say it, but it's probably the first thing I would have tried. Good luck.

EDIT: I see your question was months ago. I assume you've done something by now. Got an update? I'm having problems with my clutch as well (am believing hydraulics), would like to know how yours turned out.