Now you have me wondering. I replaced some very soft hoses that would fall off. Couldn’t figure out why someone would put those on.
Going to have to look into this!
Yep the hoses would get swollen, soft and very limp. Almost like cooked pasta. I ended up using a ziptie to hold them on cause I couldnt figure out what was going on.
Then I replaced the shift modulator and replaced the hoses and it never happened again. Vacuum hoses are not rated for chemicals like ATF or oil so after a bit the fluids attack the hoses.
ATF in general I think causes it. I think its a chemical reaction between the vacuum hose rubber and the fluid itself. Vaccum hoses state they are not for automotive fluids such as engine oil, which I think also includes ATF. Mine didnt really swell too much, they swelled some but they generally became super soft and just the weight of the hose would cause it to fall off the firewall mounted vacuum tree as the rubber was now so soft it couldnt hold onto the barb.
Decided to check out my vacuum modulator today.
Thought I’d pull the vacuum line off and see if it was moist, but got a little shower!
Put a new one in and it drives great.
Glad the rod stayed in my old modulator, that could be easily missed. Had a bit of a hard time getting the rod back in. Put it in so I could feel it better, then put the new modulator on the rod and it slid in nicely.
Thought it would be a quick and easy job, but not so, took awhile and a bit messy.
Glad you mentioned those hoses Rusty.