I have inherited a 98 F150 form my dad. He got himself an 08 with only 45,000 miles on it. I am new to this site, but certainly not new to F150's. I love them!

Anyway, I just got finished replacing all of the transmission cooler lines as they were crumbling. I noticed what I though were wires, but upon closer inspection, they were vacuum lines. They go from the passenger side of the motor (sort of back behind and below the Battery), down over the front axle, and into a "something"? This "something" is attached next to the front diff. I believe the lines are pink and blue. Someone has done something to this truck and the vacuum lines were laying over/on the front drive axle and rubbed holes in the lines. A hose is also broken within 1/2 inch of where it goes into the "something." The temps are in the teens right now and I am not going to crawl under the truck again to see the extent of the issue...at the moment.

Can anyone tell me what the part is that the hoses hook into and what it does?

 

They are the vacuum lines for the front differential lock actuator. While the hole is there your front diff will not lock and you won't be able to use 4x4.

 

Cripes! Just got off the phone with the dealership...the lines and the actuator are obsolete and no longer carried. I am hoping the actuator is fine and it is just the lines. I can just head to the auto place down the road and rig something up. I went into the frozen tundra and disconnected the lines so I have something to look at when buying new lines/connectors.

And thanks for the quick response by the way; I do appreciate it!

 

I don't know where you're located, but try looking at some junkyards or pick n' pulls. I am sure you can find a 4x4 with an intact 4x4 vacuum system.

 

Look up tasca ford parts. They carry a lot of new old stock. I just bought new lines from them not long ago.

 

Yea Tasca is good. All 3rd party stores should carry 1/8" vac line. It's more flexible so you'll need zip ties.

If the actuator hasn't worked in awhile you may want to lube it up and exercise it with a vac tool. Harbor freight use to sell the tool for 8 bucks.

 

Hopefully you didn't pull the pieces off the back of the actuator without marking the Pink and Blue connections. With 97/98 the service diagram is backward for some models.

There is also a clip attached to the inner wheel inside the eng compartment just above the frame rail. Route your new lines thru there.

 

I bought a truck a year and a half ago, and while messing with something else trying to trouble shoot a bad fuel pump (Protip: They fail intermittenly in this group of trucks, not completely for a while). Those vacuum lines disintegrate pretty reliably it seems. I replaced them with appropriately sized rubber, and barbed fittings. I wanna say I bought 15 feet of 5/16ths, but you should certainly double check the size. The vacuum diagram was super simple to replicate if you have enough pieces left.

Pull the battery to get at the vacuum reservoir, and just rebuild the lines with the help of the vacuum diagram. I wanna say it took me just over an hour. I got crafty and zip tied the new lines to the clips for the old lines. I think I may have slipped the new rubber over the broken ends of a couple of the nipples and secured them with zip ties. My front differential lock actuator was stuck in the locked position, so my 4WD still worked, but it was just wearing out the front differential or whatever that wears out.

 

I got off the phone with my local dealer and you can get them. They are like $50 or were a few weeks ago.