Yet ANOTHER 4WD question
- Thread starter LtFuzz
- Start date
Bounty__Hunter
Super Moderator
Where is this blue line? What year and type of jeep?
i think that the blue line is not supposed to be connected. on my old 1990 yj it was just hanging there, someone told me that it was a vent. if you rlight is not on you most likely have a vacuum problem. i would check all of the lines for cracks, holes, etc.... or you could just go with a posi lock and be confident about your 4x4 system. i think it was tug that rigged his up for less than twenty bucks and a few hours of time.
Bounty__Hunter
Super Moderator
4 vacuum lines run forward from the transfer case:
2 run to the front axle
2 run to the firewall near the battery (one ends in a vent cap, other follows firewall to intake manifold vacuum).
Check for leaks, most common is near/under the battery from battery acid. Let me know if all the hoses are intact, and I'll walk you through some more troubleshooting. See if this diagram helps any:
2 run to the front axle
2 run to the firewall near the battery (one ends in a vent cap, other follows firewall to intake manifold vacuum).
Check for leaks, most common is near/under the battery from battery acid. Let me know if all the hoses are intact, and I'll walk you through some more troubleshooting. See if this diagram helps any:
Bounty__Hunter
Super Moderator
Quick troubleshooting of the 4wd system on a YJ:
If you've got no vacuum at the front axle, move back to the transfer case and feel for vacuum coming from the intake manifold. If you gave vacuum to the transfer case in 1 line, the switch in the transfer case is bad. It's what the 4line vacuum connector connects to. Easy to replace.
- Jeep running and in neutral or park, tires chocked or locked
Unplug the double vacuum plug at the front axle disconnect
Feel for vacuum in each port while somebody shifts from 2wd to 4wd and back
Vacuum should be strong in 1 port for 2wd, in the other port for 4wd
If you've got no vacuum at the front axle, move back to the transfer case and feel for vacuum coming from the intake manifold. If you gave vacuum to the transfer case in 1 line, the switch in the transfer case is bad. It's what the 4line vacuum connector connects to. Easy to replace.
Bounty__Hunter
Super Moderator
What'd it take to fix it?
so my light works.....but its still dim....i saw this on another site and thought i'd post it....i need to know where i can purchase a vacuum harness
*******
That "blue hose" is part of the vacuum harness for the front
axle disconnect system. Being as anal as I am, (all hoses
must be accounted for), I to wondered what function did that
"blue hose" perform.
The vacuum harness, (which I had to replace), runs between
the front axle, the firewall mounted vacuum switch and the
Tcase, (if you look on top of the xfer case you will find
where the harness ends, and the "blue hose".
At the end of the "blue hose", (the end in question/under
the battery) there should be a small plastic disk about the
same size as a $.50 piece, and approx .25in thick with a
nipple on each end, (mine appears to be 2 halves glued
together white/black).
This disk is a "one way" release valve. Whatever you do
don't plug it up with gasket sealer otherwise your axle
won't engage and you will be forced to purchase the whole
harness when you "puncture it" trying to get all that goop
back out...8(.
Unfortunately you must purchase the whole harness in order
to get the valve, wasn't bad under $20. The whole
installation including removal took about .5 hour.
- author unknown (but an excellent bit of info!)
******
*******
That "blue hose" is part of the vacuum harness for the front
axle disconnect system. Being as anal as I am, (all hoses
must be accounted for), I to wondered what function did that
"blue hose" perform.
The vacuum harness, (which I had to replace), runs between
the front axle, the firewall mounted vacuum switch and the
Tcase, (if you look on top of the xfer case you will find
where the harness ends, and the "blue hose".
At the end of the "blue hose", (the end in question/under
the battery) there should be a small plastic disk about the
same size as a $.50 piece, and approx .25in thick with a
nipple on each end, (mine appears to be 2 halves glued
together white/black).
This disk is a "one way" release valve. Whatever you do
don't plug it up with gasket sealer otherwise your axle
won't engage and you will be forced to purchase the whole
harness when you "puncture it" trying to get all that goop
back out...8(.
Unfortunately you must purchase the whole harness in order
to get the valve, wasn't bad under $20. The whole
installation including removal took about .5 hour.
- author unknown (but an excellent bit of info!)
******
Bounty__Hunter
Super Moderator
What'd it take to fix your 4wd?
XJNick said:
Unfortunately you must purchase the whole harness in order
to get the valve, wasn't bad under $20. The whole
installation including removal took about .5 hour.
thats what i was told...so i dont know.....as for my 4WD, i found out where the line had been broken and "fixed" with tape, so i fixed that up and it kinda started workin again.
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