4wd vacuum hub solenoid
08-05-2018, 09:51 AM
#1
4wd vacuum hub solenoid
Ok guys get this . If I put the truck into 4wd , I have to tap on solenoid in order for truck to engage. I replaced solenoid with a new dorman solenoid and same thing happens. To clarify, if I disconnect upper vacuum line to solenoid and put truck into 4wd I won’t get vacuum out the upper port. Then if I tap solenoid, I will get vacuum. Then as soon as I switch to 2wd then back to 4wd I will not get vacuum until I tap on solenoid. Any help would be appreciated. 2001 Ford F-150 lariat super crew 5.4
08-05-2018, 12:53 PM
#2
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Sounds like a sticking solenoid, you either have power, vac to hubs, or no power, hubs vented. You could run a voltage test on the pigtail at the solenoid, but I'm not sure what voltage you'd be looking for, common sense tells me 12 volt though. Clean the electrical plug with some contact cleaner, and lube it up with a little dielectric grease. Check vehicle side of plug for loose wires. Just an idea.
Personally, I try not to use Doorman products, but that's just me.
That top hose should only get a "squirt" of vac, that's your vent, at least on my truck. The solenoid should be closed to vac when you switch to 4X4, and the vent open.
Personally, I try not to use Doorman products, but that's just me.
That top hose should only get a "squirt" of vac, that's your vent, at least on my truck. The solenoid should be closed to vac when you switch to 4X4, and the vent open.
Last edited by johnday in BFE; 08-05-2018 at 12:57 PM.
08-05-2018, 01:17 PM
#3
Sounds like a sticking solenoid, you either have power, vac to hubs, or no power, hubs vented. You could run a voltage test on the pigtail at the solenoid, but I'm not sure what voltage you'd be looking for, common sense tells me 12 volt though. Clean the electrical plug with some contact cleaner, and lube it up with a little dielectric grease. Check vehicle side of plug for loose wires. Just an idea.
Personally, I try not to use Doorman products, but that's just me.
Personally, I try not to use Doorman products, but that's just me.
08-05-2018, 01:25 PM
#4
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08-05-2018, 01:56 PM
#5
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Sounds like a sticking solenoid, you either have power, vac to hubs, or no power, hubs vented. You could run a voltage test on the pigtail at the solenoid, but I'm not sure what voltage you'd be looking for, common sense tells me 12 volt though.
Does the new solenoid have a voltage label on it? If it is 12 volts+- , can you run a couple of wires straight from the battery to the solenoid?
If that works, look at how the solenoid is grounded. Older vehicles are prone to corrosion at their grounds, because it is usually an open, metal-to-metal, unprotected connection.
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johnday in BFE (08-05-2018)
08-05-2018, 01:58 PM
#6
Senior Member
9 volt batt will work too.
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johnday in BFE (08-05-2018)
08-06-2018, 01:41 PM
#7
Just a tip here, the 2001 F150 does not use an IWE system like the '04< they use a center disconnect setup where it has a
vacuum actuator mounted to the front axle, with 2 vac lines attached, 1 is used for 4x4 moving the actuator 1 way will engage
a sliding gear in the front differential, vacuum applied to the other vac. hose moves the actuator the other way disengaging
the front axle. there are 2 solenoids used for this purpose both mounted on the same bracket if memory serves. swap the
new solenoid back with the one you changed, then swap it with the other one. chances are tapping the one gets the one next
to it to open.
vacuum actuator mounted to the front axle, with 2 vac lines attached, 1 is used for 4x4 moving the actuator 1 way will engage
a sliding gear in the front differential, vacuum applied to the other vac. hose moves the actuator the other way disengaging
the front axle. there are 2 solenoids used for this purpose both mounted on the same bracket if memory serves. swap the
new solenoid back with the one you changed, then swap it with the other one. chances are tapping the one gets the one next
to it to open.
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