I was just wondering how you can disconnect the front hub vaccuum lines on a 98 4x4? Wanted to do it because I'm going to do the "quick hub fix" and don't want the vacuum lines hooked up to the hub anymore so they won't disconnect the hubs. If anyone could descibe what the lines look like and how to disconnect t hem, that would be great. Or if you know how to just disable the vaccum pump (if that's what it uses) that would be good to. Thanks in advance.

 

If your goal is to convert the PVH system on your Ranger to something similar to the "constant engagement" system found on the newer Rangers, then there is more to it than just disconnecting (and plugging) the vacuum lines at the wheel ends. Take a look: '98-'00 Ranger PVH Conversion

 

Ahhhh.....I had read up on doing all that, but i was under the impression you also had to disconnect the vaccuum lines. Thanks a lot rockledge!!! The pics will help a bunch, I'm sure!

 

Well, I have to give a big Thank You!!!! to Rockledge. Went out today and fixed the hubs. I have to say, that was about the easiest thing I had ever done to the ranger. Took less than 10 minutes to do both sides and now the 4wd works better than brand new. Took it up to about 80 (for about 1 minute ) on the interstate and there were no shakes or vibrations or anything, so it should be good to go. Thanks a lot for including the link to those pictures, it helped out a lot.

I think I will hit up a junk yard and find a couple of those plastic hub pieces with the metal part still intact and keep them for when it get warm out again and I won't be using 4wd. So that way I can have the front disengaged when i won't be using it for a while. I wouldn't even bother, but it'll probably take less than 5 minutes the next time

 

You're welcome.

Let us know how it goes if/whenyou decide to disengage the hubs when it gets warmer out.

 

I found out I had the same problem today...thanks for the fix!

What is the weakness of this system that these hubs fail? The function of them seems so simple...

 

Ya, I was kinda wondering the same thing. I had always assumed before that it had to do with the plastic pieces failing, but when i took them apart, they were in pretty much perfect condition. I would assume that it is probably something with the vaccuum system that normally fails, like a bad seal or something. But really, even after taking the hubs apart, I still don't know exactly how they work. I was wondering if anyone had a link that explained in detail, and preferably with some pictures, just how exactly the PVH system works in its entirety. I'm just curious.....so if anyone has a link, please post it.

 

In a nutshell, the Ranger PVH system works as follows:

When you switch into 4WD, the transfer case motor operates to engage the front drive line (i.e., connect the front driveshaft and axles to the powertrain). After the GEM verifies the completion of the transfer case shift from 2WD to 4WD, it energizes the PVH solenoid (supplying ground for 45 +/- seconds). During this time the solenoid directs a high (full) flow of intake manifold vacuum to the wheel end hublocks. The end result is to achieve four wheel drive by engaging the wheel end hubs to the rest of the front driveline.

When you switch back into 2WD, the GEM verifies the completion of the transfer case shift from 4WD to 2WD, and the GEM energizes the PVH solenoid to allow only a low (regulated) flow of vacuum to the hublocks (supplying a ground for 10 +/- seconds), disengaging the wheel end hubs from the front driveline to achieve two wheel drive.

So based on that, there are a really only a few things to consider when the hubs are not functioning properly:

(1) A bad GEM which could be improperly energizing the PVH solenoid;

(2) A bad PVH solenoid which could be failing to direct proper vacuum flow to the hubs when called upon by the GEM;

(2) A vacuum leak (or blockage) somewhere in the system.

#3 is by far the most common problem with the PVH system. Vacuum leaks can occur anywhere from the wheel ends (hubs and knuckles) back to the solenoid. These leaks can be caused by simple things, such as disconnected hoses, as well as more complex things, such as front axle shaft retainer rings not being properly seated, allowing the shafts to move in and out (toward the differential and back) resulting in them losing contact with the vacuum seals that are located at the knuckles.

 

Has anyone tried disconnecting the vacuum source and use the hub
assembly as a push-button "off-on" actuator?

I was thinking that if you removed the vent in the outside cap or
made a small hole in the vent itself...you would be able to push on
the rubber seal to click in (engage) the hub...then when you wanted
to disengage the hub you would again push on the rubber seal (some-
thing like a ball point pen). This would be similar to manual "turn-style"
hubs on pre 98 rangers in that you would have to get out to engage/
disengage them. The advantage to this would be that you wouldn't have
to pull the metal piece out so the hub stays intact and you could always
go back to the oem configuration if you needed to. You would still have
the ability to engage/disengage them depending on your needs. Only
problem i can think of is that you would want to be sure both hubs
were the same (i.e. engaged/disengaged). I was thinking that you
may be able to tell from how far the rubber seal was pushed in if the hub
is engaged/disengaged.

I haven't had mine apart yet...but for those of you have... can you tell
me if the vent screen on the outer hub cap is removable? Also...could
you tell if the hub was engaged or disengaged by how far the rubber seal
is pushed in? (Knowing that "pushed in" is engaged ...you may be able to
tell from clicking it on and off through the vent hole which position it's in).

Thanks for any info,
Geo.

 

Actually, I remember another post about this same problem where someone's vaccum system quit working and they did exactly what you are talking about. They poked out the little screen and then just pushed one the inner part of the hubs to engage or disengage them. Altho, above you said you "click in" to engage, and "click it out" to disengage.....From what it looked like when I took it apart, when it is in the pushed in position, it is disengaged, and when it is in the clicked out postion, it is engaged. I belive this is right, because once you remove the little metal piece, you can no longer have it in the "clicked in" position.

But I don't see why you idea wouldn't work. it makes sense to me. But for me, I think I'm just gonna find another pair of the plastic pieces with the metal piece still there, and just exchange them out after winter, and keep the ones for 4wd in my toolbox in case i go off-roading. It's only a 5 minute fix, so it won't matter much to me.

 

Excellent info regarding pvh system fixes Rockledge,we have a1998 Mazda b400 4wd that has experienced all kinds of 4wd problems.briefly my son spent bigbuks at a Mazda dealer who finally said they couldn't fix it and refunded his money.He took it to a Ford dealer who replaced hubs and bearing and hub lockouts still failed.We then found your comments ondisabling the system.My question is dealer states front half shafts ,front differential,front driveshaft and transfer case is moving all the time causing accelerated wear on all components including transfer case.What do you think? Thanks for you time. Dickie from Wis

 

Performing the "direct engagement" modification will permanently engage the hubs to the driveaxles. In such case, when the front wheels spin the driveaxles will also spin along with the front diff and front drivehsaft. However, in 2WD the front driveshaft will not be engaged to the powertrain at the transfer case. In 4WD, it will.

There is nothing exceptional about this; the same setup exists on the current Rangers and it has been like that since '01 (bet the dealership didn't tell you that, did they?).

I would assume the technicians looked over the entire PVH system on your sons's truck real good and tested everything fully. However, if you and your son still want to take a stab at the PVH problems he is having, here are a few things you can try:

Pulse Vacuum Hublocks - Diagnostics

Good luck.

 

Not only are the 01+ Rangers setup that way, but so were the 95+ Explorers. Same front end setup, without hubs. They were always engaged, because they had an auto 4x4 system, that would engage the transfer case at the first sign of slippage.
The driveshaft spins, differential turns, and cv joints turn. How is that different from anything else? It's not... Shouldn't cause any problems. CV joints and U-joints will go bad at some point anyway.

 

in the main thread Bobreite wrote about "clicking" the hubs in and out manually - which leaves the hub intact.

Disconnected the vacuum lines, took off the cover - pulled the hub OUT (from the sounds of it) with a paper clip, and put it all back together.

I dont believe he has reversed the process yet (to unlock the hubs) though.

Its the method that Im going to try first because I there doest seem to be any drawbacks, and I can use my "auto" switch in the summer to engage and disenage them. (my hubs struggle to enage during th winter when its COLD - the seals of vacuum dont hold the pressure and the hubs slip in and out of engagement)

I just havent gotten to it - hasnt snowed here in a bit and its going to be warm al next week so maybe ill get to it then.

P.

 

ok everyone here is the fix to this small mishap on ford's part.
take the cover off the hub (the black piece with the screen) STOP dont take out the clip inside dont even have to take out the seal, dont go any deeper. Now put the cap on a work bench and pop the screen out of it. go through the spoked side and push screen out with screw driver just hold up one side off the bench and apply some pressure directly to the screen from the back (through the spokes) now cut out the spokes with a pair of side cuters and use a round file to clean up the hole. important make sure you file down the spokes all the way or your going to shred your finger every time you switch the hubs . put the cap back on and disconect the vacuum line. I did mine after the solinoid right where it branchs off to the hubs and plugged the line. I did it that way so there is no interuption with the solinoid operation.( did not know if unpluging the electrical conector to the solinoid would cause a fault code?) so now your done just simply push the rubber seal all the way in and your locked up and when your done playing just push in a little bit and feel a slight click and release. you will feel the tension on the cap so if there is only a little your un locked. works like a push pen. and it is all water proof and with no vacuum you wont such in any dirt. the only drawback is you have to jump out and lock and unlock your hubs but if it works 100% of the time its well worth it. if you go the other route and remove that clip inside to replace those there 180 bucks each. if your jumping in and out of the trail just leave the hubs locked and switch the t case in and out of 4wd.