Mark: Hi, it’s Mark from Top Local we’re here with Bernie Pawlik, Pawlik Automotive in Vancouver, Vancouver’s best auto service experience. How are you this morning Bernie?
Bernie: Doing very well.
Mark: So we’re going to talk about an experienced Ford, a 2004 Ford F150, what was going on with this fine Ford product?
Bernie: Well the vehicle came to our shop for a couple of reasons. First there was a check engine light on, the engine was running rough but also when driving down the road, there’s a lot of pretty horrific noise coming from the front end of the vehicle. Something in the drivetrain, so we needed to do some diagnostics on those particular items.
Mark: So what sort of diagnosis did you do?
Bernie: Well first off, for the engine issue, we plugged a scan tool and found some trouble codes all related to a lean fuel condition, did the diagnosis on that and found there’s a large vacuum leak at the back of the intake manifold. These 5.4 litre Ford’s have a plastic intake manifold and on the back, very like, really really hard to access. There are a couple of vacuum hoses that slip onto the back of the intake manifold, they can pop off from time to time. One’s a very large diameter one which actually feeds the power brake booster so if that’s off you’ll know it because your brakes will be hard as rocks but this one it was a smaller diameter hose which affects the fuel pressure regulator and the four wheel drive locking pump system. So that’s the engine diagnostic figured out. For the drivetrain, again we did an inspection on the front end and found that there was an issue going on with the locking hubs. Partially related to the vacuum leak but there was also something else going on, the hubs would not disengage properly, so they’re half locked in most of the time. Also found that the left front wheel bearing was in really bad shape too. So again, there’s play in the wheel bearing and the locking hub mechanism can be affected by that too.
Mark: So how do the locking hubs work on this vehicle?
Bernie: Well basically what they do, when you’re in two wheel drive they basically disengage, four wheel drive they engage of course, but how they work is there’s little splines on the wheel bearing and on the axle shaft and there’s a little couple unit that’s vacuum operated, this little vacuum switch, it stores engine vacuum so you push a button and when you turn it into four wheel drive it actually engages the hubs. Now if there’s a failure of that system, say a vacuum leak, it’ll actually keep them locked into the four wheel drive all the time, the transfer case just disengages so you’re out of four wheel drive but the hubs and axles and front drive shaft are always running. I’ll just share a few photos here. This is the hub actuator, there’s two of them, we replaced the hub actuators in this vehicle because there was definitely wear, they weren’t reliable anymore. This is a little vacuum port right here which takes the engine vacuum and a signal from the switch so you’re looking at each side of the hub here, bolts in from the back of the hub and this is the little collar, it slides back and forth, only about a quarter of an inch, just a small amount maybe no even that much but it’s just enough to lock the wheel bearing with the axle shaft. This is the wheel bearing, now this wheel bearing, you can actually see this, this splines here and this angled part here, a little subtle to see, you can see it there too, this is severely worn. This is actually supposed to be completely flat like the part up here. So this is worn really badly because the hub was partially engaged and just caused it to grind and wore the metal away in this hub. So that, this is from the right hand side, the one on the left is better but the one on the left surprisingly was the one that actually had the bad wheel bearing. The bearing had a lot of excess of play and then finally we get to the axle shaft and we replaced the right axle shaft on this vehicle, the CV boot was blown open, so we replaced the unit. But again, here you can see these splines here and these and these are actually in good shape on this. It was pretty hard metal but this, the wheel bearing hub sits right here beside it and that little collar slides over and locks the two of them into place when you want to be in four wheel drive.
Mark: Pretty unique system and I know that Ford certainly isn’t the only company to use locking hubs, why do manufacturers use these devices? Why not just keep the front spinning powered all the time?
Bernie: Well actually in fact, some vehicles so but it takes more energy to spin all that drivetrain. You’ve got, while the wheels turn you’re rotating an axle shaft, you’re rotating the front differential, you’re rotating the front propeller shaft, drive shaft to the transfer case, so those are all extra items that are being moved. Takes energy to move them. So by disengaging the hubs, you’re not moving those parts. It also I guess, theoretically prevents them from wearing out but also at the same time it’s good to have them working every once in a while because if you don’t, if you only engage your four wheel drive every couple of years and those parts have been sitting unmoved, you know there might be some issues going on there. Lack of usage is just as bad on the vehicle as too much usage so, but overall it’s really an economy thing. You don’t need those parts moving so why not just keep them, what’s the word, not moving and I guess the other good reason to have it not moving as well as it keeps the noise down because whenever you’ve got gears moving and things moving it adds a little extra noise too. So you don’t have the noise associated with those moving parts. Most manufacturers do have them but there are, as I mentioned, some, I’m thinking like older Jeep Cherokees, Grand Cherokees where actually everything is engaged all the time. And of course, if you have an all wheel drive vehicle that’s always going to be in place, it’s really for a two wheel drive to four wheel drive vehicle that has the locking hubs.
Mark: So is this a common issue on Ford trucks?
Bernie: We fix a few of them from time to time, you know we run into problems a lot with the vacuum system on these but to the extent of the wear on this truck, not not so much. This truck has a fair amount of kilometres on it, it’s well used so it’s not unacceptable that it would have this kind of wear but we do run into these issue on a few Ford trucks but overall the system is pretty reliable.
Mark: What about on the different models, is this used on the F250’s and F350’s?
Bernie: They do use a similar system, of course the wheel bearing on the 250’s and the 350’s are much larger but they use a similar system on most of them but also on a lot of the larger 250 and 350 trucks, they also have an option to manually lock the hub as well so, which is a good thing because if there’s some sort of failure in the system you can always go in and manually lock the hub in also. So they actually, a lot of them have a dual system.
Mark: So there you go, if you’re looking for service on your 4x4 in Vancouver, the guys to see are Pawlik Automotive. You can reach them at 604-327-7112 or check our their website pawlikautomotive.com or you could check out our YouTube channel Pawlik Automotive Repair. Thanks Bernie.
Bernie: Thanks Mark
