Difference between 2wd and 4wd knuckles

[MikeTX]

So what's the difference between the steering knuckles on the 2wd and 4wd besides the hub assembly? Because I have a 2wd and I'm 99% sure it needs rotors and new wheel bearings. I'm not sure if the spindles are damaged, but the truck has 170k on it and whoever owned it before me didn't take great care of it, so there could very well be damage to the spindles. And if so, I don't want to keep replacing bearings every few months and I've had a hard time sourcing new spindles that aren't lift spindles.

So I was wondering, if I went to a salvage yard and grabbed a pair of OEM 4wd/awd knuckles, would it bolt into my steering and suspension without any problems? Like are the diameters of the ball joint pins and tie rod ends the same between the models? And would my factory break caliper and caliper mount work on the 4wd knuckle or would I have to swap to the 4wd caliper and mount?

I figure if I can pick up a set of knuckles for cheap enough, grab a set of hub/bearing assemblies off ebay, then new rotors and pads, I could get the ease of the 4wd setup for future break jobs, and the longevity of the one piece bearing assembly should it ever go out. I'm just not sure if it's possible. Any input?

 

[delexploder]

The awd/ 4wd knuckle will swap directly , I can't recall on the breaks but if you are grabbing the parts from a junkyard just grab all of it to be sure , now here is the bad news , the unit bearing needs the half shaft and nut going through it to keep it from splitting apart, so at that point you either cut the ends off a set and use them like a giant bolt or you just keep going and install an entire front diff ,

 

[Willcall]

I came on here to ask this exact question for my 98 XL Fleet. My next question is this:

Why do you need the shaft going through the bearing?

This is my understanding of the Explorer's 4WD front driveline:
The CV axle mates to the bearing's moving portion. The moving portion is one piece and press fit into the bolt on portion. If the CV axle shaft was holding the bearing together, wouldn't it grind on the bolt on portion? And if the whole CV axle pulls the bearing in, wouldn't the bearing grenade as the CV axle moves in and out?

I ask this because the 3rd & 4th Gens use almost the exact same wheel bearing design on both 2WD/4WD and have no problems.

 

[MikeTX]

Well I don't want to install a front diff and actually do a 4wd conversion just yet. I could eventually, but right now I just don't know about it all. As far as the half shafts go though, it wouldn't be difficult to cut a set and make the "bolts" to hold the bearings together.

From the digging I did this morning, the part numbers for the brake pads are the same between the two models, so it seems at least the calipers are the same, and if the pads are the same, the parts kit are the same, which should mean the caliper mounts are the same. So it should all bolt up the same. Where I'm concerned is the ABS system. The 2wd has the reluctor ring pressed in the back as a part of the hub/rotor assembly with the corresponding sensor bolting to the back of the spindle, where as the 4wd has the sensor as part of the bearing hub and is replaceable with the unit. So I'm concerned about swapping the ABS systems and whether or not the plugs will just swap without tripping the ABS light.

 

[delexploder]

New unit bearings come with the sensor installed with a long harness that plugs in up on the frame so you would be fine there,

 

[MikeTX]

Yeah I knew the 4wd hub would have the sensor and harness pre-installed, I just wasn't sure if it would be plug and play on the 2wd harness. With that out of the way, I've priced the parts and it's only marginally more expensive doing the conversion than rebuilding stock, and the ease of future break jobs, for me, makes up for the extra $40 in parts.

 

[swshawaii]

If you find a 2001-03 Sport or 2001-05 ST. Not sure if the slightly larger rotors are beneficial, just another option. GL

http://www.explorerforum.com/forums/showthread.php?t=381870

 

[pjtoledo]

a 2wd Ranger from 2003+ should fit. BUT IT HAS TO BE TORSION BAR, NOT COILS up front.
from about 98 on, there are 2 types of front 2wd spindles, coil or torsion bar.
forget the coils, they don't swap into a torsion bar truck because the top ball joint/control arm is different.
from about 98 on there are 2 different sizes of front torsion bar spindles, 11.25" rotors, and 12" rotors. the holes move outward for the 12", the brackets and calipers are the same.
I know 2001 sport tracks had the 12" 2wd spindles, I have a set. found out the hard way they will not fit my 2005 coil Ranger.
about 2003 the Rangers with torsion bars/heavy duty suspension changed from 11.25" to 12" front rotors, the spindles are the difference as the holes were moved out.
the 4wd hub bearing assembly is designed to need a 150 lbs/ft preload. with out something in the middle supplying the preload that bearing falls apart soon.

the regular 2wd tapered roller bearings should easily last 100,000. I would repack them every 50k or so. inspect the spindle shaft for galling, that's about all that can go wrong if the bearings are tightened properly.
removing the outer races from the 2wd hub/rotor assemblies is "not easy", unless the hubs have notches in them. most don't.


have fun.

 

[pjtoledo]

I came on here to ask this exact question for my 98 XL Fleet. My next question is this:

Why do you need the shaft going through the bearing?

This is my understanding of the Explorer's 4WD front driveline:
The CV axle mates to the bearing's moving portion. The moving portion is one piece and press fit into the bolt on portion. If the CV axle shaft was holding the bearing together, wouldn't it grind on the bolt on portion? And if the whole CV axle pulls the bearing in, wouldn't the bearing grenade as the CV axle moves in and out?

I ask this because the 3rd & 4th Gens use almost the exact same wheel bearing design on both 2WD/4WD and have no problems.

for the bearings that require the 150lb/ft preload:
they are double row bearings, the outer race (the part that bolts to the knuckle) is a single piece but there are 2 inner races.
the center hub/splines goes thru both inner races, the outside one is pressed against the hub. for the inside one the inner race overhangs the hub/splines. the CV contacts that inside inner race, and is drawn tight by the nut on the outside of the hub, thus putting tension between the 2 inner races.

 

[MikeTX]

I'm switching from spindles to knuckle/hub assembly. So I'm not too worried about spindle sizes. As for getting around the bearing coming apart, as someone said above, I'll take a set of front axles and cut them into a sort of bolt that I can shove through and torque down to keep it from coming apart. That shouldn't be much of a problem at all.

Reason for doing all this is I'm sure my spindles are shot and I know my bearings are. Sure I could just swap it all and keep the stock parts, but if my spindles are screwed then I burn up bearings faster. If the bearings fail, then I have to replace them and the races, and I don't have a press. Spindles are a PITA to tear apart every time you need to do a break job or replace bearings. And the 4wd setup is over all just much simpler.

 

[pjtoledo]

I'm switching from spindles to knuckle/hub assembly. So I'm not too worried about spindle sizes. As for getting around the bearing coming apart, as someone said above, I'll take a set of front axles and cut them into a sort of bolt that I can shove through and torque down to keep it from coming apart. That shouldn't be much of a problem at all.

Reason for doing all this is I'm sure my spindles are shot and I know my bearings are. Sure I could just swap it all and keep the stock parts, but if my spindles are screwed then I burn up bearings faster. If the bearings fail, then I have to replace them and the races, and I don't have a press. Spindles are a PITA to tear apart every time you need to do a break job or replace bearings. And the 4wd setup is over all just much simpler.

no need to cut anything, remove the cage & balls from the CV joint. the outer shell and stub shaft is all that's needed.

 

[1996BLKBauer]

The easiest way to see if the spindles are messed up is to pull off the rotors and check, if you see any grooves, then they are toast, if not, buy new rotors and bearings and you will be fine. New rotors and to pack some new bearing should take about an hour. If you have any play in your current ones, you can always tighten up the nut a bit, but that will only get you so far.