1994 Ford Explorer XL 4wd - "plastic thrust spacer" & "cam assembly" in hub: how check condition and alternate names?

Hello friends,

I just replaced the rotors and bearings, I’ve got the wheel bearing adjusting nuts and locking keys placed. There were no “plastic thrust spacers” there when I took it apart (anything to worry about?), and now I’m to the “cam assembly.”

While cleaning the old cam assemblies I found that the inner ring separates from the outer ring. I’m not sure if it’s supposed to do that. I was going to go look at a new one to compare it to, but the auto parts suppliers I’ve looked at online don’t have a part by that name.

  1. Do I need “plastic thrust spacers”? [if so, what are they called at the parts store?]
  2. How do I know if I need to replace the “cam assembly”?
  3. What other name or part number is the “cam assembly” called?

Thanks for reading


My early 70’s 4WD Ford truck w/manual locking hubs has a similar configuration, but not exactly the same as yours. Mine doesn’t use that small locking key for example. At least I don’t recall anything that looks like that. I’m guessing you lock the hubs using a control in the passenger compartment, right? If so, the locking key probably related to that function.

As far as the thrust washers, I expect that , yes, you do need them for it to work smoothly. Mine has washers like that, thin metal rather than plastic as I recall. On mine there’s a sort of clutch mechanism that allows it to slip if too much force applied, involves a 2-piece gadget, the pieces keyed to each other, interlocking teeth of a sort. I don’t think that’s the cam though, it’s further in. I doubt there’s a problem with your two-piece cam though. Just the way it is supposed to be I’d guess. (Actually now I think about it, I believe I’m remembering my hub cam as having two pieces, one is sort of a ring and the actual cam rotates within it. See where that arrow is pointing on the cam ass’y? That’s the ring I’m referring to. )

I’ve never had to purchase any of those parts, so no idea which vendor might have them. You mght try LMC Truck. I doubt they have them, but they may know who does. If you don’t have the free LMC Truck catalog for you truck, good time to order that up as well. Very useful info for the truck-owner diy’er.

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Agree well worth the price. :smiley:


The price of the catalog is not how much it is gonna cost you. When I page through my catalog my mind is saying “I want that!” Then a few seconds later “I want that too!” … minute or two later “I must have that as well!” … lol …

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"George_San_Jose +
When I page through my catalog my mind is saying “I want that!” Then a few seconds later “I want that too!” … minute or two later “I must have that as well!” … lol …
Also true of any catalog. :smiley:.

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The answer is simple.

If Ford Motor Company has it in their illustration of the cam assembly, they’re required.



Thanks for the catalog tip. Unfortunately in this case for some reason the 2 wheel drive diagram includes all the parts out to the grease cap, but the 4 wheel drive ends at the nut and doesn’t include the “plastic thrust spacers” or “cam assembly”.

That’s because you are just looking at bearing parts not the 4WD parts.

Have you gone to the parts department of a Ford dealer?

Likely b/c LMC doesn’t sell the parts for the 4WD front locking-hubs. You’ll have to find another vendor that specializes in Ford 4WD components, or from wrecked version of your vehicle from an auto-recycler. Prior to the pandemic there were several magazines covering 4WD trucks. Peterson’s 4WD and Off Road, Classic Trucks, & Four Wheeler are examples. Pandemic has been hard on these sort of magazines, but maybe some of them still internet-published at least. If so, the adverts may provide some clues for after-market sources for those parts. Front axle vendors etc. If you know the manufacturer for the front axle (possibly DANA), that’s another potential source.

If you are simply looking for a diagram of the parts and how they are arranged, aftermarket repair manuals for your truck should have that info, Haynes, Chiltons. May require a visit to your local public library. And you can probably find a copy of Ford’s Shop Manual for your truck in CD-ROM (pdf) format for a reasonable price somewhere on the internet.

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Not yet. The nearest one is considerably farther away than any number of auto parts stores, so not my first choice. This is the first time I haven’t been able to find the parts I’m looking for online so I was thinking that maybe I was calling them the wrong thing. But the dealer is on the list if necessary.

A “thrust washer” is any washer located between something that rotates and something that doesn’t. Which is what most washers do. I think those particular washers make it easier for the cam to turn and push the 4WD actuator in and out against a spring force, to engage or disengage the front wheel from the axle. A truck-parts catalog could easily refer to that part as just a “washer” or possibly b/c they are plastic, a “friction reduction washer”.

Thrust Washers - What is a thrust washer? AMG.