Steering knuckle rebuild

[mikeM43]

Hello,

Im in the process of replacing my wheel cylinders and flexible brake hoses. Since I already took the drums and brake shoes off I thought about going further with this and stripping down the entire steering knuckles and hubs and replacing the seals and bearings. I can see that gear oil is getting into the knuckle and as far as I know it shouldnt sip past the seal like that, correct? I have bought a set of hub seals but I also realized that there is an additional seal and bearing inside the axle tube. Is this the culprit here? I want to be ready and have the parts on hand once I start digging into it. I only have time to work on the truck once in a while. How hard is it to pull out the seal? Do I need to replace the bearing as well? I would very much appreciate any advise on this. See below pictures of the knuckle, its caked with grease and oil and dirt. I will try o clean it once its disassembled.

mike

[NAM VET]

I can't give you any help with our "knuckle" rebuild, but in doing my own truck's refurbishment I pressure washed the grimy and greasy parts first, so I could see what I had better before diving into any component. Just my own thought. NAM VET

[Elwood]

Hello,

Im in the process of replacing my wheel cylinders and flexible brake hoses. Since I already took the drums and brake shoes off I thought about going further with this and stripping down the entire steering knuckles and hubs and replacing the seals and bearings. I can see that gear oil is getting into the knuckle and as far as I know it shouldnt sip past the seal like that, correct? I have bought a set of hub seals but I also realized that there is an additional seal and bearing inside the axle tube. Is this the culprit here? I want to be ready and have the parts on hand once I start digging into it. I only have time to work on the truck once in a while. How hard is it to pull out the seal? Do I need to replace the bearing as well? I would very much appreciate any advise on this. See below pictures of the knuckle, its caked with grease and oil and dirt. I will try o clean it once its disassembled.

mike

If axle/differential lubricant is getting into the hubs (not unusual) then it's time to change the seals (500057) on the axle drive shafts. As with all seals, use modern, new production seals, not new-old-stock.

Having the parts on hand is a good idea, but that plan also depends on (a) how much wear and/or damage you find upon disassembly, and (b) how much you're willing to replace. I'd assume that the seals and bearings (plain and tapered roller) will need replacement, but you might also discover that the axle shafts are worn beyond the limits where they turn in the bearings, or that the Tracta joints are worn out (before lock out hubs were applied to many of these trucks, the front axles turned all of the time, even if the transfer case wasn't engaged for 4WD).

If you don't already have the three basic military manuals for this work (TM 9-8030 Operation and Organizational Maintenance; TM 9-8031-2 Power Train, Body and Frame; and ORD 9 SNL G-741 List of All Service Parts) I'd strongly suggest you obtain and review the relevant sections prior to starting this work. My experience has been that the printed reproductions are much better than the scanned digital on CD, which (at least the ones I have) either omit information, or reproduce some of the numbers and letters incorrectly.

Lots of good info here on G741 using the search function. You might start with this thread: http://www.g741.org/PHPBB/viewtopic.php ... ild#p65498

[Elwood]

I can't give you any help with our "knuckle" rebuild, but in doing my own truck's refurbishment I pressure washed the grimy and greasy parts first, so I could see what I had better before diving into any component. Just my own thought. NAM VET

Always easier to work on these things once they've been degreased.

But as the knuckle seals are clearly failing, hitting them with a pressure washer will force water into the closed knuckle, so once they're clean on the outside, opening them up should be the next step.

[milstencil]

Go here https://imageevent.com/moosecreekmaple/ ... 51.camel_s
complete instructions plus other goodies.
Rick

[Cal_Gary]

And as far as removal goes, I had to pull the center chunk on mine then drive out the seals and bushings from the opposite side using a 6-foot piece of pipe.
Gary

[mikeM43]

Go here https://imageevent.com/moosecreekmaple/ ... 51.camel_s
complete instructions plus other goodies.
Rick

Rick, that is a wonderful tutorial. Thank you for the link. Although it is missing the part on axle seel and bushing removal. Is it possible to remove those parts without removing the differential and reaching from behind like Gary said? Sadly I dont have any specialized tools/pullers...

Thank you Gentlemen for all the answers. Looks like I have a whole lot of additional parts to order. Im in Poland so the shipping takes a while and like I said before I can only work on the truck during some weekends so I need all the parts before I start disassembly.

Are these the seal and bushing that I need?

https://store.midwestmilitary.com/product-p/924432.htm

https://store.midwestmilitary.com/product-p/924249.htm

[milstencil]

Here's a parts list from the Memphis catalog

I used an inexpensive slide hammer set to remove the bearing and seal

I trimmed down a 2x4 to drive the seal and bearing back in. You can also use a socket from
your tool box.
If the parts list is not large enough, email me at rick@militarystencils.com and I will send a jpeg
that you can enlarge.
Rick

[ashyers]

Rebuilding the knuckles is not too tough, just greasy!!!!

The puller I use to do them looks like:

puller.JPG (10.96 KiB) Viewed 3221 times

Put that sucker on a large slide hammer and have at it. As far as install a large socket and extension work our you can fab up a bearing driver.

Andy

[mikeM43]

Thanks guys! You are very helpful! I will give it a try with a slide hammer and this puller if I can find it online somewhere.
Another thing that I was wondering about are the shims. What is the purpose of those? Do I need to replace them or can I re use the old ones?

Thanks again!
mike

[ashyers]

Mike,
I assume you're talking about the shims to set the preload on the steering knuckle bearings?

If that's the case when you order your rebuild kit it will come with shims and you'll have the shims that were in the existing assembly. Mix and match to get the correct preload. As far as the steering knuckle bearings you can go for the solid brass ones or with tapered rollers. A search will describe both. I've done both. The rollers steer very nicely, but I've been told they are not as durable. The brass gets better after it gets a few miles on it.

Andy

[Elwood]

Thanks guys! You are very helpful! I will give it a try with a slide hammer and this puller if I can find it online somewhere.
Another thing that I was wondering about are the shims. What is the purpose of those? Do I need to replace them or can I re use the old ones?

Thanks again!
mike

I believe that OTC (Owatonna Tool Co.) makes these pullers in various sizes. You should be able to buy just the puller(s), or the whole kit with slide hammer and plastic case, depending on what you need. They're available online from the usual tool suppliers (Tooltopia, Amazon, etc.)

[PoW]

In all my years of M37's, I've found nary a set of Tracta joints worn out: They just didn't get enough mileage on them with the way the military used the trucks.

Once in awhile, I'll see one cracked, but that is always in a rig that went to a mine or some such hell-hole life. Water leakage will kill wheel bearings.

The bushings are usually OK, and the internal seals will be guaranteed bad. Make sure the surface on the axle is smooth, or it will ruin your new seals pronto.

Don't overthink things, I put over 250K mi on a set of used front axle shafts (lots of off-road miles) with no problems.

Cleanliness is important, so is the right lube: use one that won't eat brass/bronze everywhere in the truck.

PoW

[mikeM43]

Hello everyone,

Its been a while since my last post but I didnt have time to work on the truck too much. Can you please tell me which side of the seal goes into the axle tube? I have bought a set on ebay and Im having a hard time trying to figure it out. Also when installing the seal and the bronze bushing do I tap them in separately or both together? Can I use a piece of pipe or a wrench socket to seat them in place? Thanks!
mike

[Elwood]

The spring side goes towards the liquid or grease that you want to retain. If the seal is used against a liquid, I usually apply a thin layer of some sort of sealer to the outside diameter of the metal seal body before installation. I apply a sealer even for grease, but it's usually not as critical.

Install the bushing, then the seal. If you try to drive the bushing in with the seal, you will probably damage the seal body.

As for a driver, I like to use something softer, such as a bearing race driver or a piece of PVC pipe of the correct outside diameter (cut square on the end!), but sometimes a socket is the only thing handy. Best to use a something with an OD close to the ID of the bore.