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Ethan

Spicer 25 Worn Out Steering Knuckles and Axle Housing Ball Ends

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I am rebuilding the axles in my 1951 CJ-3A. I decided to do the front first. It is very worn and during disassembly the knuckle bearing cups just pull out. New cups are not a tight press fit. They push in pretty easily. Is it time for a replacement housing?

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Ethan, this is not uncommon if the axle is old and has seen pounding, usually exaggerated by loose knuckle bearing preloads.  Worn bearings also loosen the preloads.

 

If the bearing cups fit properly but simply rotate from lack of an interference fit, there are a couple of possible solutions:  1) the use of Loctite 640 Bearing Retainer or a similarly recommended Loctite product for bearings and collars, or 2) flash the surface by brazing method then machine or sculpt to size.  (I'd likely turn to Weld Mold Company's 26C high tensile brazing rod for this kind of shock load.)

 

Note: TIG welding the iron casting, though feasible, brings challenges and would likely be overkill for this situation. 26C is around 100,000 tensile, way in excess of the iron casting's tensile.  26C is an extraordinary material for the brazing process.

 

It comes down to the extent of wear at these bearing bores in the axle housing and cost effective fixes.  If there is a concentric bore with just very slight wear (enough to allow the bearing cup spin but not enough for wobble), then bearing retainer compound might do the trick.  The compound is only 3,100 tensile, though, and this is not a lot for the application at hand.  Personally, I would opt for restoring/reducing the bore size by hard brazing method then refinish or machine the bore(s).

 

If the problem were the knuckle(s) and not the spherical ends of the axle housing, replacement 1941-71 new knuckle castings are available for the left and right side from Omix-ADA and others:   http://www.omix-ada.com/rh-steering-knuckle-41-71-willys-jeep-models.html and http://www.omix-ada.com/lh-steering-knuckle-41-71-willys-jeep-models.html.  Bearing caps are also available. 

 

The axle housing spherical (ball) end bearing cup wear does require either a quality repair or another axle housing.  If you consider used parts, have them magnaflux checked for cracks or flaws.  The spherical ball end is a safety part, and the bearing cup areas must be free of cracks or damage.

 

Moses

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Thank you Moses for the great response to my question. I probably could have been a little clearer in the details. I was referring to the bearing cups pressed into the spherical ends of the axle housing. I am aware of the availability of reproduction knuckles. It is the axle housing I am keen to avoid replacing if possible. As a bicycle mechanic, I am familiar with using Loctite as a repair. I see Loctite retaining compound as a temporay band aid fix unless there is only very slight wear. I like the idea of hard brazing for a long term proper repair. Do you think I can machine the bearing cup seat at home after brazing or should I take it to a machine shop?

This was my first time posting on a forum. I was afraid my question was too elementary for a response. Thanks again for helping a home Jeep mechanic do a better job.

Ethan

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Ethan, I revised my earlier comments to fit with your actual need here.  With proper technique, you could do the brazing with 26C from Weld Mold Company:  http://www.weldmold.com/weld-mold-26-c/.  As a bicycle mechanic, you know brazing technique.  1600-degrees F is well below fusion welding temps, and the tensile of 26-C is 100,000 psi, well beyond gray iron casting material.  This braze filler is in the league of nodular or ductile iron.

 

26-C is hard.  A carbide reamer might restore the bore, though you would need to minimize braze buildup during the brazing process.  Cooling is critical to prevent cracking in a location like these cup flanges.  I would cover the ball end with a Kevlar welding blanket immediately after brazing and let the housing cool completely before any follow-up work.

 

Note: Use of Weld Mold Company's 85-C brazing rod or the spray welding technique are other options that I discuss with JohnF around his Jeep/Buick 225 V-6 block repair.  Check out this exchange, especially our later discussion at:  http://forums.4wdmechanix.com/topic/245-jeep-cj-dauntless-buick-225-v-6-rebuild/.  I describe 85-C and other Weld Mold Company brazing and welding alternatives.  In any choice, the aim is to avoid creating cracks at the spherical ends.  Powder spray welding is popular for repairing iron cylinder head damage at valve seats and hard seat insert bores.  The right powder filler can be machined with conventional valve seat insert cutting tools. 

 

Knurling is another approach for "shrinking" a bore if slightly out of round; however, there is also a reduction in the surface contact area, perhaps acceptable in this application.  Machine shops knurl piston skirts and other surfaces to increase size.  These axle housing spherical ends would be harder material but could be knurled.  You simply want a solid, concentric "surround" for the bearing cups.

 

Some thoughts...Let us know what you wind up doing and how this turns out, Ethan.  I'm available as a sounding board.

 

Moses

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Thanks Moses. I will let you know how it works out. There is my rear axle to do as well. This is my busy season at work so personal fun time is at a premium. Hopefully the axles will be finished before too long.

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Ethan...Here are details on the Weld Mold 85-C filler: http://www.weldmold.com/weld-mold-85-c/.   Weld Mold Company is good about providing instructions for use.  Compare the 26-C with the 85-C when considering this axle ball end repair...Very interested in your approach here, I understand the work involved with changing out the axle housing and your desire to avoid that option.

 

Please take pictures and share them with us.  It will help illuminate the damage and your repair options.  I will comment back.

 

Moses

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Ethan...The traditional "end" of a closed knuckle front axle is when the spherical (ball) end face(s) become so scarred and damaged that the seal will no longer have a smooth surface to ride over.  This occurs from damaged or worn felt seals (first line of defense), trail damage, icy debris stuck to the knuckle or felt seals in frigid climates, or abrasive material scraping endlessly against the ball ends.

 

We didn't discuss the condition of your Spicer 25 front axle's ball end faces.  Are they okay?

 

Moses

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You bring up a good point. One which I have been thinking about. The seal wiping surface is indeed worn but not horribly so. No major gouges but a rough surface nonetheless. I have seen these axles powder coated to restore a smooth wiping surface. It seems to last for quite a while.

The idea of restoring my original axle is exciting and would be very satisfying for me. But at this point I am seriously considering finding a better core to work with. My Jeep is no longer original so a replacement axle would not scar a prime piece of history. Some would say not to mess with a Spicer 25 but swap in a stronger Dana 30 or 44. Options for sure but I think a 25 in good shape should be fine. Do you have any opinions on this Moses? If you are wondering, I have a Buick 231 V6, SM420, saginaw steering, and 32/9.50-15 tires. I am changing to 4.88 gears with the axle rebuild.

Ethan

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Ethan, given that the CJ-3A is tastefully modified with traditional upgrades, it would not be "wrong" to consider a Dana 30 open knuckle front axle.  If you want the option, disc front brakes help, too, providing you mount them all the way around or at least front discs with 11" x 2" drum brakes as a match at the rear.  The 9" x 1-3/4" factory brakes are notoriously light duty, though they do stop the vehicle when the lining is dry.  A common solution in the day was 11" x 2" all the way around.  If drum brakes sound okay, a Dana 30 front axle from a '72-'75 CJ could be a prospect.  Upgrade the rear brake capacity and master cylinder at the same time.

 

Not sure whether you have a copy of my Jeep CJ Rebuilder's Manual: 1946-71.  I did a disc brake changeover at the time with a Warn kit that is no longer available.  It has worked very nicely, an upgrade dual master cylinder made the vehicle even safer for highway use.  Off-road, you can also build a good argument for disc brakes, though your SM420 makes a wonderful compression braking solution with the 5.38 gears. 

 

That brings up the point that a Dana 30 front axle would require a mandatory axle ratio change, as there was no Jeep Dana 30 axle in stock form offered with this ratio.  Not an issue, you can find aftermarket ring and pinion gears and may even want to go taller, like 4.10s or 4.56s, with the 32" tires, Buick 231 V-6 and that remarkable compound 1st gear ratio in the SM420!

 

Post some photos of your classic and sensible Jeep flatfender build!

 

Moses

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