MTFCA Forum

Hi all,
I have a question regarding my somewhat damaged keyway in the rear axle. Does anybody think it's a BAD idea to JB Weld the key into the keyway? Is there any reason that the key should be removable for the duration of its life? Thanks.
John

Worth a try, but it probably won't hold.

You can buy oversize key stock.....

https://www.grainger.com/category/faste ... tAQAvD_BwE

How is it damaged and how bad is the damage? If the slot is a little wide, I do one of two things; use the stepped key stock and fit or work the edges down till the stock key fits. If there are chunks missing all bets are off and axle should be replaced because good chance there is/are crack(s).

Would have to be a stepped key or the wheel hub wont fit. Depends how bad the wear in the axle is. If not too bad - use a .2500 key & center punch both sides where it fits into axle for a tighter fit.
Taper is supposed to hold the wheel. if taper is rough, lap it with valve grinding compound untill the wheel "sticks". Dont use shims. tighten axle nut real tight 80-100 lbs.
Recheck axle nut torque after a hundred miles or so.

JB welded on did not work...welded one did not work...found used axle it worked

Loktite make a product called Quickmetal for such purposes. It is used to restore the fit of worn gears/pulleys/ bearings on all sorts of shafts. I had never heard of it until a farmer put me onto it. Apply it to the key and keys at,with a smear around the axle, and it will dip any voids and make the assembly right.
I have used it, at a customer"s behest, for just this same problem. It worked a treat and saved a pull down until required.
You need hear to break the bond for removal, but not enough to even blister the paint.
Allan from down under.

NY John T wrote: ↑

Thu Mar 18, 2021 2:52 pm

Hi all,
I have a question regarding my somewhat damaged keyway in the rear axle. Does anybody think it's a BAD idea to JB Weld the key into the keyway? Is there any reason that the key should be removable for the duration of its life? Thanks.
John

It's a really bad idea. And it's probably a dangerous one too. Get a new, or better, axle. Don't screw around with your safety and that of others.

I agree with Jerry, 110%. JB weld or any epoxy is just a plastic bandaid and a very poor one, but especially , PLEASE don’t use it anywhere your life depends on it. IMHO , that’s anywhere on an auto.
I’ve bought way too many things over the years that have been “fixed” with JB weld

JB Weld has its place but not where, as here, you have side thrust. No way will it hold up to the rotational forces bearing the key.

I can't help but wonder what the rest of the axle looks like. My tapered ends and keyways looked great but the axle had spots where the hyatt bearings had scored the axle. I ended up replacing both and going with floating hubs....not cheap but safety is paramount.

Richard, please tell me where it’s Ok to use, for other than a cosmetic, temporary “fix”. I will challenge anybody that thinks it’s some kind of miracle substance to scrape it or slide a knife blade under it. It’ll pop right off. Smack it with a hammer, it’ll break right off. Buy a couple of cars with it covering up freeze cracks and you might feel like I do about it. Buy a car where epoxy resin was poured into the wood structure to “restore” it. You will feel the same way I do about it. There is nothing Steel in products that say instant steel. There is no Weld in JB Weld. It’s plastic.
As for its use in Australia, jimmy cracked corn. I Don’t plan on being there motoring any time soon. Have you ever touched the hub after a vehicle is driven? I’d say that’s hot enough to release any bond , and not raise the paint.

Looks like everyone asking you to include a picture of the keyway to get the best solution. Lots easier than explaining the damage.

If the keyway is damaged, the axle shaft needs to be replaced.

Stephen

Hi Tim. To answer your question, I've used JB Weld with success on ds bushings, kingpin bushings and 3rd cam bushings. In short I use it as a glue to hold bushings with undercut ods so I can align them. I've also used it to fill veed out cracks in engine blocks and water pumps with and without window screen. Also to fill cheese holes in fenders and pans. Probably more I can't think of.

Right on answer, Stephen. Richard, I’d say you and I have vastly different definitions of “success “. IMHO , respectfully,as always. I’m not close to being an engineer, but from my humble experience, the original model T axle , in excellent condition, is barely enough to handle the stresses involved. Add to that, 100+ years of age, damage to the key way, rust pits, wear on the mating axle hub, higher speeds used today, hard braking , axle damage from bearing or bearing cage wear, grooves from old leather oil seals, and you have a disaster waiting to happen to recommend anything other than a correct replacement. We are so lucky to have new axles available, at less money than you could even buy a small stick of the right metal, not to mention the correct machining of said stick of metal.
If you’ve followed this forum for any length of time, you know nothing gets my hackles up more than a recommended plastic epoxy repair of an antique auto. Nothing! Of course it works for the fellow that does it, because if he/she dies in a crash we will never know of the failure. My concern is for the poor person who will someday be the new caretaker of the auto, and have no idea of a hack “repair” until it’s maybe too late.
So, just know next time you smear a gob of this on a split radiator seem, to build up a bushing, to fix a key way, or cracked part, there will be a day when someone has the fix it correctly, and it takes more time to do so than fixing it correctly in the first place. I guess , Buyer Beware is what you need to remember, rant over, time for a shot and a beer!

Just wanted to say "Thank you" to all those who made suggestions. Here is a photo of the axle end and keyway. When I took off the wheel, it was very loose and the key fell out. I put in a new inner seal and replaced the wheel bearing and sleeve and noticed that the upper edges of the keyway were raised.
So I used a hammer and metal shaping dolly and dressed down the raised edges. This made the new key fit better, though not a snug fit. So the next thing I'll do is try Locktite quick metal and epoxy in the key. Anybody have any concerns with this. By the way, the axle housing dust cap didn't fit very well; and I had to really hammer it in, which distorted it a bit. Anybody have any similar issues with these dust caps??
Thanks,
John

The key way is the least of your problems. The threads are shot, too. Those nuts are supposed to take 100ft lbs. Back before torque wrenches, that was tighten until just before they break. If you decide to fix it as you mentioned , make sure your insurance is paid up. In case you need more bad news, from the looks of the axle your hub is probably shot from being pounded by a loose axle. Again, JMHO

Yes, outer seal cup must be press fit. I use an old transmission drum shaft & a 3lb brass hammer.

It's also best to find a place for that thin/large washer INSIDE the dust cap.

this thread has become such a rolling disaster, I'm looking to see if April 1 hasn't come early.

Your axle is no good. Your patch will not work. In good conscience I wouldn’t recommend anything but replacement. I hope no one gets hurt when it fails.

Andy

One of my friends, Joe Andulics, made me this copy of the rear axle nut wrench, used back in the day by ford mechanics to tighten that nut. That was their “torque” setting. I’ll bet most those skinny guys back then stood on it. It’s 26”long! If the nut or axle failed, they would get another $5 job out of you to replace it.

I have an original Ford Z tool for that nut - I'll get a photo tomorrow !

Yes, Joe did too. He converted it into a lot of lettuce, and water jet cut a couple of users.

Hi all again,
I do have another rear end which has axles that look a lot better. Been sitting outside for awhile but I checked a new key in each axle keyway and they are somewhat tight. My only hesitation previously in using it is, I'd have to break down the whole thing and I'm new to this and never taken apart a rear end. Add that to the fact that I'm in the process of moving out of my house and have limited time. It's becoming a truck filled with cans of worms. I do love the T though.
John

NY John: As others have said, you definitely need to replace that axle, just make sure everything else inside the differential/drive train is in good shape and safe. The condition of the axle suggests the rest of the differential may be well-worn too. And if the axle thrust washers are babbitt, make sure you replace them with modern brass ones.

Tearing down a differential is not difficult, tho it may be a little messy. Putting one back together with proper gear mesh, bearing and thrust clearance is not difficult either, but it will take time to do it right. In addition to the guidance and suggestions you find on the forum, make sure you obtain a copy of the MTFCA 'Front and Rear Axle' repair handbook. Good luck with your project, hope you are on the road again real soon. jb

The tapered axle/key/hub assembly is much like the connecting rod to crankshaft fit in that while it is a fairly simple construction, all the parts must be in good condition and they must be correctly fitted to one another and properly torqued or it will not hold up.

Yes your keyway looks bad, It wouldn't hurt anything to jb weld it, Or you could loc tite it! I have run such things. Your threads look good, the reason as stated, your key way is bad was it was run loose. The hub will also be worn. Axle shims and a specially built key will take up the slop. Most important is to tighten it!!!!! Drive it and re tighten it until it stays tight. Good luck.

JB Weld has it's place, but it's not good at resisting torque.

When I a poor high school teacher, I JB Welded a fuel line fitting to a hogged out carburetor inlet on Plymouth Valiant. The thing held for 3 years and was still fine when the car was run over by a front-end loader (while I was in the car).

Lab Metal.
Just use their solvent, and make sure the surface is clean. After it sets, you can grind, file, drill, mill, or machine it any way you desire.
Works great for key ways, hollowed out holes, etc.

Ditto what Tim said.

That axle shaft is junk. Your brakes rely on the fit between the axle shafts and wheel hubs. A failure here means no brakes and possibly losing a wheel. Any repair short of replacing the axle shaft is an accident waiting to happen.

Stephen

Stephen_heatherly wrote: ↑

Tue Mar 23, 2021 2:29 pm

That axle shaft is junk. Your brakes rely on the fit between the axle shafts and wheel hubs. A failure here means no brakes and possibly losing a wheel. Any repair short of replacing the axle shaft is an accident waiting to happen.

Stephen

Agree 100%!!!

There is no magic fairy dust that will make that shaft anything other than dangerous. No glues, pastes, putties, epoxies, shims or center punching of any kind, will adequately replace or repair the streteched and fatigued metal that's still there.

As Tim states, I'm also done here, as I can't state it any more clearly that the axle shown here is junk.

John, the photo is most helpful. Had it come earlier, I would not have suggested Quick Metal as a fix. The damage is down to the wheel being loose on the taper, so the keyway, key and hub will all be worn.

When everything is in order, the key does nothing. The axle is held on the taper and it is this taper which transmits the driving/braking forces, just as it does on taper drills/chucks on a lathe tailstock. The key is there as an insurance policy in case things get loose. The hub should not exert any force on the key, either in braking or under driving. If the taper on the axle and that in the hub are in correct fit, that will be the case. This all depends on the axle nut maintaining that tight fit.

Various products, Quickmetal included, are quite satisfactory in ensuring a correct fit, but they are not meant to be a repair medium for flogged out parts.

Allan from down under.