MTFCA Forum

Wanted to see if the brain trust can give potential confirmation or guidance as to a drive train issue.

I was driving the 13T to a car show and made slow right hand turn at an intersection. As I accelerated in low gear through the turn, I heard a bang which sounded like it came from underneath me. I lost low gear. I quickly discovered I also didn’t have the service brake or high gear. The engine continued to idle along happily as if nothing had happened. As far as safety, all was well as I was going fairly slow and I have accessory brakes. I called a wrecker and had the 13T towed home. Once home, I opened the inspection cover and all the bands and drums appeared in good condition.

Like many of you, I’ve spent countless hours reading this forum. One common problem with the drivetrain is when babbitt thrust washers break. I know my grandpa toured extensively in the 13T but he and I never discussed if he had changed over to bronze thrust washers. I’ve read previous threads that suggested a potential way to diagnose this particular drivetrain issue was to jack up the rear axle and check the lateral movement of the wheels.

I decided to give that a try. I jacked up the driver’s side rear axle and the wheel had barely any lateral movement or wiggle to it. I switched to jacking up the passenger side rear axle and found the wheel would easily move in and out with approximately a 1/4” of lateral travel. I followed up with an endoscope in the differential but didn’t see any obvious signs of damage.

Does this sound like a classic babbitt thrust washer issue? Would that issue have an asymmetric result like I have or is it symmetric and both sides would have lateral movement? Are there more things I can do to verify it is a broken thrust washer or if it isn’t something else, driveshaft etc?

I’ve purchased a MTFCA front and rear axle repair and restoration manual and have the Model T service manual; however, curious if y’all had any thoughts before I take any additional steps.

Thank you for your time,
Darin

Not the best pics but the lateral movement best demonstrated as the amount of visible rear drum exposed between the rear brake lining and the wheel/hub spokes.

Darin

Sheared pinion key

you very likely had the excessive passenger side movement before this and that is another issue entirely. A broken babbit washer will result in the ENTIRE differential assembly moving and the passenger and driver side wheel cannot help but move in this case. This is not the case. Lose the passenger side babbit and pinion/ring gear mesh hard and growl. Lose the driver's (left) side babbit washer and ring gear moves away from pinion with grinding, skipping/gnashing/drama. No grinding, no skipping, no noise, no drama...just "bang" and everything is gone. That's a pinion issue, and it's a relatively easy fix. Relatively.

I am not suggesting, relating, or opining about anything else; what to do, when to do it, why to do it... I am just stating what the very strong likelihood of your specific on the road failure is.

What happens if a axle key shears?

Scott,

This is why I asked on this forum… such great corporate knowledge. I’ll start looking up that issue on previous threads.

Thank you,
Darin

I am with Scott, from your description most likely one of three things. 1) A split pinion gear, 2) a sheared pinion key, 3) a sheared drive shaft or broken key way. Remove the rear end from the car. If $$ funds are tight and you are running stock 3.63 gears and the problem is the pinion or pinion key you may be able to replace pinion and/or key. The other option is to due a rear axel and driveshaft rebuild in which case you will use new brass / bronze thrust washers.

Darin, First, I would take the hub cap off the passenger wheel, lift it off the ground and see if the wheel is loose on the axle shaft. When you were originally checking for lateral movement, did you have both wheels off the ground at the same time? I believe that would be the only way to tell if a thrust washer was bad. Because both axle shafts and the differential will move as one assembly in the housing.
Good luck,
Bill

Regardless of whatever the damage is, the rear axle assembly will have to be pulled and stripped to make a fix. The prior diagnosis becomes irrelevant at this point. I'd be into it out of curiosity. Then we'd like to know what you found.

Allan from down under.

Really the only thing that would cause the symptoms you describe is a failure somewhere in the rear axle. Regardless of what failed you're going to have to pull out the rear axle assembly and fix whatever is wrong in there.

Stephen

Regardless, at this point you are looking at going through the rear end and at the minimum at least inspecting for serious issues and finding and fixing whatever it was that broke.
There is a fair chance that it being a 1913, it might have had bronze thrust washers originally. They were used on some cars during those late brass era years. It is also possible that your grandfather or someone else might have replaced the original washers (whatever they were?) at some point. Thrust washer failures may not have been common during the model T days, but they weren't rare either. Original parts catalogs and service information show such failures and replacements often. Bronze washers were offered for sale throughout the late 1910s, 1920s, and beyond. Even so, a lot of failed washers or routine repairs put Babbitt washers in instead (hey, they were good enough most of the time?).

During the 1950s, and 1960s, hobbyists pretty much accepted the Babbitt thrust washers as being okay. When I started working on my first model T (about 1970), hobbyists were still debating whether they needed to be change or not if they still looked decent. I was fortunate, and chose my mentors well. They advised me to replace them with the bronze ones that were then available, and gave some good reasons. As I was working my way into engineering and the sciences, it didn't take me long to know they were right! Yet the debates over changing them or not continued for a couple more decades.

In the 1960s, the original Babbitt washers were only around forty years old. Their biggest weakness is the unknown amount of grease contamination and physical abuse any given washer has been subjected to. The poor quality Babbitt is very vulnerable to any amount of water/condensation that gets inside and creates a mild acid in the grease. That mild acid WILL degrade the molecular cohesion of the Babbitt. Now, those same washers are nearing a hundred years of age! Sixty more years of unknown degradation.
As I said earlier, I decided very quickly that my chosen mentors were correct. The ultimate proof to me was that on my first model T, I went through the rear end. One of the Babbitt washers in it was far and away the finest most beautiful original era Babbitt washer I have ever seen, before or since. But I took their advice, and replaced it anyway. When that project was done, I was picking up my tools, junk and extra parts and putting them away. I had a work area set up in my parent's back yard. As I walked back to the garage carrying that really nice Babbitt washer fully intending to hang it on a nail on the garage wall, I stumbled on a gopher hole. Just a mild stumble, but I clenched my fingers slightly, and that beautiful and shiny Babbitt washer instantly broke into three pieces!
So, no. I don't want to ever use a Babbitt thrust washer in there, no matter how good it looks.

Darin H.
I had the same problem with a good Friends Car last month .
See pictures . Toon

For the next Hunderd year !!! Toon

I have brass thrust washers in all of my cars. However, I have to tell you. Several years ago I purchased a 1913 runabout with the original rear end in it. When I tore the rear end down to remove the 3-1 high speed gearing, I discovered it had the original babbit thrust washers on both sides in perfect condition. I'm not sticking up for babbit thrust washers, only commenting on what I found. The car now has standard gearing and brass thrust washers!

Original Smith wrote: ↑

Sun Apr 03, 2022 10:57 am

Several years ago I purchased a 1913 runabout with the original rear end in it. When I tore the rear end down to remove the 3-1 high speed gearing, I discovered it had the original babbit thrust washers on both sides in perfect condition.

They wouldn’t have been the “original” thrust washers. Likely much more recent. ‘13 had bronze thrust washers!

Yep, the rear end needs to come off, be torn down and inspected. I was surprised nobody suggested a failure of the universal joint. Couldn't that explain the problem?

The right side in & out movement is quite telling. The differential with the ring gear attached cant move out that much. That would be an over mesh of the gears. Cant happen unless the DS bearing is gone, in which case, there would have been a ratcheting noise in the gears.
The right axle is stopped from inward travel from the center fiber washer .062" The axle is stopped from outward travel by the 2, 1/2 round keys about .090" thick. For the axle to move outward, those keys would have had to both fallen out & the axle to gear fit dead loose.
The last possibility is a broken axle right side.
I suspect, by trying a little harder & rotating the wheel, it could be pulled out further than the 1/4" currently. At that time note any degree or lack of friction in any internal parts when pushed in & pulled out. The only thing to prevent the wheel/axle from coming completely out is the point where the axle diameter increases from its bearing size of 1.062 to the raw shaft size of around 1 1/8" & encounters the bearing or internal seal.
The axle assembly does need to come out for a complete rebuild.

Do let us know the outcome, with pictures if possible of the specific failure.

Oldav8tor wrote: ↑

Sun Apr 03, 2022 1:43 pm

Yep, the rear end needs to come off, be torn down and inspected. I was surprised nobody suggested a failure of the universal joint. Couldn't that explain the problem?

Tim,

A broken u-joint usually doesn't result in a total "disconnect" of the driveline. Just loads of backlash and a horrendous noise. Not to say it's impossible however...

The club publishes two booklets covering this situation. Front and Rear Axles, and Ruckstell Axle. Depending on whether or not you have a Ruckstell in your car, you should purchase the book pertaining to your rear axle. It is not hard to remove from the car and to disassemble. Then go through the whole thing and replace any worn parts and assemble with the clearances described in the book and it should run like a top. You are fortunate it didn't cause you to have an accident.
You can do the work with common tools. If the axle gears need to be removed it will take a large hydrolic press and the pinion gear will take a puller. A good machine shop can help you or if you are a member of a local club, the members should be willing to help you or to suggest someone reputable who can help.
Norm

"A broken u-joint usually doesn't result in a total "disconnect" of the driveline. Just loads of backlash and a horrendous noise. Not to say it's impossible however..."

Thanks Jerry....I've always thought the u-joint and it's means of lubrication was a weak link. Keeping the ball full of grease is one of my priorities. Your description of a failure is about what I'd expect and you're correct in that it's unusual to hear of a failure. I can't remember reading about a single one.

Over packing, filling the U-joint is not a good thing Tim. Half full or less is better. Why? The rear end when hot must vent like the engine, excessive grease prevents this, thus causing pressure to vent blowing out the outside wheel seals into the brakes. Keep the driveshaft lubed well but do not over do the u-joint.

Hank

I have reservations on whether the venting of the diff could over compress the air space in the drive tube.

Thank you for the replies. No Ruckstell axle, normal differential.

Darin

I've had leak issues with modern axles with a plugged vent. Clearing the vent solved the issues.

Hmmm.... I just saw Hank's post about not overfilling the universal joint. I'm still new to the hobby but everything I've ever read says to pack a lot of grease in the ball, which is what I've done. The seal isn't perfect so it does leak out over time.

I just spent a little time looking thru some of the original Ford publications which wasn't very helpful.... Statements like "pack the ball full of grease" are part of what guided my approach to lubrication. I also did a search of the forum and found most commenters saying to use lots of grease in the ball.

I have floating rear hubs so I'm not worrying about forcing grease out of the hubs but don't want to cause problems elsewhere. I've seen no evidence of grease getting into the differential. Anyone care to share their opinions or experiences?