Transmission autopsy: Bad driving?

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Steve Jelf
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Transmission autopsy: Bad driving?

Post by Steve Jelf » Tue Jan 28, 2020 5:30 pm

I always preach aggressive use of the pedals, tromping down and not letting the drums slip. But I'm afraid I may have been guilty of carelessness in that department. Today I cleaned up the broken low drum from my 1923 touring and collected all the little bits I could find.

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Looking closely at the remains, it appears to me that there may have been at least one crack in the web. But the dark color around the outside of the drum suggests heat, which makes me suspect that I may have been careless with the low pedal.

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The look of the break at the far right side makes me suspect there may have been a crack there.

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Whatever the cause, the bad drum totally shredded the lining and broke the band.

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Here's another look at the break which suggests to me that there may have been cracks at that spot.

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These teeth make me think I should look for a better hub.
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Re: Transmission autopsy: Bad driving?

Post by DanTreace » Tue Jan 28, 2020 6:18 pm

Steve

Ah, bad luck there. Have yet to experience busted low drum, but know of several who have.

My guess is old drum, and old crack perhaps. Although treating the low speed engagement with my old T's, have tried to keep in mind the parts turning are 1908 technology, and worn and need respect.


Have always engaged low pedal slowly, but firmly, and then up to speed, 8-10 mph, withdraw the foot and work the levers to gain high speed. To me, heavy hard foot on initial take off from dead start, lots of strain on the trans and rear axle. Easy does it.

There are times to push hard and firm on low, when you are hill climbing and high is stumbling the motor, at that time going to low pedal requires a stomp. The T is moving already, slowly, but now low gear needs to be engaged quickly and firmly to get to the crest.

Described very well by Murray Fahnestock, Oct. 1922.

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Re: Transmission autopsy: Bad driving?

Post by Allan » Tue Jan 28, 2020 6:25 pm

Steve, and old crack will show signs of the interfaces being somewhat polished, as the two sides 'work' on one another. When the calamity comes, the break lines will be clean and sharp. This may give you an idea of what happened in what order.
I agree that gear is worn too much for re-use.

Allan from down under.

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Re: Transmission autopsy: Bad driving?

Post by RajoRacer » Tue Jan 28, 2020 7:46 pm

By the looks of the discoloration towards the outside edge of the drum - looks as though there was "a whole lot a draggin' going on" ! That only comes from heat !

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Re: Transmission autopsy: Bad driving?

Post by DanTreace » Tue Jan 28, 2020 8:00 pm

Steve

Any insight for us on how this happened? Pulling a hill?

One of the exploded low drums have viewed in the past, was due to hard stomp acceleration.

Launching on the sand for fast start at Ormond Beach, FL antique car speed trials. Owner said he took forever to clean out Kevlar shreds everywhere in the motor. The engine was hopped-up too. ;)


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Re: Transmission autopsy: Bad driving?

Post by Les Schubert » Tue Jan 28, 2020 8:12 pm

Looks like Kevlar band lining.
I ONLY use Kevlar for the brake lining.
For reverse and low I use cotton or wood only


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Re: Transmission autopsy: Bad driving?

Post by Jack Putnam, in Ohio » Tue Jan 28, 2020 8:21 pm

As Steve said the outer blue discoloration is indicative of a lot of dragging. Your low band has been too tight or slipped aggressively causing excessive heat which has caused the drum to crack and come apart. The heat came first then the drum was rendered asunder.


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Re: Transmission autopsy: Bad driving?

Post by old_charley » Tue Jan 28, 2020 8:22 pm

Steve, Sorry to see of your disaster. That definitely looks to me like heat caused the discoloration around your drum and that also looks like Kevlar lining material. I think the Kevlar is the real source of your problem. Perhaps your low pedal technique as well but it doesn't sound like it from your description. Kevlar is great from the standpoint that it doesn't wear out but it's terrible from the standpoint that it doesn't wear out. I would bet that your low band was dragging from either being set a bit too tight or from the band being distorted out of round when installed. Cotton linings will wear down if incorrectly adjusted. Kevlar won't.
Personally, I would never install Kevlar through the transmission inspection door. There is too much of a chance that the band could become distorted out of round and you'd never know it. Also, the Kevlar lined bands should be adjusted, once they are "broken/worn in", as loosely as possible and still be able to tighten on the drum. That way you'll minimize the possibility of dragging.
The "weak link" in the transmission needs to be the band linings, not the drums!! It's much easier to change linings.


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Re: Transmission autopsy: Bad driving?

Post by Norman Kling » Tue Jan 28, 2020 9:43 pm

After two broken low drums on the same T, I looked farther into the cause. I was and still do use Kevlar lining, but this is what I found. The low cam and low notch were very worn. The problem was that I could only get one inch above the floorboard by tightening the band so tight it would drag all the time the engine was running. Only time it would not drag was when in low when the band was locked. With a bit of experimentation, I found that the only way I could get it adjusted to run freely in neutral, reverse, or high was by adjusting it so the pedal would lock the drum lower than the floorboard. I replaced the shaft, notch, and cam. Now I get the proper adjustment and have not broken a drum since.

I would not think there are enough hills in Kansas to cause a problem with slipping band. But if the band is too tight, it will drag all the time.

When things are adjusted correctly, you should be able to put the parking brake lever in neutral on a level surface and crank the engine without moving the car. And you should also be able to push the car without turning over the engine. If it is too tight, the car will move in neutral. Note, in cold weather, the drag could be caused by stiff oil in the high speed clutch. But with the engine warmed up, you should be able to push the car in neutral without the engine turning over.
Norm

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Re: Transmission autopsy: Bad driving?

Post by havnfun » Tue Jan 28, 2020 11:49 pm

Steve,

Sorry about your misfortune, this thread has some very good to excellent responses.
Thanks for posting pictures and information on your dilemma, hopefully this will help others learn and understand the inner working better. I know I have learned a few things from the comments, so thanks everyone for your contributions.

Best of luck with your repairs and many more miles of safe travels ahead of you.
Regards,
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Re: Transmission autopsy: Bad driving?

Post by Dan McEachern » Wed Jan 29, 2020 12:56 am

One thing no one has mentioned is the excessive wear on the low drum gear teeth. What caused that?? My 1st guess is the triple gears were not timed correctly, but. . . . . .


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Re: Transmission autopsy: Bad driving?

Post by J and M Machine » Wed Jan 29, 2020 9:30 am

To all concerned. Since majority of engine parts are reaching the 100 year old mark. Notwithstanding I would recommend any part in an engine to be "Magnafluxed" Crack inspected. As Mr.Jelf found out the hard way that, I would recommend it for any and all moving parts in a engine.

That's why we ended up making new ones and gears as there were so few good cores in our area.
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Re: Transmission autopsy: Bad driving?

Post by Dan B » Wed Jan 29, 2020 9:53 am

Ok I’ll ask what everyone wants to know.

What kind of band linings are going back in your fixed up transmission?
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Re: Transmission autopsy: Bad driving?

Post by Steve Jelf » Wed Jan 29, 2020 10:56 am

What kind of band linings are going back in your fixed up transmission?

Believe it or not, I'm leaning toward Kevlar. The reason is that I think it was the drum that destroyed the lining, not vice versa. I was misled by this being a recent transmission rebuild. I assumed that having to adjust the low pedal was the normal breaking in that comes with new linings. But thinking back on it, I realize that it took too many adjustments. The pedal kept going lower as the lining was eaten by the bad drum. I believe this idea is backed up by the brake and reverse drums and linings being perfectly OK. The brake sees a lot more use than the low gear, so if the lining was the cause I would expect to find evidence of it on the brake.


John's comments and pictures show why I intend to bite the financial bullet and replace this broken drum with a new one.
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Re: Transmission autopsy: Bad driving?

Post by RustyFords » Wed Jan 29, 2020 11:03 am

This topic causes me to lose sleep at night. Ok...I'm exagerating, but I do worry about hurting my old Ford because I am running Kevlar bands. My fears are somewhat allayed by the fact that Ross Lilleker inspected and turned my brake drums when he refreshed my engine last year.

My oafish, rookie driving technique didn't do the drums any favors during the first few weeks that the car was returned to the road. But, I'm pretty smooth with things now and have since tried to carefully use all the proper techniques described above.
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Re: Transmission autopsy: Bad driving?

Post by old_charley » Wed Jan 29, 2020 12:40 pm

Steve,
Given your description, you're most likely correct that the low drum developed a crack across the face and that's what chewed up the band lining. Given the heat discoloration, please do consider the likelihood that a dragging band and the resulting heat is what caused the drum to crack in the first place. I've seen it several times before.
I'm sure you know the correct way to install linings on the bands. You may already know the following as well. If you decide to use Kevlar again, do be certain to form the lined bands around an old drum to make sure they are round, round, round! Install them around the drums and wire or clamp them in place before you install the pan. That will eliminate any possibility of distorting the bands. Plus, it's just easier that way.
Properly installed and adjusted, and with minimal slippage while engaging, Kevlar should be just fine.

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Re: Transmission autopsy: Bad driving?

Post by Steve Jelf » Wed Jan 29, 2020 3:20 pm

It just gets better and better. :(

IMG_4683 copy.JPG
The seized bushing and untethered triple gear aren't the end of it. I also found this: https://www.youtube.com/watch?v=oNnh0acvDlY.

This is new territory for me. Is the flywheel toast, or can it be fixed?
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Re: Transmission autopsy: Bad driving?

Post by Norman Kling » Wed Jan 29, 2020 4:13 pm

That indicates the bushing was too tight on the shaft. Better too loose than too tight. That also explains why the gear teeth on the low drum were worn. Looks like you need a complete transmission rebuild.
Norm


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Re: Transmission autopsy: Bad driving?

Post by Allan » Wed Jan 29, 2020 4:50 pm

Steve, the seized bushing can be removed by grinding out the side to relax it off the pin. My concern is the pin which is protruding from the other gear. This may indicate that the pin has moved in the flywheel, in which case I would indeed replace that flywheel.

Hope this helps,
Allan from down under.

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Re: Transmission autopsy: Bad driving?

Post by CudaMan » Wed Jan 29, 2020 5:47 pm

Maybe it's my bad eyes, but it looks to me in Steve's video that the pin is loose in the flywheel and is moving with the triple gear when Steve wiggles it. :?
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Re: Transmission autopsy: Bad driving?

Post by dykker5502 » Wed Jan 29, 2020 6:16 pm

CudaMan wrote:
Wed Jan 29, 2020 5:47 pm
Maybe it's my bad eyes, but it looks to me in Steve's video that the pin is loose in the flywheel and is moving with the triple gear when Steve wiggles it. :?
That is exactly the issue! The pin is loose in the flywheel.
@Steve, it looks like a new flywheel! It may retire for use in a HCCT though.
(You may swap one from a HCCT if you have one)
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Re: Transmission autopsy: Bad driving?

Post by J and M Machine » Wed Jan 29, 2020 6:52 pm

Mr.Jelf the flywheel is toast.
It's not uncommon to see bushings fused to the pins but another to see the pin moving!
I stated earlier that all parts should be crack checked and flywheel is one of those parts.

There is one triple gear pin hole that lines up with two other holes on the flywheel and this is where they crack.
While you have it all apart I would also check magnets to see if they're broken by hitting them against edge of table, don't be surprised if some break.

It's not rocket science to rebuild the flywheel you just need some tools to do so.

You need to remember to push the pins out the right way towards the magnets, not the other way.
Other thing you'll need to check is the pin hole size and size of triple gear pins as there are some oversize ones floating around out there on parts shelves. If you don't you'll crack the flywheel. I believe Bob's has the correct bushings and pins unless you want use Dan Mceachern's needle bearings and pins.


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Re: Transmission autopsy: Bad driving?

Post by otrcman » Wed Jan 29, 2020 7:20 pm

In his original post for this thread, Steve questions his pedal operating technique. Having read the many transmission failure posts over the past 15 years, it seems to me that today's drivers, Steve included, are being plenty careful. If you think about how drivers back in the day must have treated their cars, we would call them downright "abusive" today. Think about all the people who had never operated a piece of machinery, and then learned by a single demonstration by a salesman, or by an untrained acquaintance. And think about all the "bull in a china shop" people who were just going to do it their own way regardless of any instruction. And think of all the people who used Fords for really rough duty, driving in muddy fields, pulling stumps, climbing steep inclines, etc.

If Ford transmissions failed as often then as they seem to today, how many overhauls did it take to wear the letters off the pedals ? And how did the Model T develop such a sterling reputation for durability ?

This all suggests to me that a large part of our problem today is trying to use parts that have been rode hard and put away wet too many times. Yes, careful magnaflux and dimensional checks help us to cull for the best available components, but that doesn't seem to be good enough.

I've yet to face up to a transmission or engine overhaul, but it seems to me that the most economical route today is to buy the best quality new components that can be found.

Dick


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Re: Transmission autopsy: Bad driving?

Post by Jerry VanOoteghem » Wed Jan 29, 2020 7:24 pm

Something else to consider. A worn pedal cam will force you to adjust your Kevlar lining too tight. With the reduced actuation from the worn cam, leaving the proper lining clearance will not allow the band to grab when the pedal is depressed, conversely, a good band engagement will only be had at the cost of the band being adjusted too tight to allow proper clearance.


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Re: Transmission autopsy: Bad driving?

Post by Nv Bob » Wed Jan 29, 2020 9:49 pm

I found its not a quick but a firm push of the pedal and if running Kevlar set them up loose yet dont let them slip.
Alot of these failures are do to people not checking for cracks by magniflux process and only using visualy looking

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Re: Transmission autopsy: Bad driving?

Post by Steve Jelf » Wed Jan 29, 2020 10:51 pm

Even when I asked if the flywheel is toast I was pretty sure of the answer. Fortunately I have a few others, so finding a replacement should not be a problem. I also have several low drums, so it should also be no trouble finding a better gear. I believe this hogshead has a new low pedal notch and cam, but it's been over two years since the work was done, so I'll check to be sure.

I suppose replacing the flywheel means I'll need to pull the crank shaft and balance it and the flywheel together after the magnets are installed. I guess I should look at this as an opportunity to get some much needed mechanical experience.
:)
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Re: Transmission autopsy: Bad driving?

Post by Allan » Thu Jan 30, 2020 5:04 am

Steve, on our RHD cars the cam is part of the low pedal. A new notch only partly cures the wear problem. To
fix it requires the pedal to be removed from the shaft, the ramps built up and then hand filed/ground to suit. The first time I did this, I built up the ramps to take out ALL the play on the notch, so I had no neutral.

Hope this helps.
Allan from down under.

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Re: Transmission autopsy: Bad driving?

Post by DanTreace » Thu Jan 30, 2020 10:00 am

Steve Jelf wrote:
Wed Jan 29, 2020 10:56 am
What kind of band linings are going back in your fixed up transmission?

Believe it or not, I'm leaning toward Kevlar. The reason is that I think it was the drum that destroyed the lining, not vice versa. I was misled by this being a recent transmission rebuild. I assumed that having to adjust the low pedal was the normal breaking in that comes with new linings. But thinking back on it, I realize that it took too many adjustments. The pedal kept going lower as the lining was eaten by the bad drum. I believe this idea is backed up by the brake and reverse drums and linings being perfectly OK. The brake sees a lot more use than the low gear, so if the lining was the cause I would expect to find evidence of it on the brake.




Steve

Could have been the drum, as you posted. On tour last year a fellow's T kept loosing low pedal, so it was adjusted continually until the T just couldn't move in low pedal.

Examination showed the Kevlar lining on the low drum was thinned so much, and closer view showed the culprit......a crack across the lining surface, that ate away the lining. The un-detected crack was the reason low band had to be adjusted so frequently.
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Re: Transmission autopsy: Bad driving?

Post by J and M Machine » Thu Jan 30, 2020 11:32 am

Steve Jelf wrote:
Wed Jan 29, 2020 10:51 pm
Even when I asked if the flywheel is toast I was pretty sure of the answer. Fortunately I have a few others, so finding a replacement should not be a problem. I also have several low drums, so it should also be no trouble finding a better gear. I believe this hogshead has a new low pedal notch and cam, but it's been over two years since the work was done, so I'll check to be sure.

I suppose replacing the flywheel means I'll need to pull the crank shaft and balance it and the flywheel together after the magnets are installed. I guess I should look at this as an opportunity to get some much needed mechanical experience.
:)
Not the flywheel and crank together.! Who told you that? You'll need to rebalance the flywheel and weight match the triple gears .
You don't need to balance the crank to replace the flywheel : Unless you want to.
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Re: Transmission autopsy: Bad driving?

Post by jab35 » Thu Jan 30, 2020 1:38 pm

Here's a used set of drums http://news.cornell.edu/stories/2020/01 ... ose-jan-31 The small chip in brake drum posed no problems to previous owner. I know these are '26, but obviously quality parts nonetheless. I have no affiliation with this seller. jb


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Re: Transmission autopsy: Bad driving?

Post by Mark Osterman » Thu Jan 30, 2020 6:09 pm

Is pushing quickly and firmly the same as stomping? This is how I’ve applied pressure on bands since 1979. Have yet to have catastrophic failure. But there’s still time. I’ve used Kevlar for the past seven years. But am thinking of making some cork lined bands for installation this summer.


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Re: Transmission autopsy: Bad driving?

Post by Scott_Conger » Thu Jan 30, 2020 7:10 pm

Mark

Personally, to minimize strain to things, my choice of definition as I equate it to your question, is: quickly and firmly

if done at idle speed of the engine, heat buildup is minimal and very brief

I've always felt that the faster you lock up low, the more it is like throwing a stick into bicycle spokes, with maybe the same results...and the slower you do it, the more heat you generate. I thus keep RPM to a very minimum and lock up quickly but not harshly. Many thousands of miles with no trouble.
Scott Conger

Tyranny under the guise of law is still Tyranny

NH Full Flow Float Valves
Obsolete carburetor parts manufactured


otrcman
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Re: Transmission autopsy: Bad driving?

Post by otrcman » Thu Jan 30, 2020 9:51 pm

For those who advocate a specific technique to avoid transmission abuse, I recommend watching this video. People doing the "teeter totter" in their Model T's. This was a popular event in the past, although I haven't seen it much lately.

My dad regularly participated in teeter totter events whenever car games were held back in the '60's and '70's. He claimed that the Model T was the perfect car for teeter totter because you could just set the throttle and then put one foot on the clutch pedal and the other on the reverse. I don't remember him ever having to change the bands, nor any discussion of excessive wear. Pretty sure they are Scandanavias.

If you want to save time, start watching at about 2:00.

https://www.youtube.com/watch?v=ld-PNDQan6U

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Steve Jelf
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Re: Transmission autopsy: Bad driving?

Post by Steve Jelf » Sat Feb 01, 2020 1:07 pm

Not the flywheel and crank together.! Who told you that?

Nobody. I've just seen it done that way. If I can do just the assembled flywheel on the balancer, that's what I'll do.

I'll be gone for a couple of weeks, so this work will have to wait.
The inevitable often happens.
1915 Runabout
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