Missed me by that much! or Upgrade your brakes

[Thorlick]

I have been enjoying my 1927 roadster pickup between rain days. Rusty sat for about 4 months after the driveline blew up whilst my daughter was teaching a young gentleman how to drive a T. I knew all signs pointed towards a major problem so I let it sit for over 3 months. That didn't seem to cure the problem so I finally started to work on the car and after a month of repair work Rusty is back on the road!

After careful study I determined that a failed original bolt conspired with a lot of worn parts to cause a significant problem.

broken bolt

This bolt was in the ring gear holding it to the differential casing. It sheared off and was held to the ring gear by it's safety wire. As you may see in the photo it lived that way long enough to get tumbled like a rock at the beach... rounding off the edges until the safety wire broke. The bolt head then found it's way between the pinion and ring gears. This snapped the pinion in half and broke the Woodruff key and the keyway of the driveshaft (on the taper). The force was so great that the differential casting broke. This sudden jam caused the triple gears which were on worn pins to jam teeth together (because of looseness on the pins) and snap off a triple gear tooth and allowing the triple gear to go out of time seizing the transmission. The result was broken shafts and bushings on the low and brake drums, trashing the drums. The bushing on one triple gear shattered and bent the triple gear pin trashing the flywheel.

As a result of this I had to do some repairs even I feel to be significant. I built up and balanced a flywheel and a transmission. Replaced the drive shaft, differential case, pinion, ring gear bolt, Woodruff key, brake and low drum, clutch shoes, flywheel and all the magnets. Other stuff not due to the damage caused by the bolt was replacing the clutch drum and clutch plates, and the 4th main.

The amazing thing is my daughter said she didn't hear anything, just the engine died! I can't figure that one out, I'm almost deaf but she isn't!

All of this came back to mind this morning After going on a semi-rural drive with Bill Mitchell in his 1923 Touring T and my 1927 pickup we finished up at the donut shop. Rusty was running great as one would expect with a driveline almost completely made new! Whilst feasting on wheels of death we noted that the local hot rod club was filling the parking lot with their vehicles. One of the guys there came over to tell me he witnessed an incident I had the previous week during a test drive in Grass Valley.

At this point you may be wondering what caused my Don Adams/Maxwell Smart experience... Missed me by that much! What the fellow had noticed follows:

The scene was a narrow two lane portion of Main Street. I was driving down the hill and noticed a Tundra on the opposite lane stopped to turn left after I pass. As I approached the Tundra I heard a crash sufficiently loud to be heard over my Model T engine followed by significant plastic and metal shrapnel immediately followed by a Nissan Z car skidding sidewise into my lane heading towards me at what appeared to me to be a rapid pace. I immediately stomped my brake pedal to the floor and depressed the clutch pedal and started to steer to the right. The error of my response was evident as the Z car chose to head for the the spot I was steering for. I immediately reversed the steering wheel causing Rusty's skid to also change direction. Rusty skidded to a stop not 4" in front of the Tundra without touching it. The Z car kept it's sidewise skid up the hill and passed the rear of Rusty with a good 2" to spare finally coming to rest in the parking lot of an auto repair shop about 100 feet further up the hill. Only the Tundra and the Z car were damaged and NO ONE WHAS HURT!

This was lunch time in Grass Valley and I am sure that the massive traffic snarl caused by the collision was not anything bringing joy to anyone in town...except me. I was quite happy that the police officer said I was a witness rather than an involved party. After giving a statement I was on my way. The fellow talking to me today said that was some of the best driving he had ever seen, he expected to see a smashed T!

The Z driver was a young man who had been a patient of mine over ten years ago. The car was purchased by him the day before and was his first car. He couldn't figure out what had happened and was very agitated, as was the Tundra driver. I am proud to say that my agitation was minimal and my clothing clean!

Now the point of my story. I feel that Rusty and I are uninjured because of several factors. Large is that the driveline had been gone through and set to rights a couple of days prior to this... including the brakes. I use the 1927 1.5" wide by 8" diameter service transmission brake in addition to aftermarket external accessory brakes with a pedal interlock. For more than 15 years I have been driving with an interlock (sometimes called a slider) which I designed. It looks different from the one the brake vendor sold me but performs the same function. If you are unfamiliar with this device it allows your brake pedal to operate the stock brake and the accessory brakes. The lever also will operate the (lined) parking brake and the accessory brakes. This interlock operated flawlessly allowing me to stop instead of contacting the truck. Had I hit the truck I would have bounced back into the path of the car!

Prior to redesigning the slider I used the one which I purchased with my accessory brakes. After using it for a short time I found that the brakes faded in use. The problem was that the 5/16" all-thread rod used in compression to push the brake mechanism failed by bending in the middle. You can see in this photo that even after straightening the inadequate rod retains a bend.

Vendor designed slider

slider5.jpg (33.62 KiB) Viewed 3532 times

Next you can see the design I came up with to replace this setup. I used 1/2" galvanized pipe, a 1/2" bolt, and two clevis adjusters. They were welded together and replaced the manufacturer slider. The pipe piece slides over the 1/2" bolt piece and is adjusted with the jam nuts. There is more than enough of the 1/2' bolt inside the pipe to keep the interlock from buckling. I have been testing this design for over 15 years and probably over 30,000 miles.

Horlick design slider

This design is both adjustable and so stout that it continues functioning under the forces encountered in the most severe panic stop.

I urge all of you who do not have accessory brakes to get them. If you have an accessory brake make sure it works by your pedal as you may not be able to grab your brake lever in time. Don't use an under-designed interlock which could cost you, your passengers, or others involved in the accident an injury.

Horlick Slider in place... one week after "incident"

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Please look at your interlock and see if it is assembled with parts like 5/16" all thread which are meant for tension NOT compression or which have poor insufficient welds. If you have such an item on your car I urge you to consider upgrading to something safe. If you are thinking of buying an interlock please evaluate your choice and forgo one which has light, possibly inadequate design and construction.

IMHO, TH

[Dennis Prince]

I am glad that you made that upgrade and drive a T enough that you reacted and didn't have to think "I am driving a T what do I do". I made a slider exactly like that for my roadster about 15 years or so ago when I built my brakes, like you I wanted something stout enough to do the job under any condition and it work flawlessly. I sometimes need all of the brakes I can get.

DSCN1234 (1).JPG (57.63 KiB) Viewed 3483 times

[TWrenn]

Yep Terry, your story is all the more reason now I'm super glad ALL three of my Ts have Rockies on them! Despite all the
dissing about them in reverse, I've had no issues regarding reverse stopping, and they sure are great stopping forward!!
I inspect my linkages all the time too.

[TeveS-Nor Cal]

I got some fresh underwear over here you can borrow! Please return it clean!

[paul hoogendoorn]

Hi Terry,
An interesting modification, I would love more info. Does pressing the brake pedal now also disengage the clutch or is your slider a completely separate system. Maybe a simplified drawing will do.

[Thorlick]

Paul,

I am using all the parts from a popular aftermarket manufacturer except for their interlock which I have found inadequate.

The brake lever has a pivoting yoke on it which actuates an equalizer pulling the accessory brakes when the parking brakes are pulled.

The service brake pedal works the transmission brake when pushed, but it also works the interlock which also pushes the yoke... and therefore the accessory brakes.

To work the clutch you must either push the low pedal or pull the brake lever... either, or both, will do the job. BUT stomping the brake pedal WILL NOT work the clutch. That is why I pushed the low pedal 1/2 way down as an automatic, ingrained, part of mashing down on the brake pedal.

In every normal stop the emergency stop procedures are practiced. Some people always throw in the hand brake on every stop to make the addition of the parking brake part of a normal stop and therefore part of the E procedure. I frequently practice this but not enough to make it automatic. I am now glad that I don’t make that automatic because I had to have both hands on the wheel to steer. If I had one hand on the brake lever I couldn’t have avoided the Z car!

Since I don’t go for the brake lever in an emergency I am relying on my interlock to do it’s job. If I still had my fold-up slider interlock I suppose I would always use the lever as the actuation of the outside brakes would be risky otherwise.

This is why I posted my interlock photo now as well as about 15 years ago.

TH

[speedytinc]

All neat stuff.
What really gets me is the mass destruction from 1 ring gear bolt. "For want of a nail the farm was lost"
I guess the answer is not to take short cuts. Rebuild an unknown rear end. Dont reuse bad hardware.

[Thorlick]

John,

I'm not sure if you would consider that rear end "unknown". I completely went through it when I built it up about 25 years ago and then a second time about 20 years ago after I destroyed the set of needle bearing thrust washers, replacing them with bronze thrusts. Then again about ten years ago when I replaced the bronze while it was all apart to replace the failed ten tooth pinion.

I am thinking that the ring went on 20 years ago and the safety wire was replaced ten years ago. I don't routinely replace all fasteners when I am working on the car so the ring gear bolts are probably 90+ years old. I think that we are all at (a small) risk of this type of failure as parts age... even if we have "known" assemblies!

cracked differential carrier

There was enough force to break the differential carrier casting in several places.

broken pinion (removal date)

diffy5.5.jpg (15.06 KiB) Viewed 2982 times

Here we see the pinion placed in around 2001 and broken (coincidently about 100 yards up the same hill from the current incident) in around 2009. On the left we see the pinion used for about 12 years (2009-2021).

IMHO, TH

[speedytinc]

I dont replace ford ring gear bolts either. Come to think about it, i do many more rux rear ends. I do inspect carefully for stretch, etc. & use a torque wrench feeling for "funny" stuff. Not unusual to find a bad bolt here & there. Your "double failure is REALLY interesting itself" Stuff still do happen.

Maybe some sort of negative harmonic convergence around your neighbor hood.
During an auburn national tour, a newbie fellow club member broke a ring gear. His first national tour. He was quite depressed about being down for the count. Local club guys gathered possibly needed parts. He trailered to our next nights stop. We pulled the left axle housing in a reno hotel parking lot. we found the diff carrier ring gear flange bent. We borrowed an axe & beat it back close. Nothing to lose. He was back on the road. I am told that axle has not been apart since. 20-25 years ago. The good old days.

[Erik Barrett]

Glad you and rusty are OK Terry. You and your pickup are survivors. A few years ago I witnessed Terry saving a man’s life with his rusty roadster pickup. We were touring hill country in Northern California. A gentleman driving an all original 24 or so coupe broke his Ruckstell. No Rocky Mtn brakes, acres of plate glass surrounding him. I was following the man when we crested a hill and it ran away from him when he shifted the Ruckstell and broke it. He ran into Terry who was able to bring them both to a stop. Good memories instead of bad ones fortunately.

[Thorlick]

Erik,

Thanks for the unearned praise. Also a huge thanks for some of the parts I needed to resurect Rusty. Erik kindly provided a replacement drive shaft, a wooden wheel '26-'27 drum, and a handful of ring gear bolts! Without Erik's help I never could have served as a target for that Z car!

On a killer steep winding downhill Lee's coupe broke it's Ruckstell shift tower going into free-wheeling mode. Lee had only his service brake, and apparently no lined parking brake. This car is one which Lee had bought and driven throughout high school at least 30 years previously. He finally got it going and this was one of the first tours he had driven. Below is a photo from the rest stop previous to the accident, Lee had been driving near the back of the pack but since this was to be the last stop he moved up to the second slot behind the leader car, Rusty. Lee slammed into the rear of Rusty doing at least 50 mph, my Horlick design interlock was part of the winning combination that time around. The following summer 2010 photos were after Lee, Rusty, and I got the procession stopped at the side of the road.

I later got Lee a new Ruckstell tower, but over the past 11 years that coupe has sat in Lee's barn awaiting repair.

Here are a couple of photos from that day:

Rusty at right Coupe in center... just before crash.

Rusty right where he stopped Lee's Coupe.

Lee pointing out the dime size mark his coupe left on Rusty.

TH

[Erik Barrett]

I remember walking around trying to get cell service to call AAA. And watching Matt Ryan drive his speedster up the hill beside the road. At the end of the day we all made it home. Good memories, can’t believe it was that long ago.