Disc Brake precautions

[1925 Touring]

Hi all.
I have decided that I am going to install a set of disc brakes on my 22 touring. I've decided that being able to stop better in my mind is better than going 100% original. I know that this can be a controversial topic, like alternators, oil and waterpumps, but it's not invasive to the car, and can be removed if desired.
I am wondering, for those of you that have auxiliary brakes on the rear wheels, what are some precautions or things I should pay close attention to when installing and using these brakes? As we all know, the braking power usually comes from the transmission in a stock model t. With these new brakes, all of the braking power will be directly at the rear wheels and will be putting more load on parts that may not have had it originally. I am having my rear axle and driveshaft rebuilt (with as many original parts as possible) and do not want someting to break that I could have prevented earlier. I am also in the process of refurbishing my wood spoke wheels. I have clincher demountable wheels, if that is of importance. I am interested in hearing what experiences those of you have had with wear and tear on your car. Has anyone had any issues caused by the brakes, and what did you do to fix it?
I can post pictures of anything that would be in question if needed. I do not have my 'new' rebuilt rear end yet.
Thanks
Happy T'ing
Austin

[TXGOAT2]

Be sure your axle assembly, radius rods, and engine mounts, including pan arms, are in good shape. Don't brake any harder than you need to, and don't run oversize tires. I'd look the frame over very carefully for cracks, missing rivets, heavy corrosion, etc. Be sure the ball cap and related parts are in good condition. The tire size and lack of any front brakes will limit braking even with disc brakes. The main advantage of disc brakes is that they will not overheat on long, steep downhill runs that require a lot of braking, and they will probably work better in reverse.

[Jerry VanOoteghem]

There will be no more stress on anything as long as you still brake as if you're driving a Model T. Very hard stops will now be possible, but should be avoided, if possible, which probably goes without saying. Actually, while the same stresses will be put on the torque tube and axle housing, (under normal braking), far less load will be placed on the axle shafts, and zero load will be placed on the driveshaft and the ring & pinion.

[TXGOAT2]

Stopping ability will be limited by narrow tires and lack of front brakes. Actual panic stop ability will be about the same as a stock "improved" T in good condition, handled properly. Earlier Ts have very little braking ability from the stock axle brakes, and the transmission brake is smaller than the late models, though the older cars are usually lighter if not heavily loaded. The brakes can quickly overheat and fail on a long descent. Prudent handling of the car will prevent this.

[Craig Leach]

Hi Austin,
Not knowing the history of your T there is a possibility that it's whole life it has transferred all of it's power & braking through the 8, 1/4"
rivets in the brake drum? Now would be a good time to pull the fourth main ball cap check the Babbitt & those 8 rivets.
Craig.

[Gracie'sDad]

I installed a set of Texas T disk brakes 7 years ago and I have nothing but good things to say about them. The only caution I might offer is with panic stops it's easy to lock the wheels up due to the small tire contact area. Otherwise install a set and enjoy the confidence you'll have in being able to stop.

[richc]

Actually, the woodruff key that anchors the pinion gear on the driveshaft is all that keeps you from having motion and brakes! The 20HP engine in a Model T can only provide so much torque for acceleration, however, stomping on the brake pedal can put more stain on the driveshaft and that little key. Making sure the pinion gear is securely tightened on the driveshaft is an important safety consideration. Having disc brakes might help you sleep better at night...

Rich C.

[Shannon_in_Texas]

So with the disk brake setups the transmission brake is completely disabled?

[Norman Kling]

Depends a lot on what you are trying to accomplish. If you have a stock engine and drive train or modified power train. With a stock engine you are going to have top speed around 45-50 mph. It runs best around 35. If the car is a speedster, you make any modifications you wish as long as it has a T block. With a stock engine the Rocky Mountain brakes work very well and the way I set them up is to have the internal transmission brake adjusted as normal. Then the Rocky Mountain brake is adjusted to apply first before the transmission brake. That way if you stomp hard, both brakes are used and if you just hit it lightly only the Rocky mountain brake is being used. On your car you would have a larger drum next to the wheel. This type adjustment also lets you use the transmission brake if you push hard. That will hold the car from rolling backward on a hill. The parking brake is adjusted to apply first when you pull back the lever and one more notch will apply the rocky mountain brake. Regardless of what kind of brakes you use, you should still shift down when going down a steep hill because you only have rear wheel brakes. This is especially on a winding road where you could skid and of course on snow or ice. I like Ruckstell because you have an intermittent range between low and high. Good for going down steep hills. If you don't care if your car is ugly, than use the disc brakes. I, myself, like to use parts available during the era of the Model T. The Rocky mountain brake will rattle a bit more than stock T but it works fine at normal T speeds.
Norm

[Gracie'sDad]

Shannon, I did not disable the original braking system on my '23. I de-adjusted the brake band so that it did not contact the drum when braking but was there (as a safety net) if the disk brake apparatus were to fail.

[dobro1956]

The disc brakes apply all the braking force thru the rotor and caliper brackets that are bolted to the ends of the axle tubes and backing plates. The axle keys, axles, ring and pinion gears, drives shaft, and u-joint have no braking force applied to them when using the disc brakes. The rotors are welded to the new brake drum that comes with the kit. So the rotors stopping power is applied to the tires thru the hubs and hub bolts. You will have to remove your hub bolts and brake drums to install the ones that come with the kit. Everything you need will be in the kit. I highly suggest to get the optional stainless flex brake lines. Makes everything a lot easier to install and work on. I made 2 steel plates the thickness of the rotor to use as temp spacers between the shoes, wired in place to keep them from falling out, when bleeding the brakes. That way you can have the bleeder screw on top when bleeding the brakes. The stainless flexlines make that possible. The instructions that come with the kit are very good. I mounted my brake fluid reservoir under the seat. After everything was installed I painted everything a satin black except the rotor brake surface. It helps make them not quite as noticeable. One question above was do you disable the stock brake? No, it is adjusted to apply about 1 inch above the floor boards. The disc brakes will apply before reaching the stock brakes. In the event of a disc brake failure the brake pedal will then apply the stock brakes. That is why the welding of the tab onto the Ford brake pedal is critical and is to only be done by the Sure Stop Disc Brake makers. Placement of the tab is critical. I agree that safety is more important than being 100% stock. One other thing to remember. If you have a auxiliary transmission or even a Ruxtell then getting the trans or Ruxtell into a true rolling neutral will make the Ford stock brake useless. This also applies to the folks using the Repro Rockies. If you get into a true neutral by missing a shift, you can have no brakes in reverse. If you miss a shift with the disc brakes you still have a good brake in reverse. The disc work just as well in reverse as foward. A missed shift in our 27 touring car that had repro Rockies on it caused us to have no brakes on a small hill , rolling back and off the road , down a steep embankment, turning the car upside down. We were not hurt, but it was just a miracle we were not hurt. I will never have a T that I drive very much without the disc brakes. I'm pretty sure you are going to love them, especially if you have experienced stock brakes.

[PSJ]

Hi Austin, thanks for posing this question and to all of you who have weighed in with your advice. I'll be installing disc brakes on my 17 T in the next few months and really appreciate these posts with actionable pointers. After running a 60 mile countryside tour last Fall (my first tour), and a few harrowing moments, I decided not to do another tour until I have the disc brakes installed.

[Gracie'sDad]

Pat, I'm glad you have decided to join the ranks of happy Model T motoring with disc brakes. I think you'll find the instructions complete and easy to follow. The only difficulty I had was in bleeding the air out of the system. A brake bleeder gadget would be helpful. Some auto parts stores are willing to lend them for free. Have fun!!

[Allan]

"Having disc brakes might help you sleep better at night...." I suffer from sleep apnoea and have to use a ventilator. These medical machines cost dearly. Would I have been better off buying disc brakes instead?

Allan from down under.

[1925 Touring]

Thanks all for the ideas and advice.
I'd respond to everyone, but that would take a while!

It will be a learning curve, I'm sure, learning how to modulate the new brakes, but panic stops and excessive braking is going to be something I'm going to try my best to avoid. I dont want to leave my rear end in the road, or shear valve stems.

Thanks all for the ideas and comments!

[Oldav8tor]

Don’t get too worked up over disc brakes, they’re great! If you drive conservatively you’ll only notice that you stop with a gentle pressure on the brake pedal, similar to brakes in a modern car. I’ve briefly locked my brakes twice in thousands of miles of driving, both times on loose surfaces. Keep your tires inflated and they’ll be fine.
Since you work on airplanes, one suggestion is to fill with fluid through the bleeders on each brake so as to avoid air in the system. Just like you’d do with Cleveland hydraulics.