I have a 1926 rear end. I put Rocky Mountain brakes on it with the transmission brake coming on after the Rocky Mountains. I do not have any original park brakes. If I pull the emergency brake on the Rocky Mountains, it holds the car fine. What I want to know is this safe or should I put on the original emergency brake shoes in the drum. Your opinions will be much appreciated. Kevin in Utah.
Why are the original parking bakes missing?
Are the RMB old(original) model or new model?
The later don't hold very well backwards.
I would want as many brakes as possible. Besides, the Rockies don't stop/hold well in reverse. So, if you're parked on a hill, with the pointed uphill, using the Rockies for a parking brake might not be a good idea.
In a T, the more brakes you've got, the better off you'll be.
Should read, "with the car pointed uphill".
If you always turn your car so that the front is pointing downhill it might hold, but the way the band wraps the drum, the leverage is to loosen the brake when the wheel turns backward. It is like trying to use an oil filter wrench backward.
Actually you need to install the parking brake and make it come on first before the Rocky Mountain brake. That way you can use it for parking. Always use a chock too.
Since you live in Utah, I would think you have many hills to climb. If your car should break an axle or driveshaft or have problems with U joint or ring and pinion, while going uphill, you will have the misfortune of rolling backward with no brakes. That is the reason for having parking brakes and having them come on before the Rocky Mountain brake.
It is a safety feature. Unfortunately, many people who install the Rocky Mountain brake have a problem with getting both parking brake and Rocky Mountain brake synchronized, and so they remove the shoes from the parking brake. I know of a car which had no parking brake and no transmission brake, but relied on Rocky's only. The driver went up a steep hill and killed the engine. He rolled backward and tried to turn the car around. Resulting in about $5,000 damage. Fortunately no one was killed or seriously injured.
It is my firm belief that all driven model Ts should have two complete, independent (except for the wheels themselves) braking systems. The transmission drum brake should not be on the same pedal as the RMs. The service brake and the emergency/parking brake should not use the same cross-shaft or brake rods. It is easy to set them up as separate systems, and much safer under many circumstances.
Drive carefully, and enjoy, W2
How would you do this without two pedals and two levers? The traditional way puts the Rocky first, then the transmission brake. Only time this would cause a problem would be if the pedal itself broke. The transmission brake is a backup for the Rocky. Likewise, with the cross shaft, the movement of the parking brake lever also moves the Rocky brake. How would you lock the Rocky's if they weren't connected to the parking lever? Your system would use 3 legs, two pedals and two levers and two left arms.
I know of a car that has the hand lever apply the RM's!
The way the equalizer is designed it's all most impossible to setup both the RM's and original parking brakes so many people just left them out. One of the members here made a very simple equalizer that hangs off the cross shaft that allows both brake systems to function independently of each other, believe it was Jack. I have made a couple but don't have any photos.
One brake handle, one brake pedal, two cross shafts and two sets of brake rods. NO band in the planetary.
The problem with having the planetary band adjusted to work after the rear brakes is that adjustment changes due to things like wear, and even temperature. Several years ago, I knew of someone that broke something in the drive-line. He slammed on the brake pedal only to discover that he had been using the planetary brake and NOT the RMs he thought he was using. He hit the brakes, killed the engine, and hit something. Fortunately, the damage was minor. I also knew someone years ago that thought his planetary would stop him on a hill, only to find that wear had shifted the adjustment enough that no matter how hard he pressed the pedal, he could not hold his car on a hill.
My belief is that the false sense of security is one of the greatest dangers in this practice. There are, however, many circumstances where the intertwined braking systems can fail you when you are least prepared.
The best, safest, non-modern (and limited to two wheels) braking system is to have the brake pedal on after-market outside brake bands, and the brake handle operating on inside shoes. RMs are okay in spite of the problem with holding in reverse provided the driver is aware of and used to this potential problem, and knows how to handle it using the emergency brake. Small drum lined shoes are adequate (barely) for the emergency brake as long as they are properly maintained and adjusted. Small drum outside bands (such as AC) are also adequate for the service brake as long as they are properly maintained. The big problem with small drum outside bands or inside shoes is that the small surface area wears faster than the large drum varieties. This requires more frequent adjustment and occasional replacement.
Both my coupe and boat-tail have large drum service brakes (the coupe has RMs). The coupe has large drum inside emergency brakes, the boat-tail has small drum lined cast iron shoes for the emergency brake. I feel very secure with both of them with their independent systems.
The original Bennett Brake pedal on the boat-tail operates the outside rear brakes only. That original pedal was made so that it cannot operate the planetary band. That would seem to be the way they wanted it also.
The second cross shaft is easy to make. I made the one for my boat-tail. Someone else made the one for my coupe long before I got it.
Drive carefully, and enjoy, W2
The idea that you can have the transmission brake and the RM's adjusted so the Rm's work first and then the transmission comes on when you press harder is just plain stupid. Yes it works at first but for how long?
If you look at the actual mechanical advantages both systems use to apply their brakes you will find one need more pressure and travels less than the other the opposite and after a few applications you have no way of knowing which is doing most or all of the work, as Wayne pointed out.
My Kamper has a Moore box (so a proper neutral exists)and RM's and has separate lined hand brake, and original transmission brake 20,000 miles and no adjustment to any of them. A bit unoriginal as the brake pedal is split in two so the Rm's and the transmission brake can be applied separately but its so good to know that you have good brakes forward, good brakes backwards good brakes in the wet and a park brake that can allow parking on any hill.
Having the two foot brakes separate makes it really obvious that trying to join them together is a bad idea as you can drive the car and compare the two against each other, a few minutes doing stops with both quickly shows just how different they are in effort needed to stop the car.
To get rid of the problem Mark mentioned (having RM's and parking brake work together) if you use a slotted end on the hand brake lever and adjust it so it pulls on the brake shoes in the rear just after neutral is selected the RM's can operate by themselves and the parking brake and RM"s will both work when parking.
Thank you Peter K! I have seen photos of your split brake. It is quite interesting, and I think a good idea.
Drive carefully, and enjoy, W2
Peter, Can you post a link to your split pedal or some info about it. It sounds interesting to me. On my 22 touring I installed an original set of AC brakes, using their stock cable equalizer. I made a "fourth pedal" and bracket that attaches to the hogs head to activate the ACs. It just added another pedal beside the stock brake pedal. That way I have a factory parking brake, a factory transmission brake, and a separate AC brake system. It also gives something to talk about as to "why" I have four pedals.
The Kamper is RHD, so the trans brake pedal moves right when applied. I made a longer pedal shaft out of an old axle bushed the Rocky Mountain pedal (the one with the spring attached on the left side) It just pivots on the shaft.
The Trans brake in on the right it is connected as per normal. This fix has not butchered the car except for modifying the two pedals so it can easily be returned to normal.
I can use either brake or both in an emergency. Being separate I can always tell how they are working. When driving across the USA most of the time I just used the RM brake. in the wet or backing up I used the transmission brake.
You can see I took the right and left side off the two pedals to make them closer and added an 1/8" plate top with ears to make the pedals easier to operate.
Very clever, Peter, well done!