Yesterday was the first time that I took my 1927 Tudor out in the rain, after the body restoration was finished this past spring. I have Rocky Mountain Brakes installed and followed the directions outlined by those who posted instructions on the forum when I put things back together. As I left the house, the car braked just fine. After I took drove the car for a couple of miles, the brakes hardly worked at all; in fact, pressing the low speed band slowed the car down more (I wasn't using it for braking - I had the rpms slow enough that I could transfer from high to low). The handbrake stops the car extremely well in the rain, for which I am thankful as I had to use it to come to a full stop at the traffic light.
I have .22 thousands at the tightest spot on the drum (the where they clamp together at the front) and a bit more at the loosest place. Theoretically, the transmission brake should be engaging the further down I push on the pedal, but I am thinking that it isn't doing it's job. The brake pedal is 2" above the floorboard when fully depressed. The transmission was rebuilt in 2010 with new bands installed and I put about 70-80 miles a month on the car, with no miles on it between Sept 2014-April, 2015. At the time that I put the car back together, I inspected the bands and there is plenty of material on them.
My three questions are:
1) Is this the norm for the Rockies to be mushy in the rain?
2) Is my pedal too high so that the transmission brake not doing the job?
3) As a test, should I disconnect the Rocky Rods, secure them to the frame, drive the car and see how well the transmission brake is working?
It sounds like the transmission brake is not working. You need that for wet weather and when braking in reverse.
Modern RM brakes don't work well in the rain or in reverse. You have a good emergency brake in the improved models to back up your transmission brake. It works well in the rain and in reverse.
I do not understand a auxiliary brake design that requires you to use the transmission brake it was designed to replace in case your auxiliary brakes don't work.
Royce Peterson senior built his own external drum brake that worked well forward or reverse and in the rain. He felt part of the secret of his brake was the softness of his lining. His linings contained asbestos and were much softer than the lining supplied with modern RM brakes
1.) Rocky Mountain Brakes are known for being significantly less effective when wet.
2.) If your brakes can positively keep the car from rolling backward while waiting at a red light on a fairly steep incline, you're probably okay.
3.) I don't see why not, as long as you avoid hills until after you've gotten solidly favorable test results on level ground.
Sure stop disc brakes!
After my first attempt at driving the t in the yard and nearly going thru my neighbor's fence I was determined to get sure stop brakes and i was not going to drive it until I did. There will be those that say they are ugly, I don't think so, and that the are not original but when it comes to safety disc brakes are best.
Like the instructions from Texas T says a model t will never be completely safe compared to modern cars but sure stop brakes help.
IMO you need to re-adjust the Rocky Mtn. brakes to gain full stoppage.
Have two T's with Rocky and they stop the T. Period. Can bark the rear tires with hard pedal push.
Since you say "after I took drove the car for a couple of miles, the brakes hardly worked at all" that indicates to me you need to re-adjust. Have found sometimes the adj. tall nut can back off, and on my install I wire that nut.
As for rain, the brake lining isn't absorptive, you have to tap the brakes and rub them when running in the rain, prior to stopping, that warms the lining and drums and the moisture there will be dissipated.
Typical for RM brakes - they are terrible when wet. The most effective brakes are the Sure Stop disc brakes but you already invested in the Rocky Mountain version and they will work.
I had RM brakes on my touring car and whenever I was out in the rain I made a habit of riding them often to keep them warm and dried out, especially in congested / high traffic areas. With that technique they were almost always ready for action.
Keeping the hand brake in the back of your mind for wet weather and stops on steep hills also needs to become second nature.
My problem with my primitive pickup in rain is, besides the obvious discomfort, that the rear wheels locks and slides as soon as I try to brake hard. And that's with a standard narrow transmission brake..
I have to be very careful not to drive as fast as usual in the rain - rear only brakes in a light car is a risk factor when it's slippery.
Regardless of the brakes on your car (considering only the rear wheels braking) the maximum input is your foot. External brakes will work to equalize the pressure to both wheels where the trans brake would run the possibility of only locking up one wheel. The biggest advantage of outside brakes is the option to maintain a brake if a transmission is in neutral like a warford. If one can lock up the rear wheelS with a trans brake then you can't expect to obtain any more braking with outside as the input (your foot) remains the same force.
In your situation it would seem as though your wet RM are not allowing your tranny brake to close and the friction is reduced thus preventing good braking. I had this same problem on my mothers speedster, the brakes (RM large drum T) were always hard to push and took alot of effort to press the pedal. On my speedster with the stock brake I could lock up the rear wheels whenever I wanted.
On my next T I may very well run the outside brakes only on the hand brake as an "emergency" and backup while maintaing the stock T braking for driving.
The trans brake never locks just one wheel, Chad - when it's slippery for both, it'll lock both. There is a chance for backwards slipping with one wheel if one wheel is on ice and the other on asphalt. As long as the driveshaft is locked and the car is moving. either both wheels are stopped or they're turning at the same speed in opposite directions..
It's probably not an adjustment if as you say they worked fine at first and it was a short ride. They got "lubed" or soaked by the rain water. Modern drum brakes do the same thing when soaked. You had to ride the pedal to squeeze out the water after a trip thru a deep enough puddle. The RM's, being fully exposed, are even more prone to getting soaked.
Guess Rocky Mtn. brakes and wet is all comparative. My experience in rain and wet isn't bad, sure a bit of loss, but once you warm the brakes they grab again.
Sure do like having external contracting big drum brakes on my T's, they work many times better than the Ford tranny brake IMO.
Fording and splashing in Dixie, the '27 touring.
Dan is right. Riding them clears the water and they work again. RM's have an almost full circumference lining with only an open area at the top. That area is where the water is really scraped off the drum. Some exits sideways for sure but the real squeege action is at the ends of the lining.
Most early cars had external contracting brakes and they all have issues in the rain because until the water is worked off they are less effective. Enclosed drum brakes have the same issue if they get wet but are less likely to get wet unless they are submerged because they are enclosed. My Chalmers-Detroit has external contracting brakes and an internal expanding emergency brake. I got so tired of poor braking in wet weather that I reversed the linkage and use the internal brake as the primary brake system. Kind of makes you wonder what they were thinking when they designed them in the first place.
Not satisfied with how my car was stopping, I researched previous conversations on the MTFCA about adjusting the Rockies and found several posts by Norm Kling. I called him earlier this week and had a wonderful 45 minute conversation from everything on how to properly adjust the Rockies to old cars and kids. What I discovered while talking with Norm is that I had not properly adjusted the transmission brake last spring. I had not disconnected the clevis that connects the brake pedal to the Rockies, which gave me a false adjustment. The car was braking primarily using the Rockies with little, or no effort, from the transmission brake.
I got that adjusted last night and took the car out for spin after work today. In between squalls of this storm that is hitting the northwest, I was able to test out the adjusted brakes on dry pavement and in the rain, as well as test the brakes on a moderately steep incline. The car held with no effort on the incline and stopped dead in its tracks on dry pavement - in fact, it made the tires squeal. The car also stopped much better in the rain, much as Dan Treace described. Based on my previous experience, I could tell in the rain that the transmission brake was doing most of the stopping until the bands dried out. I feel much better about things now.
I really appreciate the feedback from all of you. This has been a fun learning experience.
Dan, is that Dean behind you?
Glad to see you got it all squared away Jim, Adjusting the R/M's to work perfectly in conjunction with the trans brake can be quite a chore adjustment wise, but well worth it in the end. I adjusted mine so that just a light touch of the brake uses just the Rockeys, and medium to full force engages both. Not sure if it really makes a difference, but i figure the less abuse of the brake drum, the better.
Happy you got the T and those big drum Rocky brakes working happy! Now you can tour with satisfaction.
Yes, that was Dean Yoder. On tour in 2011 in MN.
He ran one way thru, then turned around and splashed his T and trailer camper rig again, just to be sure he got both washed up clean and OK for that night.
All cleaned up for viewing
I have genuine original Rocky Mountain Brakes on all but one of my T's. They work great when dry, but I get real careful when raining, cause they don't work good at all, and I don't want to plow through something!