MTFCA Forum

I moved this from the classified forum where I put it by mistake.

I went to adjust my transmission bands today for the first time on this car. After driving it for a year, I was not getting a really positive brake and the pedals were lower than recommended (1 inch from the floor when full down on the low and brake). I opened things up and found that I have virtually new Kevlar bands in the car and the transmission looks like a recent rebuild. Everything is clean.

There looked to be a good bit of clearance on all the bands, so I adjusted the bands so the low and brake pedals stopped at 1 inch from the floor board and the reverse was about 1 inch lower than the other pedals when the were at rest.

But, when I started it, the car wanted to crawl forward, with the parking brake half way back where I used to have a free neutral. I readjusted the low speed band till that stopped and being concerned that the others were too tight, backed them off as well. I drove it around for a mile and it seemed to be ok, but when I put it in the garage it was wanting to creep again.

I have heard horror stories about cracked drums with too tight Kevlar bands and heard that they need time to settle in when new. How do I figure out the Goldilocks spot for these? The original manual is of little use.

Moved from other forum.
This is a reply from Scott Conger:

“Scott_Conger
Re: Kevlar band adjustment tips
Post Fri Jun 23, 2023 6:40 pm

Morgan

two thing are imperative when installing Kevlar...

1. the hog's head must be rebuilt with fresh/new pedal supports (ramps) and the pedals built up and ground to match the supports. Further, there should be very little neutral dead-band at neutral and when the band is fully locked up there should still be a lot of ramp engagement left (pedal still wanting to move sideways to tighten further)
2. the bands must be ROUND and not twisted or otherwise kinked in any way prior to installation, which would allow constant drag. The fact that adjusting low band to be 1" off the floorboard and yet is still dragging would be a red flag for me to suspect misshapen bands.

if the reverse pedal is sitting lower than the other pedals when at rest, something is awry and I'd be very suspicious of the condition of the hog's head for starters”


Thanks Scott. The reverse pedal does not sit lower than the other pedals at rest. I adjusted it so that the reverse pedal engaged fully when it was just a bit lower than the other two pedals when it was pressed. You can see the pedal at rest with the parking brake on in the photo attached.

I don’t have a lot of play on the pedal shafts and the hey don’t leak a noticeable amount of oil. The cams don’t look worn and start to cam pretty quickly and hen depressed. You can see the out side cams below.

Deformed bands would be a pisser. Only way to check would be to pull the engine.

everse pedal and cam.

The cam surfaces on the low and brake look ok to me…

I backed the low pedal adjustment off half a turn and it’s not dragging when the brake lever is back half way. I have free neutral and can roll the car in that position.

I am concerned about brake and reverse bands dragging.

One more fun thing to consider. The floorboards in the car are new and were made off the old ones that were in the car, which were not original. It’s possible that the floorboards are not made correctly so that 1 inch from the board rule does not work.

Morgan, I approach the adjustment from the low side, as you have when they are not quite working as they should. I adjust one turn on the nut, and do a test drive. If that gives you enough, do not be tempted to give it another turn to save another adjustment later on. You need to leave as much clearance between band and drum, consistent with proper engagement. It is usual to have to make three or for such adjustments as Kevlar bands settle in. Then it is rare to need any further adjustments for ages.

Hope this helps,
Allan from down under.

Thanks Allan. I am going to work on it more tomorrow. I was trying to get a bit better braking and be sure I was fully engaging the low band. Once I get the low band adjusted properly, I think I will measure the distance between the band ends when open and compressed, then adjust the other two to the same and work from there. I have always been Leary about the Kevlar bands because of their unforgiving nature. I have several old sets of Scandinavia bands in boxes on the shelf. If push comes to shove, I can install those on bands with removable ends.

I was going to pipe in with my way then read Allan reply.

Yes, agree with Allan, walk them in. And when they do the job...STOP...and button everything up for good.

I'm a fair use kinda guy...if I can find good Scandia, I'll use that; I'm really a proponent of Guinn wood and if set right they do not chirp( thats another story for another day) and then there is Kevlar where...its good....IF!

Share a funny, I did a family 26 in Kevlar, walked it in in about an hours worth of open close open time to get there. Brother in Law borrows it for a show. Get a call from one of my sons who was with him. Slips when trying to get it on the trailer!! What is the ramp angle? Closer to 45 than 30! What did your uncle do, he got on it and turned the adjuster a few turns tighter...thing tanked up the ramps like a bulldozer! This is why Uncle is no longer allowed to borrow my cars...lol...but he just bought a 13 of his own, hope it isn't Kevlar!

Not a lecture, reminder....Kevlar has 10% or so more grab than the originals. On Off binary, no issue.If you feather, that 10% turns to be 10% more heat unless the braking cycle is 10% longer. (Just linear math). The other is woven bands have a bit of squish factor for oil...Kevlar NO. This is why I brake over longer and slowly pump brakes. Works for me, Kevlar has not been negative to me.

Morgan, I would not place much cred on measuring between the band ears to make equal adjustments. Unless you have new drums, there can be considerable variation between one band and the next due to differences in drum wear, wear on the band ears themselves and maybe some slight difference in band length. All this is taken into account by the adjustment method I outlined.
Also, pedal measurement from the floor is just as flawed by worn ramps and bent pedals

Allan from down under.

My car has Kevlar bands. I've driven it a lot, probably well over 13,000 miles, and I have had no
issues and done no adjustments. The pedals are very close to the same when pressed down hard as when I got the car. I avoid slipping the bands so far as is possible. When braking, I use engine compression as much as possible, and when I do need to use the brake for more than a few seconds, I release the pedal briefly every 5 seconds or so to allow more oil to flood the brake band.

I do not drive in stop and go traffic, so my bands get less use than some, but the same operating procedure would apply.

If adjustment becomes necessary, I'm going to approach it with a less-is-better attitude.

The bands MUST NOT slip or drag.

That's true with any lining material, and especially so with Kevlar.

A well tuned engine will make it easier to drive the car with an absolute minimum of band slippage and gear-shifting, and careful driving will minimize the need for hard use of the brake, emergencies excepted.

I don't use reverse for braking. I use the brake for braking.

A high idle speed can interfere with smooth low to high shifts, and can make extra work for the brake.

Post by speedytinc » Sat Jun 24, 2023 9:09 am

The 1" "rule" doesnt apply to kevlar.

Proper low pedal setting:...With the motor running.
Back off the adjuster some. Start the motor. Tighten adjuster until you just start to hear the triple gears change their song.(from nothing to a little grumble) Back off 1/2 turn. lock down. Your band is now adjusted to its maximum optimal position with no drag. (Otherwise its a guessing game. To tight= drag = friction heat = broken drums.)
If you dont have enough pedal to lock the low drum plus some space before the pedal hits the floor, you have an issue. (New Kevlar lining takes 3 or 4 adjustment, then they are seemingly set for life.)
Out of round band, a loop in the lining or badly worn internal cams. Cant have a high spot bump in the lining.

Adjust reverse similarly. Note how much extra pedal travel. Adjust that out until you have no triple gear grumble until after slight pedal engagement.

If you adjust this way there is no unengaged friction which heats & breaks drums.

If you do determine an issue, you dont need to pull the motor. you will need the remove the HH.

For the folks playing @ home. Remember to manually oil the brake & reverse pedal cams if the pedal shafts have been made leak proof.(O-ringed or sealed). Dry pedal cams will gall & get stiff to the point they need more & more leg pressure until they eventually wont move.
Top

I tried the “listen to the triple gears change sound and adjust” method and I just could not hear it. Too many T noises, too many loud guns in my past. I adjusted the low and brake pedals so they were full on just before they hit the floorboard. I measured all three bands and the brake and reverse bands move 1/4 inch closer together between off and on. The low speed band just a touch (app 1/32) more. The drums don’t show any discoloration related to high heat. When I roll the car back and forth, then press the pedals, oil is pressed out from under the bands. I took it for a 5 mile drive and it started and stopped ok. According to my brand new speedometer, I got it up to 45 on a straight away. I think the bands could all be a bit tighter. But I will drive it some more and fiddle.

Maybe adjusting while the rear axle is on jack stands would be better. That way any drag on the low or reverse drums would be visible as wheel rotation.

Allan,
I was thinking about using measurement between the bands when tight and loose as a gauge for determining if you have sufficient clearance between the band and the drum. It seems like that would be pretty consistent unless there was a huge difference in the drum size.

If a band fully locks up the drum in low or reverse, it's tight enough. Brakes are their own animal, as you should always do your "slowing down" with the throttle and use brakes to come to a full stop and hold it there. Pumping brakes is a misuse of their designed purpose though it is safer on the drum than just dragging the car to a long stop. If you're applying brakes on a hill for a long time to come to a stop, then you should have been locked up in low just beyond the apex of the hill - "come down in the gear you'd go up". FWIW, you should be able to, and make a habit of, engaging low band fully from pretty much an idle. Revving the engine, trying to slip/grab the drum and all such drama should be avoided as much as practical, though it is regularly and proudly displayed by the majority of modern owners...in fact the best place to learn how NOT to drive a car is at a major tour. You want to drive like 25% of owners who quietly and effortlessly pilot their cars (usually the very early cars) and not like the 75% who pull away in a raucous cacophony and billows of smoke and dust.

Finally, whatever you do, do not fall for the 1970's advice to "use the reverse pedal to save the bakes". That was terrible advice then, for cotton bands and expensive advice now, with Kevlar.

I think you're progressing on your car just fine.

Thanks Scott. I learn new things about the T all the time.

I put the T up on jack stands today to see if that helps making adjustments, but the wheels with the parking brake in neutral. I adjusted the low band to the point where it fully engaged just before the pedal touched the floorboard. Interestingly, it showed some desire to crawl forward before the pedal would engage without slipping. Not sure what that portends.

it showed some desire to crawl forward before the pedal would engage without slipping

normal

perfectly formed bands drag - bent or otherwise deformed bands drag more

how aggressively they drag or how much they are allowed to slip before lock-up determines the amount of heat you pour into the drum

Reno Speedster wrote: ↑

Sun Jun 25, 2023 4:44 pm

I put the T up on jack stands today to see if that helps making adjustments, but the wheels with the parking brake in neutral. I adjusted the low band to the point where it fully engaged just before the pedal touched the floorboard. Interestingly, it showed some desire to crawl forward before the pedal would engage without slipping. Not sure what that portends.

It means you have a stock clutch. If you were to remove the low band, you would still see some "creep" tendency for the wheel to turn (up on jack stands) because the clutch is not 100% free. The tendency will normally decrease with hot oil, but will still be there.

I am not sure what clutch I have in this car. It’s possible that it has a Watts clutch. When the clutch spring is depressed, the fingers are loose. Given the condition of everything inside, it looks like the engine has been through a recent rebuild. I doubt that would be done with a notched drum. But, no way to know unless I take it apart.