I wish I could post pictures but I guess I have not figured that out yet.
I was having trouble at the end of the year with having to adjust the low and clutch bands frequently . This was a new problem as this car has been driven trouble free for several years. So, I tore into it and found one broken drum and a very ugly Kevlar band. The next problem was that the band Kevlar next to the one with the broken drum showed signs of torn wear next to the badly worn one. The second drum shows no crack and is very smooth as it should be. My question is, can the debris from one band cause the other band to show wear too? There was lots of fuzz in the screen and around the return springs and slingers. This car does not have a mag or field coil.
My intent is to replace all of the band linings and the cracked drum. I can not find any reason for the wear on the second drum. Any ideas would be appreciated. I hate to put it back together having not resolved the second band wear issue.
All of the wear appears to be abrasive and not from being hot.
A crack on the band surface is all you need to shred a band. Wood,kevlar or cotton,it's immaterial. If the band broke,debris from it could cause collateral damage. I am rebuilding a tranny right now that had a reverse drum that had such a split in the band surface,and it has never seen kevlar.
Make sure the "Fuss" is not plugging up any main bearing oil holes, rod dippers or the inside oil line. I have been using the same Kevlar linings for over 14 yrs. and no problems to date. Drums must be smooth/polished so they do not shred the linings. Bands must be round and adjusted on the loose side to survive. Also....try and keep slippage to a minimum.
Suggestion....use a high volume outside oil line like what Texas T offers and remove the slingers.....just one other unnecessary item that can fail like a broken magnet. Have been running a flywheel with no magnets or slingers for over 14 yrs. with no bearing failures or shim adjustment. I use synthetic oil 10/30 which some feel is a waist of money. Each to his own!
Happy New Year
While you are in there I would suggest you magnaflux the other drum(s). This sometimes shows up cracks which you don't otherwise notice. The fact that the other band had Kevlar for lining material makes me very suspect of the drum's integrity. Brake drums usually survive Kevlar, but I would magnaflux that one too... that test is not very expensive to do... much less than having to do a second rebuild later.
I always suggest a switch to wood liners, eschewing Kevlar, when you rebuild.
Maybe you have been adjusting the bands too tight? Kevlar is stronger than cast iron drums. It will machine the drums if the band adjustment is too tight.
Another possibility is the band not being round. If the band is not round, the lining can be in contact with the drum, again causing premature wear.
If you machine the drum to remove minor pits or scoring you are simply hastening its demise. Any removed material results in a smaller diameter drum that cannot be clamped as effectively by the band. At the same time you are also weakening the drum by removing the material. If the drum is shot, buy another one. If it has minor pits or grooves, leave it alone.
I don't think Kevlar material causes cracked drums. We had cracked drums long before kevlar bands, with the same causes.
I have always used Kevlar with no issues. Previous posts discuss wooden ones and those comments are interesting but I have no experience with them.
Rich Peterson suggested looking at the cams on the pedals for wear. Tightening the bands to a good feel with worn cams can make the band not release fully and heat the drum. I will check this as I have never had this issue before.
Magnafluxing is also a good idea as I have not seen any cracks in the second drum.
Has anyone ever put a combination of Kevlar and wood in as a test to see which one works best for that cars specific use? Maybe wood on the low band and Kevlar on the brake or vice versa? Reverse could be either one?
Thanks for all the responses so far and further comments are always welcomed.
You're right on track with the magnafluxing and the worn cams, old fatigued drums can't take the heat. While you have it apart also check the drive plate for cracks.
Kevlar doesn't cause cracked drums.old age,misadjustment and rough driving do.
This is why we decided to make new ones.
Magnaflux is the ultimate but sometimes you can spray brake cleaner on the drum and the surface will dry quickly but if there is a crack, the crack will show as a wet line on the drum. This is easier for me when I have to take it somewhere to get it magnafluxed.
Don't slip the band starting off in low and don't use reverse for a brake and both drums and bands will last much longer.
So far these comments are constructive. Not bagging out a product that is not the cause of the problem. Are the kevlar haters on holidays?
Is it possible or likely that the drum just broke due to age and not from heat from improper driving?
Very possible Tom. As another poster previously made mention, I have found old engines with cracked drums that still had cotton bands. Drums cracking has been around much longer than Kevlar. I believe many of the cracks as shown in the webs and between rivets have been that way since the car was new. Those are thin castings and if cooled too quickly during manufacture they can easily crack. Also, riveting places expansive forces on those fastener holes and I'm sure many of these have been with the drum since day one.
Here are some pictures of how a cracked drum can cause damage to more than one band. The cause here was the pedal bent so that the band was too tight when the pedal was 1 inch above the floorboard. I had to replace the cams and bend the pedal to fix this problem.
While I knew I had one cracked drum, the magnaflux found one on the reverse drum which I could not see with a magnifying glass under bright light. This is my first personal experience with this process and even though I have had engines rebuilt and paid to have the block magnafluxed, I had never seen it done. The machine shop found to do it only charged $10 per drum which I thought was reasonable. So the stock of used drums I had is now less. I guess I now know why new ones are available! And I might become a customer soon.