Yesterday, my son and I spent the better part of the afternoon opening a 1923 transmission. We removed the hogshead after applying a little heat to the bolts/nuts, and the bolts screwed off easily. We spent a long time devising homemade tools for removing the drums (thanks to other threads that showed a variety of useful homemade contraptions), but we haven't succeeded in that endeavor, yet. Those drums are still firmly in place.
Below are pics of the transmission drums. Unfortunately, I didn't get a picture after I wiped all the rusty dust off of them. They are free of cracks and gouges and pitting.
The brake drum, however, has a slight groove all the way around in the very center of the surface. It isn't very deep, but is noticeable when you run your finger across the surface.
It is hard to tell much from pictures, but do these drums appear to be salvageable?
How concerning is the groove in the brake drum? Is there a tool for measuring the depth of the groove?
Band linings will conform to the shape.
That isn't a groove in the brake drum, that is the normal interface between the rear end of the brake drum and the drive plate.
As far as usability, you'll only know after you disassemble the transmission, clean and blast the drums, then inspect them for cracks on the drum surface and in the webs.
You need first to clean it. You will be surprised to see what is usable.
Just take it apart and clean it piece by piece.
This was my 1922 before and after the rebuild. Nearly all parts were reused and it is still running great.
Happy new year to all
I don't think he's talking about the gap between the drums, but instead, the very common groove worn into lots of drums, that are of no consequence when they're not excessive.
If the groove were too big, we'd be able to see it even with the rust and crud still there. Seeing nothing, I'm sure it's fine.
Eric / Jerry, please point out the groove in question, thanks.
As I state in my reply to Eric, "Seeing nothing, I'm sure it's fine". So, seeing nothing, I can't point it out.
Given Eric's original statement, "The brake drum, however, has a slight groove all the way around in the very center of the surface. It isn't very deep, but is noticeable when you run your finger across the surface.", I wouldn't expect to be able to see it. He does not however seem to be describing the gap when he states, "...in the very center of the surface...".
I'm with you Jerry, I see nothing in the middle of the drum, which is why I thought he might be talking about the interface between the rear end of the brake drum and the drive plate
O.K., I see where you're coming from.
O.K., I see where you're coming from.
How'd I do that???
I don't see it either. If it's that minor, and is smooth, it's not a problem. The part most likely to be unusable is the reverse drum. Most of them are cracked. But as Mark says, you won't know what's usable until everything's blasted clean. My guess is that most of it will be OK, maybe even reverse. One thing that can negate that is if the thing sat for years with water in the pan. That can rust away so much of the drums that they're seriously unbalanced.
I don't see the groove except for the line separating the drum from the driven plate. However, you need to clean off the rust and then smooth the drum. If you have access to a lathe which will fit, you should turn it and with sandpaper smooth and polish the surface. Any roughness will cause rapid wear on the band and will also make the brake grab. You should get it as smooth as you can without removing much metal from the surface. The inside is also important to get smooth so that the clutch disks don't stick which would not give you a neutral.
I think the drums will likely clean up nicely.
I like what I am hearing from you all so far and I apologize for not taking a pic after I wiped them down. I will try to upload a couple of additional pics of the wiped down drums when I get home tonight.
The groove is definitely on the center drum (hopefully I correctly called that the brake drum). It is right around the center line of that drum. When I wiped it down, it showed a little more clearly, but it isn't rough and I doubt it would catch on the band lining. I just wasn't sure if there is a certain depth where a groove becomes too deep and risks a fracture/crack in the drum itself.
As far as I can tell, the engine/tranny wasn't sitting in water. There was a lot of rust dust in that hogs head and oil pan, but not a lick of water or oil (except when my son unscrewed three retaining bolts - I think that is what they're called - a bit of oil oozed out to our delight). .
The center drum is the low speed drum:
Those appear to be good drums. They aren't grooved badly if at all.
You'd be surprised how good a rusted and seized up T Transmission will clean up after soaking immersed in a tub or container of diesel oil mixed with mineral spirits.
To each his own on how to clean a transmission up but this seems to work the best for me. Once you get the transmission to turn freely and spin they come apart quite easily.
Remove the drive plate and clutch discs and slowly begin to move the brake drum by hand till it begins to turn. You can see and hear whats worn and needs repairing before you take it completely apart.
Just when I think I'm starting to get the hang of the Model T terminology and getting some street cred, I make a colossal boo boo and mix up the names of the drums. I'm obviously a long way from getting my doctorate in Model T lingo, but loving every minute of this stuff. Sorry for any confusion I caused.
Below are pics of the not so dirty drums. You can see the groove in the middle of the second drum (low speed drum). Upon closer inspection tonight, and considering the comments above, I don't think it is anything that is too concerning.
Now that I've offered a clearer picture of a cleaner drum and a groove that is more apparent, is everyone still of the opinion that the groove isn't something to be overly concerned with at this point?
Check carefully for cracks. They appear in the outside edge of the drum and in the webbing and around the rivets. If no cracks, that drum looks OK. Just make it smooth so there are no sharp edges to catch and wear out the linings. The groove down the center of a drum is usually caused by the rivets. Be sure to sink them into the lining and turn sideways so the ends face the outside edges of the drum.
Agree those look OK, the metal will wear over time, and some drums get well worn, so that the edges of the drum become sharp.
That can cause fraying of the linings. Or cause cracks and broken drums, so don't turn down drums on a lathe to smooth them.
The low drum and brake drum get the most wear, as the low pedal isn't always held firm, so slippage causes more friction, i.e. wear.
Worn linings allow the rivets to gouge the drum too.
Sometimes you find drums with deep grooves, as a some point soft rivets got replaced with steel, oh that is bad on a drum!
Some drums were made with a groove in the center. I guess to allow space for the rivets. I saw a set not long ago. These were not the result of wear from rivets. They were actually made that way.
When you buy new band material and brass rivets, check the rivets with a magnet to make sure that they are pure brass and not brass plated steel.
I think if they are not cracked, you need to chuck them up in a lathe and kiss them with a file. The idea is to get off the crud and smooth them up. Once that is done they need to be polished with several grades of emery cloth, coarser, then finer.
If they still look grungy, you might take a 5 thousandths cut on the surface. You don't want to remove any significant thickness and certainly not enough to take the grooves out of the low speed drum. The grooves are cosmetic and the least of the problems with your drums.
Eric, as others have said, new linings will conform to grooves around the drum with no adverse effect on their performance. I would be more concerned with rust pits in one location. These will scour the band linings much more than any drum groove. By far the best way to eliminate such rough patches is to have a crankshaft grinder grind the drum surface. They can remove minimal material and leave you with a polished surface which will need no further attention.
Hope this helps.
Allan from down under.
Eric: The low speed drum is bad and needs to be replaced. These are usually the thinnest but do the most work. Second I would clean and have a machine shop check the reverse drum as it cracks in the spokes. The brake drum lugs usually wear out from plates coming in contact with them. I would also inspect the gears to see what condition those are in as the teeth also wear out.
J & M,
In the spirit of educating me (and perhaps others), if you don't mind sharing some of your knowledge - why do you state that the low speed drum is bad?
Please understand that I DO NOT in any way question your vast wisdom and experience, as you have a sterling reputation for doing excellent work - my only reason for this post is to ask for more information. Yes, I do understand that this is the thinnest of the three drums,but are there other reasons why you believe this drum to be bad?
Thanks for your time...and Happy New Year.
Hello Dave: Thanks for asking. Most important first is "SAFETY". Then there is reduced surface since it's worn for band rub against
Second reason is that the drum is paper thin to begin with, though it does most work. Having it wear as it is looks dangerous as it is worn in a thin area to begin with. Notice picture I have of the underside of slow speed.
Third reason is it may be cracked as I have sample photo attached.
We've had engines come in with blown drums to go through the hogs head type explosions.
Everyone wants their T to go faster than was initially meant for so Safety of your parts should be top priority.
I have also enclosed photo of reverse drum as this also gets abuse since both feet are used to stop car and reverse gets it. Whether it cracks on spokes or where it is secured to gear in rivet holes.
Believe me it pays to have a reputable shop magnaflux them.
Eric, I see enough pitting on the drum surfaces to accelerate wear of cloth bands, both cotton and Kevlar. If after turning they are still thick enough to be serviceable and without cracks, great. I had some drums pitted like yours and had to adjust bands frequently. I installed new drums from J&M, and after initial wear in of re-lined bands (Kevlar) no adjustments have been needed. While it is apart now, is the best time to make these decisions. It may prevent having to go back in later.
Here is a picture of what happens when a low drum cracks. The car skidded to a stop and could not even be pushed in neutral. Finally had to jack up one rear wheel with a rolling jack to get it on the trailer.
Here is a picture of what can happen when a low drum cracks. The car skidded to a stop and couldn't even be pushed in neutral. Finally had to jack up one rear wheel with a rolling jack to get it onto the trailer.
Norman T. Kling
Thanks for the pictures: I reiterate my first point "SAFETY"
I don't know why this happens, but I click on the thread to see if my post is there and it is not, so I post it again. Then later, several hours I click again and find it posted twice. Why does it take so long to actually get posted after I click? It didn't used to be that slow.
I don't think we have enough info to make a decision on these drums. They need to be cleaned up and checked for cracks. The low drum appears to have the least pitting.
I suppose if you strive for perfection you could just toss these and buy new drums and gears.
The same double post thing is happening to me too Norman. I click to check, find it isn't there, rewrite it and then both posts show up later.
Allan from down under.