I have a friends engine in my garage. We are going to freshen it up and repair a few noticed problems. One of the problems was initially excess thrust clearance. When depressing the clutch pedal the drive shaft would move a noticeable amount. With the engine in the garage I tried to move the crankshaft with a pry bar, but it would not move very much. Yet pushing on the clutch pedal I can see the drums move. I did a quick measurement and found that the drums are moving at least 0.060". Looking through the hogshead hole, I can see that the flywheel is not moving. The entire back side of the transmission is moving. I am guessing that the thrust washers that are between the disk drum and the brake drum are either worn or were incorrectly assembled. Any ideas? Thanks Mike
My tranny was worse than that because the rebuilder yrs ago had installed bronze or brass washers and they had worn to nothing. Make sure you install the right spacers. Don.
If those washers are worn enough, the nearest disk can get jammed between the clutch cage and the brake drum. You will be stuck in direct drive and will have to pull the engine to fix it. You can probably guess how I know this.
(Message edited by steve_jelf_parkerfield_ks on November 24, 2017)
Steve, were you missing the distance plate?
Mike, Sounds like the disc drum is loose on the trans shaft. It is no longer a press fit and the set screw may have wallowed out the hole. If it’s a 26/27, there may be a variety of other issues.
Actually that's the distance plate in the first picture. It jammed because of almost .041" wear in the face of the brake drum.
The transmission seemed to work fine, but who knows whether or not something could have jammed up later. The engine is from a 1912 which was running fine. We have not disassembled it yet, let you know what we find. Mike
The brake drum above doesn't look like a 1912!
The brake drum in the picture is from my 1915, not Mike's 1912. And I don't guarantee that it's correct.
12 and 15 should have the brass thrust bushing or so called top hat bushing
If not or one rebushes the trans the need add the 3 washers for the trust or you have exactly mr jeffs issue
I had to install 4 of the.042” steel thrusts in my transmission recently to reduce the end float down to .022”
Also, renew the triple gear bushes with special attention to the
..006 - .010” height on the thrust face above the gear side face. Mike suggested up to .015” maximum due to possible wear on the flywheel mating face
Trans i redoing now i added an extra oil hole on the triple gears catching the spiral oil groove.
Hello N Bob: You say that you add an extra oil hole on the triple gears.Does this mean you drill a hole between the gears down to the spiral oil groove in the bushing? All the triple gears I have used have had no hole in them to start with. Just learning so any advice is welcome.I am a believer in getting oil where it is needed davids
I too ended up pulling apart my transmission. I was replacing pistons and rods and noticed way to much play on the drums. They didn't have lateral movement just down the shaft. the flywheel would also remain stationary. This also gave the triple gears plenty of movement as well. Well following the the guide book for disassembly the stuff that didnt need a puller needed one and the vice versa. I ended up with a shaft cracked down the length of it, no thrust washers that I could find and will be spending a couple K to get it back to spec. My guess for me was extreme heat but I am new to these cars but I can say that I had a car with 2 broken piston skirts and that transmission running and driving when I got into this hobby.
BTW also pulled enough of the oil rings out to make up 6 more pistons.
Driven gear shaft on the brake drum being cracked / broken is uncommon, but it is an issue more common to 26/27 than any of the earlier years. Two contributing factors on 26/27 are the rigidity of the trans and the fact that many 26/27 brake drums didn’t / don’t have rear bushings.
This morning we opened up the engine and transmission. We found that the brake drum does not have the bushing with the flange on it, and there were only two 0.042" washers between the clutch drum and brake drum. When the clutch plates were removed, we found that bottom two plates had fallen away from the clutch drum tabs and had spun around. So, looks like an additional thrust washer will be needed during assembly. Mike
Sounds like you might be missing the clutch distance plate. It's the thickness of 3 plates. Goes on first, then the rest of the disks.
Of course it also depends on what year your brake drum is. If it is the style that had the flanged type good chances are it should have the thicker disk.
(Message edited by redmodelt on December 02, 2017)
The clutch drum wears and increase the distance
I currently redoing my trans.
The clutch drum i have 3 on the bench very by .020
Do to wear
The distance plate is there. Pretty easy to see that it is thicker. How, exactly would you measure for the drum wear. Where to measure and what is acceptable? Thanks Mike
Here are some pictures to go with the one I posted above.
Here's the path worn in the face of the drum.
I applied a dial indicator to the unworn drum face beside the path and set it at 0. When I moved it over to measure the depth of the path it showed the difference of just under .041" shown in my previous photo.
My cure was to fill the path by tack welding a spare clutch disk (.040") onto the spacer. So far this has worked well.
(Message edited by steve_jelf_parkerfield_ks on December 04, 2017)
Steve, thanks for the pictures. This drum has you beat. The step on this drum is more than 0.100". No wonder there were a couple of plates jammed in place. I suppose that maybe this is candidate for a new drum. I've seen this step more than a few times, but realized the relevance. Thanks again. Mike
Yikes ... I don't remember checking this at all on my transmission when I was rebuilding it. Don't remember a thicker disc either. Fingers crossed.
Be aware that the pre 1920 clutch drums are different from the later ones. On pre 1920 clutch drums the distance from the set screw hole to the thrust surface is longer that the later clutch hubs to account for the difference in the top hat thrust washer VS the 3 steel washers. The later clutch hubs will have a ford script on the center area on the set screw side of the clutch hub. The pre 1920 clutch hubs have either no ford script or a ford script on the thrust side of the clutch hub. Using the incorrect combination of thrust bearings and clutch hubs can result in both too much end play and also not enough end play. According to Trent Boggess, the only place this was published by Ford was in one of the 1920 Service Bulletins- I believe the May 1920 one, but not exactly sure. You can search the forum archives for Trent's posting on this. Dan
Mark, your car is too modern to have the spacer.
Dan was going to say that but remember even the clutch drum will have wear
On a side note the clutch push ring is also different.
The pin to the face
I just rebiult two trans from a pile of parts
Learn alot of differences in combinations of variose parts