MTFCA Forum

Last week I made a panic stop in my 24 touring from about 35 mph and slid the rear wheels about 40-50 feet. Since then the high gear clutch has been grabby, and the parking brake lever movement is stiff. Did I break, bend, or pull something out of adjustment?

That would seem to be the case. Exactly what procedure did you use to stop the car? Pulling the brake lever back quickly may have caused some kind of damage to the cam device on the brake cross shaft under the floorboards. If so, that could affect the lever operation and the clutch action.

I only used the transmission brake, and after it hit me I that I was sliding (I didn’t even know it was possible), I eased up on the pedal and came to a normal stop with the engine running.

That's puzzling, at least to me.

Remove the trans inspection cover and jack up the rear so that you can turn and inspect the brake drum thoroughly for damage or breakage. If you were truly using only the trans brake drum, and the engine stayed running, then you obviously were holding the clutch pedal in neutral, so the clutch discs, the clutch release lever, and the brake handle/cross arm/cam were not involved. You may have cracked or broken your brake drum or the web of the drum which now affects how the clutch discs engage and disengage.

If you had stalled the engine, meaning you didn't step on the clutch pedal and go to neutral, then the discs are also involved, but you said this was not the case. If there was a Rocky Mountain Brake Equalizer mounted on the cross shaft, then a hard stomp on the brakes might bend or distort the cross shaft, but again this apparently was not the case.It appears that only the brake drum and brake band were involved in the stop. I think the drum may be damaged which is now causing clutch disc engagement/disengagement problems.

Is the parking brake lever only stiff while it's trying to rotate the clutch bell-crank to put the transmission in neutral? And, when you say the clutch is grabby, is it because it's difficult to get in disengaged by pushing on the clutch pedal?

Jeff, I may very well have stalled the engine in the slide, but I did release pressure on the brake before the car came to a complete stop, then used the brake and clutch ( to get neutral) to roll to a normal stop. I definitely remember the car idling as I was collecting my thoughts.

Jerry, by the clutch being “grabby”, I mean that when releasing the pedal to shift from low to high, no matter how slow I let out the pedal it shifts abruptly, which it didn’t do before. One other person that drove it described it as shifting like a “jackrabbit” clutch. Also, it’s more difficult now to find neutral with just the pedal. Pulling the brake lever to straight up still gets it into neutral ok.

I have noticed that one of the items on the MTFCI tour safety checklist is to verify that the brakes are capable of locking up both rear wheels under hard braking, so I didn’t think it was a big deal at the time.

Miles,

Remove your transmission inspection cover and have a look where the transmission output shaft is riveted to the driving plate. Hard stops can sometimes cause those rivets to shear off or loosen. While looking at that joint, rock the car back & forth, looking for movement/play in those rivets. Don't drive it until this issue is resolved.

Here is an extreme case... viewtopic.php?f=2&t=18908&p=144005&hili ... ts#p144005

"...one of the items on the MTFCI tour safety checklist is to verify that the brakes are capable of locking up both rear wheels under hard braking, so I didn’t think it was a big deal at the time."

I've always been a bit troubled by that statement. Being able to lock up the wheels, in my mind, is more of a theoretical thing. Given how my braking in general feels, I have a "sense" that there's more braking available to me, should I need it, and that I could lock things up. I would never actually test the "lock-up" however to see if that's true. You only get so many of those stops with a T before something goes "pop". Locking up T brakes is always a big deal. With hard stops, also learn to use the parking brake as an additional assist. It keeps some of the strain off of the driveline. What you don't want, is to glide to a stop with the brake pedal on the floor, knowing that you couldn't possibly stop faster if you had to.

I do not know how the clutch disks got broken, but in some used transmissions I have picked up as spare parts over the years, the clutch disks will be blue and sometimes will be broken. So maybe that is what happened. If you went into neutral at a very high speed and stayed in neutral, they could get hot, or the heat of the brake drum could cause the disks to get hot and then when you came to an abrupt stop, some could break.
Or depending on whether you have the original type disks or one of the modern replacement clutches, such as Jackrabbit or Watts, you could also have damaged something inside. You might not be able to determine just what it is without disassembly.
Norm

I'd look very carefully at everything on the outside, front to rear, including the rear hubs, before tearing into it.

Jerry VanOoteghem wrote: ↑

Tue Jul 12, 2022 9:33 am

Miles,

Remove your transmission inspection cover and have a look where the transmission output shaft is riveted to the driving plate. Hard stops can sometimes cause those rivets to shear off or loosen. While looking at that joint, rock the car back & forth, looking for movement/play in those rivets. Don't drive it until this issue is resolved.

…

I’ve rocked the car in 3 different positions so I could see all the rivets, and they all seem tight.

Looks good Miles. Your brake band lining is a little scarce on the left end, but that's not your immediate issue.

It's possible that one or more clutch lug shoes has cracked or broken.

Could it be that a piece of the brake lining folded under & is creating extra drag? You might try backing off the brake bane & see if there is a change. Your band is way gone, near metal to metal, if not actually. The return springs dont look stock. They appear much weaker in function.(probably not related, just saying for future reference)

This drum is unlikely to have the replaceable shoes. There is a strong possibility that the lugs are deeply grooved, (arent the all?) effecting clutch disengagement.

The clutch adjusting bolt is riding the edge of the cam on the brake cross shaft. That could affect how the brake lever operates, especially if there is any side play in the brake cross shaft or in the clu tch release shaft. The bolt should contact the cam face near its center.

You do not have a proper "leading ramp" on the cross shaft clutch cam! That probably is not the cause of your trouble, but does need to be corrected.

With a proper leading ramp on the cam lever, the small end of the bolt digs in and drags a bit much when the brake lever is pulled back. So I usually grind a bit of a ramp in the bolt's head, and flip it over so that the head of the bolt, with the ramp properly facing the leading ramp of the cam lever, is down below the clutch shaft arm. Put the locking nut on the top side once the clutch is fully adjusted.
The clutch and hand brake work mush more smoothly that way.

I hope you find your immediate problem.

Well spotted Wayne. I wonder how it came to be that way with no lead-in ramp?

The brake drum on the transmission shows that the driven plate, the edge of which is part of the brake drum surface, is not being contacted by the band. This is a common fault when piecing together a transmission from assorted parts. The driven plate has been worn more than the drum, so the band is just engaging on the narrower drum surface. It is often difficult to find a good combination of driven plate and drum to get a full width brake surface. Too great a difference between the two components will lead to compromised wear on the band linings.

Allan from down under.

I drove the car about 5 miles after the above picture, and another 5 miles after arriving in Hamilton, and could feel an occasional slight “bump” in the pedal on moderate braking. Upon checking the oil screen I found it completely plugged with lint, and even more of the end of the lining gone - time to change the brake band lining. Fortunately, it being a big tour, I had LOTS of help to get the job done. Unfortunately, because of an unusual style of brake band, we didn’t discover it had removable ears until AFTER we’d pulled the hogshead . Only one of the long-time Model T guys helping had seen bands with screw-on ears before, and he didn’t show up until the rest of us had the hogshead off…
Once we got the brake band out, we found that the lining had completely separated from the first rivet in the forward direction of rotation, and I’m sure others were soon to follow suit. The good news is that all drums are in good shape and crack-free. That apparent scoring on the brake drum is just a “polished” line where that first rivet had just started dragging, nothing that could be felt with a fingernail.

Whether my fault or the vendor (I haven’t gone back and checked the order), the band lining kit I had with me was for a 26-27, with the wide brake band. The low and reverse linings in the car looked serviceable, so we only replaced the brake lining. The engine is due for rebuild this coming winter, so the other linings will get replaced at that time.

I did ask about the clutch cam setup (the guy who was familiar with the unusual bands), and he said his was set up the same way. It may not be obvious in the above photo, but there is a lead-in ramp on the end of the bolt. He did say that the linkage clevis and pin were worn excessively, and should be replaced before long. He adjusted the linkage a bit, and it does shift a bit smoother now.

After getting the hogshead back on and the bands adjusted, we were running out of daylight and having an issue getting the starter bendix reinstalled, so we just put the bendix cover back on without the bendix to get the car back in the trailer for the night. Once we get the bendix reinstalled and deal with a moderate oil leak it should be good to go. I am truly grateful for all the help available in the Model T “family”!