MTFCA Forum

My low speed pedal notch is bad, really bad. I thought by the way my brake and reverse pedals worked they seemed ok...however take a look what do you think of my pedal notches are they still acceptable or not ?

Larry, because the ramp is part of the pedal, it is not easily corrected, as new pedals are not available. A new notch will help, but the pedal needs to be removed from the shaft so the ramps can be welded up and refinished to compensate for the wear. Just don't add too much weld and remove all the play between pedal ramp and notch. There has to be some to be able to hold neutral with your foot on the pedal.

Hope this helps.
Allan from down under.

Check the pedal notch fit with a new hogshead notch and go from there. Good luck to you,

Ok.. thanks, that's what I'll do hold it against a new notch and make it fit..

Please excuse me for butting in, however in relation to this I wonder if anyone has specifications for the pedal cams?

I've had a look at the service manual but it doesn't mention anything - perhaps they were all too new when that was written - but it'd be useful to know what the cam/ramp dimensions should be?

My reasoning is that I have some obvious wear in my 1st gear mechanism, but I'm not sure if it's the 'notch' or the pedal - or both - that needs replacement or building up. Without a standard by which to measure I remain in the dark...

Thanks.

Is your car RHD or LHD?

Scott,

Mine's LHD - '25 trans, if that makes a difference.

LHD cars have a replaceable pedal support (inside) and a notch, which slides over, and is riveted onto the low speed pedal shaft. On the low speed pedal itself, there are no pedal ramps to wear out or require building up. As JAB35 mentioned to OP, Replace the pedal support and notch with new and you should be good to go (though you might wish to replace the shaft, too, if it leaks too much oil).

Shaft replacement and lip seal installation is an entirely different subject.

Thanks Scott. Our RHD cars are as I indicated. The pedal shown at the start of the thread is a LHD brake pedal? That shows ramps like our first gear pedal. I missed the fact that it is not a first gear pedal. Given the use the brake pedal is likely to have had, the same repair procedure as I outlined could be used, but with the brake pedal there is no need for play between the pedal ramp and the notch ramp. Or am I still missing something?

For those unfamiliar with RHD hogsheads, there are external adjusters on the brake and reverse pedals, and internal adjustment on the first gear pedal, the exact opposite to LHD covers. Hence the differences in pedal ramps.

Allan from down under.

Allan

I don't think you missed a thing (and I agree with everything you said)...I was just responding to Luke in sort of a sidebar regarding his low gear question (that's why I was asking Luke if he had a LHD car, knowing he lives in RHD-land and didn't want to confuse things!)

Scott,

Thank you very much, however I mixed up my pedals - it's the brake pedal that's the issue, not first gear, sorry!

Do you know of any dimensions for that pedal, particularly around the ramp boss?

Luke, if you purchase a new notch, let that be your guide as to how much your pedal ramp needs to be built up. On a brake pedal, the two are a neat fit. Build up plenty, so you have plenty r to work with. The working surface is both angled and twisted. Some beating blue will keep you on track as you work the ramp.
Hope this helps.
Allan from down under.

Was wondering why the slow speed notch looks so different, spring end looks shorter then the replacement (pin to end distance). Also the notch & cam need to mesh properly - one could be more worn than the other but due to the effort I replaced both. Also don't forget the O-rings.

OH its the Brake pedal - I believe that the flat spots on the notch is important for pedal return on the cam (good springs too). No idea what dimensions are supposed to be.

Don't have the time read everything that's been written above, so if it's already been mentioned, than please excuse me.

Both the notch/cam AND the pedal need to be replaced/repaired in order to make things work right. One is no good without the other.

As suggested above, using a new notch/cam as a gauge is excellent advice. However, even if the ramp of the pedal cam matches the new notch nicely, you still want to assure that there is minimal play between the two before the pedal engages with the notch and begins to ride up on it.

you can carefully weld the pedal and dress to where you have full contact. It’s a slow process, but the end result is close to new.

Allan wrote: ↑

Fri Feb 14, 2020 3:59 am

Luke, if you purchase a new notch, let that be your guide as to how much your pedal ramp needs to be built up....

Yes, thanks Allan (and others), however I don't have a new notch at this stage - and don't know if need to get one or not without any standard to measure it or the pedal by.

Larry and others may be in a similar position too; while one could get a new notch and then 'adjust' the pedal to suit it may not be necessary. In my case while I'm happy there's more play than I'd prefer between the pedal and notch it may be that the owner prior to me just put in a new notch and didn't do anything with the pedal.

I could buy a new notch and go from there, but they're ~8,000 miles from me so with a fair bit of postage and a Govt that wants to tax the hell out of everything it's a lengthy and expensive process, especially if not needed. Hence my enquiry around whether there were any published dimensions I could use to measure the wear on my pedal (and, by association, notch)?

To be fair I'm being a bit lazy as I've not really had a good look around myself. I did check out the service manual, thinking there might be some wear limits mentioned in there (there weren't), but hadn't gone much further. When I saw Larry's thread it seemed an opportunity to enquire...

Obviously one could just make an experiential assessment and built up one or both components to reduce the play, but IMV it'd be better to keep as close to the original design specs as possible. If I should come across anything I'll report back

Here is the answer to your question:

If you can get full, hard band engagement with the pedal just off the floorboard, AND there is NO chance of the pedal running up/off the support when fully engaged (you gotta look), AND when the pedal is released, your bands are SLACK on the drums, AND there is little to no "creep" with the car after starting, then things are not too worn, and you are good for that band. Check all 3.

Heat, overheated drums, and damage can and will occur if you must run bands so tight as to be effective when ramps are worn out. I believe this is equally causative of transmission damage as poor driving habits which is typically blamed as root cause to drum damage.

All ramps/notches ARE worn and not to spec unless you have fully rebuilt things, but as you suspect, some wear can be lived with.

As noted in previous posts, unless two new components are fitted, all existing components are worn somewhat. In the absence of specifications, a new ramp will eliminate half the wear problem, and give a reference for the wear on the pedal.
With a built up pedal ramp, finishing it to work well on a new ramp takes time and patience to get a good close relationship between the two components. The ramp is a spiral. By using bearing blue as you go, it will give you a guide as to where to remove material to get a good sliding fit. A real complication is the fact that BOTH built up surfaces have to be worked on simultaneously so each makes contact at the same time. For this reason alone, I would never contemplate building up both worn components and attempting to get each to relate accurately with the other, especially when one of the two is available new.

Allan from down under.

And where did the repro manufacturer obtain the specs. or possibly NOS examples to produce what's available currently on the market ??????

While I am aware of a replaceable low speed notch I don't know of a source for the other pedals other than replacing the pedals (used) or operating on them with a welder/grinder. What Allan just pointed out about getting the notch & cam to mate correctly is really necessary to get the pedals to snap back better and with desired free play. That also helped me understand what I may need to do next on my pedals.

Some time ago, I thought my notches were too worn, because I was having to adjust the bands so low engaged near the floor. I decided to take a scientific look at it. I gathered a bunch of notches, (1) my original one, (2) a spare used one, (3) a new one from Snyders, (4) one thought to be NOS, and (5) one of the reconditioned ones that Townsend used to sell. I put a dial indicator on the end of the shaft and measured the angle of the pedal with a digital angle gauge. I got the graph below. The maximum difference was only about 10%, so I cam to the conclusion that this is a nonproblem. - Larry Young

Larry

are you saying it was a non-problem for your situation or are you saying worn cams are a non-problem for the hobby?

Larry,

Top marks for the quantitative analysis!

However it appears there's no free play shown? Was there indeed none, or did you start the measurement at first engagement rather than say with the pedal lightly back against it's stop?

I didn't plot the free play. I'm not saying notch wear is never a problem, but I am saying that I couldn't find a significant problem for all the used notches I could put my hands on. You could always do similar measurements and compare to the graph.

Thanks for clarifying.

So, ignoring the free play, cams are about the same for a given rotation. Not surprising to me as ramps don't tend to wear "flatter" to any real degree in my experience.

So, for the sake of analysis, assuming that total throw for a pedal is about 30 degrees, limited by the floorboard, then considering free play, let's say that a new pedal support rotates 10 degrees of free play and then rotates the remaining 20 on the ramps (0 to 20 degrees on the graph). And then assume a worn pedal/support rotates 15 degrees in free play and then rotates the remaining 15 degrees on the ramp (0 to 15 degrees on the graph). One could argue that total movement/rotation is more or less than 30 degrees, but it won't vary much, nor will the basic findings relative to lost motion due to wear.

For the sake of ease and dealing with only one set of numbers, I picked your original cam to input theoretical free play increase (which is how the wear manifests itself), and it shows that the movement difference of 15 absolute degrees vs 20 absolute degrees is a difference of .16" sideways vs .23" sideways "squeeze" on the band. Those numbers are I think a reasonable "guesstimate" that I figure from the low fidelity of the graph. That's a 43% increase in "squeeze" with a new notch with less free play vs a notch with typical-to-excessive wear. That difference is the difference between a blown up drum/transmission and 25,000 miles of trouble-free touring.

On our RHD cars, it is the first gear pedal which has the internal adjustment/outside pedal ramps, just like your LHD brake and reverse pedals. Unlike your problems with worn pedals/notches, when rebuilding our first gear pedal, we HAVE to incorporate some free play to be able to select neutral with the foot. I can see no reason for any free play on the brake and reverse pedals. If there is any, it will reduce the amount pedal travel available to clamp the bands. OR have I got it wrong?

Allan from down under

Allan

you're right on the money

Larry: Thanks for sharing that graph, and taking the time to make the measurements. Comparing the 'shaft movement' over the range of rotation, it appears to me there's up to 30% more band tightening motion with the new notches vs the original for the same amount of pedal travel (shaft rotation). ('Townsend' vs 'original' at rotation of 25 degrees in graph). To me, the demonstrated effect of notch wear is significant here, and in addition as others have suggested, coupling this measured wear with wear-induced increase in free play, suggests notch wear is something to be aware of even if many do not consider it a 'problem'. jb

CamMan wrote: ↑

Sat Feb 29, 2020 2:44 pm

Some time ago, I thought my notches were too worn, because I was having to adjust the bands so low engaged near the floor. I decided to take a scientific look at it. I gathered a bunch of notches, (1) my original one, (2) a spare used one, (3) a new one from Snyders, (4) one thought to be NOS, and (5) one of the reconditioned ones that Townsend used to sell. I put a dial indicator on the end of the shaft and measured the angle of the pedal with a digital angle gauge. I got the graph below. The maximum difference was only about 10%, so I cam to the conclusion that this is a nonproblem. - Larry Young

Shouldn't the "new" and "nos" lines be identical? Since they are not, they are showing up at your doorstep not being within original specifications to begin with unless I am not understanding something.

Who knows about these parts. The "new" may have been a newly made copy of a worn out notch. When people talk about NOS Model T parts, that is just their opinion, right? Just consider this a random sample of notches found in my garage.

Jerry VanOoteghem wrote: ↑

Fri Feb 14, 2020 11:31 am

.... Both the notch/cam AND the pedal need to be replaced/repaired in order to make things work right. One is no good without the other.
....

YES! Unless your someone that would use old push rods and a new cam