brake pedal pad woes

[qmdv]

I bought a brake pedal several years ago. Not even sure who I got it from. I seem to have lost the nut that goes on the stud. I tried a 1/2 fine thread nut and it is too small. I checked the thread pitch and it is 18 threads per inch. So I ordered an ever popular 9/16 -18 nut. It just falls on the stud. Much too big. So I finally got out the calipers and it measures .520 inch. Is that some sort of metric thread.

[19Fordy]

I think that thread is a tapered pipe thread.
https://www.engineersedge.com/hardwa...pe-threads.htm

[V8COOPMAN]

Originally Posted by 19Fordy

I think that thread is a tapered pipe thread.
https://www.engineersedge.com/hardwa...pe-threads.htm

I believe Jim (19Fordy) is correct. Those things are 1/4" NPT, which coincidentally is 18 threads/inch. DD

[fordv8j]

Originally Posted by qmdv

I bought a brake pedal several years ago. Not even sure who I got it from. I seem to have lost the nut that goes on the stud. I tried a 1/2 fine thread nut and it is too small. I checked the thread pitch and it is 18 threads per inch. So I ordered an ever popular 9/16 -18 nut. It just falls on the stud. Much too big. So I finally got out the calipers and it measures .520 inch. Is that some sort of metric thread.

Don't they just screw into the pedals, our 38 does

[qmdv]

Originally Posted by fordv8j

Don't they just screw into the pedals, our 38 does

I am building a 32 high boy roadster with a rumble seat. The original roadsters had a pad of sorts mounted to the top of a fender. I will not have fenders and I bought this pad to mount on a bracket I will fabricate that will be mounted to bolts that fasten the rear spreader bar. So step on that pad, then onto tire and then slip into rumble seat.

How many folks you know that have a 1/2 by 1/4 inch tee to check the threads on a Ford Peddle pad. I will just get a 3/8 by 1/4 bushing and trim it down.

[Don Rogers]

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One of the reasons for confusion is that the early pedal (B-2454) had a 7/16 - 20 threaded shaft and the later pad (40-2454) had a 1/4 standard taper pipe thread.

[petehoovie]

Originally Posted by Don Rogers

One of the reasons for confusion is that the early pedal (B-2454) had a 7/16 - 20 threaded shaft and the later pad (40-2454) had a 1/4 standard taper pipe thread.

[qmdv]

Cannot imagine why a pipe thread was used. if something heavier that 7/16 fine was needed I think 1/2 fine would have been just fine. Due to the fact that I already have the pad that is a pipe thread I am fine with a cut down pipe bushing. I am fine with using the word fine too many times

[JayChicago]

Originally Posted by qmdv

I am fine with using the word fine too many times

I love the humor I see injected into so many otherwise serious, technical posts! Puts a smile on my face, makes the day a little brighter.

[DavidG]

40-2454 was also used for the '37-'39 rumble step pad on the fender.


qmdv,

The pipe thread pedal pads were a lot easier to install on the assembly line where time is money.

[qmdv]

Originally Posted by DavidG

40-2454 was also used for the '37-'39 rumble step pad on the fender.


qmdv,

The pipe thread pedal pads were a lot easier to install on the assembly line where time is money.

There does not seem to be any taper on the stud. So with 18 threads per inch on the 1/4 pipe thread and 16 threads per inch on a 1/2 inch tread, i would think that it would take just a tiny weeny bit longer to to screw in the one with 1/4 pipe. But here I am second guessing an engineer.

[DavidG]

Sine of the reproduction pads of that type do not have real pipe threads and perhaps you have one of them. Original pads' studs are tapered.

The pads went on after the pedals were installed in the chassis and the body was installed. That meant that the workers had to reach around the back of the pedal with the pad in place, put on the lock washer and nut, hand tighten the nut and then reach around with a wrench to finish tightening the nut. With the pipe-threaded version everything was accomplished in front and the pad could be hand tightened. A tapered stud is much easier to start threading than the thin nuts used on the studs on the earlier pads. The difference in time spent would be small, but probably more than "tiny weeny" especially added up over hundreds of thousands of pad installations over the course of a model year.

In addition to a time savings there would have be a piece cost savings as the pipe thread pad was a simpler design requiring less tooling and the nuts were no longer required. Even if the nuts were only a penny's savings each, two cents times 200,000 in depression-era dollars would not be sneezed at as a cost savings.

(The 36+ versions had two round recesses in the rubber on the face of the pad and a special tool was used to fit in those recesses to tighten the pad on the pedal. That extra step cut down on the time saving.)

[qmdv]

Love this stuff

[paul2748]

If the studs seems to be a straight thread, try a metric nut on it.

[JSeery]

As David posted, there are same (maybe a lot) of pedals out there with pipe thread specs but without the taper. It is my understanding that this was just a screwup on the part of some overseas supplier.

[qmdv]

Originally Posted by JSeery

It is my understanding that this was just a screwup on the part of some overseas supplier.

The one I have is not tapered and it is made in USA

[DavidG]

Nobody's perfect.

[jimvette59]

Pobody's Nerfect ! There are straight pipe threads look on a old thread chart. JMHO

[JSeery]

Originally Posted by jimvette59

Pobody's Nerfect ! There are straight pipe threads look on a old thread chart. JMHO

Good point! I had forgotten about that!!

Straight pipe threads are designated NPSC = National Pipe Straight Coupling.
Also generically referred to as "IPS Threads" or "Iron Straight Threads".

I remember reading a lot about the different brake pad threads years ago, but don't remember enough apparently!!!

There is a 1/4-18 & 3/8-18 specification for NPSC threads. Based on Don's post #6 a supplier may have used the NPSC spec.

There are NPSC nuts, I'm seeing them listed as NPT Straight. Looks like most are brass.

[nickthebandit]

Where did you come up with 1/2"-16 thread ? The typical 1/2" thread is 1/2"-13, or 1/2"-20.