Emergency brake mechanism

Mark/WI · Post by **Mark/WI** » October 17th, 2003, 12:14 pm

I have a model AA truck. The frame and engine serial #'s match and date to June of 1929. The truck does not have a special set of shoes for the emergency brake. The emergency brake lever is found on the left side in front of the drivers door and when it is pulled it operates the same mechanism as the brake pedal. As a result there isn't a brake light switch because when the emergency handle would be pulled the brake light would be on. Is this an unusual system for a 29 AA?

Neil Wilson · Post by **Neil Wilson** » October 20th, 2003, 10:13 am

It is very unusual to have a June '29 AA truck without emergency brakes. What is the engine number?

Most '28 AA's and some early '29 AA's came without emergency brakes. This brake system is the same as the early A's.

There should be a stop light switch. The linkage rod to the brake peddle is designed to allow the side hand brake to be applied without activating the switch.

Mark / Wi · Post by **Mark / Wi** » October 20th, 2003, 12:15 pm

Neil The engine number on my AA is 1705287. The vehicle has a two tooth steering gear box and a conventional looking differential (not worm gear type). It has been a farm truck in Wisconsin all its life. I can not find any location for a brake light switch. Do you think it could be a 29 frame with a 28 cab? Any additional info. to help me find out what type of truck I have is greatly appreciated.

Mark Goretski
Fond du lac Wi

Neil Wilson · Post by **Neil Wilson** » October 20th, 2003, 5:20 pm

The original engine number should start with AA followed by a number. There would be a star on each end. Is this the case for your truck?

I don't know what you mean by a conventional rear axle. Most '28/'29 AA's had a worm drive rear axle. The '30/'31 AA's had a bevel rear axle. There was a rare bevel rear axle on some '28/'29 AA's which looked like an oversized A rear axle (i.e. it was a banjo style). Can you describe your truck's rear axle more?

The closed cab is the same for both '28/'29 and this cab was used until about May of '30. Some pictures of your truck would help.

Mark / Wi · Post by **Mark / Wi** » October 21st, 2003, 5:53 am

Neil the engine serial number has what looks to be the top of 2 A's in front but there is no star at the end. The boss is pitted so maybe there was at one time. The rear axel is the one that looks like an oversized car axel it is not the worm gear type. It was the axel, the budd wheels and the two tooth steering gear that led me to believe it is a 29. Can you think of any other areas on the truck I could check to find out what year of truck I have. I don't have the ability to send a picture now but I am working on it.

Mark Goretski
Fond du lac Wi

Neil Wilson · Post by **Neil Wilson** » October 21st, 2003, 9:00 am

Mark,
The oversized car axle was probably a late '28 and '29 AA axle. Very few of these axles were made since most '28/'29 AA's have the worm drive axle.

The '29 AA's had concave six spoke disk wheels. The '30/'31 AA's had convex five spoke disk wheels. Which style of wheel does your truck have? The '30/'31 wheels will not fit on a '28/'29 chassis (at least not properly for driving).

What is the width of the front and rear brake drums? What is the width of the front spring (should be approximately 1-3/4" or 2-1/4").

Is there a three or four speed transmission?

The brake switch attaches to the three speed transmission. With a four speed transmission the brake switch attached to the #2 cross member.

FYI - I use a 35mm camera. I have the store put the pictures on the Internet so I can send them to anyone via e-mail.

Mark / Wi · Post by **Mark / Wi** » October 21st, 2003, 11:05 am

Neil, The truck has 6.00x20 tires on a budd type convex split rim. It runs duals on the rear. The center hole is 4 9/16 inch. The transmission is a 3 speed and it has an auxillary transmission (high,low) with a shifter pedal on the floor to the left of the shifter. The hubs look like large bowls. I will have to waite for the weekend to get you the sizes on the hubs and the springs. Thanks for helping me try to narrow down the year this truck is.
I will check on the transmission for the brake light switch. Do you know of any sites that might show a picture or a diagram of the braking system I have?

Mark

Neil Wilson · Post by **Neil Wilson** » October 21st, 2003, 5:34 pm

Hello Mark,
Dual rear wheels were not available until 1930. Neither the worm or special bevel gear axle for '28/'29 came with dual wheels and the '30/'31 style wheels will not fit correctly on the '28/'29 rear axles.

The three speed with dual high is a '28/'29 feature. The side hand brake lever is a '28 to early '29 feature. If the front brake drums are the same size as the rear drums (i.e. both large bowls), then that is a '30/'31 feature.

So, your truck has had some changes over the past 70 years. It probably started out as an '28 to early '29 since it has the side hand brake. This feature would probably not have been added to a later vehicle. The later AA frame would not have been punched with mounting holes for the side hand brake lever and the cowl would not have had a hole for the lever

The stop light switch is the same as a Model A. I don't know of a diagram for the various AA brake systems.

Let me know about the measurements I requested and maybe that will yield more information.

Mark / Wi · Post by **Mark / Wi** » October 27th, 2003, 5:07 am

Neil the front spring width is 1 3/4 inch and the rear spring width is 2 1/4 inch. The brake drums are the same size front and back. The diameter is about 12 1/2 inch and the width is about 5 3/4 inch. No brake light switch and only one wire runs to the rear light which is located on a frame support before the rear axel and about 4 1/2 feet from the spare tire holder.

Mark/Wi

Neil Wilson · Post by **Neil Wilson** » October 27th, 2003, 8:29 am

Hello Mark,
Your truck is becoming more of a challenge to identify!

The '30/'31 AA's had the same brake drums on both the front and back (about 5 3/4"). The '29 AA's and some '28 AA's have front brake drums the same size as the Model A and the larger brake drums on the rear. Most '28 AA's have front brake drums the same size as the Model A and the larger diameter brake drums on the rear. However, the rear drums are only about 3" wide because there was no emergency brake bands in the rear drums.

These '28 AA's have the hand brake lever left of the steering column. The hand brake lever activates the four service brakes. Both the rods between brake peddle-and-cross-shaft and hand-lever-and-cross-shaft have a 2" slotted hole where they pin to the cross shaft. This allows the hand brake lever to move the cross shaft without pulling the foot peddle and the foot peddle will work without moving the hand lever. The stop light is attached to the left side of the transmission top and a wire linkage attaches the switch to the brake peddle. So when the foot peddle is pushed, the stop light is turned on. When the hand brake is pulled, the stop light does not turn on.

The '28/'29 AA's have 1-3/4" wide front springs. The '30/'31 AA's have 2-1/4" front springs. The tail light/stop light should be located at the rear of the frame (left side).

Check the front spring perches. Do they have shock absorber linkage balls? Check the front cross member. Is it riveted to the frame side rails? Is the throat of this cross member the same width as the front springs (i.e. is the front cross member 1-3/4" wide where the front spring fits into it)? Check the #4 cross member (the one just slightly in front of the rear axle). Is the top of this cross member flat or does it have a fairly high hump (i.e. looks like a camel)? Check the rods between brake peddle-and-cross-shaft and hand-lever-and-cross-shaft. Do they both have a 2" slotted hole where they pin to the cross shaft? Describe the spare wheel carrier (location and general design).

Mark / Wi · Post by **Mark / Wi** » October 28th, 2003, 10:45 am

Neil here comes a few more pieces of info. It seems like my AA is a 28,29,30,31. It has parts from each year. It must have had an interesting history. The front spring perch does not have a ball for a shock absorber.

The #4 cross member has the camel hump. There is a two inch oval hole in the brake rod linkage that allows for separate movement of the brake pedal and emergency brake handle. The spare tire holder is at the rear end of the frame. It looks like a straight cross member turned upside down.

Mark /Wi

Neil Wilson · Post by **Neil Wilson** » October 28th, 2003, 7:55 pm

Hello Mark,
The February 1930 Ford Service Bulletin indicates that the new 1930 style axle can be used to replace the prior worm drive axle when the emergency brake lever is in the center.

The problem with switching out the axle is that the truck owner would then be stuck with the 1930 wheels on the rear and the 1928 or 1929 wheels on the front. This situation would be a problem for carrying a spare since two different wheels would be required. In addition the front and rear lug nuts would be different sizes.

It looks like your truck had the rear axle switch and also had the front end replaced with the 1930/1931 front end. Since the 1930/1931 front spring could not be used, the 1928/1929 spring perches and spring were retained during the conversion.

This conversion was done on a truck without separate emergency brake bands which the bulletin did not suggest. Your truck must be a 1928 (possibly an early 1929) because of the left side hand lever. The emergency brake bands in the rear axle are not being used (and may have been removed during the conversion).

There should be a stop light switch mounted on the three speed transmission top. There should be two wires running from the switch at the bottom of the steering column. One wire for the tail light and one wire routed through the stop light switch for the stop light. The stop light switch is the same as was used on the Model A.

The spare tire carrier sounds like a non Ford item. If you send me a picture of it, I will be able to see if it is an origional AA carrier.

You are welcome to join the Ford Model AA Truck Club. If you send me an email to wilsmor@juno.com, I will send you a membership form.

Mark / Wi · Post by **Mark / Wi** » October 29th, 2003, 5:40 am

Thanks for all the help Neil. Do you know of any Model AA picture sites?

Neil Wilson · Post by **Neil Wilson** » October 29th, 2003, 6:11 am

Hello Mark,
I don't know of any sites with AA truck pictures. The FMAATC newsletter usually has a full size page pictures of an AA.

aa-fords.com