brake actuating arm angle

[Lona]

I have read and re-read Mad Mac's thread of 1/4/14 and the knowledgeable replies by Marco Tahtaras, Patrick L, and Purdy Swoft and think I understand the process of adjusting the front brakes on my '31 roadster. But I have another problem seemingly not covered in those discussions. My recently acquired A had been undriven for 19 years so a complete brake inspection seemed prudent even though they seemed to work ok on the short pre-purchase test runs.

On inspection, both front spindles were found to be worn, the outer bearings shot, roller tracks worn and some non A parts used. (discussed in a previous thread). Therefore, to be safe, I decided to replace all of the brake parts including the spindles but not the shoes which appear to be in good shape. Because of worn studs and threads where they mount to the spring perches, the actuating arm housings were also replaced with some used ones from Berts. These housings came with actuating arms attached.

Checking the parts before assembly, I noticed the new actuating pins are about 1/8" longer than the old ones but the same length mentioned in Les Andrew's red book. Also, the new actuating arm housings from Berts have a smaller circumference than the old ones and the grease fitting is in a different location. However, the end fits into the new king pin housings fine and the perch studs are the same. Berts actuating arm ball recesses are not new but are much better than the old ones which were a bit worn. The old setup had pills at the bottom of the actuating pins. I did not think to check the 15* forward slant of the actuating arms before removing the old parts.

After assembly, the lever appears to be expanding the shoes nicely and the springs return them ok. However, the actuating lever is well forward of the desired 15*. Hard to tell without a protractor handy but they seem to be about 25*. Is this because the actuating pin is too long? (no pills were used in the reassembly). With the adjusting wedge turned completely out, there is drag on both the leading and trailing edges of both shoes even with chamfering the shoes from the end back to the first rivets. However, the shoes and drums were matched and working ok when the car was purchased. I have not yet centered the shoes and hesitate to do that until this 15* question is resolved.

Is the excessive forward angle of the arm a problem so long as this slack is removed by final adjustment of the brake rod clevis ends? Will the arm angle reduce closer to the 15* after the shoes have been centered in the drum? By turning the drum without the wheel on, the brakes seem to lock up with the arm in the vertical position even without centering the shoes but with the car rolling, the levers might go beyond vertical. Should I do anything about this excessive arm angle and, if so, what?.............Glen

[Tacoma Bob]

Been quite a while since I did mine but collectively I think the entire system is set up with the 15' for the fronts factored in. I'm unsure if the clevises have enough adjustment to compensate. I would be concerned that 25' might be producing an "over center" issue. Not sure if that makes sense and others will chime in. Defiantly wait before buttoning everything up.

[Tom Wesenberg]

If you are certain there isn't a pill stuck in the wedge, then how about trying this with the shorter old push rod.

[Bob C]

If your old housings are tapered with the grease fitting in the
middle they are for 1928 cars.

Bob

[Lona]

Originally Posted by Tom Wesenberg

If you are certain there isn't a pill stuck in the wedge, then how about trying this with the shorter old push rod.

Tom,
Thanks, all parts are new so there are no pills in the wedge. I can try the old shorter rods but why is the arm angle excessive if every part is new and the new rod lengths are to spec? ............Glen

[Kevin in NJ]

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Here is a link to some brake part comparisons I did a while ago:

Brake part compare

See if that helps some.

[Brian T]

Hello Lona,
I had the same situation here a week or so ago, 20 plus degrees, the actuating pins were new when I repaired the brakes 4 years ago, this time I replaced the cross shaft bushings, shafts, the wedges and the tracks.
What I discovered was that the ball ends on the pins were a little to fat to sit into the sockets fully, I ground a small amount off the sides of the ball, (not the ends) until they seated properly, and all ended up at 15 degrees.
I also read all the finer comments from the above Barners, I do believe I will have excellent brakes thanks to them when I am finished, hope this helps.
Regards Brian T.

[Lona]

Originally Posted by Bob C

If your old housings are tapered with the grease fitting in the
middle they are for 1928 cars.

Bob

Bob C,

Both the old and the new actuator housings are tapered but the old ones I took off the car have the grease fitting in the middle which you feel is for a 1928 car. Mine is a '31 but it wouldn't surprise me if the previous owner used 28"s as there were other non-standard parts in the brake setup. Steve at Berts specifically asked me what model year I had as he said there are nine different styles of housings. The 31's he sent seem to fit fine but I'm unsure if the different housings are attributing to or causing the excessive lever angle. Hope others can further clarify this angle question............Glen

[Lona]

Originally Posted by Brian T

Hello Lona,
I had the same situation here a week or so ago, 20 plus degrees, the actuating pins were new when I repaired the brakes 4 years ago, this time I replaced the cross shaft bushings, shafts, the wedges and the tracks.
What I discovered was that the ball ends on the pins were a little to fat to sit into the sockets fully, I ground a small amount off the sides of the ball, (not the ends) until they seated properly, and all ended up at 15 degrees.
I also read all the finer comments from the above Barners, I do believe I will have excellent brakes thanks to them when I am finished, hope this helps.
Regards Brian T.

Brian,

Interesting you had the same problem. As the actuators from Berts were used but not overly worn, I didn't even think that the rods might not be seating in the actuator sockets. I'm away from home until the weekend but will pull everything apart and check this out soon as I get back. This would certainly explain the problem and is an easy fix. Let's hope this is the solution.................Glen

[Lona]

Originally Posted by Kevin in NJ

Here is a link to some brake part comparisons I did a while ago:

Brake part compare

See if that helps some.

Kevin,

I read your comparison of brake parts and am impressed with your analysis. Your finding that repro actuator pins don't fit into the actuator or wedge sockets and must be ground some confirms what Brian said when he had the same problem. If this is causing the problem of excessive lever angle, it will be an easy fix...........Thanks.........Glen