Front Brake Operating Pin Issue

[BillCNC]

Originally Posted by Bcontheroad

So did you figure out the original scraping noise? Inquiring minds...

No. I have about 600 miles since I addressed the issue. I'm going to be in there again this weekend to check on the rod to see if was more scraping. One of my fellow "A" breakfast run friends has the issue of his levers being about 10 degrees on the wrong side of straight up and down with brakes applied. He's going to measure his pins and he already has 2 pills installed on each side. I'm thinking his issue is a bad paw.

I'll post my finding on the scrapping pin Sat. afternoon.

Regards
Bill

[AzBob]

My LF operating pin had a step worn in it to the point it would hang up and not completely release the LF brake. I have floaters on the front and am thinking the increased side to side freedom of the floater wedge stud causes the pin to rub against the king pin hole.



How else can the pin wear like that? Doesn't the original wedge stud keep the wedges constrained to a purely up and down motion?

[larrys40]

Don’t do that. Make sure your backing plate is centered ( holes not elongated ) and tight.
Larry Shepard

[AzBob]

Originally Posted by larrys40

Don’t do that. Make sure your backing plate is centered ( holes not elongated ) and tight.
Larry Shepard

Don't do what?

Backing plate is centered, holes not elongated and tight.

[Rob Doe]

Originally Posted by BillCNC

No. I have about 600 miles since I addressed the issue. I'm going to be in there again this weekend to check on the rod to see if was more scraping. One of my fellow "A" breakfast run friends has the issue of his levers being about 10 degrees on the wrong side of straight up and down with brakes applied. He's going to measure his pins and he already has 2 pills installed on each side. I'm thinking his issue is a bad paw.

I'll post my finding on the scrapping pin Sat. afternoon.

Regards
Bill

Do his brakes work good? His drums may be turned oversize, as in 11.030" and up. He might need oversize thickness linings. I just read about this this morning. You can find the article on Santaanitaas website.
It's by Chris Wickersham "Model A Brakes and Oversize Drums"

[Rob Doe]

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Originally Posted by BRENT in 10-uh-C

Bill, I do not have the print in front of me but I can look it up come the first of the week if you like, however, the diameter of the pin just does not matter since the 'oversized' area on each end does pass thru the bore of the Spindle Bolt.

Additionally, the 15° forward location (-or 14° in your case) means nothing. This is nothing more than some restorer in modern times establishing an arbitrary number to illustrate their point when describing the desired static position. What DOES matter is the Front Brake Lever should be near-exactly vertical when the brake pedal is fully depressed. This is because that arm has the maximum amount of leverage to push that pin downward against the Brake Operating Wedge. It also does not matter what the static position of the Brake Lever is (-14° forward, or 15° forward, -or whatever #) if the arm goes past straight vertical when the brake is fully depressed. It that brake arm does travel past vertical, then it has the ability to push the pin over against the bore of the spindle.

It is also worth asking if you have verified the brake shoes are centered on the housing plates, -and the tracks, their location, the heads of the pins and the rollers are all within factory specifications. If any of those including tracks are worn or located incorrectly, it has the potential to cause the pin to travel much further distance to energize the shoes which ultimately will cause the Brake Shaft arm on over-rotate.

Brent, Bill, I've looked at the drawings of the backing plate and the dimensions of the tracks etc. 4.619-4.624. The Les Andrews red book gives track location as 1 and 5/16's and 1" from the installed rivets. I assume this is because obtaining the 4.619-4.624 measurements is out of the range of an amateur without some kind of jig to place into the center hole of the backing plate? But, a thread I read somewhere spoke of installing new tracks using enlarged or elongated holes and this could make the track locations less than wonderful... Comments please???