Check Your Rear Brakes

[Brian_Heil]

When I purchased my 1923 Model 45 Buick I found both rear brake reaction arms cracked.  I had them both welded. The material is cast steel so the welder has to know what they are doing.  
 

Fast forward 27 years and 45,000 miles.  A recent inspection found them both cracked again.  Repaired again and a successful Fall Tour in the books but I would be remiss if I did not suggest others inspect theirs. 

[IFDPete]

Brian - I am new to these early Buicks.  Appreciate the heads up and detail photo of the problem.  However, being new I could use some instruction / photos of where / what a brake reaction arm is on the car.  Thanks - Pete

[Brian_Heil]

In the pic my head is under the car by the differential looking outboard at the back side of the drivers side brake backing plate and the subject reaction arm. 
 

The cracked arm is a casting that is riveted to the axle tube and to the brake backing plate.  It’s what keeps the external brake band from rotating with the brake drum when the brake is applied. 

Edited October 20, 2023 by Brian_Heil (see edit history)

[Brian_Heil]

This should help too Pete. 

[Oregon Desert model 45]

That cracking must have been a known issue when the car was new.  The reaction arm on this 1924 axle appears to have been beefed up significantly compared to a 1923.  

[Brian_Heil]

Sure looks that way doesn’t it?

 

The crazy part about this failure is the small  triangular piece of metal that came out of the fracture was on the floor of my garage. I stepped on it in my socks taking a bag of trash out to the bin.  I picked it up at first thinking it was a piece of glass.  It was dense steel, not cast iron.  Where did it come from?  I had a guess and I was right.  
 

What are the chances of that piece falling out in my garage and me stepping on it?  Every time I greased the chassis or checked the differential lube I always gave those weld repairs a good look. 
 

Remember also, 1923 is the last year for rear only brakes so those arms do all the braking work. 
 

And if you think my garage is that clean, guess again. 

[Brian_Heil]

Here’s a pic I took before I cleaned things up with the wire wheel for the welder.  You can see the missing piece clearly. 
 

The Good Lord looks out for fools and children. 

Edited October 20, 2023 by Brian_Heil (see edit history)

[Brian_Heil]

And the arm is not solid but hollow and ~0.250 inch thick wall. Sort of house shaped cross section with the peak pointing at you and no floor. 

 

[Oregon Desert model 45]

I welded up the extra holes that had been drilled through the windshield stanchions for windwings.  I was impressed how well that old cast steel behaved during welding, and the welds came out beautiful when it was done.   

 

[IFDPete]

Brian - thanks for the heads up on this issue.  I looked at mine and all appears Ok.  I appreciate all that I am learning about this car and the knowledge shared by those who know on this forum.  As I continue the work the get my car running I am sure to have more questions.  Good luck with your repairs.  Pete