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1925 Buick mechanical brake adjustment


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I am trying to adjust the brakes on my 25-24 roadster and I believe I have a missing part on the rear drum. The Buick Shop Manual describes an anchor pin No, 11 that is located at the base of the drum. See the photo of the design drawing from the shop manual that I attached. I don’t see any threads in the attachment bracket that the diagram shows where pin 11 should be adjusted. I do see 2 sets of holes 90 degrees from each other in the adjustment bracket that seems to be for cotter key. See photo. So I am thinking that the “pin” is inserted into this bracket and then pinned in place with a cotter key. What I don’t understand is what this pin looks like and how can you adjusted it without a nut to tighten the pin. Does anyone have a photo of this pin that would help me fabricate a set?

 

Thanks

Ken

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Ken:

There is a screw with a long slot that threads into the L bracket to locate the band by pushing against the band with the thread adjusting in relationship to the L shaped bracket riveted to the backing plate. Keeping position bey the spring pressure. Once adjusted the cotter pin is inserted.

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Also notice spring in-between.

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66.thumb.jpg.0b2aa3e45e49313f749801f5eed8b00c.jpg Parts you need are 169132 and Spring169131.

I had to make them up for my friends 1919 H-45. He was driving the car for over 20 years with out this one brake being able to be useable as he was missing the same adjusting screw. And the car only has rear wheel brakes! I went to the local hardware store and bought several 3/8" X16 tpi bolts I believe. And a spring that was close. Used his vice and cut the head off then clamped 2 hack saw blades together in the saw frame and made the notch.

 Put all back together and adjusted for proper drag. Inserted the proper cotter pin.  He drove it around the block and said that the car never stopped that well in his life time.

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Part number 169132 was originally made in brass.  You can also get a piece of brass bar stock, cut it to length and thread it very easily.  Use the double hack saw blade trick.  Mine took very little work because Larry D. made mine.  Thanks Larry !   

 

Ken, Are you missing these 2 parts (the spring and the bolt) on all 4 wheels?   Let me know because I have dimensions on the spring and the bolt that I can provide if you do not have any of the parts.   Hugh

Edited by Hubert_25-25 (see edit history)
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Larry/Hugh -  

 

Thanks for the explanation and the great photos. I can see now that I don’t have that L bracket that is riveted to the backing plate. The L bracket, pins and springs are missing on both rear backing plates.

 

I can’t remember if I saw the L bracket on the fronts so I will have to go out to the shop to see if they are present in the front. Are the front pins and spring interchangeable with the rears? If they are then I can use the front pins to fabricate the pins for the rear. Not sure what to do about the L bracket.

 

Ken

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I went out to the shop to look at both the front and rear backing plates. The good news is that L bracket is present on both the front and rear. However, the pins and spring are also missing from the front brakes. So Hugh please let me know the dimensions for the spring and pin as I will need to fabricate 4 of them.

 

Thanks!

Ken

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Ken, 

    This will get you started.  These are notes from when I was looking for brake parts.   I have all the spring information here.    Hugh

1241505490_springs1.thumb.JPG.72b620fdbe3c67ca21b79e1785fefd73.JPG1139430338_Springs2.thumb.JPG.ddfb5dc8ba56c7ae8694b9770c3e3c48.JPG1904782276_springs3.thumb.JPG.27fcb05a97ae22f4193acd12197edbc6.JPG1488988927_springs4.thumb.JPG.64d48eb1f6c3e5f5923ce3a666d18ed9.JPG

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Hugh/Larry

Thanks for the specs. I’ll get some 3/8 x 16 tpi bolts. From the specs I’ll cut these 1 1/2 inches long and notch the top. I don’t think I have heard of TPI bolts before. What are TPI bolts?

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Ken,

 Brake release adjusting screw.   Master and Standard shown.  TPI is just threads per inch.  That is a standard coarse thread.   These do not have to be brass.  zinc plated steel is OK.     Hugh

 

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Edited by Hubert_25-25 (see edit history)
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Hugh -

 

I got lucky. I went out to the shop to look for some 3/8 x 16 bolts and springs to make the pins and found a set of new brass adjusting screws. My dad squirreled them way in a drawer and I just happened to see them. I knew right away that they were the pins for the brakes.

 

However, the total length of the pin is 1.015 inch. This is 0.01 inch longer than the dimension of 0.910 you have in your drawing above. My concern is I will have to tighten the adjusting screw 0.01 inch more than the shorter pin to get the cotter key in. Won’t this put too much pressure on the brake drum? Should I trim off 0.01inches?

 

The total length of the pin from the end of the threads to the center of the cotter key hole is 1.56 inches. This length is what determines how tight the pin will be. Do you have a measurement of this length on you pins?

 

Thanks

Ken

 

 

 

 

C48E9BAF-A4C1-469F-AE56-0B4D231A0C54.jpeg

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Ken, 

   I don't know who put the hole in the pin.  Disregard the hole.  That is not the cotter pin hole.  Turn the adjuster in until it just creates pressure of the brake band against the drum.  Then back it off so that you have a 1/32 gap between the drum and the band.  Put the cotter pin thru the slot to prevent rotation.  Hugh

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Hugh -

 

That’s good to hear. I thought the slot was to turn the bolt with a flat blade screwdriver. I got the brake switch installed so now I am working on adjusting the brakes using the Shop Manual for guidance.  Your instructions on how to adjust the pin is much clearer than the Shop Manual 😃

 

Thanks

Ken

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Whouu guys.. thanks for this threat.. i think i will have to adjust the brakes on my 24 after i install the rear parking brake bands

I never knew about those adjuster screws..

cheers 

Apolo.

 

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  • 1 month later...
Posted (edited)

Hello everyone, hope you are all well and healthy. Colorado just lifted the shelter-in-place order this week so I was able to get down to my shop and restart the brake project. I ran into a couple issues I am hoping you can advise me on.

 

My front passenger side brake shoe does not center on the outside of the drum. I attached a photo that shows the part of the shoe that is about 1/2 inch off the inside side of the drum. Everything looks straight with no obvious bent parts and looks the same as the driver side which fits fine. Also the shoes on the other drums fit properly.  Any ideas.

 

The other question I have is about a stop for lever No. 21 shown in the attached diagram. Hope this diagram is more readable. Lever 21 is connected to a cross shaft. At each end of the cross shaft there are 2 bolts that attach the shaft to the frame. From the diagram it looks to me like the upper bolt also must have an extension on it to function as a stop. I attached a photo of my shaft and have a small piece of tape on the bolt head where I think the stop should be. Anyone have a photo or dimensions of the stop that would help me fabricate one?

 

Also the diagram shown only one rear brake rod on each side going to the rear drums. My car have 2 rods on each side going to the drums. The diagram is from the 1925 shop manual so I have a hard time thinking the manual is not correct. I also attached a photo that shows my dual rods.

 

Thanks, Ken

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Edited by KEK
Change stay at home to shelter in place (see edit history)
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Ken, 

Welcome back.  Are you blinking a lot now that your eyes are adjusting to the light? 

Is the 1/2" off brake drum on the front or rear?  I am assuming the rear, but it makes a difference.   My drivers rear was off the other direction and the drum was wearing on the brake mechanism bracket.   

This is Larry D's photo of the bolt you are missing.  I will have to get you some dimensions.  

What is shown in the diagram is the 4 wheel braking system, and not the parking brake system.  

 Hugh

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Edited by Hubert_25-25 (see edit history)
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I don’t want to hijack this post but it’s on topic....

 

my 1927 standard, the left rear brake is hanging up.  When I park and set the hand brake, release it to back out of the garage and I can feel it hanging up.  If I gently rock the car a little it releases.  Any ideas on why it would hang up?

 

everything on the car is greased up.....

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Ken, 

     The brake stop that you are missing can be easily made from a 3/8" bolt that is not fully threaded.  Cut off the bolt head.  The unthreaded section is 1 1/4" long.  The threaded portion is 1 1/2" long.  It has a nut on the outside.  On the inside is a washer, lock washer, and nut. 

 

 Regarding your brake, you are missing some washers.  I bought brass replacement washers, but regular washers are fine.  3 washers per adjuster.  It looks as if the spring is sliding into the adjustment slots.  If the area that I am asking you to measure is basically the same on all 4 wheels, then it is in the adjuster as Kevin pointed out.  The bolt should be straight.  

How does it look at the other adjusters.  Hugh

 

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William, 

     Your car is sort of on topic, but your problem is with the parking brake. 

- Block the back wheels. 

- Release the handbrake

- Disconnect the 2 clevis pins on the parking brake rods at the rear axle.  These are the 2 inboard clevis pins of the 4 rods that are back there. 

- Check the lever operation on each side.  You may have some corrosion on one of the shafts, or the return spring in the drum may be broken. 

 

I believe these should snap back after moving the lever arm near the differential.  If one side does, and the other does not, then you know which side to work on.  It never hurts to pull all this apart and replace all that 90 year old grease.  

Hugh

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Edited by Hubert_25-25 (see edit history)
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Hugh -

 

I measured the distance between the bracket and edge of the drum on all 4 wheels as you suggested and I found that the distance for both rear drums and the front drivers side were all about 0.25” plus or minus a 1/16”.  However, on the front right where my problem is the distance at the top of the bracket to the drum edge was about 0.325” and about 0.350” at the bottom. So this bracket is clearly bent.  I will bend this bracket back to 0.250” +/-  so it is consistent with the other drums. This should push the shoe in the correct direction that I need. I will also remove the adjusting rod and straighten it out and add washers to the springs. I suspect this will solve the problem. The photos help so much. 

 

The bracket that holds the small spring are the same distance for all 4 wheels so I dont see a problem here. Also the ears look good and are not bent.

 

I can easily make a brake stop as you suggested using a 3/8 inch bolt. Is there a stop on both sides or just the one side as shown in the diagram?

 

There is so much expertise on this forum. I appreciate everyone’s help! 

 

Ken

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Ken, 

    Always great when you can find an easy fix.  The nut is just spun up against the unthreaded part of the bolt.  Nothing fancy.     Hugh

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