2525 Brake squeal

[KiwiBuickNut]

Hi All,

I have a 2525 standard 6 and its a wonderful car and I've been lucky with quiet brakes for ages but finally the pedal started to get down a bit so I needed to do some adjustment. I followed the manual on this and have a fair bit of vintage experience but now I've got a squealer !

Having trouble figuring out exactly which wheel is causing the noise and its only on the light load as you finally pull up to a stop, fine under heavy braking or at speed.

I'm sure ive got a little too much lead or trail on one shoe but struggling to find it.

Anyone got any tips or tricks to share?

 

Many Thanks

 

Steve

[Morgan Wright]

Tell us what tires you have. Skinny tires, squeal is normal since only a little slip of rubber meets the road. Wider tires shouldn't squeal.

[KiwiBuickNut]

Thanks Morgan,

Its not the tyres that are squealing its the brakes! FYI running 600-22 tyres.

[dibarlaw]

Steve:

Glad to see you are on the forum! We need accounts of your adventures with your 1925.

 After nearly 10 years of ownership and constant fighting with my 25-25 I have finally been able to take some longer trips. Stll even after new radiator, clutch, engine rebuild and on and on there always seems to be another issue to sideline us.

 At the AACA museum cruise-in after 68 mile drive. It would not start! It "took the Village" to raise it into cooperating for the trip back home. But nearly 140 miles round trip and running for over 2 1/2 hours continuously each way we are making progress.

[Hubert_25-25]

Steve, 

    I do not know if you have all these publications and if they will help your situation.   Maybe one of these has some insight to the problem.   Some if these are from different years with slight changes, but the concepts should get you there.  

Since it is occurring only on light load, start by pulling the clevis pin to the front or back brakes.  Then you can do the same to the left or right side.  That should help you isolate the wheel.  Jack up that wheel.  Pull the clevis pin on the brake lever arm.  The part that looks like a big question mark (how appropriate).  This will allow you to put light pressure on the brake while the wheel is rotated and you should be able to isolate the source.   

Hoping to resolve what ails your stopping and Larry's going.   

Hugh

 

Edited July 21, 2021 by Hubert_25-25 (see edit history)

[KiwiBuickNut]

On 7/22/2021 at 12:37 AM, Hubert_25-25 said:

Steve, 

    I do not know if you have all these publications and if they will help your situation.   Maybe one of these has some insight to the problem.   Some if these are from different years with slight changes, but the concepts should get you there.  

Since it is occurring only on light load, start by pulling the clevis pin to the front or back brakes.  Then you can do the same to the left or right side.  That should help you isolate the wheel.  Jack up that wheel.  Pull the clevis pin on the brake lever arm.  The part that looks like a big question mark (how appropriate).  This will allow you to put light pressure on the brake while the wheel is rotated and you should be able to isolate the source.   

Hoping to resolve what ails your stopping and Larry's going.   

Hugh

 

 

Wow many thanks, I have the original Buick manual but these other articles are very helpful, I will have a play this weekend and let you know how I get on.

[Mark Shaw]

If the ends of the shoes contact the drum first, they will squeal.  So, the first thing I would try is to bevel the ends of the brake material and verify the brake material is not out of round. 

[Hubert_25-25]

I'm going to post on this thread, because I have the same issue on a 1927 Buick Master.  When you apply the brakes, the Left rear (LR) brake sounds like a school bus stopping.  

 

 I went thru my extensive and not too easy to understand Buick brake adjustment procedures.  They mention that this squeal is from one brake doing all the work and acting before the others.  The LR is the first brake to start grabbing the drum.    

So I had a friend come by to help with going back thru all the brake adjustments.  There are many and moving one setting can affect the others.  

    So the big problem actually comes from the Right Rear brake.  In doing the brake checks, the equalizer bar is not parallel to the cross shaft as detailed in the instructions.  This brake drum has had some damage - likely from someone trying to remove the wheel hub with the wrong tools.  The drum is warped or out of round, so it has high and low spots.  These brake drums are hard to find and almost impossible to fix.  So I did post a request to see if anyone has an extra one. 

    Besides the warped drum, the parking brake friction shoe material was also replaced.  Kind of a good thing that it is new, but the material is thicker than Buick used and some of the braking material needs to be trimmed down so it does not rub when the park brake is not applied.  The parking brake shoe also was not assembled exactly like it should have been and sits a little high on the rest. 

    That said, the easiest fix is to remove some of the brake lining material so that the drum does not drag on it.  The hard part is you have to remove the brake drum, file some brake lining material, install it all back, check it and look for wear spots, then take it all apart again looking for marks of where the shoes rub on the drums.  

     We even went so far as to file what we could, assemble the drum, run the car on jack stands in first gear and apply a few clicks on the hand brake, to see if we can "wear off" some of those high spots.  We used a temperature gun to keep the temperature below 160 degrees.

     It is better, but we are now going to try another method of removing material.  Going to try 80 grit long sandpaper and try to take the lining down just a little more.

Of issue is that we have to get all the drag off the parking shoes in order to set the regular brake band and have no drag.        

  

      We are not entirely positive that we can resolve the problem, but we think so, and this is our only option given the condition of the existing brake drum.  

    Warped brake drums require excessive clearance between the drum and the brake band so that the drums do not drag when the brake is off.  This presents a difficulty in setting brakes when one brake band has to move more than the others.  So to make the brake pair even work close, the straight good brake drum has to be set with more clearance to keep from locking the brakes early.  This extra clearance means more brake pedal travel than normal.  In other words, because 1 drum is warped and requires more pedal travel, the other 3 drums have to be adjusted looser to compensate.  Just hoping that we have enough brake pedal travel space available.  This is not really in the brake procedure as there is not a troubleshooting section and they just tell you how to set up good brakes.     

 

The attached pictures show the wear patterns in the RR brake drum.  These should be symmetric wear on a good drum and not this curved wavy looking line of wear.  

  So I am hoping that fixing the bigger problem on this other brake will resolve the minor noise issue.  I will keep you posted.     Hugh

Edited June 5 by Hubert_25-25 (see edit history)

[dibarlaw]

Hugh:

 Thank you for articulating what I went thru on my 1925 Master. The wear patern was similar as to what I had but as I told you the drum was 3/16" out of round. The same right rear. Thanks to Fred Rawling for a better drum. Not the same ribbed style as the 1925 and up had, but useable. Of course your wire wheel style is even harder to source. 

[Hubert_25-25]

Let's start with the parking brake on the RR.  Using 80 grit emery paper was the way to go for removing friction material from the parking brake shoe.  This is not woven material like the original stuff.  High spots showed up as dark spots, so I did sand mainly on just those areas.  Finally I was able to get the RR brake drum to spin freely when the shoes were at rest.     

Now on to the bigger squealing problem that I could not address until the parking brake problem was resolved.  I began with loosening the 2 big adjusting nuts on the LR, a full turn each. 

This helped slightly, but did not entirely resolve the problem.  I then removed the LR brake band and sanded the friction surface with 80 grit paper.  Maybe glazed or contaminated?  I beveled the leading edge of the friction material.  This is new "green woven" friction material.  It has brass strands in it.  I sanded on the drum as well as there was a lot of surface rust.  Drum photos show heavy scratches in 1/2 of the drum, and heavy pits on the opposite side.  Not sure what he used to put those scratches in.  Likely a grinding stone.  You can see high and low spots too on the drum surface.  I put this all back together and gave it another full loosening turn of the adjustment nuts on this LR wheel.  Another drive, and more improvement, but can still get a squeal.  The brakes on these cars work "left side" or "right side".  Using my heat gun and finding the left front LF brake was getting the hottest.  So I loosened 1 turn on each of these 2 LF adjusting nuts.  Delaying operation (loosening) of the LF brake will delay operation of the LR brake due to the mechanisms.  The sound is almost gone now and may eventually go away as the linings wear in.  Any noise is very low on the pedal and does not occur with normal braking, so it is much improved.  This used to squeal loudly as soon as the brake pedal was applied.  The front brakes are reading nearly equal temperatures.  Adjustments are not entirely like the Buick manual says, so this is how I was able to compensate for brake drum irregularities.    Hugh

         

 

  

[28Buick]

Thank you for these valuable insights on brakes. I recently adjusted the brakes to the specifications in the shop manual and found the rears were way out of spec and seem to be doing most of the work. I do not have a squealing issue, I seek to ensure all four wheels are doing their job.  After driving and normal braking, I feel the temperature of each drum. I back out the adjustment nuts on the hottest wheel, or conversely, tighten the nuts on the cold one if others are warm. Is this okay or will this procedure get me in trouble? Is the prior mention of 160 degrees F significant? I could use my IR thermometer for accuracy, but now I am literally getting in touch with my brakes. I appreciate any opinions. Stay cool if you are in the heat dome!

[EmTee]

8 hours ago, 28Buick said:

I feel the temperature of each drum. I back out the adjustment nuts on the hottest wheel, or conversely, tighten the nuts on the cold one if others are warm. Is this okay...?

Yes, and using your IR thermometer should let you really dial them in.  Hugh did the same thing:

 

On 6/18/2024 at 12:51 PM, Hubert_25-25 said:

Using my heat gun and finding the left front LF brake was getting the hottest.  So I loosened 1 turn on each of these 2 LF adjusting nuts.