Brake Drum Spring

[harmony]

Recently there was a little discussion in a post where someone was trying to source out a supplier of the spring that goes around the outside of the brake drum.  That got me to thinking how important that spring is?  My 48 Windsor doesn't have any.  But my 46 Royal parts car has them on the front drums only.  Should I put those on my Windsor?  Will I notice a difference?

I don't really understand their purpose.  I can't imagine that it's suppose to keep the drum steel from expanding when they get hot, or vibrating. I've never been driving along in my old girl and thinking. " Boy I wish I had springs on my drums" 

[TodFitch]

The most compelling argument I have seen about why some cars had springs around the brake drums was for the control of brake squealing sounds.

 

That was mostly by process of elimination: The springs are not strong enough to control thermal expansion of the drum. They don’t add enough area to assist in cooling.

[61spit]

I think they were aftermarket items. Something you would see hanging on a card at the service station. Supposed to help quiet any brake noise from the drum vibrating. They didn't keep the drum from expanding as they are not that strong of a spring. You can stretch it around the drum and hook the ends together by hand. That was my take on them anyway.

[rallyace]

As was mentioned above, brake drum springs were used to help dampen the vibrations that we hear as brake squeal.

[Rodney_Hamon]

My P-23 had those springs you’re talking about on the front drums. I removed them when I did the brake job and they were so stiff I couldn’t get them mounted back on the drum so I left them off. Maybe I should have tried harder. Thanks for telling me their purpose as I thought it was goofy. 

[harmony]

Ok, so lets assume it was to eliminate squealing.   How??

[harmony]

25 minutes ago, Rodney_Hamon said:

My P-23 had those springs you’re talking about on the front drums. I removed them when I did the brake job and they were so stiff I couldn’t get them mounted back on the drum so I left them off. Maybe I should have tried harder. Thanks for telling me their purpose as I thought it was goofy. 

After you took them off did you have to wear ear plugs because the squealing was so loud?  lol

[harmony]

If they were an aftermarket item, it would be awesome to come across a copy of the ads that they were running.  I'd love to hear the sales pitch.

[LazyK]

spring was a  vibration damper. 

[tom'sB2B]

I posted this picture earlier. Another member was trying to figure out what the springs he had in hand were used for.

The picture posted are vibration dampener springs for a Chevy Corvette. 

I imagine they were a gimmick at the time.

[harmony]

8 minutes ago, tom'sB2B said:

I posted this picture earlier. Another member was trying to figure out what the springs he had in hand were used for.

The picture posted are vibration dampener springs for a Chevy Corvette. 

I imagine they were a gimmick at the time.

That's what I'm thinking too.

[TodFitch]

Not really a gimmick, they were factory installed on a number of makes over the years.

 

A brake drum is shaped a bit like a bell and will vibrate at some harmonic frequencies like a bell. Clamping it with some force around the outside (i.e. putting a strong spring tightly around it) will change the resonant frequencies.

[Plymouthy Adams]

hardly a gimmick and can cause some rather unusual driving problems.  Many moons ago at the service station I worked at as a youth, the shop send a set of drums out to be turned, they were dropped off later and installed.  Brake job finished up as normal.  customer returned complaining of vibration and pulling greatly to one side.  After a number of inspections and test drives the one drum was discovered to have this spring missing.  Shop that turned the drum had the spring there and when installed, it tamed the beast.  

[harmony]

When I was a boy ( mid 60's) I worked at a service station as a gas jockey but when I wasn't pumping gas I was learning how to change the oil and filter, grease jobs, and brake jobs.  So I saw quite a few brake drums over the years.  I would say that the majority of them didn't have those springs.  In my adult years I've seen less brake drums but still I've done a number of brake jobs over the years with drum brakes.  I can't even remember one of my own cars having those springs.  As I mentioned my 48 Windsor doesn't have them.  It runs smooth and straight.  I can take my hands off the wheel and go a long distance and it won't wonder to one side.  I can also apply the brakes with my hands off the wheel and it doesn't pull to one side. 

No "springs" attached.  ( note the play on words  )

Edited February 11, 2022 by harmony

[Plymouthy Adams]

it was the absence of one in relationship to the effect of the other with the spring.....grab a car with lighter cast drum (front) requiring these springs and remove one and have some fun....older drums have a very thick and often ribbed outer edge of the bell shape of the drum...

 

 

 

 

[kencombs]

To add my voice to the 'vibration dampener' crowd.  Under some conditions, with some lining material, at some temperatures, brake drums can squeak, howl, screech or something.  The springs prevent the vibration that makes those noises.  Think of it as similar to placing your finger on an instrument string to change tone or stop the vibration, or touching a tuning fork while it is vibrating. 

 

And, no I'm not a musician, but that is how it was explained to me way back in the last century.

[Rodney_Hamon]

I looked at my P-23 again and saw that I did leave the spring on the drivers side drum. Oh great,  does that mean my car will drive in circles now due to harmonic hum and absence of relationship?  It’ll be like my spitz dog who had a stroke and walked in circles afterwards.  Better put that spring back on. Ha Actually, I’m glad to hear the theory of this clever looking spring as it makes my drums look unique.  Yeah