Purpose of spring.

[Swampdog]

What is the purpose of the coil spring (screen door) that goes around the drum on the outside? I am cleaning up the read drums and mine are really grungy. I went RockAuto and the drums they sell don't have the springs nor do they have the grove that they go in.

I think I'll leave them off.

 

[Yatzee]

They cancel the harmonics that the drum develops under certain braking conditions and channel heat away from the same. Newer drums have fins in place of the springs.

 

[idrivemopar]

I was about to say they were to dampen brake chatter, but there are three theories floating around and I tend to believe number 1,
1 - Dampen brake chatter/high speed vibrations,
2 - keep the drum round when it gets hot,
3 - help dissipate heat

 

[dual fours]

Swampdog, you know not to throw the springs away, right?

 

[Swampdog]

Where can I get two? The ones I took off are probably 50 years old and very rusty. If they had ant dampening effect it is not the same as it was.

 

[Cranky]

Ain't no spring going to help keep a hot drum round! I've even heard that it was for when you had them turned so they didn't chatter but I've seem plenty of brake lathe operators use a rubber bungee cord for that and can't see the factory spending money on every car to make some brake lather operator's life easier. Help remove heat.....might be minimal. I see them as an anti chatter thing but a spring might even help induce more chatter. I always pulled them off and never have any squeal problems.

 

[69L48Z27]

Mega Parts sells them for 11" drums. New drums do not have the slight recess to keep them on the drum.

 

[Cranky]

If you need an 11" drum or two for the front that have the recess, I have a couple....also have one spring that's still in decent shape....

 

[Billccm]

I was always told this was a heat dissipation component. I believe somewhere, perhaps in Chilton manuals, it is described as a heat reduction spring.
Further evidence is the fact that finned drums have no spring.

 

[pturner]

have you ever seen the rubber band they put on the drum when they are turning brake drums on a brake drum lathe? I guess there are younger folks that have never seen brake drums turned. without it the drum starts to "whine" and a harmonic vibration starts which makes the turning not true. I guess it also could dissipate some heat.
pt in tennessee

 

[dual fours]

This is the best I can do in print so far.
From a 1971 suspension and brake book.
Read #3.

 

[khryslerkid]

I vote harmonics dampener/suppressor.

 

[Swampdog]

I going to leave them off. I 'll see what happens.

 

[66Satellite47]

That will work fine. BTW those springs got very rusty when they were only a couple years old.

 

[Billccm]

I stand corrected! Thanks for the information and education. Nice to learn something new everyday!

 

[Cranky]

That will work fine. BTW those springs got very rusty when they were only a couple years old.

That was the case if you lived in the rust belt....

 

[66Satellite47]

I guess Minnesota is in the rust belt, probably among the rustiest!!

 

[oldbee]

20+ horsepower to each rear wheel! Not really, I'm sure they were for noise control/chatter. Maybe throw off a little heat? My replacement drums have no springs & no problems.