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Drum brakes weak #1726460
01/10/15 04:54 PM
01/10/15 04:54 PM
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Wichita,ks.
jst19600 Offline OP
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I have a 70 roadrunner with manual drum brakes.Its never stopped what i would call good.Recently i put on all new brake shoes,hoses,and brake cylinders.The only thing i did not do was have the drums turned.I did scuff them up with some fine sandpaper.Could the drum linings have hardened,glazed so much that they just wont bite anymore?

Re: Drum brakes weak [Re: jst19600] #1726461
01/10/15 04:56 PM
01/10/15 04:56 PM
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Northeast
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VincentVega Offline
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Air in the system is always a possibility. But if you're trying to brake glaze, you shouldn't be using anything finer than 80 grit. You should also be very sore afterwards


Looking for 1975 through 1978 B body 4 door sedan sheet metal or parts cars - monaco, fury, coronet. Please let me know
Re: Drum brakes weak [Re: jst19600] #1726462
01/10/15 05:03 PM
01/10/15 05:03 PM
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Lincoln Nebraska
RapidRobert Offline
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What bore MC? (is the pedal effort normal/travel normal just not enough "grab" at the (4) corners?. when you stand on it do the rears lockup first? What I'd start with is put it up on stands & run it in gear & see how the rears brake then spin the fronts by hand as a helper hits the brakes. That'd at least be a start. Others will chime in/advise further. PS Make SURE you are braked to a standstill before shifting to park etc (the illusion fools you cuz the vehicle ain't moving)


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Re: Drum brakes weak [Re: RapidRobert] #1726463
01/10/15 05:29 PM
01/10/15 05:29 PM
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Wichita,ks.
jst19600 Offline OP
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The M/C and all hardware is all stock.Its doesnt pull to one side or the other and all brakes are working.It just wont grab hard.There is no way i could lock up the brakes.If i power brake it with the stock converter it moves very easy,i cant keep it from rolling.

Re: Drum brakes weak [Re: jst19600] #1726464
01/10/15 05:38 PM
01/10/15 05:38 PM
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Lincoln Nebraska
RapidRobert Offline
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Alright, I had that on the stock car & it was a partly crimped line. You might slide a floor jack under the pig & you could get it up & see what you get & it'd be alot faster than stands (do it safely of course) but I'm thinking it might be the MC but I would bleed it out first just cuz it'd be easier than changing it & I'm assuming the pedal does not pump up at all


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Re: Drum brakes weak [Re: RapidRobert] #1726465
01/10/15 06:04 PM
01/10/15 06:04 PM
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Wichita,ks.
jst19600 Offline OP
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Peddle is good and solid and doesnt bleed down.

Re: Drum brakes weak [Re: jst19600] #1726466
01/10/15 06:20 PM
01/10/15 06:20 PM
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VincentVega Offline
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glazing will certainly reduce braking performance


Looking for 1975 through 1978 B body 4 door sedan sheet metal or parts cars - monaco, fury, coronet. Please let me know
Re: Drum brakes weak [Re: VincentVega] #1726467
01/10/15 06:36 PM
01/10/15 06:36 PM
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Wichita,ks.
jst19600 Offline OP
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Should i have all drums turned provided they arent out of tolerence?Is it a necessity to put on new shoes again if i turn the drums?

Re: Drum brakes weak [Re: jst19600] #1726468
01/10/15 07:02 PM
01/10/15 07:02 PM
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just make sure if you get them cut you take them to a place that does drums all the time .
i have seen places try to just do a fast cut on the drums and call it good .
well that's not good .To rough of finish is bad. The car will take longer to stop as well.
Drums need to done in two steps 1 cut fast clean up and 2 slow finish.
Don't accept any less.
also try adjusting shoes up to where the drum can't be removed easy but still spins with slight drag.


1969 Dodge Charger 1969 Dodge Superbee
Re: Drum brakes weak [Re: jst19600] #1726469
01/10/15 09:14 PM
01/10/15 09:14 PM
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Lincoln Nebraska
RapidRobert Offline
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Quote:

Should i have all drums turned provided they arent out of tolerence?Is it a necessity to put on new shoes again if i turn the drums?


(1) no not unless the finish ain't right (2) no. No opinion if the drums are too slick right now giveing a coefficeint of friction not adequate enough to stop it. Tho it's gotta be that or the MC I'd think. If so I'd find a shop that does it correctly in the 2 steps as said & a huge plus would be a shop that arcs shoes to fit the drum contour (here it is
$5 a corner for a pair of shoes). You take in your shoes and the drums & not sure if the drums need to be turned just for that. You might call their shop & see what one of their techs has to say


live every 24 hour block of time like it's your last day on earth
Re: Drum brakes weak [Re: jst19600] #1726470
01/10/15 11:19 PM
01/10/15 11:19 PM
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Slidell, LA
Ronnman Offline
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How about posting some pictures of the brake setup with the drums removed. Sometimes the shoes get swapped front and back as well as the hardware. Additionally, sometimes a groove is worn in the backing plate and restricts the shoes movement. Anyway, post some pics and the forum will give you places to check.
Ron

Re: Drum brakes weak [Re: Ronnman] #1726471
01/11/15 01:13 PM
01/11/15 01:13 PM
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therocks Offline
oh wait.but hey.lets see.oh yeah.
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First is what shoes did you use?My kid had a shop do the brakes on the 66 Charger and they were crap because of the linings.I used to run notjing but NAPAs best.Now I run Advanced best.Drums should have been truned at least for a clean up.If they arent bad a 3M rolox disc on a die grinder will clean them up but they must be cleaned real good before install.My ? is whay run drums Unless its a show poodle or rare change to frt discs.You will never look back.Oh yeah I did brakes almost every day for 30 years as a tec.Rocky


Chrysler Firepower
Re: Drum brakes weak [Re: Ronnman] #1726472
01/11/15 01:28 PM
01/11/15 01:28 PM
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SportF Offline
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You need semi metallic brake shoes. They will increase stopping ability a great deal. I had a real hard time finding true semi metallic shoes last summer, and now I can't find them again. But this link does list them, and it is about what I paid for them. It would seem that the normal auto parts store, even for the cheapest to the premium, just don't work for a darn. When you get some true metallic shoes, you will definately notice the difference.

http://brakeperformance.com/brake-shoes/Premium-Brake-Shoes.php

8392361-IMG_0202.JPG (145 downloads)
Re: Drum brakes weak [Re: SportF] #1726473
01/11/15 02:00 PM
01/11/15 02:00 PM
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Beeware Offline
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Friend used this company. http://www.musclecarbrakes.com/bib6572charger.html
he bought both fronts and rear setup. His car really stops great for having 4 wheel drums.

Sport F thanks for the link above the semi metallics shoes are what I've been looking for!

Re: Drum brakes weak [Re: jst19600] #1726474
01/11/15 02:11 PM
01/11/15 02:11 PM
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U.S.S.A.
JohnRR Offline
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Quote:

Should i have all drums turned provided they arent out of tolerence?Is it a necessity to put on new shoes again if i turn the drums?




Depends on how much you have driven it with the shoes wearing to the uneven surface of your worn drum.

Seriously you should upgrade at least the fronts to discs , the drum brakes never worked that great even when they were new .

Re: Drum brakes weak [Re: Ronnman] #1726475
01/11/15 03:07 PM
01/11/15 03:07 PM
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Mattax Offline
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Quote:

How about posting some pictures of the brake setup with the drums removed. Sometimes the shoes get swapped front and back as well as the hardware. Additionally, sometimes a groove is worn in the backing plate and restricts the shoes movement. Anyway, post some pics and the forum will give you places to check.
Ron


I agree with this. Pictures would be good. Check for primary and secondary for being swapped. Since you changed wheel cylinders, I assume the whole system was bled thoroughly. Might be worth checking the wheel cyl. diameters just in case something was changed since 1970.

I also agree with RapidRobert on cutting, and not cutting if not needed. If you do resurface on a machine, then the shoes ought to be arced to match. Not many places still do this. Porterfield and Rochester Brake and Clutch are two places that do.

The lining material can also make a huge difference. With drums on all 4, I almost always have preferred semi-metallic, which was getting harding to find at run of the mill parts stores even 20 years ago. You may have to go to Rochester Brake or similar to get what you want.

On most brands, you can get an approximate idea of the friction generated by the lining from the edge code. For all participating manufacturers, this is either ink or impression stamped on the edge of the friction material. EE is fairly typical, FF is better. Lower second letter, such as FE, indicates the friction reduces as the lining gets hot. A lower first letter, such as DE, indicates friction improves as the lining gets hot.

Friction is just one characteristic of the lining material. If you were talking to people in the business of friction materials for racers (like Porterfield or Rochester) you could discuss how 'grabby' and how well they release as well as the amount of modulation available from different linings.

Re: Drum brakes weak [Re: jst19600] #1726476
01/11/15 04:06 PM
01/11/15 04:06 PM
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Lincoln Nebraska
RapidRobert Offline
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Quote:

If i power brake it with the stock converter it moves very easy,i cant keep it from rolling.


I understand drums ain't discs but lets see if we can find out whats fubared. Even power braked the shoes oughta hold it still


live every 24 hour block of time like it's your last day on earth
Re: Drum brakes weak [Re: RapidRobert] #1726477
01/11/15 04:15 PM
01/11/15 04:15 PM
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Phila. Pa.
Mattax Offline
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Quote:

Quote:

If i power brake it with the stock converter it moves very easy,i cant keep it from rolling.


I understand drums ain't discs but lets see if we can find out whats fubared. Even power braked the shoes oughta hold it still



I agree and based on this we know the problem impacts on or is in the front.

Re: Drum brakes weak [Re: Mattax] #1726478
01/11/15 05:33 PM
01/11/15 05:33 PM
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Let's all fly off on wild tangents.

Are your front brakes properly adjusted? I'll bet no.

If they aren't then nothing else will work properly.


They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
Re: Drum brakes weak [Re: Supercuda] #1726479
01/11/15 07:34 PM
01/11/15 07:34 PM
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Wichita,ks.
jst19600 Offline OP
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At first yes the front shoes were installed backwards.Once i got the shoes correct it did stop better but i know it can be alot better.Yes i do have cheap Orielly's (Brake Best) brand on it and i never had the drums cut.The brakes are adjusted correctly.The car is rarely driven which doesnt help much.

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