drum brake crash course, or refresher

[Billccm]

Hello Experts!

My 68 RR drove and braked pretty good for the first 10 miles I drove it, but the more I drove it the brakes started to degrade FAST.

Seems under medium braking a HARD pull to the left.

Right drum is off, and to my surprise everything looks great. Shoes have plenty of surface, drums not scored whatsoever, and wheel cylinder dry and no evidence of fluid leaks. Brake dust was minimal, too.

Moving over to the left side later this week, but any of the experts advice is appreciated. What should I look for other than a snug shoe adjustment?

 

[brian6pac]

Drum diameter must be the same or very close as is within .010 or closer

 

[WileERobby]

"degrade fast" and "hard pull" to me, are 2 different things. Look at your adjustment & if any grease on the left side pads/drum

 

[Billccm]

I 'assumed' pull to the left meant the right brake was weak? Am I thinking the opposite?

Degrade fast meant that the braking was acceptable. The more I actuated the brakes, an increase with the pulling severity.

 

[67belvedere/225]

im guessing you have drums all around, i would also bleed them . how old are the brake hoses , sometimes they get blocked on the inside and limit the fluid flow , if you have poor fluid flow at w/c that may be part of problem
good luck

 

[Billccm]

It seems all of my old aerosol cans are out of gas; no brake kleen. Here is a picture raw with no cleaning.

 

[Mike in Boston]

My guess is the brake hoses are bad causing a restriction on one side

 

[Billccm]

No self adjuster, also?

 

[brian6pac]

If I remember correctly they did not have self adjusters.
Depending on the material the hotter they got the worst they worked, this is where the drum diameter comes into play the larger the drum the less area of contact on the shoe making them heat up much faster.

 

[moparnation74]

The 11" HD brakes with manual adjusters....Maybe one wheel adjusted to tight? Tight and heat can be an issue causing pull on one side..

 

[MarPar]

brake hoses could be swelling during braking as well. does the pedal get "squishy" the more you drive?

 

[Billccm]

brake hoses could be swelling during braking as well. does the pedal get "squishy" the more you drive?

You maybe on to something. Yes, I think so, but not entirely sure. The hoses can't be original as they look pretty good.
Bonus: Shocks look like new. Brake fluid is also very clean in master cylinder!

 

[Billccm]

So, recalling from memory adjust the shoes while spinning the drum until resistance, then back off one tooth, correct?
The brake tool pulls down to tighten, correct?
Have not done this since my mid 20s (back in mid 1980s). Makes me miss my dad; he was the neighborhood shade tree mechanic (machinist was his day job) and I was always at his side when he wrenched from the first day I could walk. He always supervised my brake jobs.
Thanks for the education.

 

[Yatzee]

Hello Experts!

My 68 RR drove and braked pretty good for the first 10 miles I drove it, but the more I drove it the brakes started to degrade FAST.

Seems under medium braking a HARD pull to the left.

Right drum is off, and to my surprise everything looks great. Shoes have plenty of surface, drums not scored whatsoever, and wheel cylinder dry and no evidence of fluid leaks. Brake dust was minimal, too.

Moving over to the left side later this week, but any of the experts advice is appreciated. What should I look for other than a snug shoe adjustment?

A friend of mine has a 66 Imperial with drums all round and the braking is fabulous for a 3 ton car although adjustment of the front shoes has to be spot-on to prevent pulling to one side. In your case I would suspect drums that are glazed or slightly different diameters, one shoe is glazed, wheel bearings misadjusted or the arc of the shoes doesn't match the arc of the drums. Your shoes may actually be of the wrong material, you did say there wasn't any brake dust present. That's peculiar. The car never did that from the factory so someone has changed something over time - usually with economy in mind. Either that or the time has come to replace some pretty important components like master, drums and shoes. Poor alignment will also contribute to what can appear as braking issues especially pulling to one side but if the suspension components are worn a correct alignment may be impossible. Good luck and if you can't resolve or afford fixing, remember "Ride to the right!" especially if that's the way it pulls.

 

[Billccm]

Either that or the time has come to replace some pretty important components like master, drums and shoes.

I'm trying to avoid spending any money on these drums as I'm saving money for a front disc conversion.
The seller claimed the car was 'driven less than a thousand miles' in the past year, but receipts really do not show any brake work I can find?
Yes, I expected more dust than I saw.
Glazing would be 'shiny', correct? I do not see any glazing.
Plan is to get some brake kleen and wash off, repack bearings, and move to the opposite side and pull the drum.
Thanks for your help!

 

[69L48Z27]

The service manual is a great resource for brake diagrams. I pulled one down from MyMopar.com. My drums were setup like yours, no adjusters. I rebuilt everything and added self adjusters. I found no evidence in the service manual that adjusters were an option or not used on 11" brakes. I'm curious to learn why that theory exists.

This is the first manual drum car I've owned and once I went through everything I have to say I will be keeping them. For what I do with the car I see no issue with reliability or safety. Car locks up all 4 reliably and it's repeatable over several stops back to back.

The pulling could also be alignment and road crown. I do notice I get some pull when I do a panic stop but it's not dramatic. Car stays fairly straight but it will follow the road.

 

[brian6pac]

So, recalling from memory adjust the shoes while spinning the drum until resistance, then back off one tooth, correct?
The brake tool pulls down to tighten, correct?
Have not done this since my mid 20s (back in mid 1980s). Makes me miss my dad; he was the neighborhood shade tree mechanic (machinist was his day job) and I was always at his side when he wrenched from the first day I could walk. He always supervised my brake jobs.
Thanks for the education.

FYI Adjust the shoes till they wont turn then tighten them up a little more, this compresses the wheel cyl and seats the system then back them off till they spin with very little drag.

 

[Dennis H]

I know you said cost is too high, but these have worked perfect for over 10 years. Spot on, no pull, good modulation.

www.musclecarbrakes.com

 

[BeeKool]

I'm trying to avoid spending any money on these drums as I'm saving money for a front disc conversion.
The seller claimed the car was 'driven less than a thousand miles' in the past year, but receipts really do not show any brake work I can find?
Yes, I expected more dust than I saw.
Glazing would be 'shiny', correct? I do not see any glazing.
Plan is to get some brake kleen and wash off, repack bearings, and move to the opposite side and pull the drum.
Thanks for your help!

It still looks relatively clean. From the picture the cylinders look good.
2 days ago I helped my bro-in law with rear brakes on his truck. Yours look much better.
Some shoes and you should be good

 

[MarPar]

I know you said cost is too high, but these have worked perfect for over 10 years. Spot on, no pull, good modulation.

www.musclecarbrakes.com

I agree wholeheartedly. I purchased these brakes for my Newport on Dennis' advice, and once they were bedded in, they work freakin great.