Can someone write up rear brake shoe step by step?

[teranfirbt]

On resurfacing/replacing:

New brake shoes/pads *REQUIRE* a fresh cast iron surface for proper break in *every* time. Brakes don't work by creating friction between pad material and cast iron, they create friction between the pad and a very thin layer of the same pad material embedded in the rotor/drum when you *properly* bed in your brakes. Using new pads with old rotors/drums means you're trying to make different, possibly incompatible friction materials do your braking. This can lead to reduced braking in the rear, accelerated pad wear, and noise. If your rotors or drums don't have enough material to turn down, you must replace them.

[Petros]

You know Teranfirbt, I have been thinking about this post for well over a month, it has been bugging me since it was posted. For the life of me I can not think any reason this should be valid.

If there was enough pad material embedded into the rotor or drum, the surface would be dull and fuzzy, not shinny. So this is contrary to our everyday experience. This sounds like the silly nonsense people tell you when they are trying to sell you something you do not need. I have never heard of such silliness, nor have I ever seen any evidence that brake shoes or pads failed because of incompatible materials. You can put fresh cut drums or rotor with old shoes or pads, or with new ones, as well as uncut used drums and rotors with new pads or shoes. There is no "brake in" other than to perhaps smooth out the rough surface from a poor resurface job.

The pads would gouge and score if they were braking against similar material. There has to be a large hardness difference between the materials to prevent grabbing and gouging. That is why for instance bearing material on the crank is very soft metal compared to the crank hardness. You ALWAYS have to have large hardness differences to prevent problems. There is just not enough porosity or voids in the surface of the metal to take enough brake material to matter. In fact, any incidental brake material would hinder good brake performance, hence the trend toward grooved and drilled rotors, it helps clear away the worn material and gases from the surface.

Please do not go around repeating this kind of nonsense, and if anyone sells you anything using think kind of misinformed logic, set him straight.

IF your drums or not damaged, resue them. IF you worry about pad material on them, clean them with brake parts cleaner. Resurface if you have to, or replace them with new.

[thekaz]

On resurfacing/replacing:

New brake shoes/pads *REQUIRE* a fresh cast iron surface for proper break in *every* time. Brakes don't work by creating friction between pad material and cast iron, they create friction between the pad and a very thin layer of the same pad material embedded in the rotor/drum when you *properly* bed in your brakes. Using new pads with old rotors/drums means you're trying to make different, possibly incompatible friction materials do your braking. This can lead to reduced braking in the rear, accelerated pad wear, and noise. If your rotors or drums don't have enough material to turn down, you must replace them.

never heard that one before

guess my decades of mechanical training were wrong but I am a mechanic NOT a writer so here is some good reading on the subject
http://www.aa1car.com/library/2003/bf110322.htm
http://www.aa1car.com/library/brakefix.htm
http://www.aa1car.com/library/drum_brakes.htm

[takza]

I've tried various methods to clean up rotors on and off the car...best method seems to be to use some 150-200 (?) grit sandpaper on a flat block of wood and carefully hand sand both sides of the rotor in a circular pattern going around the rotor EVENLY and LIGHTLY. By CIRCULAR...I mean with the block in your hand...make small circles...and do this evenly around the rotor...both sides. This cleans up some of the high spots.

[4wdchico]

I've tried various methods to clean up rotors on and off the car...best method seems to be to use some 150-200 (?) grit sandpaper on a flat block of wood and carefully hand sand both sides of the rotor in a circular pattern going around the rotor EVENLY and LIGHTLY. By CIRCULAR...I mean with the block in your hand...make small circles...and do this evenly around the rotor...both sides. This cleans up some of the high spots.

I have done the same sanding on rotors with good results.

[skyerunner]

Allright.
So I pulled apart my drums just to get some info on what was going on yesterday. As I said, braking has been feeling a little less than snappy lately and the emergency brake hasn't been holding super well either.

DSC_4013.jpg

This is the general condition of the brakes. A bunch of that black powder fell out when I opened it up. I hope I didn't breathe too much of it (didn't wear a dust mask - novice move). My first novice move was that I had left the parking brake on so couldn't get the drum off at first... duh. I couldn't get the drum off the passenger side no matter how hard I tried even after the parking brake was off. I don't happen to have a drum puller either...

DSC_4018.jpg

Pretty clean. No grooving in the brake drum but it is worn out maybe 1/8 of an inch or a little less. Should I just get a new drum?

DSC_4019.jpg

Closeup comparison of the old vs. new brake shoes. I was surprised to see that the old shoes didn't look super worn (though I don't know what they're supposed to look like). The brake cylinder on the drivers side looked like it was leaking something...

So. I have the shoes. Do I need to replace the brake cylinder, drum, or mounting stuff (spring etc)? How long of a project is this if I need to bleed all of the brake lines too and replace the fluid?
Cheers,
JB

[Petros]

You do not need a drum puller, put two long bolts (12mm head size) into the threaded holes between the lugs, it will force the Drum off. Sometimes if the shoe has worn are depression or "track" into the drum, it can be difficult to get the drum off. It might help if you can get a screw driver into the slot in the backing plate and back off the adjuster a turn or two. Otherwise sometimes whacking the drum with a large wood or rubber mallet, it will sometimes wiggle the shoe free of the drum. IT is it bad enough, forcing it off can be done, damaging the clips that hold the shoes against the backing plate. Not a big deal, but I have had to do it before.

If you have leaky wheel cyl. you must replace or rebuild them. A rebuild kit is cheaper, but remanufactured wheel cyl are not a lot more expensive, usually worth the little extra cost in time savings, unless you are really strapped for cash. Pull the dust boot off, if there is any moisture/fluid under the boot, the wheel cyl has to be rebuilt/replaced. If you are going to rebuild the wheel cyl PM me and I can give you specific instructions on what to watch out for when doing it.

Rear shoes last a long time, they do not get nearly as much wear as the front. Based on the pictures, if your drums are not warped and there is no wheel cyl. leakage, I would continue to drive on them and save the new shoes until later. You likly have 30 to 40k or miles worth of life on the one pictured. Redoing the rear brakes is a pain in the fingers, I hate drum brakes because they are so much trouble to install and adjust properly (the first 3 cars I owned had drum brakes on all four wheels!). Being in the rear they do not need to be replaced much. You need to inspect the other one, sometimes one side can ware faster than the other if something hangs up or is not working properly.

You usually do not need to replace any of the springs or mounting hardware unless it is damaged. Take detailed notes to make sure you get it back together correctly, the springs can be different size and shape front and back shoe. Or just do one side at a time, using the other as an example to check.

If the drums are not warped, scored and within speck for max dia, they are just fine to reuse. Most brake shops resurface or replace the drums and rotor every brake job, I say no way. They are so light you can only resurface them once. So I suggest reusing as-is unless they are damaged and need resurfacing. IF they are warped I would just replace them, they do not cost that much and resurfacing a warped rotor or drum will almost certainly cause it to warp that much easier in use.

IF you do not open up the wheel cyl. than you should not have to bleed the brakes. However it is a good idea to flush all the old fluid out of the system every few years. Brake fluid can break down, absorb moisture (causing corrosion) and cause mushy brakes, so it should be changed every few years. IT takes two people to bleed the brakes unless you have access to a power bleeder. Most of the other one person bleeding procedures do not work well. Find a neighbor kid to pump the pedal if you do not have a friend to help. It should take quite a while to pump all the old fluid (and any air) out of the system. One advantage in using a clear tube is you can see any air bubbles and the color of the fluid as it comes out of the wheel cyl.

Good luck.

[toughtercel]

while by your self , i just get 400 Ml (10 oz) juice jar ,add brake fluid less than 1/4 fill at bottom and nice 12-16 inch long rubber hose put one end to brake nipple and other end into jar with brake fluid , when depress(slow) the brake padel to the floor, it either air bubble or brake fluid come out ,when release the padel , it will suck the brake fluid into the hose without air . Normal every time I start bleeding , i just release the bleeder nipple and let self flow into the jar till bubble stop then pump the pedal.
Add another thing , it better wash whole drum system with water before start taking apart to protect your health.