Brake shoes in my '44 are cracked

Happened to have the drum on passenger side of my D44 (rear axle) today. I re-built and installed this axle about 16K miles ago, installing both a new drum and shoes at that time.

Well, I observe cracks in the asbestos pads on both front and back metal shoes. It appears that this asbestos is glued to the metal shoe so I guess the asbestos won't fall off.

Should I be worried?

Thanks!

I'm not.

First - it's not asbestos - and hasn't been for a nuber of years. It's an organic friction material that is highly tolerant of heat, but it's not asbestos. They stopped selling asbestos brakes shortly after they stopped selling asbestos insulation. Properly, you'd just call it "friction material" if you don't know what sort it is.

Second - brake friction is not only subject to a great deal of stress and pressure - and heat! - it's also subject to it intermittently, and not all at the same time (when you have the park brake on, the material is compressed, but isn't heated and isn't under shear load. When you stop, it's got all three. After you've stopped and you're starting again, it's hot, but not stressed.) This will result, eventually, in cracking of the friction material. With the bonded material - even if it falls to bits it should stay in place long enough to get a couple stops - or one good stop. Rivetted is sometimes also bonded, but the advantage of rivetted friction shoes is that heat is transferred from the friction (heat source) to the metal shoe (heat sink,) and can get transferred to the axle faster to reduce failure.

As long as you don't have any heavy cracks (you can't slip a piece of heavy paper into them,) and you don't have any chunks missing, they're nothing to worry about. It's common to notice heat cracks or heat checking in brake material - both friction material, and cast drum & rotor surfaces. Again, as long as they aren't too wide or deep - or you note a straw-coloured or bluish discolouration, you should be find (if the metal is discoloured, replace it - don't get it turned, since the discolouration will indicate a hard spot in the surface of the rotor/drum.)

Hope this helps.

5-90

mhead said:

Happened to have the drum on passenger side of my D44 (rear axle) today. I re-built and installed this axle about 16K miles ago, installing both a new drum and shoes at that time.

Well, I observe cracks in the asbestos pads on both front and back metal shoes. It appears that this asbestos is glued to the metal shoe so I guess the asbestos won't fall off.

Should I be worried?

Thanks!

Click to expand...

Do you have a receipt for the shoes? I just warrantied the shoes from my old drums and the shop exchanged them without asking any questions.

First, I would change them right away. If the material has started coming apart it's going to keep coming apart.

Could be the bonding just wasn't solid and was worked too hard in the break in period. This is old school stuff and after you put on a new set of shoes you are supposed to "burnish" them with a series of gentle stops from about 30 MPH. That gives everything a chance to settle into place so there is an even contact pattern between the shoes and the drums, settle all the springs and cables and levers into their home positions and so forth. Getting them smoking hot right away will damage the lining and reduce it's effectiveness & shorten it's life.

A proper initial adjustment will help too. I like to use a little tool called a Brakeblok that I got from Napa about a hundred years ago. It's a plastic pin the same size as the anchor pin. A deep socket that's exactly the right size would work too. Drop the shoes and adjuster into the drum on the bench, put the Brakeblok in place at the top of the shoes, and turn the adjuster wheel until the shoes can just be moved inside the drum. Now, as long as you don't change the length of the adjuster during the installation process, you will have a proper initial adjustment when assembled and if there is any binding when you're putting it all together you'll know it's because something is out of place. That little gizmo works a hundred times better than a caliper IMHO.

Mine did the same thing,they cracked around the circumfrance (sp) Car Quest replaced them for free.They told me that they were a Raybestos brand.What broke were bonded shoes,replaced with riveted ,Of course the rear brakes on our XJ are soo good that-------
Wayne

Well, my shoes are Raybestos ProStop. Not very expensive at $15 total to do both rear wheels. Based on responses I decided to replace them since Pep Boys will do this free if I return the shoes and claim that they have a manufacturing defect.

I removed all shoes (4 of them) from both back wheels. All 4 have cracks that run about the middle of the pad along the circumference (and not across the pad.) One crack branches out to the sides of the pad. Cracks are just about big enough to the a thumbnail into.

Since all 4 shoes have the cracks I'm guessing it is not a manufacturing defect unless there was a completely bad batch. I expect that the new shoes will do exactly the same thing. As to whether the cracks affect the shoe performance I simply don't know the answer. Next time I'll buy the more expensive shoe (at about $34) and see if cracks appear. Cost is minimal compared to the couple of hours required to swap shoes and return them to Pep Boys, and especially compared to costs of brake failure should this result from the cracked pad somehow.

I didn't do as suggested and try the shoes in the drum first. But I'm really gentle on braking and have done the suggested initial stopping to wear them in.

Thanks for the info in the replies!