Trailer Brakes

Thanks Brulaz, It may be that during the cleaning process prior to installing the new assembly, there is some left over residue that inhibits the magnets from making good connections therefore poor braking performance. I think I will just hook up and go for an hour or so drive around the county (Pinellas in Florida). I'm sure the stop and go traffic will seat in the pads and magnets.

[Wavery]

If your old brake shoes were worn out, the drums were surely glazed to some extent.

It is always best to machine the drum surfaces to remove all glazing and rough up the surface to facilitate the "wearing-in" process of the new shoes. As the shoes contact the roughed-up surface, they develop a wear pattern to the exact contour of the drum. If the drum surface is smooth, the brake lining will bot wear-in properly.

If you did not at least sand the drums with 80-100G sand paper, you may want to consider doing that (I would recommend sanding the new shoes also and check them for cracks). If you don't, it may take a long time to wear in the shoes.

The magnet surface of the drum should also be sanded.

[T and C]

Originally Posted by harveyrv

If your old brake shoes were worn out, the drums were surely glazed to some extent.

It is always best to machine the drum surfaces to remove all glazing and rough up the surface to facilitate the "wearing-in" process of the new shoes. As the shoes contact the roughed-up surface, they develop a wear pattern to the exact contour of the drum. If the drum surface is smooth, the brake lining will bot wear-in properly.

If you did not at least sand the drums with 80-100G sand paper, you may want to consider doing that (I would recommend sanding the new shoes also and check them for cracks). If you don't, it may take a long time to wear in the shoes.

The magnet surface of the drum should also be sanded.

I am going to ask a question about drum brakes. It might, or might not, bring out some more information on this topic.

When I was a youngster, my family had a series of "Shoebox" Fords. Those are the 49-51 series cars. They had drum brakes all around. We did most of our own work on those cars, including brakes.

When we replaced the brake shoes my dad taught us to take a flat file and file off the corners and file off the sharp angle at the edges of the brake material all the way around the shoes.

He believed that this would help the brakes to "seat in" and would prevent the new shoes from causing noise. I kept on doing this up through my '61 Ford p/u. Don't really know if it helped or harmed.

Anyone ever heard of this? Any thoughts?

Tom

[Wavery]

Originally Posted by T and C

I am going to ask a question about drum brakes. It might, or might not, bring out some more information on this topic.

When I was a youngster, my family had a series of "Shoebox" Fords. Those are the 49-51 series cars. They had drum brakes all around. We did most of our own work on those cars, including brakes.

When we replaced the brake shoes my dad taught us to take a flat file and file off the corners and file off the sharp angle at the edges of the brake material all the way around the shoes.

He believed that this would help the brakes to "seat in" and would prevent the new shoes from causing noise. I kept on doing this up through my '61 Ford p/u. Don't really know if it helped or harmed.

Anyone ever heard of this? Any thoughts?

Tom

It was the practice of the time. I believe that most drum type brake shoes are now beveled on the ends.

Electric brakes are a bit unique because the force of the shoe against the drum is caused by a magnet that activates a lever, drawing the shoes against the drum. Once the shoes hits the drum, inertia from the forward motion of the drums gives the force needed for braking.

When the brake shoes are new, they don't lie perfectly flat against the drum thus the full inertia is not applied and heat is built up over a smaller surface area of the shoe. As the shoe effectively gets "ground down" by the rough surface of a newly turned drum, the shoe starts matching the contour of the drum and more surface area makes contact. That's why it is important to rough-up the surface of the drum when installing new shoes. A smooth surface in the brake drum may take a long time to wear-in the brake shoes.

BTW.......it's important to adjust the newly installed brakes too. If the brakes are not adjusted properly, they won't wear-in properly.