Barrett brake shoe grinder
- Thread starter wkeene
- Start date
Skyman
Well-known member
I don't have an answer for you, but that's a cool score. Congrats.
disston
Well-known member
It is mostly for old cars. Anything really with drum brakes.
You'll notice on a new set of brake shoes for drum brakes the friction material is a even thickness through out. If used this way when the brakes are applied only a portion of the shoe contacts the drum. You loose efficiency. The act of arching the shoes matches them to the drum so when applied all the friction material contacts the drum.
It's a most desirable tool for anybody doing the brakes on old cars. Not a tool that everybody has, for sure. In the old days we would take the drums and the shoes to a shop that would do the arching for us.
Most often what happens is that mechanics that don't have this tool or access to one use the new shoes as is. It works. Danger may be brake fade if a heavily driven car. As time passes the shoes will arch themselves so things get better but that is thousands of miles.
You'll notice on a new set of brake shoes for drum brakes the friction material is a even thickness through out. If used this way when the brakes are applied only a portion of the shoe contacts the drum. You loose efficiency. The act of arching the shoes matches them to the drum so when applied all the friction material contacts the drum.
It's a most desirable tool for anybody doing the brakes on old cars. Not a tool that everybody has, for sure. In the old days we would take the drums and the shoes to a shop that would do the arching for us.
Most often what happens is that mechanics that don't have this tool or access to one use the new shoes as is. It works. Danger may be brake fade if a heavily driven car. As time passes the shoes will arch themselves so things get better but that is thousands of miles.
nadogail
Well-known member
I last had my hands on one of those Brake Doctors 65 years ago.
rancherbill
Well-known member
You're in a tight place. Many have asked for a manual and none show up.
Somebody that know about brake arcing says they are all basically the same. This manual was suggested.
Somebody that know about brake arcing says they are all basically the same. This manual was suggested.
Is this arching across the inner & outer sides of the drum? I would've thought that the inside of the drum is flat from the outside to the inside.
If it is for the leading & trailing edges of the shoe, that doesn't make sense because the drum, shoe and backing should all be smaller concentric circles.
Skyman
Well-known member
If the drum's radius isn't consistent across its face axially, this needs to be solved by either resurfacing (turning) the drum, or replacing it with new.
In an ideal world, yes, the shoes and drums would have exactly the same radii. Manufacturing variances, wear on used drums, etc, come into play. Matching the radius of the shoe to the radius of the drum provides full contact of the lining to the drum surface when the shoes are new. If this isn't done, the shoes will wear to the point that their radii will match the drums' radii, but initial braking performance can be sub-optimal.
In an ideal world, yes, the shoes and drums would have exactly the same radii. Manufacturing variances, wear on used drums, etc, come into play. Matching the radius of the shoe to the radius of the drum provides full contact of the lining to the drum surface when the shoes are new. If this isn't done, the shoes will wear to the point that their radii will match the drums' radii, but initial braking performance can be sub-optimal.
disston
Well-known member
Asbestos is illegal on all new manufacturers. Back when this was a new thing my housemate bought all the old asbestos brake material he could find. Not finished shoes and pads but pieces of asbestos ready to fit. He was out of town when it arrived so I had to stack it all.
If you are working on an old car that last had brakes renewed in 10 years or more chances are there is asbestos involved. Also watch out for this in clutches. There are many other places where asbestos can be found on old cars like heat shields. Maybe inside mufflers? But I'm not sure about that one.
The danger is from breathing the dust. Other than that it worked really great.
If you are working on an old car that last had brakes renewed in 10 years or more chances are there is asbestos involved. Also watch out for this in clutches. There are many other places where asbestos can be found on old cars like heat shields. Maybe inside mufflers? But I'm not sure about that one.
The danger is from breathing the dust. Other than that it worked really great.
like2wheel
Well-known member
I think I have an old Ammco shoe radiuser up in the rafters.
Picked it up long ago but never actually needed it.
Picked it up long ago but never actually needed it.
Thanks. This Barrett is extremely intuitive to use, one practice shoe and (without instructions) I got it. What I was hoping for was a manual showing recalibration procedures. I think a good cleaning would do it some good and I don't want things to be off after reassembly. Right now if my drum gauge reads 10.03" and I set the grinder to 10.03", the ground shoe fits the drum very, very well and I'd like keep it that way.
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skulldrinker
Well-known member
I have two. 880 and 890.I was looking for an Ammco since I have an Ammco 4000, just so I could have a matching set. The lathe needs some reconditioning and reassembly though - cuz I need more projects
