Brake drum adjustment slot?

[Marv 49]

I had noticed on each drum there was what I thought was a “cut” in each one some time ago. Is this the slot where you are to measure the adjustment for the brake shoes? It just came to me this morning that each slot was in the same location and had a purpose, not just a random cut that my grandpa had done.

[Alaska Jim]

My '51 Mercury has those slots on the drums as well they are there to correctly adjust the brake shoes. If I remember correctly, the clearance on the '51 Merc. was a bout 10 thou., I could be wrong on this measurement, and may be different for different years. It has been several years since I last adjusted the brakes. My factory service manual goes into great detail as how to correctly adjust the brakes using a feeler gage through these slots-- Jim

[Ford Freak]

Interesting! Is it like that on '49-'5i Fords, too? - F F

[19Fordy]

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According to the Lincoln Mercury 49-51 , Vol. 1 Overhaul Manual on page 14 it says when doing a brake adjustment: Steps 1-3 are not req'd to answer question posed.
Step 4. Place vehicle on jack stands and remove wheels
Step 5. Loosen parking brake cable at equalizer.
Step6. Place a .010 thickness gguage in drum slot and turn drum slowly checking at several points.
Step 7. If clearance is more or less than .010, remove the backing plate adjusting slot cover and turn adjusting screw until brake linings are within .010 in. of drum.
Step 8. If brakes shoes are not centered and it is impossible to obtain adjustment, slightly loosen the nut securing anchor pin and taop nut with a brass hammer until shoes are centered. The hole in the backing plate is slotted and will allow an up or down shifting of the anchor pin to correctly center the shoes. Torque anchor pin nut 110 - 120 ft. lbs.
Step 9. When brakes have been properly adjusted, no more tahn one-half the pedal
travel will be required when full pedal pressure is applied.
Step 10. Adjust parking brake at equalizer.
Step 11. Install wheels and tiorque wheel nuts to 60-65 foot ponds.

It seems like the .010 slot measurement is made first to see if brakes need full adjustment.


Step # 8 reminds me of the procedure for adjusting the Boling Bros Lincoln brakes.