1. When I measure the brake drums (across the inside diameter) I get 12 3/16 inches diameter and 2 inches deep.
Thus, I am pretty sure I am supposed to have the 12 1/8 X 2 inch shoes, but after a search I cannot find the maximum allowed interior drum diameter for 12 1/8 inch drums. Does anyone have those specs? Is 1/16 over too much? My primary concern is over-extending the wheel cylinders...
I know that these are the original drums but I do not know how many times they have been turned....The drums are in good shape and I do not think that I need to have them turned again (at least not this time and if I can get everything else repaired...I might do the disc brake conversion the next time that I need brakes).
2. I remember years ago that when we installed new shoes we would hit the shoe with a heavy rubber mallet to conform the shoe to the drum as needed. Doing so would help the shoe break in evenly. Is this practice still recommended and if so, what is the best procedure for doing so???
3. The local parts store wants about $125.00 for the two sets of 12 1/8 x 2 brake shoes. Have any of you had any luck ordering such parts online and if so, from whom? I noticed that MAC's wants about $80 plus shipping...
"Machine to" spec is .060 over standard and "discard spec" is .090 over standard. We typically do not "arc" the shoes to the drums any more. Drums should always get a new surface when installing new linings to ensure maximum performance out of the brakes, whether ny machining (if there is enough material), or replacing.
'05 Excursion LTD 6.0 4X4, 01 F250 7.3 4X4 Crew
73 Bronco, 66 F100 CC LWB, 62 Uni LWB
69 Cobra 428CJ, 4-speed, 64 Fairlane 2dr Post
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I am terrible at math, how does .090 translate to measured inches?? My drums appear to be 1/16 over the 12 1/8 original size....
One last question, if you do not mind....if the drums are close to the .090 mark, would that cause the wheel cylinders to over-expand even if the adjusters (manual on this truck) are properly adjusted?
When I pulled the drums the wheel cylinders were, in fact, over extended (and terribly corroded as this truck sat idle for about 15 years) so I am replacing them (and all lines and master) but if the drum is now too large will that cause the wheel cylinders to blow out again?? They may have blown out previously due to improper adjustment, I have no way of knowing...
We (the O'Reilly parts guy and myself) are still having trouble figuring out what brake shoe fits these 12 1/8 inch drums on this 66 F250.
The part number "33" shoes are listed in some parts books as 12 x 2 and some as 12 1/8 x2 ??? Can anyone give me the correct part number for my shoes? Maybe if someone can give me a current FORD part number I can have it cross-referenced. The fellow at my parts store argued that there was not a 12 1/8 x 2 shoe for this truck until I got him to look up the drums and there they were....12 1/8 x2, so he was stumped....
On RockAuto, the Bendix, Monroe, Wagner and Raybestos 12 1/8 x2 shoes show part numbers with the "33". Autozone, O'Reilly, Advance Auto all show the part number "33" as 12 x 2. NAPA only shows a 12 x 2 1/2 shoe.
My Raybestos catalog shows 33APG as the part# for 12 1/8 X 2. Most aftermarket companies (Raybestos, Bendix, Wagner, etc.) will use some form of that number, the prefixes and suffixes will change. 316PG is the Raybestos number for 12 X 2 1/2. Raybestos book shows both available for 1966.
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