Brake Lining Mistake

[Paul Bennett]

I got ahead of myself with new front brake shoes and when one drum went super easy and other wouldn't go on at all, a light bulb lit went off. I realized the pair of shoes aren't all identical. One shoe has more longer lining than the other and goes on to the front, or is it the rear. As they aren't stamped (my only excuse) I obviously installed short lining shoes on one side and long lining shoes on the other side. Fortunately the ill-fitting drums afforded the clue.

Question, does the shoe with long lining face front or rear?

I googled the issue and found "early Fords are the exception" so I'm asking the pros here for the definitive 50 Merc answer.

[alanwoodieman]

short shoe to the front on self-energizing brakes, long shoe to front on fixed position brakes

[Paul Bennett]

Please define 'self-energizing' and 'fixed position'. What do I have?

[JSeery]

Bendix brakes are self-energizing. You really need to know what type of brakes you are working on in order to know how they go together and how to adjust them. I'm not a mercury guy, so I'm not sure what they had on them.

[Ronnie]

http://www.flatheadv8.org/rumblest/brakes.pdf

R

[cas3]

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have they been arced to match the drum diameter?

[JSeery]

Originally Posted by cas3

have they been arced to match the drum diameter?

Shouldn't be that big a deal on Bendix brakes.

[Paul Bennett]

I've got my answer. And found a brake thread on HAMB (entitled 'Which Direction') which is comical with the different ideas plus many photos and diagrams.

Thanks to you all having helped me learn about newer Bendix brakes. I feel self-energized now.

[Brendan]

mercs have Bendix brakes

[Brendan]

i always forget what shoe goes where, i have to look in a manual

[Mart]

I always remember for early Fords, big end of cylinder and big (longer) shoe to the front.

Mart.

[flatheadmurre]

It´s basicly the shoe taking the biggest force and wear most needs the longer lining so both wear out in the same time...
On a fixed the front gets the rotational force of the drum and the cylinder force so that needs the longer lining.
On a floating setup the back one sees the force of the first shoe plus brake cylinder force so needs the longer lining.

[richard crow]

they sell repro shop manuals i think it will be a great help to. you every facet of repair is in it you will be able to understand the workings of your car

[19Fordy]

Paul, looks like you are doing a ton of work on your Merc.
Follow Richard's advice. Buy these manuals. You will be amazed
with the wealth of info. Things you didn't know you didn't know.
A "must" if you own a 1949-51 Merc.

[flathead4rd]

48 and back long shoe to the front. 49 and up short shoe to the front.

[Dec211975]

On a self energizing brake if the wheel cylinder is on the top the front shoe would be the primary shoe (short lining) and the rear shoe would be the secondary shoe (long lining). Usually the secondary shoe has a better grade of lining than the primary. So when the car is rolling forward and the brakes are applied the front shoe is pushed forward to the drum, the shoe contacts the brake drum
and then transfers that motion through the adjuster and applies the longer shoe, this shoe is stopped from rotating by the solid shoe anchor at the top of the backing plate so the longer lining does the majority of the braking. Driving in reverse the brakes have much less stopping ability than in forward. If the brake anchors are on the bottom obviously the shoes would be opposite of what I just described.

[supereal]

The best way to remember is that the long shoe goes to the large end of the wheel cylinder in the Lockheed system. In the Bendix system (self energizing) the primary (short) lining goes to the front. Getting them reversed will cause reduced braking power.