Juice brakes rear wheel cylinder direction

I have read that the slightly larger end of the rear wheel cylinder should face forward.
First question:
What is the philosophy behind this?
Second question:
My 40-48 juice brakes are fitted to my model a rear axle, therefore I have modified to fit by turning the backing plates forward to have wheel cylinder clear spring hanger. This is all set up perfect but I need the wheel cylinder small end forward. Is this a problem?


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The big piston puts more pressure on the shoe. You want that shoe to be the front one, since that one does the most braking going forward.

 

On 40-48 Fords the big shoe and the larger dia. wheel cylinder should face towards the front of the car because this system uses the Lockheed style brakes. The Bendix style brakes have the larger shoe on the rear of each drum. It's kind of pricey but if you use MT Products Lincoln brakes kit , I think your problem will be solved. The Lincoln brakes are Bendix style. Check them out.

 

I have seen many threads of guys fitting setups to model a rears. Some face big side forward some not. Question is can it be backwards and do the job?


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If big side forward, even with the backing plate rolled the line inlet then faces back and still issues with spring hanger/shock ball.


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It will work. Not as well supposedly but it will work.

 

Ok. Any body else agree with junk yard kid? I thought it not reeeeaaally matter. Better but not necessary.


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There is a right and left cylinder to get the inlet facing correctly...

 

Yes but if you put the right on the right in correct position with large end forward the inlet faces back ( at least on mine) causing clearance issue.


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Can you swap the right and left, giving the correct outlet and the big ends forward?

 

No. Can swap sides, the outlet faces forward and perfect fit but large end faces back.


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If you do the math, the "slightly" larger end actually exerts about 20% more hydraulic force, quite a bit when it comes to proper function of the brakes, especially Lockheeds which are not self energizing.

Maybe the best solution would be to re-drill the backing plates and rotate them to the rear as usual.

 

What will happen if I run the wheel cylinder small side forward?


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This is right on the pressure difference and the reason for it is that the front shoe when applied is somewhat drug forward by the drum rotation also known as servo action. The rear shoe is being pulled away from the drum as it rotates because of the fixed end in relation to the drum.

The reason for the different size ends is to apply even braking force to both shoes. As mentioned above these brakes are non-servo or non-self energized making them less than stellar in their performance and any modifications like reversing them just makes them worse.

Wilson Welding sells Lincoln brakes that are the servo type but you would want to use them on all 4 wheels or the rear will have a tendency to skid in an emergency situation. The best you can do with the stock brakes is to make sure they function as intended, even if it requires more modification. Hope this clears things up for you. Jim (55willys)

 

http://www.jalopyjournal.com/forum/showthread.php?t=124112

In the tech archive above I see he has done it exactly how I did it. Obviously he saw no issue with putting small end forward....


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mine are backwards and it stops fine i can lock up the rears. The model a is lighter, since your useing the stock rearend your probably running the banger or a flatty, so your probably not gunna go to fast.

 

I agree with junk yard kid. I'm goin with it as I got it. I'm not putting the backing plates upside down and I don't want the rear brake lines crammed into my suspension. Mine is a fender less model a pick up rod, with a '32 4 banger, so..... Light and not so fast....


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Another question. I'm running 1/4 inch brake line front and rear. Have heard of different sizes for lines on front than rear? Any body got input on that? Appreciate the responses guys....


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When a wheel cylinder actuates the "top" of the shoes, the large piston points to the front of the car, as well as the larger shoe faces forward. When the wheel cylinder is moved lower on the shoes as with later model vehicles, the big shoe is placed to the rear of the vehicle. I just read this in an old repair book, because the position of the shoes on my 40 juice set up threw me...i thought it was backwards, but was actually installed correctly as I stated in my example above.

 

This is correct the small end does go forward therefor applying more force to the rear shoe and less to the front shoe to balance out the rotational counterforce.

 

No, the larger bore on the wheel cylinder faces forward even if it does not agree with your interpretation of how Lockheed brakes work.

 

wouldnt the rotation wanting to push the back shoe away from the drum put hydrulic pressure back though the wheel cylinder to the front drum?

 

Did you finally get your drums/backing plates to work without binding?

 

Line size does not matter ,early Ford used 1/4 " stock. Funny thing ran the exact same setup years ago and had no issues with the backing plate oriented correctly getting lines hooked up without any more than minimal clearancing on the spring perch. You seem to be looking people to agree with you rather than the correct way. What you want will work after a fashion,but what are you doing about the incorrect angles for the emg. brake cables.

 

John Evans, I am looking for the "correct" way, but also the overall best way for the application as well. Remember this is a traditional hot rod not an actual 1948 Ford so a lot of things are different here. I simply have seen it done both ways with mixed opinions. The most important thing here for me really is that I don't have a big safety issue. 32 four banger and a light overall truck. This is what I found thru hours of head scratching and multiple retrys to work best, but for the possible issue of small wheel cylinder forward. As for the e brake, I haven't got there yet, but I am ***uming the slight tilt will not screw things up as guys of done this a million times one way or another. I started my venture going by the suggestion of method on Les Andrews book.


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I also have heard of later fords having the large end facing back. As I said, I have seen it done both ways and am just seeking knowledge, and trying to build it as best I can. If junk yard kid has it backwards and can lock em up, it musta worked for him, no ? Lol I'm so mixed up now.


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I did get them to stop rubbing and binding, but had to take more than the 1/8 most took from the backing and drum. And I used two .010 shims on each side. All seems good although with all cranked tight, I can move the drum in and put ever so slightly, like minute, as in 1/32. Is that common or?


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Next time mechanical brakes! Lol


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Here's a pic so you all can see what the hell I'm building...


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