Mdawg's 67 Patrol.

[mdawg4x4]

After looking closely at one of the service manuals and the 1970 parts manual, it looks like one shoe should have the square hole at the top, and the other would be at the bottom. It would make sense that the friction material is then spaced equidistant around the surface of the drum. Pairing up the square holes on the top or bottom leaves a much larger gap on that side. Applying the braking force at the pedal would then apply an unbalanced force against the drum and subsequently against the wheel bearings. Hmmm, maybe this is why my drum brakes never seemed that effective?

Interesting thought. However, that may cause a problem with the springs as the top and bottom springs are different lengths. The spring holes was one of the determining factors in how we positioned the shoes. I wish there was something inside to look at before we started, but there wasn't on the rear.

[nizmut]

20161029_170614 (Medium).jpg

20161029_170603 (Medium).jpg

[Esteban]

All this is very interesting! I have put the 3 different setups for the rear brakes side by side in the enclosed picture. I found the 3 of them to be correct based on what each member had to deal with. It also points to the fact that Nissan was not consistent at all regarding the rear shoes, because there are some clear differences between the 3 of them. Hope this can provoke some discussion.

Rear Brakes Comparison.jpg

[mdawg4x4]

All this is very interesting! I have put the 3 different setups for the rear brakes side by side in the enclosed picture. I found the 3 of them to be correct based on what each member had to deal with. It also points to the fact that Nissan was not consistent at all regarding the rear shoes, because there are some clear differences between the 3 of them. Hope this can provoke some discussion.

Rear Brakes Comparison.jpg

Very interesting! I'm getting close to buttoning these things back up. Got the new 7/16"-20 to 3 AN fittings to get the flex lines connected from the frame to the axles and at each end of the front axle.
Just checked the online manual and it shows both square holes at the top.

[rjiggy]

Some more visual fuel for the discussion. This is one of my rear backing plates as I disassembled it during the disk brake conversion. I remember putting everything in the places I found them in case the conversion did not pan out. No idea if this is correct, just how they were installed on my rig.

[mdawg4x4]

My coworker and I are thinking the wheel cylinder is at the top on the rear axle, therefore the majority of the friction would occur at the top if the majority of the wear surface is at the top. We think the most efficient use of the wear surface would therefore be at the top nearest the wheel cylinder.

Then again, should the majority of the wear surface be at the bottom to spread it out more effectively?

[Esteban]

Some good reasoning there, Mike. But out of 4 examples so far, yours is the only one that has all the material at the top. On the other 3, including the latest one from Rjiggy, don't. Maybe a way to prevent the rear wheels from locking too much?

I've been fixing my Patrol for over 40 years, and after going through this discussion, I realize I know nothing about brake shoes and the way lining should be applied. I'm more confused than ever!

I tried to read and make sense of the following article, but has some complicated issues there. Nevertheless, it's a good read, specially what refers to the "leading shoe" and the "trailing shoe" and how the composition of forces acting during a brake, tend to self apply additional force in the "leading shoe". No wonder one of the shoes always ends up with more wear that the other. But the article never addresses the portion of the shoe without lining.

http://www.engineeringinspiration.co.uk/drumbrakes.html

[mdawg4x4]

Well there you go. Looks like the leading shoes need to be flipped if it fits the cylinder and adjuster OK.

[rrodriguezsal]

Hello

Maybe this is a too late information.

The pictures is taken from Service Manual

Thanks

[mdawg4x4]

It shows the square hole in both shoes at the top, but also shows the lining such that the extended length is opposite. It also neglects to mention LH/RH lining preference. It isn't too late for me to change how I have them, but everything is a little confusing when it comes to the actual lining orientation on the different shoes.
I think I am going to turn the front shoes over and see how they fit to the adjuster and cylinder.
I also ran new hard lines along the rear axle last night. There will be NO pictures as they aren't nice and tidy running along the axle like the original ones were. I am using pre-flared easy bend lines. The length is close to original, so I had to accommodate a little extra line. I have to get the front flex lines installed, and the 2 drop lines from the master cylinder. Then we will see how many leaks I have!