transmission brake shoe orientation

timbr00 · Apr 30, 2023

I've got myself totally confussled over the correct orientation of any transmission brake shoes. I've been searching YouTube and looking at pics but to me they all seem to be fitted different ways! could someone please confirm what is correct?
1st pic shows them as I took them apart, 2nd the new ones assembled.

tottot · Apr 30, 2023

You need to flip brake shoes 180.

timbr00 · Apr 30, 2023

as in top to bottom or each one in same position but reverse face outward?

timbr00 · Apr 30, 2023

tottot said:
You need to flip brake shoes 180.

as in top to bottom or each one in same position but reverse face outward? How do you tell the leading edge?

tottot · May 1, 2023

Look at your pics again, in the pic of old the knotch/cut out in the shoe inner edge is by the expander. with the new ones you have it by the adjuster. See it now?

timbr00 · May 1, 2023

tottot said:
Look at your pics again, in the pic of old the knotch/cut out in the shoe inner edge is by the expander. with the new ones you have it by the adjuster. See it now?

Thanks, yes I see that the trouble is I’ve watched loads of tutorials etc online and have seen it both ways. As for the shoe lining itself one side it starts at the edge of the shoe and the other has an inch of shoe before the lining begins. This would make it opposite to the old ones?

v8250 · May 1, 2023

Watch from 6.50s

+ from 10m25s

Drums are very simple devices, just remember the importance of leading and trailing edge on the shoes

timbr00 · May 1, 2023

v8250 said:
Watch from 6.50s

+ from 10m25s

Drums are very simple devices, just remember the importance of leading and trailing edge on the shoes

Thanks for those. I’d only watched his transmission brake one which made me think I’d installed them incorrectly. Can you confirm what identifies the leading Edge? Using the side with the lining set about an inch from the edge of the shoe or does something else signify it? The definition of the leading edge is what’s causing me some confusion I think

v8250 · May 1, 2023

v8250 · May 1, 2023

The leading edge is the edge of a brake shoe that is expanded by the the brake cylinder into the brake drum :. it leads the brake shoe to the brake drum.

The trailing edge is the edge of the brake shoe opposite the brake cylinder, usually based around the pivot point.
**but this not always the case as some brake drums have twin brake cylinders for theoretical greater braking efficiency**

ps a copy of the workshop manual is your friend

timbr00 · May 1, 2023

v8250 said:
The leading edge is the edge of a brake shoe that is expanded by the the brake cylinder into the brake drum :. it leads the brake shoe to the brake drum.

The trailing edge is the edge of the brake shoe opposite the brake cylinder, usually based around the pivot point.
**but this not always the case as some brake drums have twin brake cylinders for theoretical greater braking efficiency**

ps a copy of the workshop manual is your friend

Thanks for this explanation, think I’m getting there! Probably very simple but hard to get my head around. The adjuster on the left is my pivot point? The expander on the right, pushes both pads to the drum
Both shoes have a leading and trailing edge? Both leading edges should be on side of expander? Not sure I have that quite right should the leading edge of the lower one be on the left?

v8250 · May 1, 2023

timbr00 said:
Thanks for this explanation, think I’m getting there! Probably very simple but hard to get my head around. The adjuster on the left is my pivot point? The expander on the right, pushes both pads to the drum
Both shoes have a leading and trailing edge? Both leading edges should be on side of expander? Not sure I have that quite right should the leading edge of the lower one be on the left?

The pivot point is at the bottom of the backing plate connecting the two trailing edges. The expander is the brake slave cylinder that hydraulically pushes out the leading edges of the shoes [there is no expander on the right]. The adjuster is of a cam/snail type that is adjusted from the back of the brake backing plate [the round disc seen top right in photo with one end of the red return spring attached].

Turboman · May 1, 2023

v8250 said:
The pivot point is at the bottom of the backing plate connecting the two trailing edges. The expander is the brake slave cylinder that hydraulically pushes out the leading edges of the shoes [there is no expander on the right]. The adjuster is of a cam/snail type that is adjusted from the back of the brake backing plate [the round disc seen top right in photo with one end of the red return spring attached].

Handbrake drum brake is mechanically operated. Unless I am wrong about the brake he is talking about.

timbr00 · May 1, 2023

Turboman said:
Handbrake drum brake is mechanically operated. Unless I am wrong about the brake he is talking about.

I think that's what's confused me. photo shows a leading and trailing shoe, I thought I had 2 identical shoes each with a leading and trailing edge. taking it back to basics if I had the shoe in my hand how would I know what the leading edge is?

tottot · May 1, 2023

You are over thinking it now, set up should be as in the pic of the unit when you took it off.
The pics above by other members are of axle drum brakes that have hydraulic activation which are a little different.
He is asking about the Hand Brake drum set up chaps as per turboman.
Re read my post above as to how to identify.

Turboman · May 1, 2023

timbr00 said:
I think that's what's confused me. photo shows a leading and trailing shoe, I thought I had 2 identical shoes each with a leading and trailing edge. taking it back to basics if I had the shoe in my hand how would I know what the leading edge is?

Like he says^^^^^^^^. Put them back in the same way they were in pic 1 in your post.

To be honest, I doubt if it makes any difference anyway, as you should not apply a transmission brake when moving.

timbr00 · May 1, 2023

v8250 said:
The pivot point is at the bottom of the backing plate connecting the two trailing edges. The expander is the brake slave cylinder that hydraulically pushes out the leading edges of the shoes [there is no expander on the right]. The adjuster is of a cam/snail type that is adjusted from the back of the brake backing plate [the round disc seen top right in photo with one end of the red return spring attached].

in this screenshot from trailblazers YouTube I have the style on the right. I have assembled them with the notches for the spring on the left at the adjuster as per his video but bottom right you can see there is an inch of plate with no lining. mine only has 10mm with no lining. I can't rotate it 180degrees as that would be the same and flipping them would put the notch on the opposite side against the adjuster.

2nd screenshot from another forum shows them assembled notch on right hand side. it seems to me that mine cannot be installed as per the trailblazer video but should be as per the 2nd screenshot.

timbr00 · May 1, 2023

Turboman said:
Like he says^^^^^^^^. Put them back in the same way they were in pic 1 in your post.

To be honest, I doubt if it makes any difference anyway, as you should not apply a transmission brake when moving.

timbr00 · May 1, 2023

tottot said:
Look at your pics again, in the pic of old the knotch/cut out in the shoe inner edge is by the expander. with the new ones you have it by the adjuster. See it now?

I missed this post!!! totally agree with what your saying - notch by the expander and it'll look just like how they came off. what's confused me is the multitude of videos and forum pics of the notches on the adjuster side.

tottot · May 1, 2023

Yea, Sod the video's, not all are right or good. Britannica restorations is one of the best.

transmission brake shoe orientation

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