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1970 Front Brakes - Dual-Twin or just Twin??

Jefe & Elsie

New Member
Jan 13, 2023
Country Flag
I am getting a real education on brakes here.
I finally understand what "twin leading" brakes are and the difference between "twin leading" and "dual twin leading" brakes.
I have also learned that pretty much all the earlier models had DTL brakes on the rear.
But I am unsure of my front brakes. The book says the earlier models started out with TL front brakes, then went to DTL brakes for a few years, then finally disc brakes.
My FJ40 has a build date of September, 1970. I don't think I can trust that the cylinders on it now are correct. (The guy who did them was paid as he worked, with beer.)
Plus, I've never felt that my brakes were really "right".
Does anyone have the scoop on this? Which year did they change the front brakes from Twin Leading to Dual Twin Leading?
Are the shoes different for the two systems? If so, how can I tell if I have the correct shoes?
Thank you very much for your time and help!
I finally understand what "twin leading" brakes are and the difference between "twin leading" and "dual twin leading" brakes.

Sorry, I'm not understanding your terminology there. Twin leading has a pair of pistons, one in each cylinder, with each the leading edge of each shoe adjacent to the piston. They're often used on front drums. The common alternative is a single cylinder with two pistons, one driving the leading and one driving the trailing shoe, which is often found on rear drums. There's been a few motorbikes that used 4 leading shoes in a single front drum and maybe some cars [?] but not the vehicles we're dealing with.

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Twin leading is as you say, two wheel cylinders per wheel. The dual twin refers to the fact that both ends of each wheel cylinder have a piston, whereas in non-dual only one end of the cylinder has a piston while the other end is solid.
According to the information I have the year of change was 1971.

I am attaching to scans of the two types of braking system.


frt brakes 40 early.jpeg

post 1971 frt brakes 40.jpeg
Thanks. Intriguing way to do it. Wonder if it has any advantages over twin leading?

That fits what I currently find on my front brakes, so that's a relief.
Although it's all messed up - shoes backwards, pistons pushing on trailing edges, no consistency in adjusting rings so you can't tell which way to tighten/loosen them.
Looking forward to seeing how well the brakes work once they're done right.
It kind of seems like my LC was built in a tiny window of change. The build date is 9/'70. When I look for brake parts I often find parts for '68 through 7/'70 and for 9/'71 through 7/'80, but hard to find 8/'70 through 8/'71.

And to Jules' question, I am also curious. Because with the dual piston cylinders, one piston is pushing on the leading edge of one shoe but the other piston is pushing on the trailing edge of the other shoe. The other cylinder is doing the same thing at the other end of the shoes. So why do they still call it a dual twin "leading" system?
Oh well, as long as I can make it stop when I want it to.
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... but if both of the cylinders have two pistons it would seem to do away with the need for an adjuster, so what are the adjuster rings for?

Looking at diag 10.9 it appears that it's a standard twin leading shoe with the piston [part 11 in diag 1, bottom right of page 174] only acting on one end of the shoe with the other end being a conventional adjuster. I reckon the cylinders only have one piston each, though anyone who's pulled them apart can easily confirm/deny this.

Also diag 1seems to confirm this with the adjuster fitting into a blind passage [no access to the fluid system] on the opposite end of the cylinder to the piston.

Wow, don't try googling leading/trailing shoes, there's a lot of complete misunderstanding out there!

This is pretty good to illustrate both types, though it's not a twin leading as illustrated in the diags above. The "expander" cylinder in the diag below has two pistons:

leading v trailing


The big advantage of leading is that they have a [self] servo action. If, by some chance, single piston cylinders have been installed the wrong way around, you get twin trailing shoes which will significantly reduce the braking.

For twin leading you need both pistons in the LC twin leading shoe system pointing in the direction of rotation.

My guess is that all they mean by dual, twin leading shoe brakes is that there's a pair of twin leading shoe brakes, one for each side of the car. A sales pitch maybe?

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