FJ40 brake drum compatibility across years (1 Viewer)

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flx

flx

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Hi,

The cylinders in my 1974 FJ40 front drum brakes decided that 49 years was enough for them and all started to leak.
Right are very slightly leaking and does not cause any issuez for now:
1684881799832.png

(I noticed the spring is on the wrong side)
1684881814098.png


One from the Left is more seriously leaking and is oiling the brake shoe causing asymetric braking...
1684881943756.png


It's temporary fixed with the help of some emery cloth but I need to do something for my cylinders:
1684882107778.png



I have been looking and the cylinders are listed available on Amayama and local equivalent but almost nowhere else. Local price is quite steep (100€/piece) though.
Do someone knows if those cylinders are actually available OEM?

In the EPC all the parts for drum brakes change with the front axle update of 09/75 (that I guess was made for compatibility with the new disc brakes for the US). But are complete drum brakes from a 1976+ FJ40 bolt in compatible on my 1974 axle? I would tend to think not but I can't find what would make them not compatible? The bolt-in pattern of the rear flask look the same and from a 40 the drum width should be the same?

Complete units if good drum brakes from a 1976+ seems to be easy to find and cheap.

And actually I have a friend that have a pair ubolted from his 1981 FJ45 that I could have for reaaally cheap. But that brings an extra question because I think the 45 drums are wider. So not sure how that works out but seems common for people to have installed them on 40: FJ40 Drum Brakes - https://forum.ih8mud.com/threads/fj40-drum-brakes.968155/
The drum in question:
1684882627365.png


I searched but I only found information from people swapping to disc regarding the difference between before and after 09/75.

Thanks for anyone with knowledge on this that can share it! :)


(PS: not willing to swap to disc so not needed to propose it)
 
Sorry, can’t help you on the question regarding drums…BUT…the springs you refer to are supposed to have one on the front side and the other on the back side.
 
OGBeno said:
These parts have been discontinued for years.
Click to expand...
That's whet I though, when I search I only see an aftermarket Japanese part mentionned.

But do you know if a 1976+ complete drum brake can be bolted to a 1974 front axle?
I understand that you can't do that for disc brake but can't figure out what is the difference/problem for the drums.
 
@flx

Clarification update (in red): (Thanks to @cruisermatt for his knowledge regarding later model FJ40's)

US Market FJ40 brake drums, according to Toyota parts fiche, are all the same, front, rear, all years from 6903 - 8007.

FJ45 are definitely different.

1684954439015.png


1684954668575.png
 
Last edited:
73FJ40 said:
@flx

FJ40 brake drums are all the same, front, rear, all years.

FJ45 are definitely different.

View attachment 3331339

View attachment 3331342
Click to expand...
Mhh I think it's beacause you are looking at a North American Master Catalog where all 40 went to disc, if I look at the EPC for Europe I get:
1684955250177.png

1684955269283.png



Also the issue is I think more for the flask part of the complete drum brake system, I can't find if there will be an issue to bolt it between pre and post 1976.
1684955482884.png

1684955520274.png

(RH side only presented)
 
So, I'm having a hard time figuring out what exactly you want to know.

Are you looking for the actual drum part numbers for a 40 series?

The wheel cylinders are only available aftermarket as they are discontinued OEM (as I stated above).
 
flx said:
Mhh I think it's beacause you are looking at a North American Master Catalog where all 40 went to disc, if I look at the EPC for Europe I get:
View attachment 3331344
View attachment 3331345


Also the issue is I think more for the flask part of the complete drum brake system, I can't find if there will be an issue to bolt it between pre and post 1976.
View attachment 3331346
View attachment 3331349
(RH side only presented)
Click to expand...
Looks like you had the answer to your question before you asked?

So, like @OGBeno asked, your title is looking for "brake drum compatibility" and it seems you are actually looking for something else...
 
OGBeno said:
So, I'm having a hard time figuring out what exactly you want to know.

Are you looking for the actual drum part numbers for a 40 series?

The wheel cylinders are only available aftermarket as they are discontinued OEM (as I stated above).
Click to expand...
Sorry for the confusion, my number 1 question is: Can I use the complete front drum assemblies from a 1981 FJ45 on a 1974 FJ40 axle?
This would be the simplest and cheapest solution for me.
1684882627365-png.3330596

When I look at the bolt pattern of the backing plate with the brake shoes it looks similar to the one on a 1974 axle. But as 1976+ disc brakes are not compatible with <1975 axles I imagine something must be blocking here.
Just can't figure what could be the problem or if this will just bolt in?


If this solution is not possible then I will have to look for other solutions with the correct drums.
 
73FJ40 said:
Looks like you had the answer to your question before you asked?
Click to expand...
All the part numbers change without superseeding, yes I already have this answer. But my understanding is that it may just means that a 1976+ brake shoe can't go with a <1975 backing plate. The complete drum assembly with all the parts from 1976+ could (or not) mount on an older axle.
 
flx said:
Maybe I can ask my question the other way around:
Why the OEM disk brakes (from 1976+) are not compatible with pre-1975 axles/knuckles? Did the bolting pattern changed?
Click to expand...

Because apart from the missing caliper ears the pre 75 drum spindles and birfields and wheel hubs are shorter.

The later/larger drum brakes use the longer/later disc-style spindle/birfield/wheel bearing hub, so you would have to change those as well to use those later drums. At which point you may as well put discs on it :meh:
 
Ahhhhhh thanks I had not thought it could be extra ears for mounting the disks! Now that you said it I see the extra ears represented on the schematics 😅
1685039222731.png
1685039229497.png



cruisermatt said:
the pre 75 drum spindles and birfields and wheel hubs are shorter.

The later/larger drum brakes use the longer/later disc-style spindle/birfield/wheel bearing hub, so you would have to change those as well to use those later drums. At which point you may as well put discs on it :meh:
Click to expand...
For sure if I have to change knuckles it's not worth it and I will go the route to find the parts and restore my originals.

Does the longer spindle and hub really make a difference for the braking system and wheel? Because they actually go through the drum and wheel and it can clearly be seen from outside that newer 40 have longer hub that older ones.

The 45 drum is clearly wider than the 40 one but the mounting surface is recessed on the 45 one versus the 40 drum has a raised mounting surface.
1685039858189.png
1685039880263.png

Still need to check if it matches but that should be easier to measure and I think there is a chance.
 
go for it. :meh:
 
So, to complete this topic and answer my own question:
1981 FJ45 big front drum brakes bolt straight onto a stock 1974 FJ40, no problem and no modification required.
The longest part for my garage was, as usual, to properly bleed and adjust the brakes, but braking is great now.

Not able to take a picture for now but will try to add that later on.
 
flx said:
So, to complete this topic and answer my own question:
1981 FJ45 big front drum brakes bolt straight onto a stock 1974 FJ40, no problem and no modification required.
The longest part for my garage was, as usual, to properly bleed and adjust the brakes, but braking is great now.

Not able to take a picture for now but will try to add that later on.
Click to expand...

Which wheel bearing hubs and spindles and birfields did you use? I was assuming those had to change but it sounds like not?
 
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