Recommendations for Brake Fluid

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talibraza101

talibraza101

Joined
Jul 16, 2025
Threads
6
Messages
34
Location
MD, USA
Hello! Attached is an image of two reservoirs within my 1971 Columbian FJ40. It seems the reservoir on the left (which I believe is a brake fluid reservoir) is getting low. Could someone help a beginner like myself verify whether this is in fact a brake fluid reservoir, as well as give me a recommendation on what fluid I should purchase to fill this reservoir back up? I have drum brakes. Thank you so much!
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Yes, it’s a brake reservoir. I would suggest DOT 3 brake fluid.

Would be a good idea to include your vehicle info in your signature line…make and year along with any mechanical changes.


EDIT: just to be certain, please show a picture of where the one on the Left is attached. It either goes to the clutch or the brake, but off the top of my head I can’t remember which. A picture will clear it up.
 
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It is the brake that is low… use dot 3
 
You should plan on adjusting the wheel cylinders, as you bleed the system to then refill/flush it. I would start with spraying/applying each nipple several times a penetrate of some kind over say a week. Kroil is the best. Buy a big bottle of DOT3.

Motorcraft voltage regulator isn't OEM - Chevy is more common with Toyota. I have a Delco distributor and a Rochester 2 BBL for example.

Anyway free manuals download

Land Cruiser Factory Service Manuals (FSMs)

Factory service manuals (FSMs) for your Toyota Land Cruiser ! From the 1950s to the present!
www.cruisercult.com www.cruisercult.com
Coolerman's wiring diagrams
 
Thank you so much for all your help guys. Attached are images of my brake fluid reservoir level as well as where it attaches at the drum. Forgive me for any misuse of terms, I’m still getting acquainted with this stuff! It seems the level of fluid is quite low but is still a yellow color (which I’ve read is positive). Upon glancing at the drum brakes i dont see any noticeable leakages. Forgive me for sounding stupid, but what happens if i simply top off the cylinder with more DOT3? Would this be inappropriate? I was under the impression that this fluid should be a dark brown before it required flushing? Thank you so much for the advice.
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It's ok and you need to top off the resoiviour with 3 dot fluid. New fluid is pretty clear. It's very low. You might have a leak someplace. This is concerning because you have a single circuit brake system. Top it off and keep an eye on it.
 
I would top it off … fill it to the line … like it is on your clutch

You could have gotten air in the system because that is quite low … so see how it feels … pump it good and hard and check for leaks

It could be a leak running down the inside cab firewall from the master as well
 
I would highly suggest you upgrade to a dual circuit brake system.
US spec, mid year 1970 was changing from a single circuit to a boosted dual circuit system
no need for boosted unless you want but a dual circuit is a huge safety upgrade
if you lose the fluid in a single circuit you lose all brake function, dual circuit atleast 1 circuit either front or back will still function
adding a booster adds more work as the firewall rib is in the way
adding discs versus drums adds more stuff

just noticed the Ford voltage regulator
 
3_puppies said:
I would highly suggest you upgrade to a dual circuit brake system.
US spec, mid year 1970 was changing from a single circuit to a boosted dual circuit system
no need for boosted unless you want but a dual circuit is a huge safety upgrade
if you lose the fluid in a single circuit you lose all brake function, dual circuit atleast 1 circuit either front or back will still function
adding a booster adds more work as the firewall rib is in the way
adding discs versus drums adds more stuff

just noticed the Ford voltage regulator
Click to expand...
This! I added a dual circuit non-boosted 80 series MC to my disc/drum 40. Very happy with the braking and peace of mind. Definitely do the dual circuit when you can.
 
If you look at the exploded diagrams for the US market, you will see that your brakes match the 1970 and older systems we had here. The junction on the backing plate changed in 1971; an obscure feature I recognized immediately.

If your master is low, the fluid went SOMEWHERE. Top candidates are out the back of the master cylinder, running down the firewall inside the cab, or out one of the wheel cylinders, leaving streak marks on the inside of one of the tires.

In either case, refilling the system won’t help much, especially if it got low enough to get air in the line.

If you decide to replace the master cylinder with a dual circuit as recommended, I sell the adapter and master. All four of my Landcruisers are pre-71 US market, so I had a vested interest in developing a dual circuit adapter 33 years ago.

Marks Off Road Home Page - https://marksoffroad.net/index2.html
 
65swb45 said:
If you look at the exploded diagrams for the US market, you will see that your brakes match the 1970 and older systems we had here. The junction on the backing plate changed in 1971; an obscure feature I recognized immediately.

If your master is low, the fluid went SOMEWHERE. Top candidates are out the back of the master cylinder, running down the firewall inside the cab, or out one of the wheel cylinders, leaving streak marks on the inside of one of the tires.

In either case, refilling the system won’t help much, especially if it got low enough to get air in the line.

If you decide to replace the master cylinder with a dual circuit as recommended, I sell the adapter and master. All four of my Landcruisers are pre-71 US market, so I had a vested interest in developing a dual circuit adapter 33 years ago.

Marks Off Road Home Page - https://marksoffroad.net/index2.html
Click to expand...
Thank you so much for your reply. Could you walk me through which parts I need to purchase off of your site to replace the master cylinder with a dual circuit? Could anyone provide a sort of high-level tutorial or step-by-step on how this replacement job is carried out? Thank you all for your feedback 🙏🏽.
 
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Installing a dual circuit master is going to require running some new brakelines. Your 40 is an import, so B4 opening your wallet i would assess the rest of your brake system. There's no telling how it was put together. I'd pull wheels and drums and inspect them. Find the leak. You're sort of at crossroads. They may need to be completely overhauled or upgraded. You might find going to disc brakes might be more beneficial and economical than overhauling 4 wheel drums brakes. Fj40 drum brake systems are old and antiquated.
 
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Your first thought isn’t so much which master cylinder to buy, there are many styles available. And everyone has an opinion. I installed a Toyota T100 dual circuit (1” bore), works well for non-power assist but others on this forum may have better suggestions.

Your fist thought is how do I split the rear brake circuit from the front. If you trace the your brake line from the master, you should come across a tee fitting on the drives side of the engine where one line goes to the rear brakes and the other to the fronts. This will be where you will split the system.

The next thought is what parts do I need, you’ll need brake line, fittings, and tools to re-flare the lines. If you’ve never done this before, there are several videos on youtube that can walk you through the process.

Getting the correct fittings has always been my personal issue. Toyota uses 10 mm long and short, in a previous life, I’ve made several purchases of the same fitting to get the correct one and had to re-flare a couple of times to get it right (not leaking).

For tools, look at Amazon, Eastwood, etc….your flaring tool, tube cutter, line straightener, etc…..be prepared to spend some money, and think to yourself….after this job will I ever use these tools again?…..

By this point, you should be thinking, is it really worth the dual circuit master cylinder or do I just look for the leak and fix that, rebuilding what I have.

I would recommend watching as many brake line tutorials as you can tolerate, and once you get the tools, practice flaring the different style flares (there are 3 basic flares if I remember correctly), then go off a concur. Not trying to deter you, just look at it from a common sense approach.

Good luck!
 
Thank you again for your honest feedback Mr. Jennings and pb4ugo. I will definitely try to dig deeper and learn as much as I possibly can before pulling the trigger on equipment. I so appreciate your guidance. I will keep you all posted!
 
I also have the firewall rib, so I went with an adapter to upgrade my master cylinder on my 1967 single reservoir system.

For my brakes, I bought a few rolls of 3/16 nickel copper, some 10mm inverted flare nuts, a few 3 way tees, a TGR flaring tool, and new bender.

I’ve lost circuits on a dual bowl master and hate risking a single bow master.

If you aren’t comfortable with it, there are some great guides on how to do this kind of work. It was one of the more fun projects on my ‘67.

The goods news is that it looks like someone has upgrade your likes to Mickey copper already, so like others have said, map out your system and see where things are split.
 
I found a picture of my dual bowl conversion, with my disc residual pressure valves and adjustable proportioning valve:

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single circuit on a south american ......what could possibly go wrong?......
 
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