I would have liked to go that route but I went the easy way using the JT Outfitters disc brake kit for all 4 corners. The kit has a mini truck brake booster and a plate for the firewall to attach.
Tech Talk: Ultimate 40/55 Series Disc Brake Conversion Parts Thread (Work in Progress)
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- #22
Great looking Cruiser. While disc brakes would be a great upgrade, you should absolutely be able to solve your current brake woes. Is the master good/bad? Is there a pinched or damaged brake hose or line? Are they bleeding them correctly? All of those can be issues with a disc brake setup as well.
We can absolutely assemble a front disc brake conversion and/or complete axle. You would need to reach out to the team at Cruiser Outfitters (this is our vendor thread but pricing and quotes need to be done via the shop) at info@cruiseroutfitters.com.
On the rear axle, it would be a net neutral to switch to a US spec rear drum brake axle. I'd suggest before you entertain any axle swap or brake upgrade you sort what is actually wrong with your current system. If it has a pinched frame side brake line for example, the problem will be there with the disc conversion too. We stock a great deal of parts for the non-US drum setups and/or can setup a disc conversion as outlined here in post #1.
- Thread starter
- #23
That is covered in post# 1 here:
Skip anything that has you reusing course spline birfield outer axle and uses adapters to fit GM calipers and rotors. Like hard pass skip. These require you to re-use your course spline (low strength) outer birf joint and free-wheel hubs, both of which have no options for upgrades.
- Thread starter
- #24
We've sold and installed hundreds of disc brake conversions over the years, here is one we recently did here in the shop 
This is great info! can you specify what you mean by "swap an inner axle shaft with your original if using the longer 6x stuff" I have identified a donor fj60 axle for my 1968 fj40. Do I also need to swap the axle shafts from the fj60 housing? Thanks in advance!View attachment 3051929
Skip anything that has you reusing course spline birfield outer axle and uses adapters to fit GM calipers and rotors. Like hard pass skip. These require you to re-use your course spline (low strength) outer birf joint and free-wheel hubs, both of which have no options for upgrades. If you have a 1958-10/67 4x axle, you'll also want to upgraded your entire front axle assembly not just the knuckles/brakes. The 1958-10/67 axles don't feature an inner axle seal (can be overcome with a conversion seal) but also have smaller diff studs, course spline inner axle shafts, etc. You can find inexpensive 68-75 front axle housings and differentials that will be great recipients for the disc brake parts. Likewise 1958-7/1970 Land Cruisers have a smaller 9mm brake line system, both at the master cylinder and the hardlines, hoses and wheel cylinders. Any disc brake upgrade is going to be 10mm fittings and thus you'll either need to convert from 9mm on the frame to 10mm on the axle OR upgrade your entire vehicle to the 10mm lines. This will also hold true for the master cylinder. If you choose to upgrade the master on your 9mm fitting 1958-7/1970 Land Cruiser, it too will only be available in the common 10mm fitting, so you'll need to address that as well.
Where to get the disc brake parts:
Source a donor axle from a 9/75-1/90 4x/5x/6x/7x Land Cruisers or a 79-85 PU/4RNR with factory disc brakes. Generally speaking the later the parts, the better, bigger steering arms, better brakes, etc.
Armed with the core axle, a good rebuild kit and some minor conversion parts (depending on the source of your donor parts) you can swap all of the disc brake components from the disc axle to your existing drum axle (so long as you have a 1968+ axle housing) and it stays all Toyota.
Don't forget to address your master cylinder by either modifying the front circuit to work with the discs (delete residual valve) or replace with a new cylinder, the FJ80 cylinder is a popular option. You may also consider adding a vacuum brake booster (though not mandatory), all 1958-7/70 Land Cruisers will have a rib on the firewall that will either need to be removed (not always ideal) or use a brake booster adapter to mount a common 6x/7x/8x booster. Some engine conversions will make the longer booster/master tough to fit.
All in it can be done for $500-1000 depending on parts needed (Can the used rotors be resurfaces/turned? Are the used calipers serviceable? Wheel bearings in good shape? Etc). Perhaps even cheaper if you get a good deal on an axle and it's in good shape.
Consider your donor axle:
9/75-1/79 4x/5x: Easiest as parts are a direct swap, no grinding, no conversion steering arms or shims, no swapping inner axles on the disc birfs. Downside is a less common birf, small knuckle studs/pattern (but the same as your current drum axle pattern so you can reuse your current hardware, steering arm and bottom bearing cap if needed). You will need everything from the birf outward (birfs, knuckles, spindles, hub bodies, calipers, free-wheel hubs). Combine this with a knuckle rebuild kit and minor parts and you're ready to convert your front axle.
1/79-1/90 4x/5x/6x/7x: Bigger parts but a bit more swap work, you need to grind the inside of the axle ball (super well documented), convert steering arms and swap an inner axle shaft with your original if using the longer 6x stuff. As these are far more common (6x in particular) this is likely the best solution and gets you birfs that are easy to upgrade/source should you start pushing them hard. You can also upgrade brake calipers to the 89-95 V6 PU/4Runner with some minor backing plate trimming. You will need everything from the birf outward (birfs, knuckles, steering arms, bottom bearing caps, spindles, hub bodies, calipers, free-wheel hubs). Combine this with a knuckle rebuild kit, tie rod end shims (Part# TRESHIM) and minor parts and you're ready to convert your front axle.
79-85 PU/4RNR: Requires grinding, steering arm conversion and swapping both inner axles with your current ones (nothing to be afraid of). Worth upgrading these rotors/calipers to vented while you're there. Same birf as the 79-90 Land Cruiser too. You will need everything from the birf outward (birfs, knuckles, steering arms, bottom bearing caps, spindles, hub bodies, calipers, free-wheel hubs). Combine this with a knuckle rebuild kit, tie rod end shims (Part# TRESHIM) and minor parts and you're ready to convert your front axle.
(It's late and but I'm pretty confident on these dates/specs
If you don't want to bother with used OR your donor axle is missing some of the parts, we can help there too!
You need:
LH Disc Brake Knuckle (Available new @ Cruiser Outfitters)
LH Steering Arm (these must match your knuckle era) (Part# ST60060RH)
RH Disc Brake Knuckle (Available new @ Cruiser Outfitters)
RH Steering Arm (these must match your knuckle era) (Part# ST60060LH)
(2) Bottom Knuckle Caps (these must match your knuckle era)
(2) Disc Brake Spindles (Available new @ Cruiser Outfitters) (Part# FA60060AFT or FA60060 or TG140205-1-KIT)
(2) Disc Brake Birfield Joints (Available new @ Cruiser Outfitters) (Part# FAXT60016JP or TG301476-1-KIT)
(2) Disc Brake Wheel Hubs (Available new @ Cruiser Outfitters) (Part# HUBFHT008)
(2) AISIN freewheel hubs (Available new @ Cruiser Outfitters)
LH Caliper & Support Bracket (Available new @ Cruiser Outfitters)
RH Caliper & Support Bracket (Available new @ Cruiser Outfitters)
Brake Lines (Available new @ Cruiser Outfitters)
Other parts to consider: (All available from CruiserOutfitters.com - part numbers will be added soon)
Front Knuckle Overhaul Kit (1 x Part# FA7590, FA7590KWB or FA7590KWB)
Inner Birf Clip (2 x Part# FACL27091)
Tie Rod Ends (Part# TRE69045 or individual ends)
Tie Rod End Shim (2 x Part# TRESHIM) - Required when using 6x/7x Series and/or 4Runner/PU donor steering arms.
Replacement Brake Calipers (1 x Part# BRC60021LOAD)
Replacement Brake Caliper Hardware (Included with BRC60021LOAD)
Replacement Brake Pads (Included with BRC60021LOAD)
Repalcement Brake Rotors (Available @ CrOut)
Replacement Brake Hardlines (Available @ CrOut) (Part# FAXTBPELIMKIT)
Replacement Brake Hoses (Available @ CrOut) (Part# FAXTBPELIMKIT)
Backing Plate Eliminator Kit (Available @ CrOut) (Part# FAXTBPELIMKIT)
Front Wheel Studs (inspect donor axle studs) (Available @ CrOut)
Knuckle Studs & Hardware (inspect donor axle studs or available @ CrOut)
Hub Studs & Hardware (inspect donor axle studs or available @ CrOut) (HUB6997KASET or HUB6997KSET)
Spindle Hardware Kits (2 x Part# FA60011K)
Replacement AISIN free-wheel hubs (inspect hubs from donor axle or available @ CrOut)
Brake Master Cylinder upgrade (Available @ CrOut)
Parts:
View attachment 1905065
Brand new OE calipers with all Japanese parts! - Part# BRC60021LOAD
YWST: Brand New Japanese OE Loaded Brake Calipers for 4x/5x/6x/7x Models
Yeah, We Stock That! We are very excited to introduce our loaded brake calipers. These brand new pairs feature 100% Japanese components from 3 different OE Toyota parts manufacturers. It took nearly a year to line up production and transport but they are now in stock! Applications include all...forum.ih8mud.com
View attachment 1905069
Pick your color of AISIN hub. Wes stock these and more @ Cruiser Outfitters
View attachment 1905066
We have a variety of new bird options from RCV, Nitro, Longfield, etc
View attachment 1905067
We have several different disc brake spindle options, Japanese, Chromoly, etc.
View attachment 1905068
Finish off the disc brake conversion with a new spindle nut kit
View attachment 3051925
View attachment 3051927
- Thread starter
- #26
The 6x Series long side inner axles shaft is too long for your 40. You will separate the existing long inner from your drum brake birf and combine with the disc birf from your donor. You'll need the FACL27091