1975 Fj40 disc brake conversion

[Captain M]

Hi all,
I am in the process of rebuilding the knuckles and installing new tie rods on my 2/1975 FJ40. Since I have this torn down, I am seriously contemplating doing a disc brake/fine spline birfield/aisin hub swap using a newer 40 axle. Here is what I think I need:
-76'-78' fine spline birfields
-disc brake knuckle housings
-rotors,calipers,pads
-hubs
-spindle??
Is there anything i am missing?
Thanks in advance!


Any help would be great!

...via IH8MUD app

 

[White Stripe]

You will probably need a different master cylinder as well. You could check with Colorado Toyota Specialists or Classic cruisers for used stuff if you want to go that route.

 

[RWBeringer4x4]

I did this conversion on my 6/75. Unless you are really against grinding the knuckle balls, I'd suggest going with the larger pattern birfields and knuckles off a mini truck, FJ60, or 78+ FJ40.

Only additional complication is getting a shim for the steering arms so you can mate the larger pattern steering arms to the smaller FJ40 tie rods.

You will need to remove the residual valve from your existing master cylinder. If you are converting to rear discs, remove the rear circuit residual valve and plumb in a proportioning valve.

I wrote up a lot of the procedure in my build thread (in my signature) starting with FJ60 donor parts. Start looking around page 15 or 17...the conversion info is all there scattered across about 10 pages of other simultaneous projects!

 

[RWBeringer4x4]

I also posted this thread, which lines up the entire knuckle assembly, if it helps:

https://forum.ih8mud.com/threads/disc-conversion-knuckle-rebuild-parts-lined-up.805219/

 

[Captain M]

^ Thanks for the info gents. RWBeringer4X4, looking forward to reading your thread.

 

[broth9640]

This is a picture of the shim/bushing that allows fj40 TRE to fit the large pattern FJ60 steering arms. Cruiser Outfiters also sells large pattern steering arms that fit the fj40 TRE without a bushing.

 

[RWBeringer4x4]

^ Thanks for the info gents. RWBeringer4X4, looking forward to reading your thread.

Sorry - I sent that from my phone last night. In my build thread (signature) the clean up of donor parts starts on page 15. The tear-down of the drum brakes starts on page 19. The conversion itself is about page 20-27. It's mixed in with a diff rebuild, suspension work, new brake lines, some painting, etc. but there's lots of good info if you can stomach my rambling.

I've been told I'm scatterbrained and long winded...it shows.

 

[Josie'sLandCruiser]

Hi all,

I swapped to front disc brakes on my '74 in 2000. Used the drum brake master cylinder until 2008 or so. Works just fine.

X 2 on going with the post 1978 large pattern knuckles & disc rotors (as found on 1979-85 4wd mini-trucks, FJ60/70, etc.)

Regards,

Alan

You will probably need a different master cylinder as well. You could check with Colorado Toyota Specialists or Classic cruisers for used stuff if you want to go that route.

 

[Captain M]

Decided to go with FJ60 parts. Thanks for the advice. Broth9640, where did you source the shim/bushing? Not sure if my steering arm will come with that.

 

[RWBeringer4x4]

I tried to use Chevy starter bushings as shims (Part number SB0) as others have on this site. They wound up not working our - didn't take up enough slack. I ponied up for the steel, purpose-built shims. I think I bought the from Georg at Valley Hybrids (OrangeFJ45 here on MUD). Kurt at Cruiser Outfitters might have them too. I know Kurt usually carries late FJ40 steering arms - which have the large pattern knuckle bolt pattern, and the small FJ40 tie-rod-end pattern. Not sure how much the cost, but as @broth9640 mentioned - no shims required.

 

[broth9640]

Call Kurt at cruiser outfitters. If your not on a tight budget I would spring for the arms that he sells. Super beefy and no shim/bushing required. Towards the bottom of the page. $87.50 each. The shims on the other hand are cheap, but not a perfect solution.


http://www.cruiseroutfitters.com/steering.html

 

[White Stripe]

Decided to go with FJ60 parts. Thanks for the advice. Broth9640, where did you source the shim/bushing? Not sure if my steering arm will come with that.

Any parts store should be able to get the SBO bushings. They worked well for me.

 

[shelfboy1]

ive always used 79 steering arms for those conversions only because i have them and dont have to buy them .one conversion we used a toyota pickup tie rod backwards and hooked the relay rod to the steering damper hole .just depends on whats lying around here as long as its a bolt together conversion using factory parts

 

[cruiseroutfit]

Call Kurt at cruiser outfitters. If your not on a tight budget I would spring for the arms that he sells. Super beefy and no shim/bushing required. Towards the bottom of the page. $87.50 each. The shims on the other hand are cheap, but not a perfect solution.


http://www.cruiseroutfitters.com/steering.html

The arms are nice. If the shims are desired, we stock those too, part# TRESHIM

 

[Bearzerker]

Howdy Gents- I had my axles rebuilt last year on my Jan 76. I had big plans for this rig but it has the cancer real bad. While looking for a tub, I found a great deal on a rust free 75 and I bought it. Can I just take the axles off the 76 and put them under the 75? I've talked to a few vendors about this and was told that the master cylinder should work just fine from the 75 on the 76 front discs. To complicate things slightly, the 75 has had a shackle reversal. The springs seem to measure the same length in both rigs, but it's hard to get an exact measure. I also want to exchange the suspension from the 76 (OME Dakkar) to the 75 as someone put ridiculous heavy springs in it at some point and the OME suspension is pretty new and pleasant to ride on.