Minitruck Front Axle Disc Brake Conversion For Dummies (FAQ)

[PabloCruise]

currently in the process of doing a conversion from drums ( fj40 1975) to disc ( complete 60 series knuckles, calipers, rotors, , with fj55 30 spline axels/birfs and aisin hubs.

the problem i have run into is once i put have placed the aisin hub cover, and then the outer c clip onto the axel, i go to install outer hub cover and spring, and it wont fit!! it seems as though the axel is to long by around 3-4 millimeters.

after reading this thread a couple of more times... it seems as though the clip for the axel can be a tight fit?? again, i can install it easily..no need to pull axel out, and have around 5 mill bhind the clip before any of the other hub internals.. i have tapped/lightly hit the axel end to try and move it further into the diff housing...no go....

anybody got ideas?? pulling my hair out atm!!!

thanks in advance
Luke

Luke,

Did anyone get back to you on this? I was just re-reading this thread and it didn't look like you got any responses.

55 birfs are the long body birfs that will not fit in a 60 Aisin lock-out body with the clips. You will either need the longer body Aisins that came to the States on '76-'79 Pigs, or go with the shorter birfs found on '80-'84 40 or a 60 series.

Does that make sense?

 

[sloanstavern]

I have re-read the thread, and am still not clear on one thing -
I have an '86 FJ60 front axle donor going on to Dec'74 FJ40.

Do I:
1. Swap the complete inner and outer axles from the '86 to the '74
2. put the '86 outer axles on the '74 inner axles
3. Keep the '74 inner and outer in place

Thanks,
Scott

 

[vk7ybi]

Option 3.

 

[PabloCruise]

I have re-read the thread, and am still not clear on one thing -
I have an '86 FJ60 front axle donor going on to Dec'74 FJ40.

Do I:
1. Swap the complete inner and outer axles from the '86 to the '74
2. put the '86 outer axles on the '74 inner axles
3. Keep the '74 inner and outer in place

Thanks,
Scott

Option 3.

Why keep the '74 outers? That will give you coarse birfs that will require drum brakes?

 

[sloanstavern]

Appears to be a tie on the axle question.

Next Item - I had two different rotor's on the donor axle. One is ~ 2X thickness of the other and had a scalloped edge that holds the hub. I assume that one was OEM and the thin one is after market.
I just picked up after market rotor's from Checker and they are really thin. Can comments or concerns about running the after market rotors or should I try and find OEM?
Thanks

 

[John Smith]

Post up pictures of this axle. If you have non-vented rotors, those are stock mini truck and I would return them for vented LC rotors. There are also two different types and you want to make sure you get what matches your hubs.

 

[sloanstavern]

Morning,
The donor axle ( '86 FJ60) came equiped with mis matched rotors ( see pics 1&2). One is very thick and has scalloped pattern where hub goes. the other is very thin and round opening. The two new , matched rotors, are thin and have round opening. I bought them as front rotor's for '86 LC

 

[John Smith]

I don't know what's up with the weird rotor but those are vented LC which is what you want. What you don't want are the non vented mini truck rotors.

 

[1973Guppie]

bump for the hell of it.......

 

[tequila4x4]

hi guys.

I am doing my this convertion on my 72 fj40 this weekend and I just wanted to know if I need to do any thing to the brake mc.

Do I need a proportioning valve?

I got a 86 fj60 front axle for the swap.

thanks for your help and lots of thanks to1973guppie fot this write up.

oscar

 

[1973Guppie]

I would suggest using an fj80 master cylinder, you can get them from marlin. You will need a prop valve if installing rear discs....

 

[kitch17]

ok im doing this converion on my 67 fj40 and i dont have berfs cans i use my old axles shafts and make my factory warn hubs fit?

 

[bikersmurf]

Post up pictures of this axle. If you have non-vented rotors, those are stock mini truck and I would return them for vented LC rotors. There are also two different types and you want to make sure you get what matches your hubs.

hi guys.

I am doing my this convertion on my 72 fj40 this weekend and I just wanted to know if I need to do any thing to the brake mc.

Do I need a proportioning valve?

I got a 86 fj60 front axle for the swap.

thanks for your help and lots of thanks to1973guppie fot this write up.

oscar

You can reuse your dual circuit brake mc. You'll need to remove the residual valve from the front circuit and add a factory (or adjustable) proportioning valve to the rear circuit.

 

[bikersmurf]

ok im doing this converion on my 67 fj40 and i dont have berfs cans i use my old axles shafts and make my factory warn hubs fit?

Not 100% certain... But I'd say no. What I do know is that the pre 75 hubs that were matched up to birth fields are shorter. From everything I've read here in the years, you'll need to find a birth field axle housing.

I'd personally look for a 40 disk axle, clean it up, install it, and call it a day.

 

[driggs]

Just went through this this weekend. And unfortunately no. Your existing axles are too short with the mini stuff installed. The outer axle does not extend outside the hub so the outer snap ring cannot be installed. I am going to try and swap a birf axle in.

 

[tequila4x4]

finished the front disk convertion on my 72fj40. everything works great.
rear brakes are next.

thanks guys.

oscar

 

[My71FJ40]

I just took a look at the last page here and was wondering did you all start at the beginning of the thread before posting questions? Just a thought

 

[EricG]

I used this excellent thread to do a step by step of the process,

http://www.geocities.com/Baja/Dunes/6948/

I printed it out and followed it to put the axle back together, along with a printout of the pics I took of the breakdown of the axle, with these 2 things the conversion was fairly easy.

Excellent thread! About to do this myself. Unfortunately the referenced site above has vanished with the demise of geocities. Anybody know if it's been rehosted or otherwise preserved?

Also - I've got an 83 minitruck axle that I'm pulling the knuckles & birfs from to put on a 74 FJ55 front axle. Can I use the minitruck inner axles? Pretty sure the answer is no.

 

[1973Guppie]

Excellent thread! About to do this myself. Unfortunately the referenced site above has vanished with the demise of geocities. Anybody know if it's been rehosted or otherwise preserved?

Also - I've got an 83 minitruck axle that I'm pulling the knuckles & birfs from to put on a 74 FJ55 front axle. Can I use the minitruck inner axles? Pretty sure the answer is no.

No, I believe you need to use the stock fj55 axles....

 

[Christian]

Excellent write-up with good educational pics, thumbs up!
I have one Q:

I have a 1980 HJ45 with drums front, and HJ60 knuckles, discs, calipers etc. that I will use for my swap. My Q is; can I reuse the inners and brifields from my HJ45 axle, it has AISIN locking hubs, if that makes the answer easier...? Or do I have to take them apart and use the HJ60 birfields?

Thanks alot!