FJ40 swap front axle with discs

[roller99fxstb]

Hey guys, I thought I would post a question as I get ready to install my front disc axle into my 72 FJ40. I rebuilt a complete front end from a 77 FJ with disc's and plan to install it into my 72 FJ.

Will I have to purchase a master cylinder and or brake booster for a 77 in order for it to work. My 72 had a power brake booster and dual cylinder master but I think the are different from a 77.

I am sure plenty of people had done this upgrade but I am not sure if switching the maser and booser are necessary???

Thanks in advance for the feedback!

 

[cardinal fang]

You are still running drum rears? IIRC, I made no modifcations to the master when I did the front discs. A master cylinder from a 94 4x4 Toy pickup will work fine in your 72. I have one in my 73. See pics belowl. Hmmm, now that I think about it, you might want to stay with 73 master cylinder, since you are still running drums in the rear. The 72 has valve in the rear circut to keep pressure on the drums. The 94 master does not.

 

[pbgbottle]

what about the residual valve in the 72 master for the front drum brakes .it will need to be removed won't it ,when swaping to disc's

 

[Klunky Chris]

if your booster and master cylinder are in good shape keep them.
you WILL need to remove the residual valve from the front or your calipers won't release after the first tme you brake.

A post 1975 FJ40 master will only have a 7/8" bore.... NOT the 1" bore you have. 1" has more braking power / less pedal pressure needed.
a FJ80 NON-ABS master cylinder for a drum brake rear will also work for you and have a 1" bore

you will most likely need a proportioning valve for your rear drums as they take less pressure and will lock up long before your front discs.

I used one from Summit racing.

 

[roller99fxstb]

Thanks for all the info guys. I thought this would be a pretty easy swap as I am sure it's done often. I will plan to stick with my original master and remove the valve. If after using it a couple of times I find I need a prop valve I will get one.

Cheers!

 

[pbgbottle]

you will probably need one .(prop valve) did a quick look on ebay ,a few around .lots of new ones

old Wilwood

http://cgi.ebay.com/ebaymotors/Wilw...egoryZ133199QQihZ004QQitemZ140127274263QQrdZ1

http://cgi.ebay.com/ebaymotors/MOPA...tegoryZ42605QQihZ015QQitemZ250126990184QQrdZ1

new Wilwood

http://cgi.ebay.com/ebaymotors/Wilw...tegoryZ42605QQihZ017QQitemZ270129614957QQrdZ1

 

[Josie'sLandCruiser]

Hi All:

Like has been mentioned, if your existing drum brake master cylinder and booster are O.K. go ahead and use 'em. Yes, you need to remove the residual valve from the front brake circuit, but that is simple (PM me if you don't understand what is neccesary.)

No, you don't need a proportioning valve for rear drum brakes (that is only for the Monte Carlo/El Dorado DRB swap.) I ran a '78 disc front end under a '74 FJ40 with the '74 drum brake master & booster for several years w/o any issues.

FYI, you can swap the brake hardline that runs along the top of the axle tube from your '72 onto the '77 assembly to ease the installation.

Good luck with the project!

Alan

 

[pbgbottle]

OOPS! my bad !

i was thinking you where also adding rear disc brakes

 

[Klunky Chris]

I definitely needed a proportioning valve for my rear drums with my 74 MC. I guess everyone has their own situation and opinion. I got all the same arguments from both sides.
BTW: disc front 40's have a factory proportioning valve as well.

 

[PabloCruise]

if your booster and master cylinder are in good shape keep them.
you WILL need to remove the residual valve from the front or your calipers won't release after the first tme you brake.

A post 1975 FJ40 master will only have a 7/8" bore.... NOT the 1" bore you have. 1" has more braking power / less pedal pressure needed.
a FJ80 NON-ABS master cylinder for a drum brake rear will also work for you and have a 1" bore

you will most likely need a proportioning valve for your rear drums as they take less pressure and will lock up long before your front discs.

I used one from Summit racing.

I thought 7/8 bore exerted more pressure, meaning less pedal effort?

I put discs on my '74 55 and kept the '74 master. It works fine but pedal effort is higher than I would like...

 

[allan man]

Pls. update us on your disc swap once completed....it will help us foks here on mud for there future swaps and goodluck!

 

[PabloCruise]

I thought 7/8 bore exerted more pressure, meaning less pedal effort?

I put discs on my '74 55 and kept the '74 master. It works fine but pedal effort is higher than I would like...

Can anyone speak to this?