Brake booster swap fj40 booster to minitruck

[effjay76]

I recently replaced the brake booster on my 76 fj40 (stock front discs, stock rear drums) with a brake booster from a 91 4runner/mini truck. There seems to be a lot of questions regarding this so i thought i would do a write up.
I needed a swap because i destroyed my fj40 booster removing the brake pedal I called my local toyota parts dealer, after telling me that he couldn't look up the parts for my vehicle because I only gave him a 10 digit vin , he said the only available parts are two rebuild kits, the cheapest one was still over $300. So I got on mud and did some research, bought a 1991 4runner/minitruck brake booster and master cylinder on ebay for $70.00. I also got the vacuum check valve for another $7. Here's a picture of my destroyed fj40 brake booster.

 

[effjay76]

Both boosters

Here are both the boosters together with their respective master cylinders. After removing both master cylinders, its time to test fit the booster(I do it without the master cylinder attached because it is lighter and easier to move around). The fit is tight, and if I want to remove the clutch master cylinder for any reason, now I will have to take the brake booster off too. So if it has been a while since your last clutch master cylinder rebuild, its something to consider doing now. I had to bend the brake lines a tiny bit but nothing major. The booster on the right is the new one.

 

[effjay76]

Pedal

So to attach the booster to the brake pedal the bolt needs to be cut because the brake pedal will continuously engage the brakes if it is not. I took a half inch off and that gave me enough room, I could have taken 3/4 inch off and still be fine. I used an angle grinder with a cut-off wheel, a hacksaw will also work. The pictures show the process. more test fitting follows.

 

[effjay76]

Here is the end result, since my brakes are still stock, I used the fj40 master cylinder. An important note, the rod that pushes on the master cylinder in the new booster was shorter than the old one, it is adjustable so you just have to back the screw out until it matches your old length. Be sure to bleed the brakes if you disconnect the brake lines.

 

[Josie'sLandCruiser]

Hi All:

Nice write-up!

When I went to replace the dead drum-brake booster in my '74 FJ40 (which had a retro-fitted disc brake axle at the time) I used a donor booster from a mid-1980s Toyota 4wd mini-truck/4Runner.

Fits well, works well. No clearance issues with the clutch master cylinder.

Good luck!

Alan

Here are both the boosters together with their respective master cylinders. After removing both master cylinders, its time to test fit the booster(I do it without the master cylinder attached because it is lighter and easier to move around). The fit is tight, and if I want to remove the clutch master cylinder for any reason, now I will have to take the brake booster off too. So if it has been a while since your last clutch master cylinder rebuild, its something to consider doing now. I had to bend the brake lines a tiny bit but nothing major. The booster on the right is the new one.

 

[elbigsam]

Nice now do mine next

 

[matchan420]

Thanks for the good info, easy to read btw... enjoy!

 

[Waterboy]

Nice wright up.

 

[birddog019]

Very good write up. Thanks

 

[MicahMan]

Sweet

Nice WRite UP!!!!
I did this last weekend after mine went dead.

Booster, hose, and check valve Pick and Pull $18 dollars.
New oem that must be made of gold $450.

Getting a dual diaphram that probably won't ever die on me

Priceless.

Take Care!

 

[MrPaulSims]

Just to make sure i'm reading this right.. You're using a 91' 4Runner Booster, w/ your OEM master cylinder? Master cylinder bolted right up, just adjusted the push rod. And hack a little off the brake pedal side to make it fit? And you're good to go?

 

[bikersmurf]

Sounds about right. I did the same with an 80 series booster. I did have to rotate it 180 deg but that was super easy.

 

[sproggy]

No changes in pedal pressure or braking ability or anything? That's great news. Sounds easy to swap. Thank you for the details. Now to check my booster. I know that info is on here somewhere.

 

[SC Forester]

Josie's Cruiser,

Do you know what year booster you used? Did you use the mini truck master cylinder too? I may have a 1983 that I may be able to get some parts off of. I was gonna use the booster and master cylinder off of a 1997 4Runner but I think it will get in the way of the clutch cylinder too. I'd love to use the stuff off this 1983. Thanks.

Brake booster swap fj40 booster to minitruck

 

[Alz Toy]

When i did mine, i grabbed the booster along with a metal plate that spaced it out from the firewall. Didn't have to do any cutting anywhere. Was there a plate on the truck you nabbed the booster from?

 

[Drake2]

Thank you for the write up!

 

[bikersmurf]

No changes in pedal pressure or braking ability or anything? That's great news. Sounds easy to swap. Thank you for the details. Now to check my booster. I know that info is on here somewhere.

With an 80 series booster & Master... more braking for less input pressure. A quick jab to the brake pedal, with two fingers, can lock up all four discs on dry pavement at 30 mph. The brakes in no way are grabby, but light pressure will stop the rig quickly and easily... a big contrast from trying to stop with a dead booster.

 

[effjay76]

Just to make sure i'm reading this right.. You're using a 91' 4Runner Booster, w/ your OEM master cylinder? Master cylinder bolted right up, just adjusted the push rod. And hack a little off the brake pedal side to make it fit? And you're good to go?

That’s correct, it’s been 8 years now and it still works great. I switched to rear discs but still using the same booster.

 

[effjay76]

Josie's Cruiser,

Do you know what year booster you used? Did you use the mini truck master cylinder too? I may have a 1983 that I may be able to get some parts off of. I was gonna use the booster and master cylinder off of a 1997 4Runner but I think it will get in the way of the clutch cylinder too. I'd love to use the stuff off this 1983. Thanks.

Brake booster swap fj40 booster to minitruck

Mine was from a 91, as long as the bolt pattern lines up you should be able to make it work. This one covers the mounting bolt for the clutch master but I didn’t have to modify anything for it to fit.

 

[effjay76]

When i did mine, i grabbed the booster along with a metal plate that spaced it out from the firewall. Didn't have to do any cutting anywhere. Was there a plate on the truck you nabbed the booster from?

I got mine on eBay and it didn’t have a plate but I suppose you could use one and it would solve the pin length issues.