New Master Cylinder w/ JT Outfitters front Disk Upgrade?

Joined
May 15, 2014
Messages
949
Location
New York
Getting ready to replace the front disk brakes on my 75 FJ40, and wanted to see if I should also be upgrading my mater cylinder for the best performance?
 

Pighead

Stop calling it an FJ
Joined
Aug 31, 2004
Messages
8,905
Location
Camino
What do we mean by "best performance "?
With drum brakes properly adjusted, my 74 Pig stopped really well. When i added front Toyota discs it stopped really well. So i added Poser's rear discs. Still stopped really well. So i finally swapped out the original booster and master for a Cityracer booster and 80 master. Stops really well now.
I don't do any high speed driving, or measure my braking distance in feet. I just drive around town and the occasional Rubithon. I have never had bad brakes in a LandCruiser. Well, maybe with the drums after a water crossing.
There are variations between the bores & strokes of different masters. I forget what they do.
 
Joined
Jul 11, 2013
Messages
1,521
Location
California
Find a mini truck or 60 front axle and steal the outside hardwear to upgrade your brakes. You can also run the 60 booster and it’s master cylinder. There are multiple different combos that work. I’d definitely avoid anything that’s not Toyota For a disk upgrade.
 

1911

chupacabra
Joined
Aug 11, 2006
Messages
6,907
Location
Parker County, Texas
Getting ready to replace the front disk brakes on my 75 FJ40, and wanted to see if I should also be upgrading my mater cylinder for the best performance?

When you convert the rears to disc is the best time to upgrade master cylinders, because the FZJ80 (non-ABS) master is the first factory Cruiser to have 4-wheel disc brakes and the proper residual valves to go with them. Until you convert the rears, there is not a huge advantage in upgrading the master cyl., in my opinion.
 
Joined
Apr 2, 2008
Messages
10,866
Location
Victoria, BC
For starters, if you are looking for the best performance, JT outfitters isn’t the way I’d go. OEM Toyota use 4 piston brake calipers vs Single piston calipers for JT outfitters.

4 piston = best available on market - often out perform 6 piston (or equally well)

1 Piston = basic - get the job done… not high performance.

80 series booster is the way to go if, and I emphasize if, your calipers are up for the performance.

BTW, don’t let your insurance company figure out your modified brakes weren’t DOT approved… and someone was injured as a result. They’ll be tickled pink to invalidate your coverage.
 
Last edited:
Joined
Feb 14, 2013
Messages
853
Location
Wake Forest, NC
I did the JT Oufitters upgrade both on the front and rear. I think JT Outfitters recommends master cylinder from a ‘90’s T100. That is what I did. Many people use 80 series master cylinders as mentioned above. That is always a good option. I also added a Wildwood proportioning valve to the rears.
 

DSRTRDR

I can mangle anything ...
SILVER Star
Joined
Jan 4, 2005
Messages
15,644
Location
Baton Rouge, LA and Fountain Hills, AZ
when I did the Man-a-Fre front disk conversion on my 40, the only thing that was required of the brake master cylinder was removal of the residual valve thingie behind the big hex nut outlet for the front brake circuit - and proper bleeding the air out of the entire system

if the rear still retains the drums, the rear circuit at the master is left untouched - once the rear gets converted to disk brakes, that residual valve needs to be taken out as well, and an external proportioning valve is typically needed to dial in the relative braking force towards both axles
 
Joined
Apr 2, 2008
Messages
10,866
Location
Victoria, BC
when I did the Man-a-Fre front disk conversion on my 40, the only thing that was required of the brake master cylinder was removal of the residual valve thingie behind the big hex nut outlet for the front brake circuit - and proper bleeding the air out of the entire system

if the rear still retains the drums, the rear circuit at the master is left untouched - once the rear gets converted to disk brakes, that residual valve needs to be taken out as well, and an external proportioning valve is typically needed to dial in the relative braking force towards both axles
My experience has been that the rear wheels will lock way too early without a proportioning valve in the rear circuit once you have front disc brakes.

X2 on residual valve removal… although they are now much more powerful with an 80 series master & booster. That said, I never had any complaints about a 40 master until the booster went out.
 

DSRTRDR

I can mangle anything ...
SILVER Star
Joined
Jan 4, 2005
Messages
15,644
Location
Baton Rouge, LA and Fountain Hills, AZ
My experience has been that the rear wheels will lock way too early without a proportioning valve in the rear circuit once you have front disc brakes.

fair enough, I suppose it depends on the stopping power of the front disk conversion - which was the best I ever had with the Man-a-Fre kit

X2 on residual valve removal… although they are now much more powerful with an 80 series master & booster. That said, I never had any complaints about a 40 master until the booster went out.

yeah, I ran a 40 master for ~10 years until the front was converted to fine spline birfs and a 4Runner master/booster combo was installed (60 brakes turned out to be too weak in that combo, so Tunda calipers were used) - this brake set was never as good as the Man-a-Fre kit, and required dialing the rear braking force of the also new-to-me drum brake 60 rear axle to almost zero

when the 4Runner booster failed this fall, I went to the dual-diaphragm Cityracer booster, coupled that to the drum brake 40 brake master, removed front residual valve, but still need the proportioning valve - I haven't seen the need to switch away from the Tundra calipers, but am not finished yet tweaking the proportioning valve setting
 

Users who are viewing this thread

Top Bottom