4runner brake booster (1 Viewer)
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It's not so much that you lose braking power, but due to the larger bore of the MC it just takes more actual force against the plunger (ie: more foot pressure against the pedal) to get the same mechanical advantage as a smaller bore MC. Now for equal pounds of pressure against the pedal, yes, the larger bore MC gives you less mechanical advantage than the smaller bore MC. Tradeoff is you have less pedal travel with the larger versus the smaller bore MC.
I haven't tried it yet myself, but from what it sounds like, the extra pedal force needed by the larger bore MC is mostly offset by the improved advantage provided by the 4Runner booster.
ntsqd
technerd
If you've got more boost you can run a bigger bore MC to get equal or more clamping force at the calipers. The increased boost can make up for, or more than make up for the loss overall system leverage resulting form the larger bore MC. I've posted the leverage ratios for various combos in the "Comments on Brakes" thread. After putting the 4rnnr calipers on my 60 and then doing that math I now wouldn't go with the 4rnnr calipers as my first step. I'd go with the 4rnnr booster, and then evaluate whether more was needed or not.
Looks like I might just have to bump up the booster on my list of maintenance/modifications.
Oh damn, my factory booster somehow got a puncture in the metal body. Looks like I'll have to tell the wife I NEED a new booster now....
Oh damn, my factory booster somehow got a puncture in the metal body. Looks like I'll have to tell the wife I NEED a new booster now....
Nice to have the booster part#!
No external in-line check valve needed correct? My v8 seems to have plenty of vacuum. Thanks for your replies!
What are the nominal 4Runner years for FJ60-compatible boosters? Any 2nd gen - 1990-1995?
I found this website informative on what master cylinders will work. The best MC you can get sounds like the FZJ80 MC with 2 lb dual residual valves. Take one out if running stock drum brakes in the back or keep them in if you're running disk in the rear.
I'm running a 1993 T100 MC and booster. Bolts right up with the only mod being splicing in the low brake fluid sensor.
Toyota 4x4 Brake Master Cylinder and Brake Booster Specs - Roundforge
I'm running a 1993 T100 MC and booster. Bolts right up with the only mod being splicing in the low brake fluid sensor.
Toyota 4x4 Brake Master Cylinder and Brake Booster Specs - Roundforge
Some pics from my swap here:
Master Cylinder Swap Specifics - 3 questions
Master Cylinder Swap Specifics - 3 questions
The 4-Runner booster is a good mod.
The 4-Runner master and calipers do nothing to improve braking.
The small disk size is the weak link. Unless you change the disk to the Tundra, any caliper and/or master mods are pointless.
The 4-Runner master and calipers do nothing to improve braking.
The small disk size is the weak link. Unless you change the disk to the Tundra, any caliper and/or master mods are pointless.
I've set up several.
On Frankie (FJ-60) I added the 4Runner calipers pushed by a stock master with 32" tires thinking it would help braking. It did not. Everything on the truck was new and braking was unchanged.
Shortly after I bought a bone stock FJ-62 on 31's and its brakes were very good, almost modern in the initial bite. The difference between the 60 and the 62 is the booster.
When I put a 4R booster on Frankie, her brakes immediately improved.
A good functioning stock set up is capable of locking up 31" tires without too much effort. If you have enough pressure to lock the wheels, you're at max braking. No additional pressure or pad size can improve on it.
The weak link is the inadequate disk size for heavy loads and oversized tires. One hard panic stop and the excessive heat will warp the disk and braking may fade if the pads are cheap. The fix is to bump up to Tundra brakes.
On Ishmael (HJ-61) I used FROR's Tundra mod to change to Tundra calipers and disks with 33's. Coupled with this change is the FJ-80 master (Kurt sells a ton of these and has them in stock). The stock booster works fine with this set up. This is the same disk size as the '17 4Runner. These are modern, heavy duty brakes.
I've got the pictures and disk stats to document this in a thread for Ishmael but I haven't had the time.
On Frankie (FJ-60) I added the 4Runner calipers pushed by a stock master with 32" tires thinking it would help braking. It did not. Everything on the truck was new and braking was unchanged.
Shortly after I bought a bone stock FJ-62 on 31's and its brakes were very good, almost modern in the initial bite. The difference between the 60 and the 62 is the booster.
When I put a 4R booster on Frankie, her brakes immediately improved.
A good functioning stock set up is capable of locking up 31" tires without too much effort. If you have enough pressure to lock the wheels, you're at max braking. No additional pressure or pad size can improve on it.
The weak link is the inadequate disk size for heavy loads and oversized tires. One hard panic stop and the excessive heat will warp the disk and braking may fade if the pads are cheap. The fix is to bump up to Tundra brakes.
On Ishmael (HJ-61) I used FROR's Tundra mod to change to Tundra calipers and disks with 33's. Coupled with this change is the FJ-80 master (Kurt sells a ton of these and has them in stock). The stock booster works fine with this set up. This is the same disk size as the '17 4Runner. These are modern, heavy duty brakes.
I've got the pictures and disk stats to document this in a thread for Ishmael but I haven't had the time.
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Do the Tundra Calipers and rotor require anything special or do they bolt right onto the stock knuckle and hub?
I run rear disk (FZJ80 axle) and I always heard that a larger MC was required for the increased volume in the pistons versus the drum brake cylinder.
Nice pics.
I run rear disk (FZJ80 axle) and I always heard that a larger MC was required for the increased volume in the pistons versus the drum brake cylinder.
Nice pics.
The Tundra calipers require a whole host of (expensive) and PITA changes. This mod works perfectly with FZJ-80 FF rear axle mod as the change in axle width is nearly the same front and rear.
FROR Tundra brake adapter plates
4R IFS hubs (machined down to clear the inside of the rotors)
Tundra rotors
Tundra calipers
FJ-80 master (or FZJ-80 if you swap to disks on the rear)
The knuckles must be swapped sides or the caliper mounting ears ground off
17" wheels/tires for clearance w/ 4.5 to 5.0 BS (possible 16" would work, I didn't try)
Spacers to push the rear wheels out to match the front and accommodate the 4.5" BS wheels
I've got a write up with part numbers in the works.
FROR Tundra brake adapter plates
4R IFS hubs (machined down to clear the inside of the rotors)
Tundra rotors
Tundra calipers
FJ-80 master (or FZJ-80 if you swap to disks on the rear)
The knuckles must be swapped sides or the caliper mounting ears ground off
17" wheels/tires for clearance w/ 4.5 to 5.0 BS (possible 16" would work, I didn't try)
Spacers to push the rear wheels out to match the front and accommodate the 4.5" BS wheels
I've got a write up with part numbers in the works.
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That's a lot of work to and parts availability on the trail would be a pain. But I guess the stopping power would be great?
I need to see if I can lock up my brakes with the ICON Elite SSBC calipers I have up front right now. hmm.
I need to see if I can lock up my brakes with the ICON Elite SSBC calipers I have up front right now. hmm.
@60Works, which Toyota part # did you use on Frankie? Upthread it's mentioned to use the 95, non-ABS one with a Cardone part pictured that appears dual diaphragm. City Racer shows three distinct types for that gen 4R, and not sure which one is 60-compatible.
Dual Diaphragm Brake Booster for '89 to '95 Toyota 4Runner and Pickup
New dual diaphragm brake booster for 1989 to 1995 Toyota 4Runner and Pickup. This booster is brand new. It's not a rebuilt, not a reman, and there is no core charge. OE quality seals, diaphragms and check valve. Painted finish and yellow zinc plated hardware. Note:Several types of brake...
www.cityracerllc.com
I was unaware that there were multiple options when I purchased the Cardone from the LAPS. I would recommend using whichever is stronger. There is room for a larger diameter booster on both the 60's and 62's so I wouldn't hesitate to think the 9 1/2 would fit. The 60 booster is deeper than the 62 or 4 Runner. I had to adjust the hard lines slightly to line up with the OEM master. I've purchased 4 Cardone boosters and none had the long studs for the spacer. The spacer might be perfect to keep the hard lines as original.
Conclusions without verification are: any of the 3 would probably work. If I were to purchase one of these three for a 60, I would choose either the double or add a spacer, whichever has the most boost.
HTH
Conclusions without verification are: any of the 3 would probably work. If I were to purchase one of these three for a 60, I would choose either the double or add a spacer, whichever has the most boost.
HTH
Upgrading to a 9.5 w/ spacer right now, will post what the fitment results are.
