Smaller brake master cylinders?

[FJ40Jim]

For my project, I'm looking for a smaller bore master brake cylinder. The commonly available 7/8" (FJ40/55/60) and 1" (4R/80) are too big, giving a very solid pedal, but insufficient braking.

Is there an MC smaller than 7/8" that still uses later Cruiser configuration: 4bolt mount, side outlets? maybe from a hi-lux or cressida or corona or...?

Should look like these:

Thanks for any assistance!

 

[gwalt584]

Jim,
I used a Non ABS booster and master cylinder from a 1994 Four Runner and it works great. I had to use a shim ( 4 3/8 nuts) on the back of the booster to clear the fire wall. the booster studs fit into the FJ40 firewall.

see post #32 in the time machine build thread for a picture.
however, I'm not sure about the bore size.
Gary

 

[gwalt584]

I just checked and the bore size is 1" on the one that I used from the '94 4Runner

 

[Spike Strip]

At the bottom of page: Toyota 4x4 Brake Master Cylinder and Brake Booster Specs - Roundforge

Toyota Brake Master Cylinder and Brake Booster Specifications
Model Year Bore Front/Rear brake type # of Reservoirs Fitting size Flange bolt pattern # of flange holes Booster diameter/diaphragm Notes
All Land Cruiser 1970-1975 1" Drum/Drum Dual M10x1.00 4
FJ40/FJ55 1976-1980 7/8" Disk/Drum Dual M10x1.00 4 North American spec
FJ45 1977-1980 1 1/8" Drum/Drum Dual M10x1.00 4 Canadian spec
FJ40/FJ60/FJ62/FJ70 1981-1989 7/8" Disk/Drum Single M10x1.00 4
FJ80/FZJ80 All 1" Disk/Disk Single M10x1.00 75mmx45mm 4 9.75"/dual ABS and non-ABS masters are different. Bolt-in upgrade for '79-'95. Residual valves front and rear.
Toyota pickup and 4Runner 1981-1985 13/16" Disk/Drum Single M10x1.00 75mmx45mm 4 8.5"/single/non-1 ton chassis, 10"/single/1 ton chassis,
Toyota pickup and 4Runner 1986-1989 13/16" Disk/Drum Single M10x1.00 75mmx45mm 4 8.5"/dual, 9.5"/single Suspect that dual diaphragm booster is extremely rare and may only come on specific vehicles like 2WD C&C.
Turbo Toyota pickup and 4Runner 1986-1987 Disk/Drum Single M10x1.00 75mmx45mm 4 Small diameter dual, some single Bolt-on for 1st Gen trucks.
Toyota pickup and 4Runner 1989-1995 7/8" or 1" Disk/Drum Single M10x1.00 75mmx45mm 4 8.75"/dual, 9.75"/dual, 9.5"/single V6 usually have 1" bore.
Toyota Cressida 1988-1992 1" Disk/Disk Dual M10x1.00 75mmx45mm 4 9.75"/dual ABS and non-ABS masters are different
Toyota Supra 1981-1986 15/16" Disk/Disk Single M10x1.00 75mmx45mm 4 8.5"/dual
Toyota Supra 1986-1992 1" Disk/Disk Single M10x1.00 75mmx45mm 4 9.75"/dual ABS and non-ABS masters available.
Toyota Supra 1992-2002 1" Disk/Disk Single M10x1.00 75mmx45mm 2 or 4
Toyota Tacoma 1995-2005 1" Disk/Drum Single M10x1.00 75mmx45mm 4 9.75"/dual, 8.75"/dual ABS and non-ABS masters available.
Toyota Tacoma 2005-2015 13/16" Disk/Drum Single M12x1.0 2 hole
Toyota 4Runner 1996-2002 1" Disk/Drum Single M10x1.0 2 9.75"/dual ABS and non-ABS masters available.
Toyota T100 1993-1998 1" or 1 1/16" Disk/Drum Single M10x1.0 75mmx45mm 4 10.5"/dual, 9.75"/dual ABS and Non-ABS masters available.
Toyota Tundra 1999-2006 13/16" Disk/Drum Single M10x1.0 2 10 9/16"/single
Toyota Tundra 2006-2014 15/16" Disk/Drum Single M12x1.0 2
LINKS AND SOURCES
Brake Upgrades
An excellent article on upgrading the brakes on a 4Runner.

Land Cruiser FAQ: Master Cylinder Info

Master Cylinder Info

Brake Booster Upgrades?

Dual Diaphram on a First Gen

 

[FJ40Jim]

I just checked and the bore size is 1" on the one that I used from the '94 4Runner

That's the MC I'm using now, but no booster.

At the bottom of page: Toyota 4x4 Brake Master Cylinder and Brake Booster Specs - Roundforge

Toyota pickup and 4Runner 1981-1985 13/16" Disk/Drum Single M10x1.00 75mmx45mm 4 8.5"/single/non-1 ton chassis, 10"/single/1 ton chassis,
Toyota pickup and 4Runner 1986-1989 13/16" Disk/Drum Single M10x1.00 75mmx45mm 4
Toyota Tacoma 2005-2015 13/16" Disk/Drum Single M12x1.0 2 hole
Toyota Tundra 1999-2006 13/16" Disk/Drum Single M10x1.0 2 bolt.

Thanks for that.

The early ones are 4 bolt, so will bolt to my firewall, but their lines exit at weird angles.

The tundra/taco don't bolt to the firewall and lines are wrong size. Might as well go with GM parts at that point.

Time to bolt on a new(ish) 7/8in. Brake master cylinder and enjoy the 31% improvement in braking power. A 3/4" MC would give a 78% increase in brake pressure.

 

[73FJ40]

3/4" MC has 44% less volume per unit of travel. That suggests almost twice the pedal travel for the same "braking" effect. Likely have to keep the brakes closely adjusted...

 

[DSRTRDR]

the pics don't show for me

we used a 4Runner booster/master combination - had to whack the firewall fin on the '72 just a tad due to the booster itself being slightly bigger

[Tools R Us can give you the details]

 

[FJ40Jim]

3/4" MC has 44% less volume per unit of travel. That suggests almost twice the pedal travel for the same "braking" effect. Likely have to keep the brakes closely adjusted...

They are tight 4-wheel discs, so adjustment is no issue. Right now the pedal travel is almost zero. Doubling the pedal travel & halving the effort would be OK.

the pics don't show for me

Fixed, I hope?

 

[DSRTRDR]

yup on the pics

 

[FJ40Jim]

Found the answer: 1987 4Runner Turbo.

13/16 bore, 4bolt master cylinder, 2 side outlets.

Slight problem: NLA from Advics or Toyota.

Got an Aisin reman on the way from RockAuto for $40.

current 1" MC = .785in^2
new 13/16" MC = .518in^2

increase in line pressure for a given pedal pressure= .785/.518= 1.52x

So suck it, Trebek! This is gonna rock.

 

[76 PTO]

Let me know how it works. I have a 96 80 series non abs on my 4 wheel disk conversion and it will throw you through the windsheild with about a inch of pedal travel.

 

[Pighead]

So suck it, Trebek! This is gonna rock.

"I'll take "What's FJ40Jim drinking tonight" for $200 Alex..."

 

[toyotaspeed90]

Got an Aisin reman on the way from RockAuto for $40.

View attachment 1716614

current 1" MC = .785in^2
new 13/16" MC = .518in^2

increase in line pressure for a given pedal pressure= .785/.518= 1.52x

So suck it, Trebek! This is gonna rock.

Looks like a cast iron unit. I personally do whatever I can to shy away from cast iron MC's - as the brake fluid absorbs moisture, the inner walls of the MC can start to rust/pit.

This being reman, I wonder if it's been bored out to clean any pitting, and as such, might be larger than the 13/16" you're looking for?

(I probably have the most odd setup - it's a 2nd gen MR2 brake booster with a Previa S/C aluminum master, and a 1976 FJ40 proportioning valve - all of it on a bracket pushed past the firewall fin)

 

[FJ40Jim]

The new chicomm replacement is cast iron, which I hate.

The reman unit is supposed to be an Aisin core, which is the first cast AL MC on trucks.
Cast AL because TURBO!

 

[allan man]

The reman unit is supposed to be an Aisin core, which is the first cast AL MC on trucks.
Cast AL because TURBO!
[/QUOTE]

Found the answer: 1987 4Runner Turbo.

13/16 bore, 4bolt master cylinder, 2 side outlets.

View attachment 1716612


Slight problem: NLA from Advics or Toyota.

Got an Aisin reman on the way from RockAuto for $40.

View attachment 1716614

current 1" MC = .785in^2
new 13/16" MC = .518in^2

increase in line pressure for a given pedal pressure= .785/.518= 1.52x

So suck it, Trebek! This is gonna rock.

Whats the outcome on this?

 

[FJ40Jim]

The '86 turbo 4R MC bolted on in place of the '96 V6 4R MC. Mashing the pedal in the shop shows there is more pedal travel, but I haven't driven it to see how well it actually stops. The snow has melted, but the roads are still white with salt. Should be able to test drive soon.

 

[allan man]

The '86 turbo 4R MC bolted on in place of the '96 V6 4R MC. Mashing the pedal in the shop shows there is more pedal travel, but I haven't driven it to see how well it actually stops. The snow has melted, but the roads are still white with salt. Should be able to test drive soon.

Jim any update?

 

[tonyl13]

Great info getting ready to start my disk conversion

 

[FJ40Jim]

Yes, I was driving it a little bit, but getting weird pedal. Turns out the reman MC would not always fully return. Had to send it back to Rock Auto for a refund, then buy a brand new Taiwan knockoff.

Got the new one installed and it is much better.
The pedal can actually be squished down pretty far as the rubber hoses expand. Couldn't do that before with the 1"MC, insufficient hydraulic pressure.
With a lightweight truck and tiny tires, there is no need for a booster.

One thing that has to be emphasized is there can't be any free play in wheel bearings or end play in rear axleshafts. Pad knockback is the enemy of sharp pedal response.

Pictures tomorrow.

 

[FJ40Jim]

The MC arrived from Rockauto and I was pleased to see it was a remanufactured Toyota/Aisin MC with the correct Aluminum body.

It got dressed up with an FJ60 reservoir.

It was bolted on and bled. It seemed to work OK, but was not 100% confidence inspiring. It felt like sometimes the pedal was lower than it should be. Eventually the symptom became regular enough that I was able to catch it in the act, finding the piston was not fully returned, even though pedal was all the way up. The MC was disassembled & inspected, nothing was found terribly amiss, so it was cleaned out, greased & reassembled, worked good for a day, but was acting up again shortly. Rockauto said send it back, but we have no more, so you can have a store credit instead of a warranty replacement.

No problem, I decided to order a brand new Aisan. They didn't have it in an ADVICS box, but did have one in a Centric box. It was $100, but worth it for OEM quality. Here's what I ordered:

Note the correct colored connector, correct reservoir, correct aluminum construction, correct gold anodized fittings, yadda yadda.

Here's what arrived:

Nothing OEM about that cast-iron Taiwan MC. Kinda expensive when other chinese crap is $50.
But, there wasn't much choice. It does have proper fit, correct 13/16 bore, so it gets installed.
The good news is it works. It has good feel, good pedal effort and it fully returns every time the pedal is released. There is more pedal travel, but since there was almost zero travel before, that's OK. Brakes are done.

edit: The part # for a complete new MC is Centric 130.44719.
The discontinued Toyota MC is 47201-35520.
Another chicomm number is CARDONE 1322520.