I recall seeing that one could upgrade their master cylinder by using the Landcruiser MC which had a larger bore piston.

I'm considering this mod, but which model LC MC do I use? I was thinking it was the FJ80 MC, but searching ebay for them, I saw som 93-94 MC's.

Anyone know?

I just put a 92 TLC MC ( non ABS ) in my 86 toyoya truck. It bolted right in. All I had to do was bend the hard line for the front brakes to MC . The TLC MC connection is 90 deg rotated from the original. Got mine from Marlin Crawler for 139.00 including shipping. I also did rear brakes (drum ) at the same time so I can't tell yet how much improvement it made. When the rear shoes seat I will have a better feel for how much it helped. This was a prelude to a rear disk upgrade later on.

Why do you think you need a larger MC ?

A larger MC is only needed when you make a major change such as converting the rear to disks. A larger MC on a stock system is not going to improve anything. On my 84 I have larger calipers (IFS V6) on the front and larger drums on the rear (87 IFS rear axle) and the stock MC works just fine.

If you go to larger tires you will notice a marked decrease in braking ability. A larger bore MC will indeed help. I just did the mod it worked.

Not sure what year LC mcylinder to use, but best bet is to buy the one from Marlin for $129 (it's Aisin OEM). I couldn't find any locally that included the reservoir (which is different than your stock one). The reason for going to a bigger MC is to push more fluid in cases where you have larger piston front calipers (ie using the V6 style 4 piston calipers or going to disc in the rear). However, on a stock brake system, the larger MC will mean that you have less pedal travel for the same amount of braking, not really a strong reason to do it, but if you plan to upgrade to the LC vented rotors & larger calipers in the future then might as well go to the 1" master now. If you simply have squishy brakes, an easier fix might be to flush the system to get rid of the old fluid, refill and bleed.

Check about 1/4 of the page down.
http://www.pirate4x4.com/forum/showthread.php?t=173918

Lots of good stuff on Pirate4x4.

Thanks for the link GA-Style!

Where are you in Gainesville? we're neighbors. I've live here for 30 years.

This is on an 86 4Runner with 31's. I was hoping it'd just increase braking power due to the larger piston. From memory, I thought I'd read that it'd be a help to any Toy with larger tires.

I'm about to dump some money in the truck and was trying to decide whether to include the MC in the work.

It's not that simple. Pedal travel and feel will change too.

As for bigger tires, I have the larger IFS 6 cyl calipers swapped in and larger drums in the rear (IFS rear axle swapped in) and 36" tires. The stock MC stops them just fine.

Just make sure your entire brakes system is in good order (pads/rotors/drums/shoes, no sticky or frozen pistons in calipers or rear wheel cylinders, and fresh fluid. Brake fluid goes bad after a few years, it absorbs moisture. A complete flush is a good idea every 3-4 years.

A few years back, I did the brake upgrade to my 4Runner. Installed new V6 calipers and the MC and dual diaphragm brake booster from a 90Æs V6 truck. Running 31ö tires, I could stop just a quick as any above average car. Now I run 4 wheel disks (LC rotors and 4 cyl calipers on the rear with LC MC) and can stop even better with 35ö tires.

The only reason to upgrade the MC is if you are increasing the amount of fluid to the brakes. Going to larger V6 calipers, rear disk brakes, etc. It would also be a good time to switch to a dual diaphragm booster.

If you plan to do disk brakes in the rear, go with the LC MC (92 non ABS) and a dual diaphragm booster. If you are going to stick with drum brakes in the rear, go with the V6 MC and a dual diaphragm booster and upgrade to the V6 calipers.