What are u guys doing with the brake booster? Smaller one or can I move it over? Can I get some pics under the hoods please?
You cant move the stock one over. I tried while I was building my truck and I actually moved it, but when I put the steering shaft in, it hit the booster. Some people run aftermarket ones, some make a geo metro booster work. If you want true plug and play, buy a new one from the parts store for a 79-83 2wd gasoline truck. They make different ones for the 4wd and diesel vs gas trucks during those years. Just bolt your master cylinder to it and its about 8" in diameter, so it clears everything.
Stock booster....(hits steering shaft when moved over, hits tire when laid out if its not moved) '82 Booster...(clears everything) Check out the distance between that brake line that curves around the top of the boosters..lots of additional clearance.
Additional clearance and a severe lack of boost to stop the truck. Swapping to a small booster with larger wheels/taller tires makes the brakes lessens their effectiveness and makes for some sketchy driving if you don't plan way ahead and slow down early. If you want a smaller booster WITHOUT losing your stopping ability grab one from a first gen supra. They are smaller OD like the 79-88 4 cylinder truck boosters but dual diaphragm so they are just a bit thicker so tire clearance shouldn't be an issue. I went the complete opposite way and used a 94ish V6 booster and a 15/16" master cylinder. I also swapped to braided stainless brake lines to hold up to the additional pressure created. I can STOP when I want to so long as there is traction.
I run an 81 booster and master on my 78. Went hunting at the junkyard one day and found one that looks brand new. So I replaced my leaky large 78 setup. I do seem to remember the new master is a hair smaller passage which pushes less fluid. I didn't notice much increase in pedal effort though. He is right about matching the booster to the calipers and keeping a good setup. For those who swap to 4runner calipers an larger rotors, you need to match the master bore diameter to that of the original calipers setup. 15/16 on those I believe. The older boosters use a 2 bolt master so swapping to the 81 booster allows use of late model 4runnrr and tundra masters which push alot more fluid to the larger calipers they run. I did gain a few inches clearance swapping boosters tho. I'm static but so low I had to hammer the inner fenders til they hit the stock booster. 81 unit gave me more room To hammer lol
My ass. So your telling me all these 79-83 trucks that people put 33" tires on there trucks have a " hard time stopping?" Uh. No. This truck stops when I want it to. Of course you could run a master cylinder off a late model land cruiser, which also has a bigger bore to move more fluid but these tricks are light, not moving 100mph and a 18" tire and wheel don't weigh much more if at all than a stock wheel and tire combo. Don't believe everything you read on the Internet. If you wanna start a debate you picked the right person and topic. I guess deleting the LPSV on the back is a sin in your opinion.
I mean these trucks aren't fullsize trucks and don't weigh a whole hell of a lot. Having a big master cylinder and stainless brake lines to handle pressure I mean wtf are you doing with your truck? NASCAR road course testing?
When I had my old Ford Escort it had a safety feature built in that would have made a debate like this totally unneeded. If the brakes ever needed extra help stopping the car, there was a button on the dash that when activated would make the car come to a stop very quickly. I believe they called it Air Conditioning.
As a matter of fact yes I'm saying 79-88 (4 cylinder, 4 wheel drive) trucks have a harder time stopping when equipped with taller tires. The master is 13/16 with a smaller 9" vacuum booster. The front calipers use 2 small and 2 larger pistons each side on solid non vented rotors and 10" drums out back. I've always swapped to 88-91 V6 or 92-95 4 or 6 cylinder 1" master cylinder with an 11" booster using later model V6 calipers with 4 large pistons with fj40-fj80 vented rotors and 86-95 rear axles with 11" drums. So not only does my real world experience say it but so do the basic mathematical equations pertaining to basic hydraulic fluid ratios vs the leverage of the tire height. Running a larger master with a smaller booster would do nothing to remedy the situation. It would actually exacerbate the issue due to pushing a larger volume of fluid with a smaller amount of vacuum boost helping to push that fluid along. If you want to run a smaller booster then run a smaller master to go along with it so your leverage ratio stays in spec. That will work at the expense of a bit of added pedal travel but otherwise the truck will stop as stock. The lspv is pointless. It doesn't change the flow rate of the fluid to the rear enough to do much at all. Don't assume things when trying to make a point it does nothing but make you look foolish. Use facts to back up whatever real world experience you have and you'll never fail. I've been working on these trucks for a day or 3 now and the brake systems are something I have always modified and improved upon since up until a couple years ago all I'd ever done was to lift them and run much larger tires then stock. Yes the factory stuff will stop it if you stand on the pedal hard enough but I trend towards having brakes that STOP on command. Nope no nascar for me I have no desire to have sex with any relatives. Performance plain and simple. When I stomp the brakes I want it to lock the brakes up with sticky tires. I'm planning on putting my 1uz in this truck and slapping on a huge set of sway bars and being able to drive it anywhere getting good mileage on the way then running auto cross courses and driving it home. Sounds like a whole lotta fun to me.
I'm not body dropped so clearance issues are not! But as to more stopping power ,I run 13'' Wilwood drilled/slotted rotors & 4-Runner 4-piston calipers up front, @ the rear a 11.32'' drilled/slotted rotors & single piston 48 mm calipers w/e-brake. I run a dual digifram booster & the larger bore master,also all steel braided hoses! Can stop very,very fast!! And yes my truck can hit 140,through I haven't gone past 120!! And yes the larger the wheel/rim the more rolling mass the more brake you should have!!
That's for the info! I just got the firewall and fender well cut! The 18x81/2 are hitting the booster and its not bodied yet! I'm searching for a booster! I want this truck to lay rockers with no rub issues! I will post updated pics as I progress! Seriously thanks for the info and all your time!
Summary, run the 81 booster and master. Of you upgrade the brakes, use a 4 bolt master with the right ratio for the bigger fluid demand. Good luck buddy. Post pics when ya can.
