The one ton swap thread (1 Viewer)

baldilocks

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What would you guess you have into it as a total?
Can’t remember exactly but some dollar figures are listed in my thread. From memory I’ll say something like $1200 but that included a fancy Wilwood MC and proportioning valve, new not remanufactured booster, new hard line material, a nice flaring kit, etc. I purchased a kit with new parts to save time. This could easily be done for less than half my figure. What does a junk yard booster cost? A cast iron MC can be purchased at NAPA for under $60. The firewall adapter plate would be simple to make as well.
 
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So.. mine has an alternator with vacuum pump on it and that pump seems to work quite well. I’d prefer to keep it and the Toyota booster if possible. After I swapped that vacuum pump in the brakes worked quite acceptably considering the 38’s, stock but newer brake components and weight (6BT)

I’ll be running the big D60 front calipers and the reasonable looking 14 bolt rear calipers (disc/drum). They are all dual piston calipers, rears appear 56mm diameter, fronts look like 60mm.

I get the feeling that a 1-1/8” or 1-1/4” MC would be better suited size wise.

For the budget, I think I’ll have to try and run a bigger MC and see how it works, then adjust as needed.

Also, I’m deleting the LSPV, have a proportioning valve and kit copied/purchased from info on another thread. I don’t have ABS either so that removes a bit of complications.
 
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Can’t remember exactly but some dollar figures are listed in my thread. From memory I’ll say something like $1200 but that included a fancy Wilwood MC and proportioning valve, new not remanufactured booster, new hard line material, a nice flaring kit, etc. I purchased a kit with new parts to save time. This could easily be done for less than half my figure. What does a junk yard booster cost? A cast iron MC can be purchased at NAPA for under $60. The firewall adapter plate would be simple to make as well.

Which axles/calipers are you running?
 

baldilocks

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The issue with trying to push a large bore MC with a vacuum booster is that your leg will have to make up for the lack of power assist in the stock size vacuum booster. A hydro booster can double the brake line pressure with no more input from the driver.
 
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The issue with trying to push a large bore MC with a vacuum booster is that your leg will have to make up for the lack of power assist in the stock size vacuum booster. A hydro booster can double the brake line pressure with no more input from the driver.

I wish there was some way for me to argue myself out of this but... there isn’t and your right.

Still, gonna have to try the stock booster and larger MC first before hydro boost and see how it performs. My truck isn’t a daily driver nor do I have any big trips planned, so if it isn’t adequate then I’ll have to wait to save some coin and upgrade for hydro boost as well.

At least I’ll know if it is adequate, and if it isn’t I’ll know first hand how it performs.
 

maxamillion2345

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I started off with a gm single piston 60 calipers/14b drums Sky adapter and gm 1 1/4. Could not stop a roll hardly.

Swapped to gm 3/4 front calipers - still s***

Swapped to 92 ish dodge w350 1 1/8 master and ran that for a long time but brakes were never great.

Swapped to a 1 1/16 t100 master and the brakes are very decent for 40s and 8k lbs.

I also have a wilwood rear proportioning valve.

Edit: running cummins vac pump, I did check vac on it, and reman booster
 
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I started off with a gm single piston 60 calipers/14b drums Sky adapter and gm 1 1/4. Could not stop a roll hardly.

Swapped to gm 3/4 front calipers - still s***

Swapped to 92 ish dodge w350 1 1/8 master and ran that for a long time but brakes were never great.

Swapped to a 1 1/16 t100 master and the brakes are very decent for 40s and 8k lbs.

I also have a wilwood rear proportioning valve.

Edit: running cummins vac pump, I did check vac on it, and reman booster


Hmmm.. that’s a great piece of data, especially with piston sizes.

It sounds like the 1.25” was too big, but these are dual 60mm positions instead of a single up front and yours were drums out back.

Earlier today I ordered the GM 1.25” bore truck MC, I guess I’ll have to see how it works, but we’re definitely getting somewhere being able to look at caliper sizes vs MC sizes. It’s not exact but we’re starting to paint a picture and your experience with different sized MC’s is very big piece to the puzzle as well. This should actually be a helpful thread to others trying to figure out brakes later as well. Thanks dude!!


Edit: I feel there’s probably an ideal ratio of combined caliper piston surface area to MC bore diameter somewhere. I bet someone has figured out that piece of math
 
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Edit: I feel there’s probably an ideal ratio of combined caliper piston surface area to MC bore diameter somewhere. I bet someone has figured out that piece of math

@Dirty Koala made this helpful post showing how the leverage ratio is calculated for different MC/caliper combinations, but they're for Toyota parts. You know the MC bore, if you had the piston specs from those other calipers you could easily recreate a cross-reference chart. I'm sure something like this can be found on Pirate

Yesterday I was a little bored so I cracked open a spreadsheet to layout the data and calculations needed to determine the best Master cylinder to go with for this swap.
  • The 80 Series Master Cylinder has a 25mm bore..or 0.9843"
  • The T100 Master Clyinder has a 1 1/16" bore or 1.0625"
  • The 80 Series Caliper Piston OD is 45.3mm or 1.7835"
  • The 4Runner Caliper Piston OD is 48mm or 1.8898"

View attachment 2288539

I have laid out three combinations for MC and caliper for comparison. (80 Caliper + 80 MC, 4Runner Caliper + 80 MC, 4Runner Caliper + T100 MC)
  • Establishing a baseline to compare off of, you can see that the leverage ratio of the stock setup is 6.57:1.
  • By changing just the caliper side to a 4Runner caliper, the new leverage ratio will be 7.37:1. This will result in more pedal throw (12.3%) to get the same amount of caliper piston travel.
  • By also changing the Master Cylinder to a T100 MC, the leverage ratio becomes 6.33:1. This will result in a marginally (3.7%) shorter pedal throw than the stock configuration to get the same amount of caliper piston travel.

1588093265647-png.2288539
 
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Do we have a part number floating around for the larger T100 master cylinder?


Edited for posterity. It think it should be -

(47201-34031)
 
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Dirty Koala

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I started off with a gm single piston 60 calipers/14b drums Sky adapter and gm 1 1/4. Could not stop a roll hardly.

Swapped to gm 3/4 front calipers - still s***

Swapped to 92 ish dodge w350 1 1/8 master and ran that for a long time but brakes were never great.

Swapped to a 1 1/16 t100 master and the brakes are very decent for 40s and 8k lbs.

I also have a wilwood rear proportioning valve.

Edit: running cummins vac pump, I did check vac on it, and reman booster
I've got GM single piston 60 calipers on front and rear (rear is d60 w/ discs). Do you think the t100 1 1/16" MC would be ok for this application too? I'm not sure how discs compare to drums in the rear as far as clamping power and fluid needed.
 

GLTHFJ60

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The problem IMO is that you need a larger MC with one ton brakes, but stock LC vacuum boosters don't assist enough with them, making the pedal stiff. Moving to a smaller MC (1 1/16") fixes the pedal stiffness, but makes the throw longer to get the volume needed. Best solution is a hydroboost unit and a large MC like this one, that I use with my D60/14b disks all around. Can't quite lock up 42s on dry pavement, but only just. With 35s, it stops very, very well.

Amazon product
 
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Nice, lots of good info flowing into this thread now.

I ordered a 1.25” GM MC, and a friend says he has a hydro boost collecting dust for too long I can have.

Also, as I did install an alternator with vacuum pump and the brakes are significantly improved (before starting one ton swap) I’m still going to try with vacuum and stock booster first.

I will get some more info about stock components and the math for sizing components while I move forward as well.
 

maxamillion2345

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I've got GM single piston 60 calipers on front and rear (rear is d60 w/ discs). Do you think the t100 1 1/16" MC would be ok for this application too? I'm not sure how discs compare to drums in the rear as far as clamping power and fluid needed.
I really am not certain, sorry. The nice thing about trying a t100 master if you already have a 80 master is line fittings are the same and no adapter needed.

You’ll need to swap line nuts when moving to a dodge or gm master, which isn’t a big deal for certain but just saying...
 
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Some pics of MC’s

7A0AD9B5-E328-47D0-8780-554FC5A119F0.jpeg


8CEFD182-2EC3-468C-A71A-8EE6F408DFF2.jpeg


BB7D72A3-380A-4DC7-AD8B-C6B44D3AAE91.jpeg



A couple more questions arise..

The fittings are bigger, do I upsize lines?

The “snout” of the stock MC sits in a pocket in the brake booster. The new one is larger and won’t. I can build an adapter plate, but if there is nothing sitting in that pocket against the booster will any issues come from that?

Can I just get adapters for the fittings or what’s the deal with double flare brake fittings?
 
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maxamillion2345

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I ran 3/16 line and put corresponding line nuts. Basically the same size as stock toyota brake lines. Double flare is easy with the right tool.

OEMTOOLS 24364 In-Line Flaring Tool Kit, Low Profile | Brake Repair/Brake Flaring Tool | Create Single or Double Flares in Copper or Thin-Walled Steel Tubing | Use with a Ratchet Amazon product
 

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