Brake Master cylinder question, FJ62

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Feb 17, 2007
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Need to replace my brake master cylinder. I'm curious, I intend on doing the 4Runner caliper swap in the not too distant future, but for now still have all stock brakes, with fresh pads in front, and just completely rebuilt the rears. Would it be worth it, and can I, install the larger T100 MC, with the otherwise stock brakes? Save me a little time and effort down the road.
 
Joined
Dec 11, 2008
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Whidbey Island, WA
Never understood all the hoopla over the brakes on our wagons. No they are not great but I have never failed to stop, all with the stock set up, even with some panic stops that lifted my tookus off the seat. (In both my 62 and now with my BJ60)

I would want to drive a rig with all the changes before I would spend any money on them. Be interesting to see just how much all those changes really improve things. Or are they like sway bars, minor almost unnoticeable improvements. I am sure there are believers out there but I am not convinced at this point.

Always just replaced the stock stuff with aftermarket and never had a problem. Both my wagons still stop just fine.

Tony
 

KLF

Frame waxer
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I did the swap (larger calipers and MC) on both my wagon and my mini-truck, the difference was dramatic. Well worth it.
 

ntsqd

technerd
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Apr 26, 2007
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If you swap in the larger m/c without the larger piston calipers your pedal effort will increase noticeably, but you'll have a nice, firm pedal. That means that the pedal will be firm to very firm and that you'll probably need two feet to perform a panic stop.

A slightly relevant post of mine:
https://forum.ih8mud.com/60-series-wagons/256361-comments-brakes-4.html#post6458144
FWIW Rock Auto lists the FJ80 m/c bore size as 1"; they also list the T-100 m/c bore size as either 1" or 1-1/16". I don't know which T-100 m/c is being used, but for the 1" the numbers for the FJ80 will apply. Note that the 4rnnr caliper combined with the FJ80 (& the T-100) m/c results in Less total leverage than stock. That means that the pedal feel got firmer, but that the pedal effort needed for any specific rate of deceleration will be higher than with stock parts or with the stock m/c and the 4rnnr calipers.

Pedal feel is very individual, some people prefer a firm pedal over less pedal effort. Frequently they do not realize the difference and think that the brakes got better. "Better" to one person won't be to another. My Mini truck has a less than firm pedal, it's all stock. It's not terribly confidence inspiring, but when ever I've really need to stop they have more than been up to the task.
I guess what I'm saying is do not be deceived into thinking that a firm pedal means better brakes. It means nothing of the sort.
 
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Joined
Dec 11, 2008
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Whidbey Island, WA
No tricks

I always bench bleed it with those cheesy little hoses that come with them. Hook all the lines up, usually bleed those fittings on the master a bit then onto bleeding the brakes.

Don't forget to bleed the LSP valve at the back too.

Tony
 

Dynosoar

Slightly Disturbed
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Stock FJ60 master is a 7/8" bore
4 runner is 15/16" bore
FJ80 (non ABS) 1" bore
T100 1 or 1 1/16" bore

I use the 4 runner master. I like the feel of it and it seems to work well with the 4runner calipers (go figure). The 1" bore gives a very firm pedal feel (to me). Some like it some don't. I learned all the hydraulic theory stuff in school but can't recall the calculations right now.

Dynosoar:zilla:
 

Godwin

Resident Herpetologist
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I went with '95 4Runner MC and calipers. MC bolts up but the lines have to be slightly tweaked to bolt up. A little rewiring is also needed for the switch. I went with the 1995 year because this year will be easier for me to remember when the time comes to replace parts.
 

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