Disc brake conversion - master cylinder questions

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C

courtlandfire

10 Year 15 Year
Joined
Sep 12, 2010
Threads
6
Messages
15
Location
Hood, CA
Hello all - just pick up a 1972 fj55 last week. I'm looking to put a disc brake conversion on the front axle. First where's the best place (best prices) to get parts. I've see jtoutfitters and cruiseroutfitters. Any other you could recommend? I'll probably end up picking up the rotors and calipers at the local Kragen.

We'll the main question I have is once I do the disc brake conversion can I use my stock duel reservoir master cylinder? Also do I need to install a proportioning valve?

Thanks for the help in advance and this site is awesome.

by the way I'm from Sacramento, CA.
 
Lil John - I don't know Carl but interested in meeting up with other FJ55 owners in the area. Do you guys have a club in Norcal?

What year minitruck or Land Cruiser would brake parts bolt right up? Also what is a minitruck? When you mean "hardparts" do you mean the parts I would take off the axle and reuse on my axle? Where would you recommend to buy the axle rebuild kit, brake lines?
 
courtlandfire said:
Lil John - I don't know Carl but interested in meeting up with other FJ55 owners in the area. Do you guys have a club in Norcal?

What year minitruck or Land Cruiser would brake parts bolt right up? Also what is a minitruck? When you mean "hardparts" do you mean the parts I would take off the axle and reuse on my axle? Where would you recommend to buy the axle rebuild kit, brake lines?
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I bought my disc conversion parts off of 3puppies (I think that's how it was spelled) here on mud. The parts he gave me were the birfields, knuckles, rotors, calipers and rock shields. I had new hard lines from Spector. Their shipping is expensive FYI. Mine were from a 'minitruck' an 83 I think. Minitruck just means an eighties style Toyota pickup truck. I got my axle rebuild kit from Spector as well, but cruiseroutfitters has them as well.
 
I was able to get a lot of the stuff from junkyards, like Pick&pull. Got my knuckles & spindles there. I got some calipers that I was able to use as cores for when I bought loaded 4runner calipers at Napa. Got the vented 60 rotors at Napa too.
Mark A. has some flexy brake lines, or you can get them at the hotrod shop on Sunrise (near the pick&pulls).
You can use your stock master cylinder, just pull the residual valve out of the front circuit. The Aisin hubs were the hardest part to find at the junkyard, I had to buy them over the counter. But I did find all the conewashers, flat washers nuts&bolts on the ground around the front axles of the minitrucks at the pick&pull.
I also do not shop at JTO, plenty of GOOD vendors here on 'Mud...
Oh, welcome. :flipoff2:

P.S.- you're familiar with the FAQs?

https://forum.ih8mud.com/40-55-series-tech/13571-disk-brake-conversion-links.html
 
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Might be easier, but then you still have course-spline birfs, whatever lockouts you have now and small-pattern knuckles...you can do it easy, twice, or do it the right way once.
 
PabloCruise said:
How do you pull residual valve out of front circuit on a drum brake master? Something I am totally infamiliar with.

Any pics would help!
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where the brake line goes into the master cylinder, there is a big nut. pull that big nut off the master. the residual valve is inside there.
 
master/booster

Use the toyota mini or 60,you will be happy you did.I tried to use my stock master/booster,but they didnt seem to work for me.So I found a 91 4runner master/booster for basically nothing,used a proportioning valve in the rear,and it works great.Bolts right up with no mods
 
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nuclearlemon said:
where the brake line goes into the master cylinder, there is a big nut. pull that big nut off the master. the residual valve is inside there.
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Front line or rear line? Sorry, I don't have my master in front of me...

Lil'John said:
I used stock 75ish era master on my FJ40 and it worked flawless once I removed the residual valves. Locked up 35" tires no problems and the pedal felt nice.:cool:

My FJ55 is using a FJ80 master... I'm not real happy with the feel of the pedal. It will lock up 35s no problem but it doesn't have a good feel to it... OTOH, I'm going from 99 Tacoma and 92 BMW... and the axles are 1 tons:lol:
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Do you recall the bores of the different masters? Is your ~'75 master a 7/8" bore?
Are you using the 80 master for disc/drum (early 80) or disc/disc (I think that came with the FZJ-80)?
 
SAWTOOTH 55 LC said:
Use the toyota mini or 60,you will be happy you did.I tried to use my stock master/booster,but they didnt seem to work for me.So I found a 91 4runner master/booster for basically nothing,used a proportioning valve in the rear,and it works great.Bolts right up with no mods
Click to expand...

I agree with Sawtooth, in my case I test 2 configurations , 1. 97 4Runner master and booster, works like 3 months(master and booster gone) it work very good but, be carefull if buy it used, 2. 87 fj60 with fj55 booster, currently in duty, added a valve last week :banana::banana:, and work awsome.
 
here is one pic of the master and booster
PICT0001.webp
PICT0001.webp
 
When I did mine I used mini truck parts and FJ60 rotors. The mini truck axle should be a late 81' to 85. While involved, it was an easy swap.

I have an FJ80 Master Cylinder and a 1984 Toy 4x4 booster with a spacer. I liked how my drums felt way more, but hey, it stops really quick now and straight.

When I first installed my brakes I had such a soft pedal. While the truck stopped, it felt scary and was all or nothing. It ended up being the booster, the entire housing was flexing oddly enough. A new booster helped, but they still sucked. After changing every single part on the whole brake system, I changed all the hardlines and it worked. I also had a very poor experience with JTO parts and ended up throwing them away and buying new.
 
I used a mini truck booster and an 80 series master cylinder. Works excellent compared to my old 55 MC obviously. I did have to take out .25 inches out of the pushrod but a welding place down the street did that for $5.
 
I just replaced my MC and booster with those off a 94 4 Runner.
I first replaced the MC and the pedal did not have a good feel with my brakes randomly locking up. I guess I was supposed to trim the rod on the MC side of the booster about 1/4" (oops).
Before I realized that, I ended up replacing the booster but had to use 4 3/8" washers on each of the 4 studs to space it away from the firewall. The diameter of the booster is larger than the stock and overlaps that lip behind the reservoir in post #18 of this thread. The new booster has an acorn nut that adjusts the length of the rod and now my brakes work and feel as good as the ones on my Tundra. I had to cut the threaded rod to the brake pedal on the booster about 1/3". I used a hacksaw and some m8 nuts to protect the remaining threads.
 
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