SAS'd '87 Toy master cylinder woes cured!
 

Since 2001 and the SAS conversion I've had nothing but trouble with the stock master cylinder. On average it's used one every year. After a few months the brakes begin to fade, and even when new they didn't supply enough pressure to lock up the tires. Pedal travel was long and soft even when the MC's were new. The LSPV was replaced with a Wilwood valve - that helped even up braking, but didn't cure the MC failures. The brakes were so bad it was kinda like having ABS on all the time...

There were two options I considered after researching the problem:

1. Converting to a Chevy MC:

http://www.rockstomper.com/catalog/b...mtoymaster.htm

2. Converting to a Toyota FJ-80 MC:

http://marlincrawler.com/htm/brakes/mcylinder.htm
http://allprooffroad.com/index.php?o...ask=view&id=33

The Chevy conversion works well with really large tires - up to 44". I run 35" tires w/ stock drums in the rear, so, I chose the FJ-80 MC.

It works great! I'll have to spend a few minutes adjusting the Wilwood valve to get even braking, but for the first time since converting the truck, I can lock up 4 tires. Pedal travel is firm and short.

Later

subscribed, I'm having similar problems without the SAS.
do you know if you can leave the lspv in place and run an fj80 master cylinder with rear drums?

I don't see why it wouldn't work fine with the LSPV in place.

Probably not as the 80 MC is set up to dish out all 4 wheels as discs.

FWIW the new stuff has better brakes. The 1999 base model Non-ABS MC runs the big huge Chevy Calipers on the Dana 44.

That is pretty impressive. I do have a Willwood valve to tone down the big huge drums out back. More of a GM/Toyota balance.

I would plan on the valve, if you get it from Front Range he makes you adapters and it's really easy to install.

so the fj 80 master and the valve from FROR is the way to go? or the chevy master

oh yeah,

The old MC cap w/ wiring does not fit on the FJ-80 MC, so the low brake fluid warning light is deactivated. I just unplugged the harness - no big deal...

what year fj80 master cylinder did you use? non-abs I assume. what was involved? new brake lines or rebend the old or did they fit. did it also bolt up to the booster ok?

The new stuff does not have the level sensor in the cap, there should be a plug on the side of the reservoir. If you can get the right plug, I bet you could solder it on and it would work again.

I have the AP rear disc conversion kit w/ a FJ80 MC w/ an added in manual proportioning valve (wildwood) and I can lock up the disc brakes on my 85 pretty easily if I have to...much better braking than the drums.

You have to get a new piece of hard line that has a standard 3/16" fitting on one end, metric on the other to put the mpv in the loop. You also need to remove the OEM LSPV and plug up the "tee" on the pass side front frame that went to this line. Just solder/braze over a metric fitting off the old line.

I got lots of pics on my website of what I did.
http://www.wabfab.org/project/1985/b.../reardisc9.jpg

LINKY

I'll add some text to the page later...so any questions, just ask.

:guitar:

I ordered the MC from All Pro along with other parts I needed to get the BPOS back on the trail. They only specify that it's a non ABS FJ80 MC. It bolts right up. The rear brake line goes in w/out modification, the front line needed to be carefully bent into position. After doing a bench bleed on the MC, I used a vaccum bleeder after it was installed to bleed the system. I start at the left rear, right rear, right front and finish with the left front.

After installing new front springs and Bilstein 5150's on all four corners the truck is ready for the summer!

Cool! :bigok: thanks for all the tips!

This thread perked my interest. My brakes are in stock form and they plain suck. Even if I slam my pedal down, I still glide to a stop. Not the best feeling in the world.

I'm wondering what to look for to beef this up. I would like to keep the drums in the rear. Would an FJ80 MC , proportioning valve, and maybe a new booster firm this thing up? Or am I missing something else?

I've had my MC changed before and done the routine brake jobs, but nothing seems to improve it.

...gotta few miles on the truck now, and the MC change is really working out well. It took a little time fiddling with the Wilwood valve to get it dialed in, but now I've got good consitant braking for the first time since the truck was stock.

well, havent done the MC trick yet, but I did cut off my LSPV rod and tie it up, now I can stop, still can't lock it up, but much better/safer

old thread, but i have a few q's

I have an 86 4runner...

1. Can I just install the FJ80 MC without fiddling with any other part of the system (save for the level sensor of course) including leaving the LSPV alone?
2.If i put the V6 calipers and some vented rotors on, will it help my braking power?

Nope, you will have to use a proportioning valve or all you'll do is lock up the rear tires all the time.

I think you might have the vented rotors and such already. I don't know, I'm not really an old truck guy. But my understanding was that it s was IFS calipers or SA calipers. Not motor specific, but I could be wrong.

Make sure you get the bigger 4 piston calipers, the v6 trucks/4runners came with these for sure, but I do believe sometime in the early 90s the 4cyl rigs also recieved the upgraded calipers. The smaller 4cyl calipers have 2 large/2 small pistons while the v6/late model 4cyl had 4 large pistons.

If you upgrade to the bigger, later style toyota brakes with a bigger master, calipers and rotors you may want to also upgrade the booster to a dual diaphram from a v6 truck/4runner (88-95). Proportioning valve should be used as Schaefer mentioned, and you can ditch the rear LSPV setup.

Trail Gear has the larger loaded calipers and vented rotors for about as cheap as you'll get them with FREE shipping.

Definitely a PV or you WILL just lock up the rear brakes. I have rear discs and they work great, but I've still got to upgrade my old calipers/rotors to the above that I mentioned.

Got a link or write-up on the larger brake booster? I haven't checked on Pirate yet, but that kind of stuff gets buried so easily among all the BS over there, good stuff, just hard to find sometimes. How much difference does it make w/ the larger booster? Do you know from personal experience? Just looking to upgrade everything else I haven't done already...like I said, I already did the rear discs, FJ80 MC and PV on mine...works great. Now for the front...

:guitar:

The difference between the larger, upgraded rotors and calipers on the front vs. the stock '85 brakes is very noticeable in my opinion. I've driven both setups many times, and even with 37s and upgraded brakes it still works much better than a truck with 33s and stock setup.

I have not upgraded the booster on my trail rig, as I dont have rear discs or a larger master cylinder yet but to really get the full benefit of rear discs and a bigger master cylinder it only makes sense to use the larger booster.

Minus rear disc brakes, this exact setup came stock on my 94 4runner and its a heavy truck, w/ 32s it works excellent and I plan to put this system on my trail rig, combined with rear discs and a proportioning valve it should work great.

Quick searched yielded some more good info:

http://home.4x4wire.com/erik/4runner/brakes/
http://www.pirate4x4.com/forum/showt...t=dual+booster

Thanks for the 411. I'll check out those links and do some reading. :great:

:guitar: