So I'm just waiting for the adapters to arrive from 85excab so I can bolt up my calipers. While I've been waiting I was looking at the brake hardware I've picked up...

I'm using a 1" master cyl from a toyota supra that I had for parts. I also grabbed the proportioning valve that was with it.

Now I also got the LSPV adjuster from 85excab, I know I won't need this proportioning valve, but would it be something that would be good to install as well? <---Thats the important question here...

In doing the research for this conversion I found on another site were those brackets are available he had a pic of supra calipers, I will be trying to use the ones that I have off the supra I had as long as the bolt holes line up and everything so crossing fingers on that...if not I will be getting some 92ish 4Runner Calipers...

Also for those that have done this so far anything I should watch for as I'm doing this post install thoughts and such?

 

Can you point me in the direction of a set of 79-81 loaded supra calipers? I haven't had much luck locally.

What brand mounting bracket are you using?

It seems like a lot of guys do this brake upgrade and also go for full float axles from front range off road at the same time, but its pretty spendy.

 

follow this thread...basically I'm doing the same thing...
https://www.yotatech.com/forums/f116...nstall-191482/

 

There are more questions than answers, especially regarding the e-brake.
Are you planning on using the e-brake on those supra calipers, some suggest the brackets need to be positioned correctly to utilize the ebrake function...

 

No im buying a driveline e-brake down the road to put right behind the t-case...

My only concern right now is the use of the proportioning valve...

 

From what I've read from other posts, with the Load sensing valve adjust to the minimum level of rear bias, some guys were still locking up their rears.... Now, that can wildly vary depending upon tires/calipers/pads/road surface/vehicle weight. But if you yank it and replace it with a proportioning valve its fully manual.

No answer is a wrong answer, just what works for you right?

 

Yea I didn't even think about removing the lspv just running both to give a little more control I guess...

I can see having the lspv still there for times when I am pulling a trailer or loading the rear with firewood...

hmmm I wonder if I left the lspv alone and ran the proportioning valve how that'd react...

 

Anyone else care to chime in on their thoughts for this?

 

I wouldn't run both...

IMO, and I could be wrong, the LSPV IS a proportioning valve... It's just harder to adjust than turning a round knob...

I've got an FSM for a Landcruiser and I stumbled onto adjusting the rear LSPV and that's what's making me say that...

It's prolly in a trucks FSM too.


Anywho... Run one or the other, not both. My reasoning is the two might get to a point where they conflict with one another and that might also make properly proportioning f/r bias a PITA.

Just bypass the LSPV and plumb the... Wait, what's a Supra P-valve look like?


Nevermind... I doubt a Supra has a LSPV... If ya see where I'm going with this?

All an LSPV does anyway is change the proportion the rear brakes get anyway based on the position of the arm...

For simplicity alone, I'd do one or the other.

 

Yea i was thinking about that as well.

The main reason I was thinking about doing it with both was I could use it to change the bias on it unloaded then the LSPV could still adjust for load...

here is a pic of the unit


The blue part is the PV and thats a supra 1" Master Cylinder. The hose going off to the silver part is the split for the front and then there is another port for the rears...

And there is an adjustment bolt on the bottom.

 

So I went ahead with the install of the Proportional valve and got it all installed about friday at 8:00...Went out and tested the brakes, I could not lock them up if I tried. But my stopping power is UNBELIEVABLE (in comparison to my old brakes). Towed a 5x12 Covered Trailer unloaded to spokane and loaded back to seattle...The brakes worked great when fully loaded...only got a very short (less than a second) lock up on the front left taking the HW18 Exit off of 90 and the on ramp was wet...

But these rear discs are very nice...the 1" MC from the supra works great I barely have to touch the pedal at this point.

 

Awesome! I just found a set of supra calipers, I'm going to see if I can make them work including e-brake... I'm going to yank the load sensing valve I think...

R

 

I know the calipers I had from an 86.5 did not work I ended up with some off a 92 4Runner...I do know they changed the calipers at some point on the supras...87-89ish...

 

Yep. The golden years are 79-81. I actually found a matching set of loaded calipers, remanufactured, which is pretty tough to do these days. Hopefully everything lines up without too much cutting welding and cussing

 

With the brackets from 85excab all was golden just took awhile for grinding to get the rotor to fit...other than that it was cake...

 

86.5-92 Supra rear calipers are identical.

 

Front and rear?...I thought they changed up one of them later in the years...could be wrong my supra knowledge is more limited to mk2

 

The only changes in the MKIII Supra from 86.5-92 were really just cosmetic, and they changed the wiring/connectors on the body and engine harnesses around mid year in '89. The chassis remained identical for the entire run, save for the addition of extra bracing on the rear subframes on the '89-'92 models.

Brakes were the same for all years, regardless of whether the car was turbo or N/A.

 

Shaef, 79-81 arent the same as 81.5+

and 79-81 rears have e-brake bosses

 

I know that. I was simply correcting what was said above.