AE86 proportional valves (brakes n shizno)

[Jonny Rochester]

I think the spring is a big part of it. Maybe the main differences between the Toyota valves is the spring tension. Adjustable valves use adjustable spring pressure.

To learn more about this, I surgest getting into some automotive text books. Remember, books?

Confusing exists, because some vehicles do have residual pressure valves, designed for drum brakes. Some vehicles have a 1-piece valve which uses the front line pressure in some way. There are a few types... HiLux and HiAce and some Toyota wagons have factory load sensing, adjustable rear bias valves. (Works on suspension height). Some vehicles have the rear bias valve as part of the master cylinder.

But... I know the AE86 master is the same for all models, and has no valve in it. And I know the bias valves used, have the same item used on some disk brake cars, and some drum brake cars. Which to me, means a residual pressure valve is not used.

But don't take what I say as gospel. It's an interesting topic. Sort of like ackermann steering. Lots of theory, very little application.

[rthy]

the spring in the jdm PV is significantly more aggressive, i assume the ADM was softer because it was 20+years old. i would assume the spring controls the pressure

where do i find such text books?
i might stop buy toyota tomorrow and see if i can get part numbers for springs

[Jonny Rochester]

Toyota do not list the individual parts of the valve. They only list the valve assembly. I can give you the number for that if you want, not sure if it's available new.

For books, go to your local Tafe or Technical college, and go to the library. Find the automotive section. Most automotive text books try to be very broad and comprehensive. Automotive Mechanics by Ed May, a 2 volume book, has been the Tafe text for many years now. Everyone should have it.

Go the the brake section of the book, and somewhere in there will be a little chapter on proportioning or pressure limiting valves. I picked up a Heavy Vechicle mechanics book today, and it had a bit on these valves also.

[Sam-Q]

thanks for the tip Jonny I will have a look to see if I can find that book.

So when I gutted that proportioning valve I may of just made it have a 50/50 split of fluid?

[Jonny Rochester]

Yes. No p-valve means full fluid pressure to the front and rear, both the same. Then you need to test, brake hard and see if the rear brakes lock up. If the rears lock before the front, then you need a p-valve. If they don't, then you don't need one. ... I guess.

[Sam-Q]

ha funny that, and I always thought it was a preload for the fluid that the drum brakes needed to not drag or something, how wrong I was. I have fully tested mine on the road on and the racetrack and it seems to be balanced to perfection. So I can only take an educted guess and say that the front brakes conincidently need less pressure for the same amount of braking and so forth I end up with the right amount of bias? or am I making a really silly asumption again?

On another note I have heard of people using shims to preload that spring to have the same effect

[rthy]

Well thanks to that parts post
found the Part number to the stock pv's



sexy site, has everything (for stock parts)

[Kid Karola]

yes great reference... if you have a Trueno, not complete for Levin variants especially bodywise. Still win to have online parts interpreter handy for meachical bits.

I beleive the parts I used are marked 1 and 2 in that diagram.

[Jonny Rochester]

Yes. But the hard bit comes when you want a cheap second hand part (or if it's not available), finding what other vehicle it comes on.

[rthy]

yea i paid $200 for that rear pv brand new (1) from japan
the front half (2) are no longer available

looks like they dont sell they dont sell the spring seperate too