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Discussion Starter · #1 ·
I have just had my 2nd 40/40 proportioning valve fail and leak fluid. I believe it is because I am changing the bracket from the Integra to the CRX so it will mount to the car. To change the bracket you must remove the two bolts that hold the unit together. I have tried to use a hex head bolt instead of the security head bolt so that I can torque the bolts down more witch did work for just a little bit. Every thing on the braking system is new BUT the proportioning valve. I don't like the idea of buying another used part that will more then likely leak again. I have seen some new accord valves that look like it would be a direct fit but unsure if the proportioning will work for my set up. I am not against going with an after market proportioning valve but have never done a custom job like that however not afraid to do it. What I need to know is: Are their any other stock proportioning valves that will work that I can buy NEW? If not what company/kind of after market proportioning valve can I use and is there a good write up on how to do it? Thanks for the help and here is my current set up

Front
-1991-CRX Si front stainless steel brake lines
-1990-1993 Integra 4040 proportioning vale
-1990-1991 Civic DX 15/16" bore master cylinder
-1990-1991 Civic DX 13/16" brake booster
-1996+ Integra type R calipers and brackets
-2004-TSX pads
-2007-Mini Cooper-NON-S rotors 280mm

Rear
-1991 CR-X Si rear stainless steel brake lines
-2002 EP3 Si rear calipers, pads, and rotors

Dot 4 brake fluid
 

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If you take it apart, you have to replace that o ring.
All of the information circulating on Honda prop valves is baseless. I've been at this since 2000, and have swapped rear discs on dozens of vehicles I have owned. I used to subscribe to the idea that you need a 4040 prop valve when swapping rear discs which I read on forums but never seen any actual proof or documentation. And since then, I have noticed various cars with rear discs have something other than "4040" stamped onto them. My DA prop valve doesn't say "4040".The prop valve I put on my EG came out of a Del Sol w/rear discs, and I noticed that it has the same stamp as the one in my '88 CRX Si (comes factory with rear drums).
There is no conclusive evidence that a Honda prop valve works the same as prop valves found on American cars, which is where this whole notion of needing drum and disc specific prop valves came from.
In my personal experience across many vehicles, and I've seen this stated by plenty of random people on forums (then immediately shot down by the uninformed), there is no need for a "4040".
 

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Note that the valves don't say "40/40" etc. There's never been a slash.
That slash comes from the imaginations of the folks who started the whole idea that Hondas are like American cars (they're not even plumbed the same!) and prop valves for disc brakes are diff than those for drum brakes.
These same folks thought the 4040 meant 40% front, 40% rear bias.
Let that sink in.
Imagine a car that had 40% bias up front and 40% rear, the other 20% lost to the ether.
The rear brakes do 10-15% of the braking. The bias is determined by the size of the calipers and pads. The fluid pressure at each caliper is the same.
I'd have to dig up old notes, but I believe the prop valve on my EG says "3060". On '96 non ABS Integras I believe they say "3040".
That the non existent slash in 40/40 carries forward to this day tells you that the rest of the information is bs as well.
prop_valve_disassembled.jpg
 

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I think this is the definitive answer to your question.

A proportioning valve limits the pressure to the rear brakes after a certain fluid pressure is attained. Before that transition point, line pressure is equal front & rear. Your initial brake bias (under light duty braking) is controlled exclusively by weight over the front & rear axles, the vehicles center of gravity, tire compound, pad compound, rotor size, and caliper piston size. The auto manufacturer builds your car with more front bias so that hard stops will be more stable (fronts lock up while rears still slow the car keeping it straight). Switching to a 40/40 creates more pressure in the rear lines only under hard braking. This is good, but if the rears lock up before the fronts, the car will start to spin (especially in a turn). The closer you can get to a 4 wheel simultaneous lock up, the shorter your stopping distances will be. Always error on the side of the forward bias (for safety's sake).

Some interesting facts:
Lowering your car increases forward bias
Adding weight to the rear of your car increases forward bias
Stickier tires also increase forward bias
Larger front brake rotors (with the same size caliper pistons) increases forward bias
Larger front caliper pistons increase forward bias

If you have these mods, you may want to look into increasing rear bias, and a 40/40 is a good start...

All you will ever need to know about brakes & brake systems can be found at http://www.stoptech.com. I've read their stuff from front to back.
 

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Discussion Starter · #7 ·
I found that the fluid is leaking from the rubber stopper I need another brake proportioning valve. I can not find a new 40/40 valve. I am trying to find something new that's close to a 40/40 or the next best thing. Reading that you can use prop valves meant for drums that the difference is very little between the valves. These are the valves I have found new witch one would be closet to 40/40 and best for circuit racing trying to avoid rear lock up. If you know of a site or other valves I could get new please let me know.

Accord:
46210-SM4-A05
46210-SV4-A01

Civic:
46210-SR3-013
 

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test for the 9th time fuck dammit!
screw it, im leaving this forum there a billion other ones, this software is retarded
 
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