4040 Prop Valve lines: which really goes where

[af_1132]

Hey all, the guys who install the 4040 valves on their Del Sols or Civics do not hook it up like those I have heard on here.

On here, I have heard that people do a direct line swap with the 3030 valve hookups, which have the lines to the master going to the right passenger side of the prop valve. Our front left brake line is on the top left of the prop valve and our front right goes to the bottom left of the prop valve.

Well, hooking it up this way may have caused my LX Master Cylinder to fail. Fluid was leaking out the back of the MC onto the booster, and brakes were squishy. It is making me think that I DID in fact have the 4040 lines hooked up incorrectly. I mean, it was installed in 2013 and I tracked the car with rear brakes one time after swapping to the 4040, so maybe it failed because I should have swapped the master out for the EX variant. It's entirely unclear, but I got an EX style MC this time and am installing it after I get these lines hooked up properly to the 4040.

Those doing the swap on HT have shown that the lines to the master need to be attached to the driver's side of the 4040, like the following pics, but they are otherwise inconsistent.

This pic below shows a pairing of right side brakes on top with the MC front port, and left side brakes on bottom with the MC rear port:

http://www.classictiger.com/HondaCRX...lveRouting.jpg

This other pic shows a pairing of right front and left rear on top with MC front port, and a pairing of left front and right rear on bottom with MC rear port:

http://i158.photobucket.com/albums/t...g?t=1282349190

It's all so confusing.

What did you guys who are still on here do, and what do you recommend for me? I really want to do this correctly so that I have solid brakes that respond to bleeding as they should.

[Grumpys93]

This is how I ran it and haven't had any issues:

4040 goes up, black rubber bulb is up, exposed threads up and torx heads down towards the ground. Just like the original PV, nothing has changed. Do not install upside down!!!

Next is the layout of the 4 ports. Your point of view will be looking at the "4040" on the PV from the front of the car (just like in the pic too). Again, same as stock, nothing has changed.

Upper left: front m/c port/fitting (closest to front of vehicle)
Lower left: rear m/c port/fitting
Upper right: to front left brake (driver side for us LHD folks)
Lower right: to front right brake (passenger side)

I am still running my original LX Brake booster, though I notice a small leak, so maybe its time to change it out. But this was not due to the 40/40 valve looks like it's just showing its age.
That was copied from the DIY and Granite posted it.

[af_1132]

Right on, that is what I was leaning towards, it's just quite a stretch to make the left front brake line mate up with the upper right hole due to its short length.

I definitely installed it wrong then before! The two front lines that were supposed to send fluid out were receiving inward pressure from the MC! I'm thinking this is why my MC failed.

I could never find his post, did he say anything about the two lines going to the rear, which is to the left rear and which is to the right rear?

Thanks, Grumpy!

[SSMAccord]

I will chime in. I’ve been running the 40/40 for a longish time also. My install matches the brake line layout that Grumpy listed. My 40/40 numerals are inverted however. I can’t say that I have ever had a MC blow as you’ve described while running the setup this way.

[af_1132]

It failed (leaked out the rear onto the booster) when I had the lines installed as instructed in the 93 Accord manual. This setup has the MC inlet lines on the right/passenger side of the prop valve and the front brake lines on the left/driver side.

I ordered an EX MC from Rockauto (Dynamic Friction) but had to return because the rear MC port has threads for a larger fitting than the front. I have to look up whether that is wrong or if rear disk brake lines are actually bigger to accommodate this larger size. For now, I just reinstalled my old Cardone MC to check for leaks after switching everything to Nick's setup. Pedal feel started out pretty firm, but seemed to get a little more squishy after driving for a few minutes. I opened the hood and think there may be some seepage from the rear side of the prop valve at the bracket. No seepage from the ball on the front, though or from the back of the MC. I will need to wipe up and do it again starting with a fully cleaned bay to be sure.

[SSMAccord]

It failed (leaked out the rear onto the booster) when I had the lines installed as instructed in the 93 Accord manual. This setup has the MC inlet lines on the right/passenger side of the prop valve and the front brake lines on the left/driver side.

I ordered an EX MC from Rockauto (Dynamic Friction) but had to return because the rear MC port has threads for a larger fitting than the front. I have to look up whether that is wrong or if rear disk brake lines are actually bigger to accommodate this larger size. For now, I just reinstalled my old Cardone MC to check for leaks after switching everything to Nick's setup. Pedal feel started out pretty firm, but seemed to get a little more squishy after driving for a few minutes. I opened the hood and think there may be some seepage from the rear side of the prop valve at the bracket. No seepage from the ball on the front, though or from the back of the MC. I will need to wipe up and do it again starting with a fully cleaned bay to be sure.

Regarding your MC concern, the 1" EX MC does have a larger rear fitting that needs to be addressed to install into an LX or DX model. The solution is to have a custom line made or cut the flare off of the existing line, remove the current fitting, install the larger fitting and flare the end. The re-flaring part is kinda tough because there isn't a lot of room to get the jaws of the flaring tool on the end of the line, but it is doable. The line itself isn't actually physically larger; the larger fitting was an error-proofing measure at the factory to prevent LX/DX cars from getting the wrong MC and vice versa. If you keep the 15/16" MC with the disc setup you will have higher pressure in the system and less pedal effort and more pedal travel. Moving to the 1" decreases pressure in the system and means higher pedal effort with less pedal travel. The difference is less of an objective performance upgrade and more a feel kind of modification.


So this thread caused me to tumble down a rabbit hole around proportioning valves...and thinking that I might have to adjust the install. Sigh... I wanted to figure out the reasoning behind the inverted install that I ended up with. It seems that the original way that the 4040 is installed in the donor vehicle has the input lines from the MC routed the Upper Right and Lower Right ports, rotating the valve moves the input ports into the position that the CB input lines are in the same place as the original. This means that the valve is mounted upside down and the rubber plug is now on the bottom.

Since I have a few spare 3030 proportioning valves on hand, I decided to dissect one of them. The upper and lower valve halves are mostly symmetric, the difference being that one has the weep hole covered by the rubber plug. The weep hole is used to indicate if the seals for one of the internal pistons fails. The assembly is constructed of the 2 connected/symmetric valves, each halve creates a circuit consisting of one front brake and the opposite rear brake. This is for the operation of the fail safe mode of the brake system; if one of brake circuits has a hydraulic failure the car still has an operational front and rear brake.

On the proportioning valve itself there are the 4 side by side ports and the rear exit ports, the side by side ports are directly connected to the hydraulic pressure at all times, the rear brake lines are connected to hydraulic pressure via the internal pistons. The amount of pressure being applied to the rear brake needs to be adjusted for rear disc setups due to the nature of how they create friction during weight transfer while braking versus drum brake setups. It does this via the internal pistons that feed the rear brake line output ports. It seems that the amount of pressure is controlled by the pressure needed to compress the springs located between the 2 internal pistons. (Different ratings of proportioning valves have different color springs which seem to indicated spring rate)

So that said, it seems that mounting the proportioning valve right-side up or inverted shouldn't affect the operation of the valve as the side by side ports seem to have no restriction of flow. The rear outputs should also be symmetric and not be affected by which goes to which port as they are mated to their original input from the MC through the placement of the hoses from the MC into the proportioning valve. I have not quite made sense of what the 3030, 3035, 4040 numbers mean yet, but seems to be a ratio of pressure.

[Grumpys93]

So your saying that there is no wrong way to install the prop valve as there are no restrictions of flow? There was are a couple ek civics in the yard, I remember reading somewhere that the Si had a 40/40 valve. I’ll have to look next time I go, if there is one I’ll pull it apart and take a look.

[SSMAccord]

It would seem that the MC input lines and front caliper output lines are able to be used in either flow direction. I think the real world proof is that your car is running the CB input lines to the factory DA output ports and I am running CB input lines to DA input lines, in the inverted position, and both of us have fully functional brake systems.

The 4040 equipped cars that I know of are:
DELSOL Si
DA Integra RS
EG Civic Si
EK Civic Si

There might be others as well, but I haven’t done any digging into those details.