I dunno if anyone else who's done the Legend 2 piston caliper upgrade has experienced this, but it seems like there's more pedal effort than before, despite the better stopping calipers.

This makes sense when you figure that the brake system is pushing more fluid to 2 pistons.

I wonder if upgrading the master cylinder would help in minimising the extra pedal effort. I was talking to someone else about this, and they suggested getting a brake proportioning valve...but I'm clueless on what this means.

Anyone know about upgrading the master cylinder on a 4th gen, or about this BPV thing? I'd appreciate any advice or information. TIA

 

If the Legend mc has a bigger bore, bolting it on will decrease the pedal deflection but will also increase effort. To do it correctly you`d also have to make the pedal ratio more agressive meaning you`d have to move the hinge point.

A perportioning valve controls how much brake pressure goes to the calipers reducing the pressure going to the rear wheels. An aftermarket one would be adjustable allowing you to change the front\ rear brake byas. Normally you want the same ratio as the cars weight distrabution but with a little more front byas to keep the rear end from locking up befor the front.

EG: The Lude has a weight distrabution of about 60% to the front and 40% to the rear. The brakes might be about 65% front and 35% rear to keep things safe. Now since you increased front braking, the ratio might be around 5% higher in the front than before. You can therefore increase the rear braking a little to add that extra little stopping umph. However, you really have to have a brake line pressure guage to do it correctly otherwise you can make the car very dangerous.

 

Great, thanks for the explanation re: proportioning valves. Let me see if I get this straight:

Swapping in a BMC with a larger bore will decrease pedal deflection (pedal travel) while increasing pedal effort (umm....pedal effort).

How would I know if a BMC was swappable into my prelude? Is it the case that they're all pretty much interchangeable (modulo bore sizes)?

Finally, about moving the hinge point on the brake pedal, is there any easy (read: without custom fabrication) way to do this? I assume you'd either have to re-weld the hinge point, or fab a new brake pedal...am I totally wrong on this? TIA

 

I `haven`t gotten as far to know if mcs are swapable yet. I do know that many abs equiped Hondas have a 1" bore tho.

The main concern is that the pushrod coming out of the booster has to reach the first piston. The next would be the mounting angles for the bolts. From those that I have looked at, about 80- 90% of them look like they would work. However, I haven`t been bable to measure them exactly yet. If the mounting holes don`t line up, I think it would still be possible to make an adapter that would move the bolt locations. All this will come soon. I`ve started a database of stock Honda brake specs and am still working on making my Legend caliper setup more efficient.

As for moving the hinge point, I`m 99% sure that some cutting and welding will be required. I haven`t looked at it closely yet tho because I`ve been out of town. Probably one of two things will have to be done. 1) the hinge location moved or 2) the booster pushrod modified and moved to a different part of the pedal assembly.

I`ll have a better idea next week when I get back home. Drop me an e-mail sometime mid next week and I`ll have a better idea of what`ll have to be done. If more people are interested, I`ll post my findings.

 

Cool, sounds like you've got a handle on this. I checked out my Helms, and I don't know how comfortable I am with moving the booster pushrod to a different part of the pedal, so that leaves moving the hinge point for the pedal itself.

I'm in the same boat as you, because I'd like to get the most out of my Legend calipers...I'll be in touch to follow up on this.

 

Do you happen to know the piston diamiter for the Legend mc?

 

I have the Legend calipers on my car with the stock brake master cylinder. The car does not need a bigger master cylinder. The OEM one is fine.

 

racerx: no I don't know the piston diameter, but I can try and find out.

AndyD: yeah, I know the stock BMC is adequate. However, there is a noticable increase in pedal travel for me. I figured that this was just a result of having to push more fluid to the calipers themselves, and would like to dial it out.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ar5enal &raquo;</TD></TR><TR><TD CLASS="quote">

AndyD: yeah, I know the stock BMC is adequate. However, there is a noticable increase in pedal travel for me. I figured that this was just a result of having to push more fluid to the calipers themselves, and would like to dial it out.</TD></TR></TABLE>

Hmmm, based on this...I think you need to bleed your brakes some more.

When I changed my calipers....the brake pedal travel was not affected at all. It works perfectly.

Try bleeding the system.

 

Did y'all clam the calipers on a board and face them 'upwards' when you bleed them?
I've read this is the best way to do it.

 

I bled mine every way possible. I used a board half the time and the other half put it on the top of the rotor. I bled them at my place twice and then took the car to a friends whos a Honda tech. He helped me bleed the system 3 more times including the abs.

I've knowticed that after a few brakes there seems to be more pedal travel. I was thinking of trying another brake fluid cause I'm pretty sure all the air is out of my system.

The reason I'm playing around with the idea of a different pedal ratio is to decrease effort. I knowticed an increase in effort when I did the swap. However, when you decrease effort you increase pedal throw. Thats why the mc and pedal mod have to go hand in hand.

 

My problem may be something as simple as bleeding the brakes again. My current setup is as follows:

Legend Calipers
Axxis metal master pads
Powerslot rotors (VTEC size)
Goodridge SS lines
ATE Super Blue fluid

I bled the brakes once, and I'm pretty sure we did it correctly. I suppose I can do it again, and see if that helps with the pedal travel...but the brakes feel strong. My only complaint is that the pedal still feels a little strange, like there's too much travel.

 

All I have are Brembo blank VTEC rotors and Axxis Ultimate brake pads with the Legend calipers

 

Whether ya'll knowtice it or not, there will be more pedal deflection with the Legend calipers. Remember that you have to move twice as many front pots compared to stock.

 

Update: The Legend master cylinder bore is 1".

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by racerx &raquo;</TD></TR><TR><TD CLASS="quote">Whether ya'll knowtice it or not, there will be more pedal deflection with the Legend calipers. Remember that you have to move twice as many front pots compared to stock.</TD></TR></TABLE>

But the pistons are smaller. Its all about the size of the area that the fluid pushes on. The total piston area being pushed on with the legend calipers ( oo ) is comperable or slightly higher than the stock lude ( O ) ones. If all the pistons were the same size I would say the pedal travel would be higher. OO &gt; O