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View Full Version : Brake booster + Mater cylinder upgrade Question



Limbo
28-06-2007, 03:27 PM
Hi guys noted that alot of guys upgraded their civic brake boosters & master brake cylinder with ITR brake boosters & master brake cylinder.

I've been told that it is possible to use Prelude brake boosters & master brake cylinder also as an upgrade, can anyone confirm?

ALso would my ek4 be able to use a BB4 Prelude brake booster & master brake cylinder or do i need a different one?

ECU-MAN
28-06-2007, 05:31 PM
the master cylinder you retrofit must be an abs master cylinder, prefibly from the same type of abs

BB4 is ABSII EK4 is ABSIII ( low pressure )

fatboyz39
28-06-2007, 09:16 PM
We use prelude master cylinder and booster. Try using the bb6 ones, there the same size as ITR.

One of the best mods to be done for the brakes.

Limbo
28-06-2007, 10:20 PM
cool thanks i was thinking that it was one of the prelude ones that worked.

ECU-Man can you confirm that the bb6 one is also ABSIII also?

ECU-MAN
28-06-2007, 10:57 PM
yes BB6 has the same type low pressure ABS system as the EK, EM, EJ ect

barefootbonzai
29-06-2007, 10:00 AM
you drive an ek4 right? the brake booster & master cylinder is already up to spec, there's no need to change it.

Zdster
29-06-2007, 11:06 AM
you drive an ek4 right? the brake booster & master cylinder is already up to spec, there's no need to change it.

What are they, 15/16th's?

fatboyz39
29-06-2007, 06:41 PM
you drive an ek4 right? the brake booster & master cylinder is already up to spec, there's no need to change it.

Fitting a larger one won't hurt ;). We just fitted a prelude brake booster/ master cylinder into a EJ8 coupe (same size booster/master cylinder as ek4) and there was a big increase in braking capacity.

CTR Coupe
29-06-2007, 07:06 PM
kinda a noobie question but why does this increase breaking?

wouldn't this just shorten the distance you can push the pedal rather than actually increasing the breaking ability of the car?
ie the car is still going to travel x distance to stop with or without this mod?

I would think you would only "need" this upgrade if you needed to move larger/more brake pistons or upgrading to rear disks (for cars fitted with drums).

I just can't get how the concept of moving more fluid decreases stopping distance.

barefootbonzai
29-06-2007, 08:13 PM
Fitting a larger one won't hurt ;). We just fitted a prelude brake booster/ master cylinder into a EJ8 coupe (same size booster/master cylinder as ek4) and there was a big increase in braking capacity.

in the case of the ek4, how would swaping in exactly the same items increase anything :p

fatboyz39
29-06-2007, 09:33 PM
Ek4 15/16 ...ITR 1'.

barefootbonzai
29-06-2007, 10:19 PM
don't preludes come with 15/16. Anyways, not worth the upgrade in imo, if you already got 15/16.

EG5
29-06-2007, 11:30 PM
also dc5r is 15/16 too

Can be fitted to EK/EG/DC2

fatboyz39
29-06-2007, 11:42 PM
BB6 prelude comes with 1' master cylinder.

BlitZ
30-06-2007, 12:21 AM
I had ek4 brake booster and MC... braking was awesome on std.

Upgrade to ITR disc and clipers and used std ek4 brake booster and MC -street was excellent.. on the track it was crap.. worst than stock.

Upgraded to ITR brake boost, mc running ITR disc and clipers - life was sweet.

however on track the braking creed was more progressive, but wasnt that much better

muhhan
07-07-2007, 01:03 AM
What's the go on using a brake booster and master cylinder from a car that has ABS on a car that does not have ABS? I'm particularly thinking in the case of upgrading the drums to discs on my ek1 and also changing the brake booster and master cylinder from a ek4. I guess the brake booster and master cylinder donor car would depend on what the wrecker has in stock.

Topendwarrior
13-07-2007, 12:34 PM
if i'm not wrong, 15/16 is the master cylinder bore size.
as i have already been through this mod, i can confirm that EK and BB has the same bore size, so it is not worth while doing.

TonySo
16-07-2007, 08:44 PM
Ok I have just done the rear disc brake conversion for my civic, picked it up tonight from the workshop. Work done: Rear disc brake conversion, vtir master cylinder & booster.

Jumped in the car, accelerate up to 40km/h and stepped on the brake. First impression was "WTF there is no brake?"

Then step the pedal all the way down and the car slow down and stopped eventually. Did a few u turns and keep repeating and realize I have to step the pedal almost all the way down to the bottom to apply the brakes.

What I used to have is completely the opposite, I tap on the pedal and I can feel the brake is working and I can adjust how much and how quickly I want to stop by adjusting how much I push the pedal down.

While at the moment, I tap the pedal, brake lights come on but it's not slowing down, I push the bottom almost down to the bottom, it starts to slow down, and if i push it all the way, it gives me about the same braking power as before the conversion. Instead of an instant stand still as I expected.

Is this what it should be? Or I should bring it back to workshop for them to have a look again. They said they have bleeded the brake 3 times to make sure no air bubble is in the system, but they are happy to do it again if I am not happy/satisfied.

Your thoughts?

bennjamin
16-07-2007, 09:06 PM
did you change the brake proportioner too ? (located on the firewall)
Did you properly flush teh brakes ?

Do both of the above , retest brakes and let us know if it helps

fatboyz39
16-07-2007, 09:27 PM
bring it back to them. Doesn't sound good at alll.

TonySo
17-07-2007, 05:28 AM
did you change the brake proportioner too ? (located on the firewall)


Umm... I don't think the brake proportioner has been changed.

How much $ will that cost?

bennjamin
17-07-2007, 06:11 PM
you probably should since you have replaced your rear drums with discs

Ive seen 2nd hand proportioner's for about $50 in the for sale section look it up

TonySo
17-07-2007, 06:19 PM
thx for the info.

Btw, what can be done to make the brake firmer.

Is it as easy as adjusting the handbrake like what you do/get in a standard service? Or is it a lot more involved?

bennjamin
17-07-2007, 06:21 PM
you can adjust the position slightly so it "feels" firmer (since it engages alittle easier) or you can get a brake master cylinder brace. (prevents firewall flex under heavy braking.

OR even get better pads

TonySo
18-07-2007, 10:36 AM
Just spoken to the mechanic and he said he has been thinking about the issue as well and recommended me to take the car back and he will put on a smaller master cylinder to see if it helps.

His reason being my front brake disc is not as big as a VtiR, therefore a smaller master cyliner will have a better result than the one he put in.

Does that sounds right? Or the general rule is the bigger the better?

Dylanamus
21-07-2007, 11:16 AM
Well I just recently fixed the same symptom (pedal sagging to the ground and only last inch of movement assisted braking). And it had nothing to do with the master cylinder. It was a leaking proportioning valve. Got one for $30.

Some good advice is get a mate to pump the pedal (engine off) while you inspect the following for leaking: master cylinder to booster connection, all brake line nipples from master cyl to proportioning valve and the mid seal between the upper and lower sections of the proportioning valve.

Also whipe down all the brake lines at each wheel so you can monitor for leaking after brakes have been pumped.

If nothing appears to be leaking, bleed the system throroughly in the sequence furthest from MC to closest ie Rear passenger, Rear Driver, Front Passenger, Front Driver. I'd repeat the sequence at least twice.

Once all the air is bled from the system, if there aren't any leaks, the pedal should be really stiff and your problem should be solved.

beeza
21-07-2007, 12:20 PM
thx for the info.

Btw, what can be done to make the brake firmer.

Is it as easy as adjusting the handbrake like what you do/get in a standard service? Or is it a lot more involved?


you can adjust the position slightly so it "feels" firmer (since it engages alittle easier) or you can get a brake master cylinder brace. (prevents firewall flex under heavy braking.

OR even get better pads

Cusco Brake Stoppers FTW!!!
http://www.ozhonda.com/forum/showthread.php?t=69104

gambate
16-03-2008, 09:29 PM
What's the go on using a brake booster and master cylinder from a car that has ABS on a car that does not have ABS?

anyone? dc2 without ABS can use dc2r MC that has ABS?

EG5
16-03-2008, 10:03 PM
anyone? dc2 without ABS can use dc2r MC that has ABS?

Yes you can .

JohnL
16-03-2008, 10:27 PM
Ek4 15/16 ...ITR 1'.

For X force exerted at pedal pad a 15/16" MC bore = more hydraulic pressure, harder application of brakes, longer pedal travel. The pedal will require less force for X braking affect, but move more.

For X force exerted at pedal pad a 1" MC bore = less hydraulic pressure, softer application of brakes, shorter pedal travel. The pedal will require more force for X braking affect, but move less.

JohnL
16-03-2008, 11:08 PM
Ok I have just done the rear disc brake conversion for my civic, ........

..........Your thoughts?


My thought (i.e. best guess) is that the piston area of the rear calipers may be significantly larger than the piston area in the drum brake cylinders, and the MC bore may be too small to move enough fluid to push the rear pistons / pads out far enough, so you are getting a long pedal (?).

Theoretically any such affect ought to be minimal since disc brakes are supposed to keep the pads in light rubbing contact with the disc, but in reality due to disc runout, slight lateral bearing play and the piston seals causing slight piston retraction the pads will develop at least a slight pad to disc clearance that needs to be taken up by some degree of initial movement at the MC piston. If the MC cylinder is too small then the pedal will have to move too far before the pads engage the discs.

Also, all else being equal a disc brake of X diameter is not as strong as a drum brake of X diameter, so you may be getting less braking performace at the rear with the rear disc conversion. Disc brakes resist fade far better than drum brakes, but as stated don't produce as strong a braking affect as drum brakes (before fade sets in that is).

This is because all the drums braking friction is generated at a greater distance from the hub centre than is the case with a disc, where some friction is generated at the outside of the disc, but some much closer to the hub centre. This adversely affects how much leverage the friction has to produce a braking affect at the contact patches.

Also, discs have no 'self energising' affect at the pads, whereas drums do. A self energising affect causes the brake shoe to be forced into harder contact with the drum than would occur only from the force being applied by the piston to push it against the drum, i.e. a drum brake shoe with a 'leading edge' is forced into harder contact with the drum by the rotation of the drum.

Some drum brakes have one 'leading shoe' and one 'trailing shoe' and some self energising affect from the leading shoe only, some have two leading shoes and have more self energising affect from both shoes. This is why drum braked cars typically don't require a brake booster and nearly all disc braked cars do require a brake booster.

If the donor car has a different proportioning valve to your car then I think you're going to need that, but also I'd be checking the relative MC sizes between your car and the brake donor. While I was at it I'd also check the sizes of the pistons in the front calipers between your car and the donor, or you might still end up with unbalanced braking affect (assuming your car and the donor have different sized front caliper pistons).

beeza
17-03-2008, 09:42 AM
John knows his shit!

Limbo
18-03-2008, 08:45 PM
you guys know how old this thread is?????

beeza
19-03-2008, 10:08 AM
Haha,yeah :)