braking difference from drum and disc

[jspec civic]

hi guys,

did a rear disc conversion on the week end onto my eg sedan.
Comparing the braking difference from drum to disc are there any big difference.

Why do brake padal feels soft when i stop. I mean when i step on the pedal did doesnt feel hard and doesnt react as quick.

help please!!

[90LAN]

did u bleed the brakes
and adjust the hand brake cables?

[jspec civic]

yeah i bleed all the brakes till theres no bubble and the handbrake is connected. my brake booster looks find (no leaks)

[Sir_vtec]

how do u know that theres no air bubbles?

While you were bleeding did u depress the brake pedal then open nipple?

To make sure u had no air bubbles, depress brake pedal open nipple then close nipple release pedal then depress pedal and repeat.

P.s did u even upgrade the Brake booster and mc???

[vinnY]

got the right prop valve for the rear disc conversion?

[SINISTR]

^^^ thats what i was just going to ask...

[jspec civic]

how do u know that theres no air bubbles?

While you were bleeding did u depress the brake pedal then open nipple?

To make sure u had no air bubbles, depress brake pedal open nipple then close nipple release pedal then depress pedal and repeat.

P.s did u even upgrade the Brake booster and mc???
im sure i did...if i dont feel safe i might bleed the brakes again

i got the whole arms stuff..prop valve?

[g.ta]

try this,
while engine is off pump the brake pedal several time, if it goes hard then theres no air in the brakes, if it is still soft then u hadnt bled the brakes properly.

[SINISTR]

proportioning valve

it allows the correct pressure of fluid to be pumped to the back - without it thats why your brakes seem like they aren't working.

[riruiz_88]

this is what a proportional valve looks like...
http://i6.photobucket.com/albums/y249/ryandaily/1b955058.jpg

i spreads the pressurised brake fluid, and proportions it to the calipers. would be a good idea changing this from a honda with a bigger brake package eg. DC2. make sure that there are no leaks/cracks in the lines as well while your lookin for problem.

[SeverAMV]

if you want better pedal feel, get a 15/16 master cylinder. factory 13/16 is good enough for drum brakes, but fairly spongy if you just swapped to disc brakes.
(assuming you didnt upgrade your master cylinder since you only said you had the arm stuff)

[jspec civic]

The brake is hard when engine is off…

Is the master cylinder from the ek1 (with rear disc) and eg sedan (drum brake) are the same size?

Does any one with standard front and rear disc have have the same feel on the pedal?

To conlude this I would need to upgrade the master boost and cylinder right?

[mr180sx]

The brake is hard when engine is off…

Is the master cylinder from the ek1 (with rear disc) and eg sedan (drum brake) are the same size?

Does any one with standard front and rear disc have have the same feel on the pedal?

To conlude this I would need to upgrade the master boost and cylinder right?

So did you change your prop valve? If not, there lies your problem

[Limbo]

Upgrading the master brake cyliner will improve breaking but will not fix the prob if you have a prop. brake issue

[jspec civic]

no i didnt change the pro value..what does it do?

[Zdster]

no i didnt change the pro value..what does it do?

Change it!

A PV determines the pressure going to each line and distributes it appropriatly. The one that you have at the moment is set up for drums and is different to a disc setup.
http://auto.howstuffworks.com/master-brake2.htm

[jspec civic]

do i just need the PV no lines etc as shown on the pics perviously.

[JasonGilholme]

the PV will connect up with what is currently there.

You should also look at geting the master cylinder and brake booster from a car with rear discs.

Theres more to a drum brake setup then the drums themselves.

[jspec civic]

thanks for the info guys..will get a pv from wreckers and hook it up..see how we go..

[Killa From Manila]

i did a rear disc conversion and didnt change prop valve or master cylinder..brakes feel bit spongey after bleeding it heaps so yea i got the same prob as u. been meaning to change prop valve n mc 4 a long time but just too lazy :P

[vinnY]

safety>lazy
fix it mate ;)

[jspec civic]

after bleeding brakes, can fluid be reuse?

[vinnY]

shouldn't be reused, toss it out

[Killa From Manila]

haha trust me its safe..its only a little bit softer than b4

[markoJEK1]

more importantly, if the gear has been sitting outside for a while and has surface rust on there, you should have got the discs machined and put new pads on, that woulda increased bite instantly. But if they were ok and they are feeling spongy, go with the above responses.

Ps I did 5 stud upgrade not long ago, first 2 days brakes were feeling spongy, and yes I did upgrade everything, master cylinder, booster, prop valve, and I prepped the discs and had new pads, few days into it, they started wearing in again, now they're perfect.

[jspec civic]

The disc where ok..got the conversion while the wheels are still on the car sitting in the garage, just had the normal rust. I will the above asap

[riruiz_88]

make sure you get your self a set of flare nut wrenches if you gonna change your prop valve. using normal wrenches will MOST likely round the brake line fittings at the prop valve. and you will have brake fluid coming out so leave a rag to reduce amount of fluid getting in your bay

[nd55]

Here is some proportioning valve info I've cut & pasted from elsewhere.
AFAIK Honda still used the prop. valve naming convention till recently.


1725 valve (88-91 CRX with rear drums)
2040 valve (90-91 CRX Si) - used with 9.5" front brakes matched with rear discs.
3030 - 9.5"(small) - rear drum
3040 valve (91 EF hatch) - used with 9.5" front brakes and rear discs
4040 valve (90-93 Integra) - used with 10.3" front brakes matched with rear discs.
3540 valve (90-91 Civic Ex) - used with 10.3" front brakes matched with rear drums.


> P.s did u even upgrade the Brake booster and mc

I thought that was only important for larger front brake caliper upgrades.


> Is the master cylinder from the ek1 (with rear disc) and eg sedan (drum brake) are the same size?
> To conlude this I would need to upgrade the master boost and cylinder right?

The master cylinder has a casting stamp/mark on it's body (middle, drivers side .. maybe) indicating the size.
It'll be something like "13/16", "15/16" or "1".

I don't think the MC is the problem.


> no i didnt change the pro value..what does it do?

1) front and rear brakes do not do the same amount of work on a motor vehicle.
2) A rear brake lockup is dangerous, because the car can swing around.
3) Brake calipers/drums have different sized actuating pistons. The size of the acuating piston determines how much force is delivered to the brake pad/shoe.


For these reasons a P.V. is used to change the pressure delivered to the front and rear brakes.
ie. Front brakes get more pressure than rear ones.

Drum brakes need more fluid than rear brakes to move the larger bits, but less pressure because the drum mechanism is "self energizing".
Different combinations of disk brakes change the front/rear balance of the brakes.

This is why there are so many different tyupes of P.V.'s.


Also, for safety, brakes are split into two different circuits. If one fails the other can still pull up the car.
On a fwd its usally
circuit 1) front left & rear right.
circuit 2) front right & rear left.

Honda P.V's are dual circuits in the one body.


Nick.

[Sp00ny]

Best bet and cheapest way to eliminate the possibility of air in the system, is to go to your local Repco store and purchase a "One Man Brake Bleeder Kit" they work a treat and really make it easier if you're unable to have another spare set of hands (or feet) at the time.

Even if you do have another person...these kits speed up the bleeding process greatly. Instead of pumping and opening etc: Fill up the bleeding kit ensure its fully primed with fluid in the reservoir and lines then open the valve and pump the brakes until the reservoir is full and repeat if necessary.

The only "con" of these systems I could see is you would consume more brake fluid. That is; if you're like me and don't like re-using brake fluid ( at all) then you would.

A spongy pedal without air in the system is most likely a faulty master cylinder. It could also be your current master cylinder doesn't have the capacity or pressure to work properly with the added pressure of new rear calipers.

As mentioned above ^^ ensure you follow proper brake bleeding procedure and wheel order as stated in your service manual or product instructions. Otherwise all this could be useless.

Good Luck.

[markoJEK1]

dont need 2 people to bleed a car, or a 'kit' from a store. Get a bottle, take lid off, get some rubber hose, crack the nipple open and let it drip into the bottle, let it go through half the resvoir for each caliper. There is no chance you can get air in the line using this method unless you run the resvoir dry :P , simply close the nipple before taking the hose off, the hose acts seal in a way, it doesnt allow the nipple to take air back in as you are tightening it.

[jspec civic]

changing the pv is it a DIY job and how difficult is it..

[markoJEK1]

simple diy job, as mentioned, get a flare nut spanner / or flange nut how ever you want to call it, you will undoubtly round off the lines that go into the PV with a normal spanner. once youve done that its as easy as alinging the lines back into the new PV and tightening them up, some might be a little hesitant to start catching the thread in the PV because of the angle they sit on, dont be scared to give them a touch of force to get them sitting right

[riruiz_88]

take note that when your attaching the brake lines back onto Prop Valve, make sure you dont re-thread the threads in the Prop Valve. if it feels like its taking extra amount of force to tighten, then stop and start again. what i did was, seat the brake line in the Prop Valve. then turn it like you want to loosen it, then when you can feel a little click then your right to tighten it.
i tried to put this as best as i could, not sure if i made sense to you.

[jdm_b16a]

When you convert from rear drums to rear disks you need:

A larger brake booster (and accompanying master cylinder)
The proportioning valve that goes with it.

Without these two things you are wasting your time trying to bleed the system for better performance.

Your original pv distributes brake fluid differently (pressure and volume) than the disc/disc combo. That's why you need the new pv.

Get the brake booster, master cylinder and 4040 proportioning valve off a DA Integra and install these. That is what I have done. I have front brake setup, rear disc conversion and all the above from a DA Integra.

http://i148.photobucket.com/albums/s40/infotechplus/EFHonda/IMG_0139.jpg

http://i148.photobucket.com/albums/s40/infotechplus/EFHonda/IMG_0126.jpg

http://i148.photobucket.com/albums/s40/infotechplus/EFHonda/IMG_0224-1.jpg

http://i148.photobucket.com/albums/s40/infotechplus/EFHonda/IMG_0233.jpg

http://i148.photobucket.com/albums/s40/infotechplus/EFHonda/IMG_0244.jpg

Also, as an afterthought, make sure you have the calipers around the right way, the bleed valve should be on top.

Peter

[riruiz_88]

thats a weird ass position for a prop valve haha. but awsome picks man, i bet it stops much harder than before

[jdm_b16a]

thats a weird ass position for a prop valve haha. but awsome picks man, i bet it stops much harder than before

Original mounting position and original ED brake lines. Only difference is the PV. :thumbsup:

Peter