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Changing front pads and bleeding brakes

Discussion in 'Wheels / Suspension / Tires / Brakes' started by adnoh, Jul 29, 2005.

  1. adnoh

    adnoh Senior Member

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    Hey guys,

    I sorta feel that I should know this shit already, but I have to ask just to be shure. I've never actually touched my brakes before.....I've swapped an engine, but left anything to do with brakes and wiring up to my mechanic. So here's my nOObile question:

    I need to swap out my front brake pads (EBC) with new ones (EBC), and bleed the fronts with some high temp brake fluid.

    The Pads are self explainitory, take of caliper, pop out old pads, replace with new ones, but because the new ones have so much more material, how are they going to fit over the rotor? How can I relieve pressure on the caliper if need be to make them fit?

    Second is adding the new brake fluid and bleeding the system. I dont really know how to do this. Also, what sorta fluid should I be running? The only thing I know about this process is when pumping the brakes while bleeding, only to go down 1/2 to 3/4 of the way or shit can get really fucked with the pistons in the caliper.

    If anyone could give me some help, I'd appreciate it. Maybe a tool list....I dunno. I'm out lapping on Monday, and dont want to run a few hot laps, have my brake fluid boil and me sit out for a while, so I gotta get this done in the next few days.

    Thanks guys.
     
  2. EGProject

    EGProject YEEEEAAHHHHH

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    Pads are self-explanitory - yes. You can usually use a C-clamp to compress the caliper enough. Additionally, since you're changing the fluid anyways, you can make it a bit easier by opening the bleed valve (small diam. nut with a nipple on it) and compressing the piston. Once the pads are in (always add a bit of Anti-Sieze to the backs of the pads, and clean the rotors), and lock the caliper in place onto the rotor.

    As for bleeding the brakes, I won't go into crazy detail - but basically start with the wheel furthest from the master cyl. - LHD Civics - RR wheel. and work your way to the wheel closest to it - LF. This is not a one man job, as the amount of air bubbles in the fluid must be judged by somone, and someone must close the bleed valve. Go through the process 2-3 times to make absolutely sure you have all the air out.

    For fluid, I'd recommend Dot-4/5 + fluid, preferably Redline or Motul. Others will do. Plan on buying 3 bottles of it - 2 should do it, but just in case.
    Tools? Well, your basic assortment of hand tools, nothing crazy. A jack is a must, as bleeding the brakes with the car on the ground, and the wheels on is an absolute BITCH. Buy a pizza, get a buddy to help you do it. It's shouldn't take more than an afternoon.

    NOTE: For best results, try to pump ALL the old fluid out before adding any new stuff.

    Hope this helps.
     
  3. asmallsol

    asmallsol Super Moderator

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    No, you can not put dot 5 fluid in a system that has rubber seals, as in every car on the road. Dot5 is made for high end racing braking systems that don't have rubber seals on the calipers, lines, or mastercylinder. Dot 5 eats away at the rubber system extremly quick and should NEVER be used on a normal braking system.

    Dot 3 and 4 however are your normal brake fluids and can be mixed together no problem. IMO, I like to run ATE superblue. They also have a clear (traditonal color) brake fluid with the exact same specs as the Superblue, and I alternate between the two so I get a complete flush.

    As for pumping all the old fluid out, this is HORRIBLE advise. This is for a few reasons. One, your going to be bleeding FOREVER to get all the air out of there. Next, when an air bubble is introduced into a mastercylinder, no matter how much you do a traditonal bleed, that air will never come out. This is because of the angle the master cylinder is at. You need to actually take the master cylinder off the firewall/brake booster and bench bleed it.

    If your brake fluid has never been changed, chances are it looks a little dirty. This makes changeing the brake fluid very easy as, once the fluid starts to come out clean, you know your done with that wheel. Use a clear hose that fits over the nipple on the bleeder screw, then put the other end of the hose in a clear bottle. This way you can see when it comes out clean and you will also see any air bubbles much easier as well.

    as for making the caliper fit over the fresh new pads, use one of the old pads and place it in the caliper. Get the c clamp and put it in the center of the brake pad and the back of the caliper on the other side. Open up the master cylinder cap (to make sure pressure doesn't build up in the system, and also potentally breaking seals on your resivior cap) and then compress the pistons down. You use the brake pad there so that way even pressure is exerted on the piston all the way around it causing it to compress straight. If you don't do it this way, there is a slight chance you will compress the piston crocked, potentially ruining the caliper.
     
  4. adnoh

    adnoh Senior Member

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    Thanks for the help guys.

    I'm a little confused about something though:

    About the brake pads, I originally asked if I would need to DE-compress the caliper to allow more room for the extra thickness of the new pads, so it could fit over the rotor with ease. Will this be necessary at all? It just seems like because the pads I have now are so thin, that by installing new thicker pads, when you go to place the caliper back on the rotor, it wouldnt fit...it would be too snug. Do you think I'll run into this problem?

    The process of bleeding is becoming a little easier to understand. I have purchased some full synthetic DOT4 brake fluid with 520f Dry, and 401f wet ratings. There isn't a drop of the Motul RBF 600 in town anywhere....long weekend, everyone's sold out.

    So the bleeding process as I understand it is:

    -start at rear right (drums on my hatch) and move closer to MC.
    -attach rubber tube to nipple, and other side into clear 2L bottle.
    -slightly open bleeder valve.
    -get assistant to press brake pedal in about 3/4 of the way.
    -brake fluid will start to run through tube and into bottle.
    -stop after a few pumps of the brakes,close valve, and top up brake fluid reservior.
    -continue this process until new fluid has run through the tube, and no bubbles are appearent.
    -move to next side and repeat the process, refilling the fluid reservior as needed.
    -same with fronts, eventually the reservior will be filled only with new fluid.

    Now is this basically it? How much of the fluid can I drain from the reservior from one brake? I know they tell you never to let the reservior go dry, but how much can I excrete from one valve on one brake? Should I balance it out or try to get as much as I can out at once?


    Thanks for anyone's help...It's GREATLY appreciated.....I just want to have a good day lapping. Last time I went, I did two laps, brakes faded and I sat for an hour...two laps, sat for an hour. no fun.
     
  5. asmallsol

    asmallsol Super Moderator

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    nope. This is how you bleed brakes. After you put the tube on the bleeder screw, keep the bleeder valve closed. Either you or your assistant pump the brakes until they turn hard (2-3 pumps) then hold the foot on the brake pedal still appling pressure. The person not pumping then opens the bleeder valve just enough to let fluid out, and the pumper presses the pedal (I have never heard of going more then 75% down is bad. I have bleed many cars brakes, many that have seen road courses pressing all the way down with out any complications.) At this time, your pedal with sink to the floor. This is ok.As soon as the fluid stops flowing, the person controling the valve closes it. The pumper then pumps the brakes again till hard, you hold pressure, then person opens then closes the bleeder valve. Keep repeating this processs.

    When the bleeder valve is open, never let up on the pedal, this is because when you let up, since the system is open, it will just suck up air.

    As for the caliper, yes you will run into this problem, but you are not de-compressing the caliper, you are compressing the piston inside the caliper. Read what I wrote ealier on how to compress the piston.

    After around 10 sets of the bleeding process, actionally check the resivior. To complete flush the old stuff out, you need to bleed until the new fluid has reached the farthest corner wheel(this is why I switch between ATE superblue and ATE Amber). Very easy to tell when . Once it does, go to the next one. Eventually, all you fluid will be changed. Just keep adding fluid into the mastercylinder and never let the level drop below the minimum line
     
  6. adnoh

    adnoh Senior Member

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    Thanks man. Makes sence now.

    What I meant about the 75% pressure is so the piston doesn't get damaged. My mechanic told me that if the piston goes past it's farthest point from too much pressure, when it retracts, there might be a small lip in the line, therefore damaging the piston on retract (causing a loss of pressure in the system). then I would be fucked.

    Thanks again dude. You've been a huge help. I'll let you know how it goes :)
     
  7. asmallsol

    asmallsol Super Moderator

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    well, that may be the case, however, when you bleed your brakes, your brakes are completly assembled minus the wheel on. Yes, the piston is should not go all the way out, but when you bleed your brakes, your piston barely moves at all since the pads and rotors are there to stop them.
     
  8. adnoh

    adnoh Senior Member

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    Not to sound like a dumbass, but could you go over the C-Clamp thing again?

    As I understand it, you put one side of the clamp in the middle of the old pad, and one on the back side of the caliper. You open up the master cylinder cap, and then press down on the brake pedal to create pressure in the lines??? Is that right? I'm guessing after you remove the c-clamp, the caliper will open up more than before to accomodate the new pads? I think I have this whole process TOTALLY wrong....I dunno why but I just dont seem to understand the concept.

    Sorry if that sounds rediculous, and for having you repeat yourself....... I just want to get it right :)

    Thanks again.
     
  9. asmallsol

    asmallsol Super Moderator

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    nope, you don't have to press the pedal at all. Once you have the c-clamp in place(exactly as you described it) and the MCR Cap off, just tighten down the clamp until the piston goes down to the bottom. Its really easy to do actually and not alot of force is needed.
     
  10. adnoh

    adnoh Senior Member

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    Ok....so just the force of the c-clamp being tightened is enough to compress the pistons, and when you release the c-clamp, the caliper will open wider than before to accomodate the new pads so they will fit over the rotor. That makes sense.

    What if the caliper opens up too wide, so when I put it back on the rotor, it's really loose?

    :lol: man, I'm annoying my self here.....I know i ask too many questions......It's really appreciated though :)
     
  11. asmallsol

    asmallsol Super Moderator

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    actually thats not a problem. Once everything is all bolted up, give the brakes a few pumps, and this willl cause the piston to go back into the normal place. The first pump, you may have very little pedal, but it will come back.
     
  12. adnoh

    adnoh Senior Member

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    Thanks very much bro, I owe you one. Maybe I'll bug you some more if I mess up tomorrow :lol:

    jj.

    Ryan.
     
  13. phyregod

    phyregod !!YTINASNI

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    My two cents...

    Go to your local parts store and purchase a brake bleeder/vacuum tester. You will love yourself for it. Autozone has plastic mityvac's for somewhere around $30. I have the same thing but in metal. It is an awesome tool. You can do a full bleed and flush yourself in about 20 minutes. No need for a pedal pusher and a wrench turner. Just be sure to keep the master topped off.

    Also, its worth its weight in gold as a vacuum tester as well. Vacuum testing can tell you an amazing amount of info about the way your motor is running.

    Google Mityvac.

    **EDIT**

    Also, for brake fluid, use DOT 4 NON synthetic.

    Synthetic fluid will cause a spongy pedal feel because it compresses.
     
  14. adnoh

    adnoh Senior Member

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    Ok, so heres the update.

    Found out half way through the install that my front right caliper was seized. Off to crappy tire to get another one. Got home, rebuilt the caliper and set the pads. Bled the entire system...chnged the fluid, ran it throught the lines..no bubbles, bled perfectly.

    My problem.....went to take it for a drive, everything was fine, when all of a sudden, I hear a screeching noise. Said fuck it, went to bed. No lapping for me today :(

    This morning I took off the wheel, flipped up the caliper and looked at the brake pad. The black shim on the outside of the plate had slid down, the clips that hold it to the pad were bent, and the lower part of the shim was grinding against the rotor. what the fuck. So I took out the pad, bent the shim back into place, rebent the clips, and reinstalled it. Took it for a spin...perfect!!!! I pulled into the driveway and Screeccchh!!! FUCK!!!!!! Slid off again.


    So my question: Do I absoulutely NEED that shim on the pad???? My old pads didn't have them at all....any of them. This is the only problem, and the damn thing keeps sliding off and grinding against the rotor.
     
  15. E_SolSi

    E_SolSi Member of the 20 nut club Moderator VIP

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    fuck shims
    i never use them
     
  16. adnoh

    adnoh Senior Member

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    Ok, so the concensus is that the shims are NOT necessary???
     
  17. asmallsol

    asmallsol Super Moderator

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    not super important
     
  18. adnoh

    adnoh Senior Member

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    Ok then.....

    Do you think it'd be worth rplacing the pad, or should I just say fuck it and rip off the shim and be done with it?
     
  19. adnoh

    adnoh Senior Member

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    So I just removed the shim, put everything back together and it felt fine...but there is still some horrid noise coming from that caliper. I duuno guys....I think I'm just going to pack it up and take it to my mechanic tomorrow...I've been troubleshooting this thing for like 8 hours...fed up to say the least.

    Thanks again guys.
     
  20. CiViC_SOHC

    CiViC_SOHC Senior Member

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    did you scratch the sides of the pads down? you can do that to prevent that horrid noise...its called wearing in the brakes...
     
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