volcom4012

Hello Everyone,

I just swapped a JDM B16A SIR II into my EG, I am losing brake pedal pressure randomly but will return after pumping brakes pedal a few times.

E-Brake works when pressure is lost, had no issues with this with the previous D15B8 motor. Brake booster line does not appear to have any leaks. MC does not have any noticeable fluid around seals.

Is is possible air got into the system via the Brake booster hose while it was unplugged?

Thank you in advance

Former User

Bleed the brakes in the proper wheel sequence.

volcom4012

Thanks! I'll give that a try. Wasn't sure if it was possible to get air in the system from the booster line.

mk378

Bleeding may help, but you will probably need to replace the master cylinder. This failure is a coincidence unrelated to swapping the engine.

volcom4012

Ya it's just odd that it would happen at the same time, I daily the car and have never had the slightest issue with the brake system.

First test drive I noticed loss in pedal pressure.

I'll try the bleed first since I have have plenty of extra fluid. I guess worst case scenario I just swap out the MC.

Thanks for the info!

volcom4012

Another odd thing, when I am sitting at idle and apply the brake the idle jumps up to about 1100 rpms

Former User

Check the brake booster check valve and the brake booster for leaks.

volcom4012

Bringing this back from the dead as I am still having problems.

Same issue at this point, it only happens if I make a U-turn oddly enough.

Lines are not pinching anywhere, booster check valve is good, I properly bled brakes.

I am at a loss, i do not lose brake pressure at any other time. Once I pump the brakes after the U-turn there is no issues. Basically at the point where i just re-do the entire system, I have not replaced the booster or MC yet and as I mentioned before there was absolutely no issues prior to swap.

I have followed all steps on https://honda-tech.com/honda-civic-2...oster-3018256/ and had none of the listed symptoms.

Any and all thoughts are welcome

hoopty hopper

i had similar issues booster was fine mc **** out after replacinng calipers/pad/rotor/wheel bearings,still feels weird but the rear wheel cylinders are both blown too alot of guys dont inpect the rear shoes/wheel cylinders/drums but something to look out for.

jdblock

Are your axle nuts torqued properly?

Sounds like pad knock back.

tony_2018

Pad knocks back? I don't see how thats possible unless bleeding was not done. The caliper slightly pushes up against the pads and there is slight drag as well.

jdblock

Guess you've never driven a road course with weak bearings. Bleeding has nothing to do with it, since the fluid is pushed back into the reservoir.

Go through a corner and the leverage from the wheel and rotor pushes the caliper piston back into the caliper. Causes you to pump the brakes to push the piston back out, and make the pad touch the rotor.

Kinda sounds like what he's describing. Right?

volcom4012

Hmm interesting, I will double check that they are torqued correctly. I believe they are but doesn't hurt to check at this point.

Side note: I've taken hard canyon turns which seems to simulate what you mentioned above and have no brake issues. It's not entirely out of the question I suppose.

tony_2018

Rotors are screwed into the hub, wheels are bolted to the hub securing the rotors. Nothing moves but the caliper.

jdblock

And all of that is pressed into the bearing, which is secured by the axle nut. Loose axle nut loose bearing.

Don't believe me? Go take your axle nuts off and drive around. See how long it takes for your wheel to fall off.

tony_2018

Axle nut comes off than the axle will be loose and will cause vibrations.

If what you say holds true than how are 1st gen crv's holding up when they remove their rear dif and axles?

jdblock

You want me to just tell you the answer? Go learn something.

You can keep trying to knock what I'm saying down, but that doesn't make it any less true. You just have to be right. Don't you?

Former User

Don't let this argument escalate any further and derail the thread. Just move on now.

slomofo

iTrader: (1)

Can you tell me the answer?

Former User

jdblock

Since you asked nicely. The rear suspension on a 2wd, uses a spindle, and a spindle nut. Which does the same exact thing as a axle, and axle nut.

<a href=http://yoursmiles.org/t-banana.php><img src=http://yoursmiles.org/tsmile/banana/t0206.gif></a>

volcom4012

As a side note, pads were replaced about a week ago. Issue was present both before and after. Verified axle nuts torqued properly as well.

tony_2018

When you replace the pads, did you replace the rotors? Or at least get them resurfaced?

Did inspect the guide bolts? the ones that hold the caliper to the caliper bracket but allows the caliper to slide back and forth? It probably needs to be greased

slomofo

iTrader: (1)

Is the brake pedal hard as a rock? If no, the booster is fine; forget everything else everyone is saying about the booster, it's fine.

Did you bleed in the proper sequence? Left Rear, Right Front, Right Rear, Left Front is the sequence to bleed.

Do you have rear drum brakes? If so, are they adjusted properly? If no, fix problem, if yes, don't worry about them.

Are there any visible leaks at your rear calipers or wheel cylinders and your front calipers?

Do you have a dial indicator? If so, check for wheel bearing play at all four wheels. If not, check for play anyway and use common sense to determine if they're good or not.

If all else has been completed and problem still persists, remove the master cylinder and inspect for visible leaks at rear of master. Are any leaks present? If no, bench bleed master and reinstall.

If all else has been completed, have somebody else pump the brakes until it pressure is good while you proceed to follow every individual brake line looking for a kink or small puncture.

If all tasks have been performed and problem still persists, then you've done something wrong and need to have a professional look at it.

volcom4012

Rotors are new, forgot to mention that.

Guide bolts had ample grease on them when I inspected.