BlueHorse

I did brake bleeding 5 months ago. I noticed today there is tiny amount of moisture inside the rubber cap on top of the rear brake bleed screws (both of them). See the attached photo. Everywhere else around the area is dry. I have not opened up the hood to check if brake reservoir is low (my guess is not as otherwise the sensor light will be on, right?).

The rubber caps are both front sides are dry.

I cleaned up the moisture, and tightened the rear end screws further (they were pretty tight to start with) before lowering the car.

Questions:
1. Should I be worried about this leak? Surprised this little fluid coming out from a leak.
2. Assuming 2 weeks later I found the rear caps moisturized again, what is failing? I don't know how the screws function, but I guess replacing with two new bleed screws is likely to solve the problem?

Thanks!

Stumpel

If you are referring to the shiny little area way inside the rubber cap, and everything else is totally dry, then I don't think you have anything to worry about. It is likely the last drop left over in the bleeder valve from when the brakes were bled. Use a q tip and see what color the moisture is, it could be water. You could try and tighten the valve a bit more, but be VERY careful not to overtighten. I would clean with q tip and look again in a week or so.

Of course, I am not a mechanic but have done my share of bleeds.

BlueHorse

oh, here is a second photo showing the area is dry when seen with the rubber cap on.

BlueHorse

I saw this moisture when I did the bleeding 5 months ago. Made sure I dried it. Now it is coming back. Used Q-tip this round too, and there is a light color (green or bluish), which I think is consistent with my brake fluid being dark blue. I will check again in 2 weeks.

My concern is whether air may get in due to this tiny leak.

If I over tighten someday, will it damage just the bleed screw, or potentially the caliber may be damaged and in some cases will have to be replaced?

Thanks!

BlueHorse

A few weeks ago, I cleaned up the brake bleed screw caps as well as hand tighten them further. Today took another look and noticed one of the screw cap is completely dry, but the other one still shows tiny trace of brake fluid (very small, like a thin line of 1mm inside the base of the cap). So apparently tightening the screws helped, but still some seeping despite pretty sure both screws are above the recommended torque.

I am wandering:
1. If I should replace the brake bleed screws with new one?
2. In replacing the screws, is it as simple as unscrew them (while fluid will be dripping out by gravity), screw new ones in, and do a fluid bleed?
3. What is the chance that some air has gotten in the system? I changed brake pads (low dust version) and rotors (with drilled holes and slots), so the braking power was less than original OEM configuration, but overall stopping power is still OK.

Thanks!

luigi524td

I think that if fluid can get out - air can get in. Maybe replacing the bleeder screw is a solution.

nairb

After bleeding the caliper and tightening the screws there is still a small bit of fluid in the end of the bleeder. Thats probbably all that you see. If it was dripping or making the caliper wet, then you have a problem. Don't over tighten the bleeder screw. it is steel in an Aluminun caliper and will strip the threads if tightened too much.

BlueHorse

I got two new bleed screws to replace the old two in the rear. I plan to keep the reservoir cap on while unscrew the old bleed screws and then put on the new ones, before doing a brake fluid change.

Is there any special steps I should do? remember someone saying that I may get so much air while swapping the bleed screws that the ABS may have air in it, and it is hard to bleed ABS - is that true?

Thanks!

545IblupasdU

Why are you changing them if theres no leak what you saw was just remnants from the bleeding you did....by taking this further without cause you may create a problem, you are risking making a bigger problem with the ABS..... If it was leaking it would be all over and if air was entering the system youd be feeling the difference in the pedal...if it aint broke dont fix it!

BlueHorse

After two years, no sign of brake fluid loss. I probably will keep drive for another year or two before changing the fluid again. Thanks guys!