Potential leaky bleeder screw?

[JHZR2]

This is the six piston Brembo caliper on my 135i. Was under to do the brake fluid flush per the schedule, and noticed that there was some dampness around the threads, and the powder coat paint is slightly damaged.

Did the bleed, and noted that while the bleeder screw would get tight, it felt like I could always give it the same torque another time, and it would turn another partial (like talking a degree or three). My concern is that these are likely aluminum calipers, and so it is highly possible that they are soft.

The car hasn’t lost enough fluid in the last two years to be noticeable in the reservoir. You can see the rest of the body is dry. But I’m concerned that once this starts, the threads just keep failing (and that’s assuming the threads are somehow damaged, I don’t know that absolutely).

Any experience with bad bleeder screw threads? Any recommendations for how to proceed?

 

[clinebarger]

Use a torque wrench (Preferably a Electronic or Dial type) & see if the bleed screw continues to rotate/creep at/near the the specified torque value.

I service many GM vehicles with OE Brembo calipers.....Never have any issues with the bleed screws. I guess you could simply back the bleeder out a few rounds & wiggle it....Should fit pretty good in the threads.

 

[samven]

Yea, dont over tighten them, that could be expensive. Normally when I am bleeding even under pedal pressure the flow shuts down even before I get them completely closed. If they are snug, start the car and have someone stand on the brake pedal while you watch the bleeder. Wipe them off good with tissue until you dont see any sign of dampness and then again after the test. Tissues are great for finding a leak that sometimes you cant see. It could be that it was never cleaned well the last time someone was under there. I would be more concerned about water getting in than fluid getting out but if you have not noticed the pedal getting soft as the brakes get hot its probably fine.

 

[AutoMechanic]

I’ve never seen an aluminum caliper. I’m sure they can be out there though. I know they make thread repair kits for calipers. That might be something too look into. Is their anything on the threads? I know sometimes if I’m using something on threads it can feel like it needs to turn more and more.

 

[clinebarger]

I’ve never seen an aluminum caliper. I’m sure they can be out there though.

Countless vehicles use aluminum brake calipers.

 

[Snagglefoot]

I would recommend you go on with your bleed. After you get fresh fluid, stop and close it. The thing about most bleeder screws is they are a metal to metal seat. They will screw-in fine but suddenly come to a stop. You still have to give it a good partial turn the make sure it is snugged down. ( but without stripping any threads.). I’ll bet that screw is good, just not tight enough.

 

[JHZR2]

I would recommend you go on with your bleed. After you get fresh fluid, stop and close it. The thing about most bleeder screws is they are a metal to metal seat. They will screw-in fine but suddenly come to a stop. You still have to give it a good partial turn the make sure it is snugged down. ( but without stripping any threads.). I’ll bet that screw is good, just not tight enough.

I did. Will be monitoring it. Frankly the fluid that came out looked only barely darker than the ATE fluid I put in. Probably wasn’t necessary for a 10 month car during COVID. But it’s done

 

[Donald]

I never understood the need for more than 2 pistons.

 

[JHZR2]

I never understood the need for more than 2 pistons.

I never understood the need for more than 67hp in a passenger vehicle either... yet here we are and some cars have it...

 

[4WD]

I never understood the need for more than 67hp in a passenger vehicle either... yet here we are and some cars have it...

Well, uh, that’s exactly what my 5.3L makes per L… way below twisty little I4T’s

 

[wolfox03SS]

Comments not withstanding... And as other, more than likely much more brilliant minds have stated:

Get up in there with blue shop towels and a can of brake kleen. Blast,wipe, blast some more, wipe some more... blast again. If you think it's clean, do it another 3x.

Fire it up so you have full brake boost assist and poosh,poosh,push again. Look for any seeps and leakage.

Run her.

Run her like a stolen Hooptie.

Beat her like a rental mule.

Come back home. Inspect again. Also check and top off certified brake fluid for your application. No leaks? Great. No fluid drop, even better. No serious weeps, drops or seeps?

Faggeddaboughddit.

 

[KrisZ]

This would concern me. Did you remove the bleeder entirely to see how the threads look like or if they are clean?
I just took a closeup screen shot and the finish damage done by the brake fluid is quite clear.

 

[wolfox03SS]

This would concern me. Did you remove the bleeder entirely to see how the threads look like or if they are clean?
I just took a closeup screen shot and the finish damage done by the brake fluid is quite clear.

Brake fluid is extremely aggressive on painted surfaces. Likely that is just paint checking from a previous service where it was not cleaned from his coated calipers and left to just etch away...

Thus I recommend a brake kleen and blue towel treatment...brake exercise, full bore crazy street and highway run and inspect. If it's showing a leak after that, tweak them snug, but not gorilla tight. If it stops, great!

If it still seeps, okay, maybe a valve replacement. If stripped and a new bleeder doesn't fix it, yeah. Caliper with hardware kit might be the order of the day.