Can anyone shed light on this. 

I bled my brakes and 6hrs later witnessed brake fluid dribble from each caliper on the front end of my vehicle. 

 

Is this normal? The reason I ask is because it has not done it since (it's been 36hrs) and I've done some decent driving since then. I've kept a close eye but am struggling to fathom how it may have happened in the first place unless there is indeed a leak at the bleed nipple threads. 

 

The thing is, when you close the bleed valve, there is a solid cone down below the level of the cross drilling in the bleed valve, so that solid cone plugs the open concave point on the calliper, so that works normally.

 

What you might have, is the bore of the bleed valve is full of brake fluid, and that is weeping/creeping up the thread of the calliper<>bleed valve.

 

If I'm being completely honest, I had never witnessed this happening until maybe 6 years ago, so now I spray brake cleaner down into the open end of the closed bleed valve and that ejects most of that fluid and then evaporates, my next plan is to do the job the way that VW Group and maybe others suggest and that is to apply compatible grease to the threads of the opened bleed valve, doing that should stop any trapped fluid creeping up and out of the threads area, AND stop micro bubbles appearing in the bleed tube.  Really a lot of overkill, but seeing as you have asked.

 

I'd prefer if there was no "wetness" around the brake valves especially as I am getting the car MOT'd soon after replacing the brake fluid.

 

Finally, if none of that sounds relevant in your case, just replace all the brake bleed valves, tightening the new ones down to 13Nm fronts if 288mm discs, or 10Nm fronts if 256mm discs, rears are 10Nm - I tend to tighten them down "by feel".

 

Remember once the dust cap has been refitted, which is good, there is only one route left for that trapped fluid especially if the callipers have been heated up by using the brakes.

Edited 11 July, 20223 yr by rum4mo

If in doubt, drop a couple of new bleed nipples in, they cost pennies and it's peace of mind. 

Put a spanner on just to make sure they're nipped up but don't overtighten.  That looks a lot for just residue.  If you have another spanner of the same size try that as spanners do vary in fit and feel.   As already put if in doubt replace with new.

 

I always put a bit if red grease around the nipple threads after loosening to act as an air and muck barrier.

 

and the final fix was?