Teflon tape on bleeder screw

[MaximaGuy]

I have a small leak from the bleeder screw even though I replaced the bleeder screw. I am suspecting the # of times I have bled over the years the seal between the bleeder and caliper has started a small leak. Is teflon tape on the bleeder a safe option.

I have read up that it is safe on cast iron.

 

[FL_Rob]

The smallest amount(very thin wrap) might be ok,of course you know the proper thing is a retap on the threads,and I would never condone driving with a leaky caliper,but if it works it bought you some time,.but does brake fluid eat up teflon tape ,I wonder?

 

[SLCraig]

In my opinion, you have nothing to lose by trying it...

 

[T-Bone]

Maxima,

The sealing surface is not the threads of your bleeder screw, it's on a seat down inside. Thus, Teflon taping the threads will only slow the leak.

Your best bet to fix it is to disassemble, inspect the sealing seat in the caliper and on the screw, clean/repair, and go. Good luck.

 

[labman]

I doubt it will help, but the brake fluid won't hurt the Teflon.

 

[Trav]

Maybe removing the bleeder and spray some brake cleaner down the hole to wash out anything that maybe on the seat will help.
A little teflon tape wont do any harm one way or another.

 

[Eddie]

T-bone has it correct as it is the bleeder seat that is not sealing. I would first remove the screw and flush the seat. Then I would use some NON-locking permatex on the screw threads. A little dab will do yah.

 

[bepperb]

"The sealing surface is not the threads of your bleeder screw, it's on a seat down inside."

I'd agree with this, but I'd still try the teflon tape, even if it was just a short (year or two) solution until I could replace the entire caliper. I think in the end that would be the solution for me, on a car with any value at least.

 

[Torino]

Yes, T-bone has it right. John--Las Vegas.

 

[Kestas]

The bottom of the bleeder screw is tapered at a certain angle, and like T-bone said, that's your sealing point. I'd inspect that part of the bleeder screw and perhaps briefly run a drill bit (with a similar angle) on the mating seat of the caliper. That may clear out the problem.

 

[Zedhed]

Put a little copper grease on the end of the bleeder screw and tighten as much as you dare. The copper grease will allow the tapered end to mate metal to metal better and may re-create a proper seal. You could also try very fine lapping compound, but I wouldn't want to get any of that into the caliper as it is gritty and could damage the caliper piston.

 

[mechtech2]

Tape is not a good fix.
Why?
The bleeder has a big hole in the middle.

If the end is not seating properly, the fluid goes up the middle, along with any on the threads.

 

[MaximaGuy]

I have decided to replace the caliper altogether. I have gotten 180K of the leaking one, it has served well.

I got a remanufactured one from local parts dealer ($65 with a $15 refund on the core).

I have been reading up on the web where some folks document replacing both calipers at the same time. Folks chime in...

 

[Zedhed]

Both, brakes are too important to not be matched.

 

[wiswind]

I don't know that it would work for sealing to keep the fluid from leaking OUT.....
I HAVE used it to seal the threads to keep air from leaking IN through the threads while using a vaccum pump to bleed my brakes.....although I found that a 1 man bleeder is even easier.

As Mechtech2 said.....the fluid runs from the seat up through the middle.
I am thinking that the seat must be damaged somehow.....corrosion (yes it is possible) or some bit of metal that got in there when the bleeder screw was tightened.

If you are replacing the caliper......I would replace both sides......if the vehicle is old....you might even consider replacing the hose that goes from the caliper to the hard line......as they are not that expensive.
The hoses on my '96 windstar looked great on the outside.....but seemed to be restricted on the inside somehow.......and replacing those hoses with the standard Raybesots ones from Rockauto made a MAJOR improvement in the braking performance for me.

 

[willix]

This is why you use the rubber cap on the bleeder to seal the nipple orfice.

 

[mechtech2]

When you are vacuum bleeding, any leakage past the threads is not relevant.
Who cares?

The listed vacuum is still the listed vacuum that is applied to the fluid system.
Close the bleeder while the vacuum is still applied - this is proper practice no matter what.

Leave the tape off of the threads.

 

[wiswind]

You know......looking back....that is what I thought.....cap off of master cylinder.......master cylinder full.....but kept getting bubbles out the mightyvac hose until I closed the bleeder screw....with vaccum applied.
Ended up with spongy pedal, happened several times.
Teflon tape solved the issue.......BUT.....from when I got the vehicle in 1999 (a '96 windstar)I was major disappointed with the braking....UNTIL, last summer, I replaced the flexible hoses that go from each front caliper to the hard line.
I had read that they are prone to break down inside....even though they look great on the outside.
I used the standard OEM style replacement hoses made by Rabestos.
That REALLY improved the braking.
So....I am thinking that the hose must have restricted the flow of fluid enough for a air bubble to be drawn into the caliper......doesn't take much.

 

[onion]

Yes, you will want to replace the calipers as a pair. With one caliper moving more freely than the other, one will end up taking more load then the other... and consequently heat up more. Might not sound like a big deal and you might not even notice a pull when braking, but it will cause the pads to wear unevenly and can make the side with the new caliper get MUCH hotter. I speak from experience.

 

[labman]

One new and one old caliper would only be a problem if the old wasn't working properly. I usually rebuild/replace routinely before they get old enough to have problems. The rubber boots and seals don't last forever.