[Motozen]

If I only crack the nipple, then hardly any fluid comes out, if I crack it more, then fluid seeps out from around the threads. Someone suggested putting a few wraps of yellow teflon tape on the top threads of the bleed nipples. Anyone tried this or have any thoughts/advice?

 

[shorton]

Maybe use liquid pipe sealer. Here's the instructions from the speedbleeder website FWIW:

Thread Sealant is Available. The thread sealant is available in 1/2 oz. bottles so that you can replace the sealant that has worn off over time. It comes in a plastic bottle with a brush cap applicator. It is available for $10.00 and can be used in many other situations where a quality pre-applied pipe sealant is required. A little goes a long way. The recommended procedure for applying is as follows:

Clean the Speed Bleeder with soapy water to remove any brake fluid or grease and dry. A hair dryer does this nicely. With the brush cap applicator apply a small amount of thread sealant evenly to the threaded portion of the bleeder screw. (Leave the first 1 1/2 threads uncoated. This makes it easy to start threading into the wheel cylinder or caliper without cross threading.) After it is applied, dry with a hair dryer on high setting for about 1 minute. When cool and dry it is ready for installation.

 

[Slowdive]

Teflon grease on the threads work ok. I've done that.

 

[Motozen]

Great idea, I even have a bottle of this stuff from my old speed bleeders. I wonder if any brake fluid will leak out when I remove the bleed nipple to apply and cure this stuff?

 

[shorton]

Great idea, I even have a bottle of this stuff from my old speed bleeders. I wonder if any brake fluid will leak out when I remove the bleed nipple to apply and cure this stuff?

Not usually much. But I'd be prepared with a spare to "plug" it in case. I've also read in other threads where people used grease like Slowdive suggested. I think a thick grease may work OK for seal, just not sure how it will be for long term loosening.

 

[shorton]

In my case I use a vaccum bleeder so my issue is stopping air form going into the threads and back out while bleeding. Makes it hard to tell what's going on.

 

[Stillrollinalong]

If I only crack the nipple, then hardly any fluid comes out, if I crack it more, then fluid seeps out from around the threads. Someone suggested putting a few wraps of yellow teflon tape on the top threads of the bleed nipples. Anyone tried this or have any thoughts/advice?

Never ever use thread tape on a bleed nipple.
Do you have bleed nipples with internal check valves? At the first crack these will need some pressure to push the spring back and open the bleeder.
If it is a standard type bleed nipple and only flows passed the thread there is something wrong in the nipple or the seat. Remove and inspect the seat and the base of the nipple and check that it is not blocked. The seal is at the taper and seat not on the thread.

If you are relying on a sealer on the thread to seal a bleed nipple you have a failure iminent. A lubricant on the thread to stop corrosion or pick up is good maintenance.

 

[Tamworth]

Absolutely no tefelon tape or thread sealer on the bleed nipple threads. Brake fluid will react with these products. Tape can keep the nipple from seating properly and hinder your ability to feel how much you're tightening it. As Stillrolling says, something is blocking the nipple.

 

[Strega]

Absolutely no tefelon (sic) tape ... on the bleed nipple threads. Brake fluid will react with these products.

No, Teflon (PTFE) seals are highly compatible with brake fluid.

https://www.efunda.com/designstandards/oring/oring_chemical.cfm?SM=none&SC=Brake%20Fluid

Replace the bleeder bolt if the male threads are worn or damaged. If the female threads are damaged, the Teflon tape can help reduce fluid leakage during bleeding.

 

[duc96cr]

I’ve used Teflon tape on nipples with a vacuum bleeder for many years on both bikes and cars and I’ve never had an issue. I have never seen the Teflon tape react with any type of brake fluid , DOT 3, 4, or 5. What kind of reaction were you thinking might happen ? It doesn’t dissolve or soften. I’ve not had good luck when using liquid sealers with brake fluid. Air forces itself past and brake fluid dissolves some of them. You have to use something or you’ll never know when you’ve gotten all the air out. I saw some bleeders with a coating on them that looked promising, but I don’t remember where. Supposedly kept them from seizing, but it might help seal during bleeding too.

 

[Motozen]

I have used the grey liquid sealer that are sold by the mfg of speed bleeders for many years on many bikes. I do not have speed bleeders on this bike. If this sealant was going to react with brake fluid, I don't believe they would sell it specifically for the threads on speed bleeders. And it seals the threads well enough that enough pressure can be applied to depress the spring and open the ball valve, and fluid does not leak around the threads.
Also, yellow teflon tape is specifically made not to react with gas, propane, etc, etc...you can read the label. There is a chance that if one used too much tape and too far down on the threads that small pieces could tear and be introduced into the system, but caution in application would prevent this.
On the front brakes, is there enough gravity that when removing the bleeder on the caliper that fluid will all drain out?
A plug in hand is a good idea, but how quickly might the fluid drain out, if it does at all???

 

[Rex Coil 7]

I have used the grey liquid sealer that are sold by the mfg of speed bleeders for many years on many bikes. I do not have speed bleeders on this bike. If this sealant was going to react with brake fluid, I don't believe they would sell it specifically for the threads on speed bleeders.

While you may be "luckily correct" on that ... it's not a good "rule of thumb" (so to speak). In other words, I'd be less certain about "If this sealant was going to react with brake fluid, I don't believe they would sell it specifically for the threads on speed bleeders" thing. All one need do is observe how many class action lawsuits are out there because a given manufacturer was afforded the benefit of the doubt by customers (Oxycontin, lethal exploding air bags in cars/trucks, talcum powder that causes ovarian cancer, weed killer that causes cancer, high-end Ducati motorcycles with nearly useless rear brakes, et al..). So while speed bleeder manufacturers sell sealant paste, I'd be cautious about giving them the benefit of the doubt regarding their judgement. I suppose I've gone off topic here, but I felt it was worth pointing this out.

 

[2004 999s]

On the front brakes, is there enough gravity that when removing the bleeder on the caliper that fluid will all drain out?
A plug in hand is a good idea, but how quickly might the fluid drain out, if it does at all???

if you keep the cap on the reservoir it will prevent more fluid draining than if it were uncapped.

 

[LA2SD]

Brake bleeder nipples and their corresponding calipers are designed to self seal. If there's leakage of brake fluid, either the nipple or the caliper need to be replaced, cleaned, or machined.

 

[2004 999s]

"It should be noted that a tiny stream of bubbles may be noticed in the hose after all of the air is bled from the lines. This is caused by air seeping around the threads of the loosened bleeder fitting and being drawn back through the fitting by the suction of the pump. Once the air is removed from within the system, these tiny bubbles will in no way jeopardize the bleeding operation, since they are present only at the fitting and do not enter the system. If you wish, you can put grease or Teflon tape around the threads of the fitting to eliminate most of the bubbles." page# 21.https://www.skf.com/binaries/pub299/Images/0901d196809b1436-824323E_MV8500_tcm_299-528299.pdf

 

[Tamworth]

"It should be noted that a tiny stream of bubbles may be noticed in the hose after all of the air is bled from the lines. This is caused by air seeping around the threads of the loosened bleeder fitting and being drawn back through the fitting by the suction of the pump. Once the air is removed from within the system, these tiny bubbles will in no way jeopardize the bleeding operation, since they are present only at the fitting and do not enter the system. If you wish, you can put grease or Teflon tape around the threads of the fitting to eliminate most of the bubbles." page# 21.https://www.skf.com/binaries/pub299/Images/0901d196809b1436-824323E_MV8500_tcm_299-528299.pdf

That's the exact instructions on my mityvac many years ago. It was sucking air and not much fluid. Started with the tefelon tape, nice clean wrap twice around. I'm very experienced with sealing threaded fittings, and this was just not satisfactory. I use the mityvac for many things but never bleeding brakes

 

[Motozen]

 

[SP3]

It seems none of those saying 'NO sealant' (I can be counted as one, usually) aren't reading the OP's complain/wish. He is NOT saying the bleeders are leaking when closed/sealed. He IS complaining about leakage around the threads when bleeding.

I have never bothered using any kind of sealant on bleed screws at any time in my life, I understand what he's trying to accomplish. I know others' who have done some variation of the tape/goop with success.

The threads aren't what seal the system, the taper/seal mating is. Therefor, compatibility of brake fluid with goop is essentially immaterial. SOME goop will, eventually (after a thousand bleed episodes?) migrate into the caliper. The amount will be insignificant but, some amount will get in there.