Coolant Bleeder Valve at cylinder head
03-31-2022, 09:26 AM
#11
As a hobby mechanic, i use my torque wrenches extensivly, for almost everything. Its a hobby, take your time and do it right.
Every time i service brakes, i remove the bleeders completly and clean it with a brass brush. I coat the thread with anti size paste and thread it back in. When i am finished with changing the brake fluid, i try to get rid of the brake fluid left in the bleeder. As brake fuid attracts moisture, it can cause corrosin. I simply grab a spray can of my favourite penetrating oil and spray it down in the bore of the nipple with the long, thin plastic straw nozzle. Place a rag over it. Brake fluid gets flushed out and is replaced with oil. Done. Dont forget the rubber cap.
Every time i service brakes, i remove the bleeders completly and clean it with a brass brush. I coat the thread with anti size paste and thread it back in. When i am finished with changing the brake fluid, i try to get rid of the brake fluid left in the bleeder. As brake fuid attracts moisture, it can cause corrosin. I simply grab a spray can of my favourite penetrating oil and spray it down in the bore of the nipple with the long, thin plastic straw nozzle. Place a rag over it. Brake fluid gets flushed out and is replaced with oil. Done. Dont forget the rubber cap.
03-31-2022, 04:21 PM
#13
03-31-2022, 08:06 PM
#14
04-02-2022, 03:50 PM
#15
Plumbing in the house, yes. Auto brake lines, no. 
04-03-2022, 12:19 AM
#16
Not the brake lines, the bleeders.
Brake lines seal via the flared end. Threads aren't part of the seal (other than providing clamping force to the flare).
Bleeders also seal with a sort of flare, except when you're actually using them to bleed.
When you're bleeding air from system, brake lines, coolant bleed, etc, you crack open this seal, so air can escape from the hollow bleeder. But air can also leak back in through the threads during the process.
But its unlikely to happen with coolant, and the slightest air pocket in coolant isn't nearly the issue that a similar amount of air would pose to a hydraulic system such as brake lines.
When bleeding brakes, especially with the traditional procedure that involves pumping the pedal, you create reverse suction when pedal released.
In a two man procedure, this isn't a big deal. Man 2 seals line before man 1 lets off pedal and creates suction.
But if you're using one of those one man bleeder hose and bottle setups, either with a check valve in the hose or a speed bleeder which is a bleeder bolt with a built in check valve, air can leak past these threads when you release the pedal.
Speed bleeders have special thread sealer to prevent this. With the bleeder contraptions with check valve in hose, instructions usually say to only open bleeder like a quarter turn. This is to help mitigate how much air can leak back during pedal release.
If you're using one of those bleeder contraptions, its a really good idea to put pipe sealer on the bleeder threads. Or at the very least, allow some gravity bleed time after pedal bleeding to help get rid of any air that crept back in the last time you released pedal.
Coolant bleeding isn't like pedal bleeding brakes. You aren't creating any suction. Air naturally wants to move up, since coolant is so much denser, and when you crack open coolant bleed, any air is going to push its up and out. Through the hollow center hole, through the threads of it has to. But up and out pressured by weight of coolant sinking and displacing any air.
Revving engine will create some suction in coolant, you can see it happen with radiator cap open. But we typically don't combine coolant bleeder with revving.
If you do, then sure, use some thread sealer on coolant bleeder. But if you just crack coolant bleeder open, then clamp it shut once the fountain of coolant spews forth, while engine is idling, there isn't any benefit to pipe sealing coolant bleeder (unlike its benefits for brake bleeders).
Brake lines seal via the flared end. Threads aren't part of the seal (other than providing clamping force to the flare).
Bleeders also seal with a sort of flare, except when you're actually using them to bleed.
When you're bleeding air from system, brake lines, coolant bleed, etc, you crack open this seal, so air can escape from the hollow bleeder. But air can also leak back in through the threads during the process.
But its unlikely to happen with coolant, and the slightest air pocket in coolant isn't nearly the issue that a similar amount of air would pose to a hydraulic system such as brake lines.
When bleeding brakes, especially with the traditional procedure that involves pumping the pedal, you create reverse suction when pedal released.
In a two man procedure, this isn't a big deal. Man 2 seals line before man 1 lets off pedal and creates suction.
But if you're using one of those one man bleeder hose and bottle setups, either with a check valve in the hose or a speed bleeder which is a bleeder bolt with a built in check valve, air can leak past these threads when you release the pedal.
Speed bleeders have special thread sealer to prevent this. With the bleeder contraptions with check valve in hose, instructions usually say to only open bleeder like a quarter turn. This is to help mitigate how much air can leak back during pedal release.
If you're using one of those bleeder contraptions, its a really good idea to put pipe sealer on the bleeder threads. Or at the very least, allow some gravity bleed time after pedal bleeding to help get rid of any air that crept back in the last time you released pedal.
Coolant bleeding isn't like pedal bleeding brakes. You aren't creating any suction. Air naturally wants to move up, since coolant is so much denser, and when you crack open coolant bleed, any air is going to push its up and out. Through the hollow center hole, through the threads of it has to. But up and out pressured by weight of coolant sinking and displacing any air.
Revving engine will create some suction in coolant, you can see it happen with radiator cap open. But we typically don't combine coolant bleeder with revving.
If you do, then sure, use some thread sealer on coolant bleeder. But if you just crack coolant bleeder open, then clamp it shut once the fountain of coolant spews forth, while engine is idling, there isn't any benefit to pipe sealing coolant bleeder (unlike its benefits for brake bleeders).
04-03-2022, 03:28 AM
#17
Registered User
Thread Starter
@ Billmann250: Thank a lot Sir! 
I allways bleed my brakes with vacuum tools. As long as you keep in mind that there should be allways a vacuum adjacent when you open a bleeder nipple, no liquid could leak from the bleeder nipple thread and no air can get in the System. I use a hand pump like a mityvac for the Motorcycle and one that works with compressed air for the car.
Some guys prefer a system that works with pressurizing the Brake fluid Reservoir at the master Cylinder, some use the 2 man method. Use what ever you like and what works best for you.
I found the vaccuum tools handy for a lot of other works. That´s why i like them. Checking motorcycle fuel petcocks just as one example.
I allways bleed my brakes with vacuum tools. As long as you keep in mind that there should be allways a vacuum adjacent when you open a bleeder nipple, no liquid could leak from the bleeder nipple thread and no air can get in the System. I use a hand pump like a mityvac for the Motorcycle and one that works with compressed air for the car.
Some guys prefer a system that works with pressurizing the Brake fluid Reservoir at the master Cylinder, some use the 2 man method. Use what ever you like and what works best for you.
I found the vaccuum tools handy for a lot of other works. That´s why i like them. Checking motorcycle fuel petcocks just as one example.
04-13-2022, 11:19 AM
#18
Every coolant bleed valve I've seen on an s2k appears to have the slightest micro leak, but looking at the bolt/plug design it looks like it should seal without teflon tape. Do they just need replacing now and again? Doesn't teflon tape need to be re-applied every time the bolt is turned at all?
Also when I bleed my car, I HAVE to bleed the rear plug on the hard line by the fire wall with the car at a rear tilt or it won't fully bleed. Never used one of those fancy funnels, though.
Also when I bleed my car, I HAVE to bleed the rear plug on the hard line by the fire wall with the car at a rear tilt or it won't fully bleed. Never used one of those fancy funnels, though.
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