Not sure what I'm doing wrong here, but I'm at my wit's end on this one. I just bled the brakes on my rebuild, and for some reason I just cannot get the bleeder screws to stop leaking. The calipers are relatively new - I replaced all four calipers when I first got the car running and driving about two years ago, and the worked fine. Took them off when I rebuilt the whole car (and they sat in the garage for about a year), and I just got around to putting them back on and bleeding them over the weekend.

Now, for whatever reason, the bleeder screws just don't want to stop leaking. They leak from the threads, the bleeder port, even the bleeder plugs are leaking! I've tried tightening them down more, I've wrapped them in teflon...nothing works. I've taken them out and inspected them, they're not crushed at all.

The screws and plugs are brand new from Corvette Central, so they should fit properly...but I'm at a loss here.

Any advice?

 

They aren't "speed bleeders", are they?

 

I didn’t even realize there was a difference. These are the ones I bought…but regardless, it’s not just the bleeders, it’s the plugs too.

 

Where did you buy the set that you are having leaking problems with? I would closely look at the seats inside the caliper to make sure somebody didn't damage the caliper hole. Then go someplace and buy a quality set of Bleeder screws from a name brand company. NAPA stores have some nice ones as I recall as would many auto parts stores.

The only ill-fitting bleeder screws I have seen were poorly made replicas from Asia. The tolerances have to be snug to keep the fluid from draining continuously. The ones I bought that were a no-name part were loose in the threads even before trying to seat. No more bargain bleeders as they will bleed you dry..

 

The ones I bought are from Corvette Central. They're pretty expensive (as far as bleeder screws go), but I don't know who the manufacturer is.

 

Lots of people having lots of issues with bleeder screws recently.
Is someone tossing metric into SAE boxes?

I have found several to be a little "undersize" and after going to a few stores, very few matched or fit correctly.

The seal of the bleeder itself is not the threads, but rather the taper on the end into the flare in the caliper.

And yes, that price above is steep, + shpg + tax.
Check your local NAPA.

 

advice i got on bleeders.. also as mentioned look very close at seats.. take a pic?
not sure if stainless would be best bet? maybe something softer may seal better?

 

Don't get me wrong, I'll pay double that price if I need to...I just want the damn things to stop leaking!

 

I actually just came across that thread - I'll likely pick those up from Rock Auto and give them a try.

 

I've had speed bleeders on my 72 for around 20 years and they've never leaked.....knock on wood.

 

I used the Speed Bleeders for a while and then switched back to the original type. They worked fine until one of them started slowly "sucking air" into the system so I replaced them with good quality metal bleeder screws. Stainless Steel is hard and brittle, not the first choice for a good sealing surface for a bleeder screw. I would want a softer metal to get the best seal at the bottom of the caliper hole where the bleeder screw seals.

The reason I suggested that the original poster check the bottom of the holes where the bleeder screws go into the calipers was to verify that the sealing surfaces were not scratched or damaged. If the bottom of the hole is damaged you might have to replace the caliper itself. The cheaper bleed screws I purchased also "wobbled" a bit in the holes that were threaded into the calipers which made me wonder if they were metric screws in a SAE threaded hole. The screw should be "snug" as it is not the sealing surface for the bleeder screws. The bottom of the hole where the bleeder screw seats is the critical surface you need to seal to.

I have received more JUNK from RockAuto.com as they use a lot of the less expensive (chinese) options. I would go to a local NAPA parts supply or equivalent and buy a quality non-SS bleeder screws. When I replaced mine I went ahead and replaced all the bleeder screws used on the caliper. I am very selective about what I buy from Rockauto any more. I bought several 02 sensors and had them be defective from the start, no replacement available from Rockauto. I ordered a new MAP sensor and when it arrived it was a "used" part in the "new" box which had been opened. No return on this part either as Rockauto thought I was trying to get a new part for nothing. Beware when you buy anything electrical from Rockauto, because if the part turns out to be defective they might not replace the part, even with a trail of receipts. I still buy from them but when I ordered one drivers side tail light housing, I received TWO passengers side tail-light housings before finally getting the correct part. What does Rockauto want to do? They expect me to keep the 2 passengers side tail-light housings because the cost of shipping was more than the part was worth????? I will likely never need 2 of the passengers side tail light housings for a 2005 Buick Terraza in my lifetime....

Having a really easy to use reverse bleeding pump, I flush my brake fluid every five years and this keeps the screws loosened up and everything working.

 

The Raybestos part number in the photo forum member interpon posted fit correctly.
I purchased those several years ago now but they were made in the U.S.A. The only difference was the area where the hex head is is just a little shorter. But still plenty of area for a line/flair wrench to grab.

 

I've not tried them myself, but some folks have used copper flare "washers" to fix damaged caliper seats. It appears Parker Hannifin makes what we're looking for: https://ph.parker.com/us/en/product/...fittings/2gf-3 (don't quote me on the size required - measure for yourself)

You can find these at Amazon, MSC, Grainger, etc.

 

The "problem" with the Speed Bleeders, is that their proper functioning relies on the "sealant" they have on the external threads, remains "thick enough" to conform and seal itself to the caliper. The seal, at this point, is what keeps the caliper from sucking in air, when you release the brake pedal. Once the sealant "shrinks", over time and usage, the bleeders no longer have a tight seal to the body of the caliper, and that's when they stop being effective.

I've used the Speed Bleeders on a couple cars, and in my experience, I got 3-4 bleeds out of them, before the sealant stopped sealing, making them unusable. I'm pretty sure that they could be cleaned and "resealed", but I just don't know what they use as the sealant.

 

Wonder if pipe dope would work.

 

I use white teflon pipe tape and it seems to be holding just fine. The idea for me is to minimize the thread clearances when bleeding - helps to also keep the bleeder from corroding in the caliper.

 

Considering what a nightmare it is when a rusty bleeder screw snaps off in the caliper,
consider buying a tube of "anti-seize".

 

I understand your point, but I doubt that the anti-seize would have the sealing capability that the "red stuff" on the Speed Bleeders has.

 

The anti-seize only has to seal long enough to vacuum bleed the caliper. So as not to get false reading of bubbles past the threads.

After bleeding, the threads do not seal the DOT3 anyway.
It's the taper / tip of the bleeder screw that seals.

 

I have had the same problem with my bleeder screws. leaked and could not seal,
It seems that over time the thread was worn in the caliper. But what you do is get the orange teflon tape and give it a few wraps and it will work. There is also a different sized newer bleeder like a thousands inch wider that would work. I don't off hand have that part that I bought from Lordco but the kit had multiple sizes
if I can find a pic I will post.
I have used pink or red teflon and the newer bleeder screw and both worked on my C3 1971

Thanks, Grant