help, brake bleeder valve
bleeding a newley installed system, thought everything was going fine then I noticed brake fluid coming out of the RF caliper bleeder valve, put the wrench on it and it was tight. It's coming out of the orifice even though It's tight, removed it cleaned it up blew air through it bit it still leaks what's up , could the bleeder be bad?
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Re: help, brake bleeder valve
Craig,
It could be a bad seat on the bleeder or a bad seat in the caliper. Take the bleeder out and examine it closely -- I wouldn't hesitate to use a magnifying glass, but us old guys have them laying around -- if we can remember where we put them
A new bleeder may solve the problem, but if the seat has been damaged in the caliper, then replacement of the caliper is, as far as I know, the only option available. Obviously try a new bleeder screw first.
Of course there is also the chance you don't have the correct bleeder screw, but that is another story. I assUme all the other bleeder screws look the same as this one.Terry -
Re: help, brake bleeder valve
Don't need a magnifying glass for this. Back in the late '60s, when I always used to carry a can of fluid in the Corvette, I used to repeatedly loosen and tighten (but not so much that might shear the valve). This seemed to have the effect of mating the seat in the caliper to that of the valve -- just a thought.
Oh yeah; '65-7 to ? should have the small 5/16" hex, and not stainless valves (that will make seating worse).
kComment
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Re: help, brake bleeder valve
Craig,
It could be a bad seat on the bleeder or a bad seat in the caliper. Take the bleeder out and examine it closely -- I wouldn't hesitate to use a magnifying glass, but us old guys have them laying around -- if we can remember where we put them
A new bleeder may solve the problem, but if the seat has been damaged in the caliper, then replacement of the caliper is, as far as I know, the only option available. Obviously try a new bleeder screw first.
Of course there is also the chance you don't have the correct bleeder screw, but that is another story. I assUme all the other bleeder screws look the same as this one.
Terry and Craig------
The caliper bleeder valve seat is fairly soft, cast iron material. The bleeder valve, itself, is steel. The steel usually "wins out" over the cast iron. So, unfortunately, the chances are it's the seat that's bad. However, the first thing to try is to install a new bleeder valve. That's simple enough and if it stops the leak, all is well.
Some of the caliper rebuilders can restore these bleeder valve seats in the caliper.In Appreciation of John HinckleyComment
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Re: help, brake bleeder valve
Good point Joe about the relative hardness of the two parts. And perhaps Wayne's suggestion regarding repeat tightening will yield positive results. Short of over torquing, it can not hurt to try it.
I have no experience regarding this issue with Corvette calipers, but I was dismayed when I got a pair of "rebuilt" rear calipers for one of my drivers. One of them was brand spanking new, but the other had a "sleeve" in the bleeder port and the bleeder screw was significantly smaller across the flats than the "original" one. This was an obvious "repair" of a broken bleeder screw. I am continually frustrated at the need to bring two sizes of wrench with me to bleed the brakes. That is more frustrating than losing points for a NTFP bleeder screw. One can only hope that the rebuilders of Corvette calipers take more care with the process than the mass rebuilders do.TerryComment
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Re: help, brake bleeder valve
I like to flush new brake fluid through the system every two years. That means the bleeders get used frequently -- that keeps them from rusting in place. That is a serious issue here in the Midwest. And yes I use anti-seize on the bleeders.
The first set of rear calipers lasted 15 years and about 200K. Full disclosure -- the first five years were in police service in North Carolina where rust is NOT an issue, but severe duty was. The rear pistons, in spite of my religious flushing, would not retract all the way into the bores, so I elected to replace the calipers. In hindsight I should have simply rebuilt them. The front calipers are the originals and since they are SEO (police specials) I am going to rebuild those when the time comes. Fronts are 17 years and 227K miles so far.
I know -- this is not exactly the kind of use our Corvettes get. Perhaps the "other problems" Clem refers to is that my car(s) are driven.
TerryComment
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Re: help, brake bleeder valve
i operate on a different theory on brakes. never open a M/C till you have a leak and my 1988 silverado 2500 went 20 year before i had to do any repair work as a wheel cylinder leaked. we here in Pa get our share of salt on the roads and i had to replace a rusted out brake line this year. they just don't build them like they used to.I like to flush new brake fluid through the system every two years. That means the bleeders get used frequently -- that keeps them from rusting in place. That is a serious issue here in the Midwest. And yes I use anti-seize on the bleeders.
The first set of rear calipers lasted 15 years and about 200K. Full disclosure -- the first five years were in police service in North Carolina where rust is NOT an issue, but severs duty was. The rear pistons, in spite of my religious flushing, would not retract all the way into the bores, so I elected to replace the calipers. In hindsight I should have simply rebuilt them. The front calipers are the originals and since they are SEO (police specials) I am going to rebuild those when the time comes. Fronts are 17 years and 227K miles so far.
I know -- this is not exactly the kind of use our Corvettes get. Perhaps the "other problems" Clem refers to is that my car(s) are driven.
Comment
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Re: help, brake bleeder valve
Had a similar problem when I got my first got my car. I was familiar with these from my circle track days. You'd have to drill out the old bleeder (with the caliper taken apart) and tap it for a 1/8" plug. I suppose it's a "Bubba" fix
nbut it will at least save the caliper.
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Re: help, brake bleeder valve
That is exactly what I found in the "rebuilt" caliper I got from NAPA, except there was no sign of gold color on mine. It does, so far, seem to be functional, and I suppose in spite of my displeasure at the need for different size wrench, it is a minor annoyance.Had a similar problem when I got my first got my car. I was familiar with these from my circle track days. You'd have to drill out the old bleeder (with the caliper taken apart) and tap it for a 1/8" plug. I suppose it's a "Bubba" fix nbut it will at least save the caliper.TerryComment
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Re: help, brake bleeder valve
Yes, most don't have a 1/4" box wrench. It's a weird size.Comment
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Re: help, brake bleeder valve update
Thanks for all for the replies..... could not get bleeder valve to seat, worked back and forth numerous times even changed the bleeder. I'm going to send the caliper back to one of the major vendors. my next question is during the process the fluid almost all leaked from the front chamber of the master cylinder. I really don't want to pull the MC and bench bleed it again, (what a mess) can I bleed the front chamber using the valve on the MC the same way I did with the lower port tube fitting that returned to the MC chamber?Comment
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