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Caliper leaking from the bleeder valve after replacement?

S

SyCo

NAXJA Forum User
Location
Spokane, WA
This is on my 98 XJ, with rear disc brake hardware from a ZJ. Issue with driver side rear.

Replaced a seized caliper today with a caliper from Napa. Installed the caliper and bled the brakes, but the brakes didn't "feel" right. Upon inspection, fluid was leaking from the threads of the bleeder port. Replaced the bleeder valve with another, same problem persisted. Replaced the Napa caliper with Duralast unit from AutoZone. Installed and bled the brakes, braking performance upon test drive felt better. Everything looked good upon visual inspection. Drove about 30 miles and stopped for gas, noticed some brake fluid around the threads of the bleeder port again. Wiped the area down, drove around the block while manipulating the brakes, checked the bleeder valve, and there was a tiny amount around the threads again. Brake pedal feels good, doesn't even drop to the floor where pushing down extremely hard. Brakes feel fine, but I'm concerned about the leak.

Has anyone had a problem like this before? It seems improbably that TWO calipers would be leaking from the same spot, but God hates me so I'm not gonna rule it out completely. Any ideas?
 
SyCo said:
This is on my 98 XJ, with rear disc brake hardware from a ZJ. Issue with driver side rear.

Replaced a seized caliper today with a caliper from Napa. Installed the caliper and bled the brakes, but the brakes didn't "feel" right. Upon inspection, fluid was leaking from the threads of the bleeder port. Replaced the bleeder valve with another, same problem persisted. Replaced the Napa caliper with Duralast unit from AutoZone. Installed and bled the brakes, braking performance upon test drive felt better. Everything looked good upon visual inspection. Drove about 30 miles and stopped for gas, noticed some brake fluid around the threads of the bleeder port again. Wiped the area down, drove around the block while manipulating the brakes, checked the bleeder valve, and there was a tiny amount around the threads again. Brake pedal feels good, doesn't even drop to the floor where pushing down extremely hard. Brakes feel fine, but I'm concerned about the leak.

Has anyone had a problem like this before? It seems improbably that TWO calipers would be leaking from the same spot, but God hates me so I'm not gonna rule it out completely. Any ideas?
Click to expand...

I had a similar issue once that I fixed with a couple of layers of Teflon tape...might be worth a try.
 
weebur said:
I had a similar issue once that I fixed with a couple of layers of Teflon tape...might be worth a try.
Click to expand...

the bleeder seals on the face at the bottom of the hole it goes into, like a flare fitting. NEVER put thread tape on any flared fitting.
 
sure it's coming from the bleeder and not creeping from the banjo bolt fitting?
 
Only thing I can think if is there is some sort of solid in with your brake fluid keeping the bleeder valve from seating all the way. Or maybe you have a tiny leak at the brake hose fitting that is spraying on the bleeder valve. Could be you are tightening the bleeder way to tight, they usually only need snug but firm, not gorilla tight. I'm out of ideas.
I always use a glass jar when bleeding so I can see what comes out.
 
Yes I'm sure the leak is not coming from anywhere else, it's clearly coming from the bleeder port, out the threads. I re-tightened it this morning and throughly cleaned the entire caliper with water and degreaser. I've driven it around all day and it's still leaking, but it's a TINY amount. I have noticed no significant difference in braking ability or pedal feel.

I went back to Napa and exchanged the caliper for another. When the guy gave me the "new" caliper I pulled out a flare nut wrench and took off the bleeder valve and inspect the "acorn seat" of the fitting and noticed a slight score around it, you could see it and feel it with your finger nail. The other bleeder valve from the previous Napa caliper had the same thing. I had them swap that for a brand new bleeder valve which had no such score and was perfectly smooth. I'm about to put this caliper on and hope that this will be the end of the issue.
 
I have had new calipers from various parts chains come with the bleeders REALLY cranked down - as in, so tight I was afraid I would round them off trying to loosen them the first time. The bleeder screws had been put in so tight there was a visible indent in the conical point.

Feel free to replace them with regular 3/8-24 speed bleeders but be aware that they aren't quite long enough, so you will have to grind about a half a mm (that's a full c-hair, for you non metric speaking mechanics) off the face of the caliper where the bleeder screws into. If you screw it in all the way and the hex head of the bleeder contacts the caliper or looks too close, pull it out, grind it down a little more, and try again. Make sure to clean well with brakleen after doing this to avoid the grinding dust contaminating the brakes.
 
GrimmJeeper said:
the bleeder seals on the face at the bottom of the hole it goes into, like a flare fitting. NEVER put thread tape on any flared fitting.
Click to expand...

I guess I should have been more specific. I had a badly corroded caliper and fitting and used Teflon tape on the threads...not the flared end of the brake line. And it was a temporary fix until I could replace the caliper.
 
weebur said:
I guess I should have been more specific. I had a badly corroded caliper and fitting and used Teflon tape on the threads...not the flared end of the brake line. And it was a temporary fix until I could replace the caliper.
Click to expand...

I might do it if I had to. but without writing a book, it would make anybody who has ever pushed the brake pedal and had it go to the floor, eyes bulge, sphincter tighten and hair stand on end, just thinking about it. Nothing personal.
I use Teflon rape on a lot of things that I probably shouldn't, but it generally works just as well as no seize and I get it for free (my sons a plumber).
 
I get it for nearly free (like 50 cents a roll... not gonna even budget for it, that's pocket change) and I wouldn't use it on a brake bleeder. If fluid is getting to those threads at all while it's closed, there is a problem at the seal/seat and some teflon tape is a band aid. Brakes are something I would only band-aid to get off the trail and back to a place where I can hitch a ride to a parts store.
 
kastein said:
I get it for nearly free (like 50 cents a roll... not gonna even budget for it, that's pocket change) and I wouldn't use it on a brake bleeder. If fluid is getting to those threads at all while it's closed, there is a problem at the seal/seat and some teflon tape is a band aid. Brakes are something I would only band-aid to get off the trail and back to a place where I can hitch a ride to a parts store.
Click to expand...
I once flattened a brake line and punched a hole through it. Clamped it shut with a pair of vice grips and drove it back to camp. LOL
 
ehall said:
I've had luck with the Dorman/Motormite one-man speed bleeders, and they come with thread sealant on them already
Click to expand...
An old truck mechanics trick. a finger full of grease smeared on all the bleeder valves and brake fittings. It will eventually wear and weather off, but really slows down corrosion and usually makes loosening and removal a lot easier. The guy who taught me that was likely born before there were cars, an old wagon mechanic.
Somebody told me Harley speed bleeders will work, I've been tempted to pick up a set. Stuff like that is rare and expensive around here.
 
8Mud said:
I once flattened a brake line and punched a hole through it. Clamped it shut with a pair of vice grips and drove it back to camp. LOL
Click to expand...
I carry my inverted flare kit, a union and a plug. Hell, last trip out I was having brake issues so I had enough bulk brakeline and fittings to replumb the whole truck.
ehall said:
I've had luck with the Dorman/Motormite one-man speed bleeders, and they come with thread sealant on them already
Click to expand...

The thread sealant is only there to keep air from gettin sucked past the threads when the check valve closes. The flare at the bottom is still what seals against the high pressure of a closed brake system

8Mud said:
An old truck mechanics trick. a finger full of grease smeared on all the bleeder valves and brake fittings. It will eventually wear and weather off, but really slows down corrosion and usually makes loosening and removal a lot easier. The guy who taught me that was likely born before there were cars, an old wagon mechanic.
Somebody told me Harley speed bleeders will work, I've been tempted to pick up a set. Stuff like that is rare and expensive around here.
Click to expand...

I'm sure that someone could pick up a set of speed bleeders and drop them in the mail to you. I'll write gift on the package...
 
87manche said:
I carry my inverted flare kit, a union and a plug. Hell, last trip out I was having brake issues so I had enough bulk brakeline and fittings to replumb the whole truck.
I'm sure that someone could pick up a set of speed bleeders and drop them in the mail to you. I'll write gift on the package...
Click to expand...

I keep a couple of rolls of brake line and assorted fittings in the garage, I've never been tempted to carry it a lonq with though. LOL

Thanx for the thought, but likely not worth the hassle. One of these days I'll trip across a set and pick them up, they are around, just not common. Parts prices do suck around here though, about double. If you order from the states, the shipping ups the cost to about the same as local prices.

Eventually though I'll need something that is just about unobtainable around here and I'll hit you up then.
 
Could the bleeder screw itself be bottoming out too soon. I know they come with the caliper but stranger things have happened. That way it'd never snug up the threads, it'd just feel like it. Might wanna try another (shorter) bleeder screw. Perfect time to buy the speed bleeders
 
Not likely but could happen. More likely the seat that the bleeder cone point presses against has a nick in it or is not perfectly collinear with the threaded portion of the bleeder socket.
 
ParadiseXJ said:
Could the bleeder screw itself be bottoming out too soon. I know they come with the caliper but stranger things have happened. That way it'd never snug up the threads, it'd just feel like it. Might wanna try another (shorter) bleeder screw. Perfect time to buy the speed bleeders
Click to expand...

if it seals at the bottom, it would be the hex head hitting before the taper was seating-- you'd actually want a slightly longer bleeder to avoid this, no?
 
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