New Member Leaky Brake Bleed Screw
06-27-2012, 03:26 PM
#1
Pro
Thread Starter
New Member Leaky Brake Bleed Screw
Hello everyone! My name is Eric and I'm a new member to the forum. I own a 2008 Corvette Z06, atomic orange metallic, that I purchased in January of this year with only 5,800 miles on the odometer. It's been a great car the past six months, with the exception of an issue that I created...
About a month ago I was preparing the car for my first autocross. One item on the check list was switching the bleed screws to speed bleeders (SB's) b/c I don't always have someone available to help with the fluid bleed process.
It's been a long trouble shooting process, so I'll try and keep it short -
Basic Problem: STOCK bleed scews seem to leak easily and require an unusually high amount of torque to seal. Here's the full story...
* 4/8 SB's did not stop the reverse flow of fluid - BUT, being the skeptic I am I had a friend on the brake pedal while I oversaw the fluid coming out. Therefore I was able to close the valve and prevent air from getting in the lines. Basically just had to bleed those normally.
* Closed the SB's and had my friend mash the pedal & made sure no fluid was coming out. Go for a couple test drives... engage ABS... all seems fine.
* Autocrossed the Z. All seemed fine until further inspection at home.
* Front/left & rear/left wheels looked like I had driven through a puddle. A closer inspection revealed break fluid had been leaking. I checked the master cylinder and saw the fluid was down only about 1cm. Lucky I didn't lose the brakes! Washed car immediately!
* Unhappy with the SB's, decided to install the stock bleed screws.
* Removed SB's one at a time, used Q-tips to clean inside the "bleed hole" (so I knew there was no debris preventing a quality seal) and screwed in the stock bleed screws.
** NOTE - fluid was slowly coming out when screwing in the bleed valves.** * We bled each corner a few brake pedal pumps to verify no air was in lines.
* Stuck sliver of paper towel down the hole in the bleed screw to see if any fluid was leaking. I had my friend mash on brakes with the engine running (for vacuum assist). A few bleeders did have a little "seepage" inside the screw. Thus I tightened those down even further. It seemed like I had to really put a lot of force to get those screws to seal completely.
* Went on a very short test drive, all seemed fine.
* Went to Vegas for a week and let car sit for 7 days. Returned home and found a *small amount* of fluid around the base of the bleed screws.
* Took wheels off to investigate and it seems like fluid had just seeped out of the threads. *Recall I put them in with fluid slowly seeping out*
* Cleaned up excess fluid, and noticed only one screw had about a drop of seepage inside the opening.
* Tightened that up and went on a "quality test drive" to really heat up the brakes.
* Brought the car home, removed wheels and noticed little to no "weeping" around threads.
Questions / Concerns:
1) I think the manual specifies 108 in/lbs (which = 9 ft/lbs) for the bleed screws. However, I put them in "wet." Wet torque shouldn't equal dry torque, right? It reduces the coefficient of friction, right?
2) To my untrained hand it seemed like I was torquing the bleed screws approximately 30 ft/lbs. I'm really nervous that I'm approaching the point of stripping the threads on the caliper.
3) Am I supposed to use some type of thread sealant? The SB's come with thread sealant preapplied.
4) Would thread sealant have helped expell fluid from the threads?
5) Brake fluid from the original leak at autocross severely stained the inside of the wheel(s). Tried a name brand wheel cleaner and that didn't remove the stain. Would acetone work, or does the wheel have some type of clear coat that I wouldn't want to dissolve with such a strong solvent?
If you made it this far, thanks for hanging with me. Sorry for the incomplete sentences, I was just trying to keep it concise & direct. I would appreciate ANY & ALL advice.
Eric
About a month ago I was preparing the car for my first autocross. One item on the check list was switching the bleed screws to speed bleeders (SB's) b/c I don't always have someone available to help with the fluid bleed process.
It's been a long trouble shooting process, so I'll try and keep it short -
Basic Problem: STOCK bleed scews seem to leak easily and require an unusually high amount of torque to seal. Here's the full story...
* 4/8 SB's did not stop the reverse flow of fluid - BUT, being the skeptic I am I had a friend on the brake pedal while I oversaw the fluid coming out. Therefore I was able to close the valve and prevent air from getting in the lines. Basically just had to bleed those normally.
* Closed the SB's and had my friend mash the pedal & made sure no fluid was coming out. Go for a couple test drives... engage ABS... all seems fine.
* Autocrossed the Z. All seemed fine until further inspection at home.
* Front/left & rear/left wheels looked like I had driven through a puddle. A closer inspection revealed break fluid had been leaking. I checked the master cylinder and saw the fluid was down only about 1cm. Lucky I didn't lose the brakes! Washed car immediately!
* Unhappy with the SB's, decided to install the stock bleed screws.
* Removed SB's one at a time, used Q-tips to clean inside the "bleed hole" (so I knew there was no debris preventing a quality seal) and screwed in the stock bleed screws.
** NOTE - fluid was slowly coming out when screwing in the bleed valves.** * We bled each corner a few brake pedal pumps to verify no air was in lines.
* Stuck sliver of paper towel down the hole in the bleed screw to see if any fluid was leaking. I had my friend mash on brakes with the engine running (for vacuum assist). A few bleeders did have a little "seepage" inside the screw. Thus I tightened those down even further. It seemed like I had to really put a lot of force to get those screws to seal completely.
* Went on a very short test drive, all seemed fine.
* Went to Vegas for a week and let car sit for 7 days. Returned home and found a *small amount* of fluid around the base of the bleed screws.
* Took wheels off to investigate and it seems like fluid had just seeped out of the threads. *Recall I put them in with fluid slowly seeping out*
* Cleaned up excess fluid, and noticed only one screw had about a drop of seepage inside the opening.
* Tightened that up and went on a "quality test drive" to really heat up the brakes.
* Brought the car home, removed wheels and noticed little to no "weeping" around threads.
Questions / Concerns:
1) I think the manual specifies 108 in/lbs (which = 9 ft/lbs) for the bleed screws. However, I put them in "wet." Wet torque shouldn't equal dry torque, right? It reduces the coefficient of friction, right?
2) To my untrained hand it seemed like I was torquing the bleed screws approximately 30 ft/lbs. I'm really nervous that I'm approaching the point of stripping the threads on the caliper.
3) Am I supposed to use some type of thread sealant? The SB's come with thread sealant preapplied.
4) Would thread sealant have helped expell fluid from the threads?
5) Brake fluid from the original leak at autocross severely stained the inside of the wheel(s). Tried a name brand wheel cleaner and that didn't remove the stain. Would acetone work, or does the wheel have some type of clear coat that I wouldn't want to dissolve with such a strong solvent?
If you made it this far, thanks for hanging with me. Sorry for the incomplete sentences, I was just trying to keep it concise & direct. I would appreciate ANY & ALL advice.
Eric
06-27-2012, 05:52 PM
#2
Safety Car
Hello everyone! My name is Eric and I'm a new member to the forum. I own a 2008 Corvette Z06, atomic orange metallic, that I purchased in January of this year with only 5,800 miles on the odometer. It's been a great car the past six months, with the exception of an issue that I created...
About a month ago I was preparing the car for my first autocross. One item on the check list was switching the bleed screws to speed bleeders (SB's) b/c I don't always have someone available to help with the fluid bleed process.
It's been a long trouble shooting process, so I'll try and keep it short -
Basic Problem: STOCK bleed scews seem to leak easily and require an unusually high amount of torque to seal. Here's the full story...
* 4/8 SB's did not stop the reverse flow of fluid - BUT, being the skeptic I am I had a friend on the brake pedal while I oversaw the fluid coming out. Therefore I was able to close the valve and prevent air from getting in the lines. Basically just had to bleed those normally.
* Closed the SB's and had my friend mash the pedal & made sure no fluid was coming out. Go for a couple test drives... engage ABS... all seems fine.
* Autocrossed the Z. All seemed fine until further inspection at home.
* Front/left & rear/left wheels looked like I had driven through a puddle. A closer inspection revealed break fluid had been leaking. I checked the master cylinder and saw the fluid was down only about 1cm. Lucky I didn't lose the brakes! Washed car immediately!
* Unhappy with the SB's, decided to install the stock bleed screws.
* Removed SB's one at a time, used Q-tips to clean inside the "bleed hole" (so I knew there was no debris preventing a quality seal) and screwed in the stock bleed screws.
** NOTE - fluid was slowly coming out when screwing in the bleed valves.** * We bled each corner a few brake pedal pumps to verify no air was in lines.
* Stuck sliver of paper towel down the hole in the bleed screw to see if any fluid was leaking. I had my friend mash on brakes with the engine running (for vacuum assist). A few bleeders did have a little "seepage" inside the screw. Thus I tightened those down even further. It seemed like I had to really put a lot of force to get those screws to seal completely.
* Went on a very short test drive, all seemed fine.
* Went to Vegas for a week and let car sit for 7 days. Returned home and found a *small amount* of fluid around the base of the bleed screws.
* Took wheels off to investigate and it seems like fluid had just seeped out of the threads. *Recall I put them in with fluid slowly seeping out*
* Cleaned up excess fluid, and noticed only one screw had about a drop of seepage inside the opening.
* Tightened that up and went on a "quality test drive" to really heat up the brakes.
* Brought the car home, removed wheels and noticed little to no "weeping" around threads.
Questions / Concerns:
1) I think the manual specifies 108 in/lbs (which = 9 ft/lbs) for the bleed screws. However, I put them in "wet." Wet torque shouldn't equal dry torque, right? It reduces the coefficient of friction, right?
2) To my untrained hand it seemed like I was torquing the bleed screws approximately 30 ft/lbs. I'm really nervous that I'm approaching the point of stripping the threads on the caliper.
3) Am I supposed to use some type of thread sealant? The SB's come with thread sealant preapplied.
4) Would thread sealant have helped expell fluid from the threads?
5) Brake fluid from the original leak at autocross severely stained the inside of the wheel(s). Tried a name brand wheel cleaner and that didn't remove the stain. Would acetone work, or does the wheel have some type of clear coat that I wouldn't want to dissolve with such a strong solvent?
If you made it this far, thanks for hanging with me. Sorry for the incomplete sentences, I was just trying to keep it concise & direct. I would appreciate ANY & ALL advice.
Eric
About a month ago I was preparing the car for my first autocross. One item on the check list was switching the bleed screws to speed bleeders (SB's) b/c I don't always have someone available to help with the fluid bleed process.
It's been a long trouble shooting process, so I'll try and keep it short -
Basic Problem: STOCK bleed scews seem to leak easily and require an unusually high amount of torque to seal. Here's the full story...
* 4/8 SB's did not stop the reverse flow of fluid - BUT, being the skeptic I am I had a friend on the brake pedal while I oversaw the fluid coming out. Therefore I was able to close the valve and prevent air from getting in the lines. Basically just had to bleed those normally.
* Closed the SB's and had my friend mash the pedal & made sure no fluid was coming out. Go for a couple test drives... engage ABS... all seems fine.
* Autocrossed the Z. All seemed fine until further inspection at home.
* Front/left & rear/left wheels looked like I had driven through a puddle. A closer inspection revealed break fluid had been leaking. I checked the master cylinder and saw the fluid was down only about 1cm. Lucky I didn't lose the brakes! Washed car immediately!
* Unhappy with the SB's, decided to install the stock bleed screws.
* Removed SB's one at a time, used Q-tips to clean inside the "bleed hole" (so I knew there was no debris preventing a quality seal) and screwed in the stock bleed screws.
** NOTE - fluid was slowly coming out when screwing in the bleed valves.** * We bled each corner a few brake pedal pumps to verify no air was in lines.
* Stuck sliver of paper towel down the hole in the bleed screw to see if any fluid was leaking. I had my friend mash on brakes with the engine running (for vacuum assist). A few bleeders did have a little "seepage" inside the screw. Thus I tightened those down even further. It seemed like I had to really put a lot of force to get those screws to seal completely.
* Went on a very short test drive, all seemed fine.
* Went to Vegas for a week and let car sit for 7 days. Returned home and found a *small amount* of fluid around the base of the bleed screws.
* Took wheels off to investigate and it seems like fluid had just seeped out of the threads. *Recall I put them in with fluid slowly seeping out*
* Cleaned up excess fluid, and noticed only one screw had about a drop of seepage inside the opening.
* Tightened that up and went on a "quality test drive" to really heat up the brakes.
* Brought the car home, removed wheels and noticed little to no "weeping" around threads.
Questions / Concerns:
1) I think the manual specifies 108 in/lbs (which = 9 ft/lbs) for the bleed screws. However, I put them in "wet." Wet torque shouldn't equal dry torque, right? It reduces the coefficient of friction, right?
2) To my untrained hand it seemed like I was torquing the bleed screws approximately 30 ft/lbs. I'm really nervous that I'm approaching the point of stripping the threads on the caliper.
3) Am I supposed to use some type of thread sealant? The SB's come with thread sealant preapplied.
4) Would thread sealant have helped expell fluid from the threads?
5) Brake fluid from the original leak at autocross severely stained the inside of the wheel(s). Tried a name brand wheel cleaner and that didn't remove the stain. Would acetone work, or does the wheel have some type of clear coat that I wouldn't want to dissolve with such a strong solvent?
If you made it this far, thanks for hanging with me. Sorry for the incomplete sentences, I was just trying to keep it concise & direct. I would appreciate ANY & ALL advice.
Eric
2) 30ft# is too much.. the safe zone is about 9~15 ft#, you can get yourself a small in-# tq wrench to be safe, this is what i do.. i tq to 100~140 in#
3) No
4) Probably, but thread sealant really is not necessary per oem
5) Brake fluid will eat through paint if it sits on it long enough, you might have to have that wheel refinished.
Good luck!
06-28-2012, 10:48 AM
#3
Pro
Thread Starter
Thanks for the reply Joe. I took the Z out a couple days ago and all seems well. I'm just concerned that it took so much torque to completely seal those bleeders. And it seemed pretty consistent with each corner. They seem to be ok now, so I'm going to keep an eye on the situation. I'm lucky that fluid only stained in inside part of the wheel. My wheels are chrome, so the outside was not affected.
Also, I like ur picture of the RSX. I also own a 2006 RSX Type-S, vivid blue pearl... Absolutely love it. Is it yours, do you race it, etc?
Also, I like ur picture of the RSX. I also own a 2006 RSX Type-S, vivid blue pearl... Absolutely love it. Is it yours, do you race it, etc?
06-28-2012, 02:22 PM
#4
If bleed screw and caliper bleed screw seats are clean, it shouldn't take remotely close to even 15 ft/lbs to seal. I always do it by feel, and have never had any issues. And yes, I always suck the inside of the valves dry by rolling with my fingers a white paper shop towel's corner, to avoid any dripping. Wonder if you had sand or other fine crap in your bleed screws. You should always do that kind of job inside your garage, to avoid that. If you put 30 ft/lbs of torque on those screws, you probably weakened the threads already (I'm even surprised they can take that much without stripping). Unfortunately, the screw threads are probably stronger than the calipers', but I'll let an expert chime in on that 
. Check your bleed screws carefully next time you bleed your brakes. Good luck.
. Check your bleed screws carefully next time you bleed your brakes. Good luck.
Last edited by JCtx; 06-28-2012 at 02:39 PM.
06-28-2012, 02:34 PM
#5
Melting Slicks
If I were you I would put on some speed bleeders. They contain a thread sealant so you dont have to torque your bleeders down really hard. Ive never had any leak.
Note - if you get the stainless steel ones, DO NOT OVERTIGHTEN, you will damage your calipers as opposed to damaging your bleeders.
Note - if you get the stainless steel ones, DO NOT OVERTIGHTEN, you will damage your calipers as opposed to damaging your bleeders.
06-28-2012, 03:06 PM
#6
Roadracing/AutoX section - have found that Speedbleeder caused problems when brake is used to the limits. Appears seat angle on Speedbleeder is slightly different than OEM. It will cause distortion and not seal properly. Racers avoid using Speedbleeders!
-----
It was a wise move on re-installing OEM. Appears your seat distortion caused by SB is not too bad, judging by your description since re installed OEM bleeders. You can further improve sealing of nipple threads by using teflon tape. Teflon tape also aides in vacuum bleeding by sealing air entry thru nipple threads.
HTHs!
-----
It was a wise move on re-installing OEM. Appears your seat distortion caused by SB is not too bad, judging by your description since re installed OEM bleeders. You can further improve sealing of nipple threads by using teflon tape. Teflon tape also aides in vacuum bleeding by sealing air entry thru nipple threads.
HTHs!
06-28-2012, 03:45 PM
#7
Pro
Thread Starter
@victorF: I've heard of using using teflon tape - does that hold up well to the "extreme" heat when racing?
@ELP_JC: Before reinstalling my bleed screws I bathed them in CLR (calcium, lime, rust) solvent, then washed, rinsed, and dried thoroughly. After taking out the SB's I used a qtip to clean inside the hold as best as I could. Fluid was slowly being pushed out of the "gaping" hole while the SB'sbleed screws were off... I assume there was a little bit of pressure in the system. I would find it odd that it took so much force to close all 8. All 8 couldn't have been dirty :-/ I performed the work in my garage and I made sure to clean around the bolts before hand. At this point I think I'm going to just keep a very close eye on the situation.
I too am surprised that the bolt / caliper threads can take that much force. If I continue to have problems I'll be sure to write back. Thanks for the advice.
@KneeDragr: I tried the speed bleeders and 4/8 did not stop the reverse flow of fluid, and 2/8 severely leaked during autocross, so I'm wary of using them. I was lucky I didn't lose my brakes. Like yourself a lot of people have posted with good experiences with them. Maybe it's a hit/miss sorta product :-/
@ELP_JC: Before reinstalling my bleed screws I bathed them in CLR (calcium, lime, rust) solvent, then washed, rinsed, and dried thoroughly. After taking out the SB's I used a qtip to clean inside the hold as best as I could. Fluid was slowly being pushed out of the "gaping" hole while the SB'sbleed screws were off... I assume there was a little bit of pressure in the system. I would find it odd that it took so much force to close all 8. All 8 couldn't have been dirty :-/ I performed the work in my garage and I made sure to clean around the bolts before hand. At this point I think I'm going to just keep a very close eye on the situation.
I too am surprised that the bolt / caliper threads can take that much force. If I continue to have problems I'll be sure to write back. Thanks for the advice.
@KneeDragr: I tried the speed bleeders and 4/8 did not stop the reverse flow of fluid, and 2/8 severely leaked during autocross, so I'm wary of using them. I was lucky I didn't lose my brakes. Like yourself a lot of people have posted with good experiences with them. Maybe it's a hit/miss sorta product :-/
06-28-2012, 06:19 PM
#9
Melting Slicks
After reading some threads on speedbleeders, I should probably stop reccomending them. Looks as if about half the people who use them have problems. Although there seems to be no consensus on exactly why, it appears that they are not a good match for all calipers.
06-29-2012, 12:20 AM
#10
To know the why, need to take measurement on both OEM and Speedbleeder. In this case, OEM is the reference and any deviation from the reference will have an improper seal. No magic there!
Roadracing & AutoX section had proven that and serious racers avoid Speedbleeder for a good reason. Street crowd don't tax their brakes and usually recommends SB!
Roadracing & AutoX section had proven that and serious racers avoid Speedbleeder for a good reason. Street crowd don't tax their brakes and usually recommends SB!
06-29-2012, 06:54 AM
#11
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St. Jude Donor '15
"In honor of jpee"
some very interesting info here. thanks! 
06-29-2012, 09:55 AM
#12
Pro
Thread Starter
Agree with AORoads, great info, and thanks for taking the time to help sort this issue out
I actually found a write-up where the author used dial calipers and measured the shaft diameter of SB's, stock Vette bleed screws, and the cheap chinese pot metal universal bleed screws you find at auto stores...
No surprise that neither matched the oem bleed screw. If memory serves... that's a huge if... I believe the oem bleed screwed were around 64.5/1000ths and the SB's were around 78/1000ths. Now, that doesn't necessarily mean the angle of the taper is different, but imho is likely. Sorry I lost the link and can't find it.
After much digging on many forums on the interwebs I have found a significant number of posts advising people to refrain from using SB's in a racing environment. Maybe it's a hit or miss product, but I think it's one of those things that's best left stock. The last thing I / we need in a 500+ hp car is to be worried the thing won't stop.
I actually found a write-up where the author used dial calipers and measured the shaft diameter of SB's, stock Vette bleed screws, and the cheap chinese pot metal universal bleed screws you find at auto stores...
No surprise that neither matched the oem bleed screw. If memory serves... that's a huge if... I believe the oem bleed screwed were around 64.5/1000ths and the SB's were around 78/1000ths. Now, that doesn't necessarily mean the angle of the taper is different, but imho is likely. Sorry I lost the link and can't find it.
After much digging on many forums on the interwebs I have found a significant number of posts advising people to refrain from using SB's in a racing environment. Maybe it's a hit or miss product, but I think it's one of those things that's best left stock. The last thing I / we need in a 500+ hp car is to be worried the thing won't stop.
06-29-2012, 01:58 PM
#14
Finally, I've always vacuum-bled my brakes, and stock bleed valves have never been an issue. If you open them 2 turns, then yes, but I never open them more than 1/2 turn, and never a drop around the valves. I never change bleed valves. And with vacuum, it's a one-man job too. Good luck.
06-30-2012, 07:07 AM
#16
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I missed you having SBs man; that explains it. It's better to NEVER change bleed valves because a slight change in seat angle on the valves distorts calipers, with the results you had. By the way, don't use Q-tips since they leave lint, although that wasn't your problem.
Finally, I've always vacuum-bled my brakes, and stock bleed valves have never been an issue. If you open them 2 turns, then yes, but I never open them more than 1/2 turn, and never a drop around the valves. I never change bleed valves. And with vacuum, it's a one-man job too. Good luck.
Finally, I've always vacuum-bled my brakes, and stock bleed valves have never been an issue. If you open them 2 turns, then yes, but I never open them more than 1/2 turn, and never a drop around the valves. I never change bleed valves. And with vacuum, it's a one-man job too. Good luck.