# Brake fluid leak



## Noangelbuddy (Dec 6, 2017)

I bought Wilwood disc brakes and Right Stuff stainless steel lines for my 65 GTO. All new quality parts, but I have a very slight leak near the rear brakes I cannot stop. I have connected, tightened, disconnected and retightened one fitting multiple times, but the leak persists. I am afraid to tighten it any further because I know I’ll strip the fitting. I am considering putting a small ring gasket on the flaired end of the tube. The flaired end looks perfectly flat. Anyone else try a ring gasket to stop a leak?


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## armyadarkness (Dec 7, 2020)

Flared/ compression fittings should never require any sealant or gasket. So, sounds to me like you have a defective fitting on the caliper? Can you take a pic of the setup?


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## kevin1727 (Aug 4, 2021)

"perfectly flat"? The tubing end should look more like a bugle or trumpet. Maybe better to replace the fitting and/or re-flare the line? I'm not an experienced car guy but did a lot of high pressure machine hydraulics. I agree with #Armyadarkness, no gasket. 
Can you tell if it's leaking at the flare or at the housing side?


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## Sick467 (Oct 29, 2019)

X3 on not using any type of gasket or seal...bad idea, if it works to begin with...it won't last for long. SS line is the most difficult to get right and it sounds like your line was not flared properly if it is truly flat. As Kevin says, bugle looking like this...










I have done my fair share of SS tubing and have found that the flare can crack or split too. If your flare looks proper and is not cracked, check it's mating surface in the fitting for chips, cracks, pits, divots, or debris. If it all looks good, you may want to try to lubricate the threads and give it a bit more of a turn to tighten it down. Lubrication allows the same amount of torque to be applied but get the fitting more tight. Of course, you have to use your own judgement whether you may strip the threads.


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## armyadarkness (Dec 7, 2020)

I bought a new $55K Jeep wrangler a few years back. Went to swap gears and found that a seal was leaking on the rear axle. Closer inspection revealed that the axle had an incomplete cast and was still machined and used. This was a new Rubicon with under 1000 miles.

So dont assume this is your fault. COuld be a poor caliper fitting or?


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## Noangelbuddy (Dec 6, 2017)

Sick467 said:


> X3 on not using any type of gasket or seal...bad idea, if it works to begin with...it won't last for long. SS line is the most difficult to get right and it sounds like your line was not flared properly if it is truly flat. As Kevin says, bugle looking like this...
> 
> View attachment 151469
> 
> ...


My bad. It is a double flare. When I said flat, I meant it looks like it would sit flush when tightened down. I thought about cutting and reflating the end, but I can’t since it’s stainless steel. Don’t have the right tools and can’t rent them. Had not tried lubricating the threads will do that next.


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## Noangelbuddy (Dec 6, 2017)

armyadarkness said:


> Flared/ compression fittings should never require any sealant or gasket. So, sounds to me like you have a defective fitting on the caliper? Can you take a pic of the setup?


Here’s a pic. Not a caliper problem. Flex hose to tube connection is the issue. You can see what the brake fluid did to my axle. Recovering from surgery can’t go back at in for a few weeks. The wife would be pissed I got under the car to take this photo, but I trust you won’t tell.


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## Duff (Jan 12, 2020)

I recently had the same issue on a brake hose from NAPA, I had it off and on half dozen times, it wouldn't seal, Napa said they've been getting hoses having bad machining on the inverted flares.


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## Duff (Jan 12, 2020)

Duff said:


> I recently had the same issue on the rear brake hose for my mustang, it came from NAPA, I had it off and on half dozen times, it wouldn't seal. Napa said they've been getting hoses having bad machining on the inverted flares. I ended up putting the original back on, it sealed up 1st time, I still have the new Napa replacement in the box, not too excited about trying it though.


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## Noangelbuddy (Dec 6, 2017)

Months ago when I connected my new SS lines to the new proportioning valve, I had my first brake fluid leak. One of the connections at the front of the valve leaked, all the others were fine. Took it apart, closely inspected the ends and retightened. Still leaked. Took it apart again and tightened it with serious force. Still leaked. Bought a new proportioning valve from Master Brakes, reconnected all the lines; no leaks.
In a few weeks I will reattach the leak in the rear. It will get fixed.


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## armyadarkness (Dec 7, 2020)

Not the best pic, but it LOOKS like you used a stainless steel hard line... If so, that's likely your issue. Many guys don't ever get them to seat.


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## Noangelbuddy (Dec 6, 2017)

Best pic I could do under the circumstances. Yes, the hard line is stainless steel. 

After my GMC truck brake line rusted out (truck spent most of its life in PA), I replaced all the original steel lines with stainless. It was a PITA job without a lift, but no leaks with the new SS hard lines.


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## Noangelbuddy (Dec 6, 2017)

Noangelbuddy said:


> Best pic I could do under the circumstances. Yes, the hard line is stainless steel.
> 
> After my GMC truck brake line rusted out (truck spent most of its life in PA), I replaced all the original steel lines with stainless. It was a PITA job without a lift, but no leaks with the new SS hard lines.


Just found great Inline Tube video on YouTube for the proper way to seat brake lines to avoid leaks. Will try it in a few weeks and post results.


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## O52 (Jan 27, 2019)

The only reason I can think of why anyone would need SS lines or fuel tank is if the vehicle was exposed to corrosive conditions or a salt air environment.


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## Sick467 (Oct 29, 2019)

O52 said:


> The only reason I can think of why anyone would need SS lines or fuel tank is if the vehicle was exposed to corrosive conditions or a salt air environment.


ONE more reason...the cool factor! I love the look of stainless lines. You have to work for it and pay more for it, but it's worth it to me.


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## Noangelbuddy (Dec 6, 2017)

O52 said:


> The only reason I can think of why anyone would need SS lines or fuel tank is if the vehicle was exposed to corrosive conditions or a salt air environment.


I had my original steel lines blow out while I was driving up a solid wood homemade ramp. Braked hard to stop when I drove up on the ramp, when I did a brake line blew out. As you know the original Pontiac brakes were prone to a single point failure back in 65. I almost rolled off the ramp and into the wall. That happened over forty years ago and I remember it like it was yesterday. I lived in NY at the time and road salt took out my lines. 
I see you live in CA. Agree with your logic, but no matter where my car may end up after I am gone; car will have SS lines and dual reservoir. I could have gone with steel lines and considered it briefly, then dismissed it and opted for SS.


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## armyadarkness (Dec 7, 2020)

Noangelbuddy said:


> After my GMC truck brake line rusted out (truck spent most of its life in PA), I replaced all the original steel lines with stainless. It was a PITA job without a lift, but no leaks with the new SS hard lines.


Preaching to the choir, there my friend. Two Chevy Silverados in Jersey, one lost brakes while trailering a 70 GTO. It's common to go to stainless, but requires special paractice. Sometimes just tightening and loosening, several times, does it.


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## armyadarkness (Dec 7, 2020)

O52 said:


> The only reason I can think of why anyone would need SS lines or fuel tank is if the vehicle was exposed to corrosive conditions or a salt air environment.


Brake lines fail all the time, here in Jersey... but those are daily drivers. HEAVY salt use here


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## Mine'sa66 (Oct 30, 2019)

Do not put anything in that union!
Stainless lines are notorious for having trouble sealing. Very hard metal, difficult to get the flare just right. You may have to cut that flare off and re-flare it.


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## Mine'sa66 (Oct 30, 2019)

armyadarkness said:


> Brake lines fail all the time, here in Jersey... but those are daily drivers. HEAVY salt use here


You have no idea.
Coastal Maine, the corrosion capitol of the world.


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## 64uber (Apr 30, 2021)

Conical Seals works well, it's the only thing we could use in commercial aircraft maintenance besides changing the fitting or line. I know they are easily available in 37 degree but not sure about 45. Soft enough a 37 might work on a 45 angle.


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## Noangelbuddy (Dec 6, 2017)

64uber said:


> Conical Seals works well, it's the only thing we could use in commercial aircraft maintenance besides changing the fitting or line. I know they are easily available in 37 degree but not sure about 45. Soft enough a 37 might work on a 45 angle.


Excellent data point. If you can use these in an aircraft, I won’t have any reservation about using them in my car. I just did a Google search and found them. The ones I saw were metallic and used in Aerospace applications. Thank you!


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## Noangelbuddy (Dec 6, 2017)

64uber said:


> Conical Seals works well, it's the only thing we could use in commercial aircraft maintenance besides changing the fitting or line. I know they are easily available in 37 degree but not sure about 45. Soft enough a 37 might work on a 45 angle.


I put the conical copper seals in two rear fittings that leaked. Time will tell, but I believe the copper will compress and fill the gap. A few pictures included for benefit of others. Thank you for the tip. Have closeup of the leak connections if anyone is interested.


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## 64uber (Apr 30, 2021)

You are welcome. Should work just fine. Here is a pic of 2 aircraft ones I had in my tool box, very similar but with an extra flange. Tried to measure with calipers, less than 0.005" and did pick up with magnet. Aircraft hydraulic systems are 3000 psi and though we didn't need to use them very often they were a life saver when we did and never had any issue with them failing. As you said they compress and fill a void, way better than overturning and creating stress.


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## Noangelbuddy (Dec 6, 2017)

64uber said:


> You are welcome. Should work just fine. Here is a pic of 2 aircraft ones I had in my tool box, very similar but with an extra flange. Tried to measure with calipers, less than 0.005" and did pick up with magnet. Aircraft hydraulic systems are 3000 psi and though we didn't need to use them very often they were a life saver when we did and never had any issue with them failing. As you said they compress and fill a void, way better than overturning and creating stress.
> View attachment 152107


IMHO stainless brake line manufacturers should offer these seals. Your suggestion should be embraced in all car forums.


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