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What flare nut wrench size for brake hose removal?

This is a discussion on What flare nut wrench size for brake hose removal? within the Technical / Maintenance forums, part of the General Discussion category; Anyone know off the top of their head what size flare nut wrench is needed to remove the brake hoses? ...

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    What flare nut wrench size for brake hose removal?


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    Anyone know off the top of their head what size flare nut wrench is needed to remove the brake hoses? This is for a 2001 NBS 4WD. I think a 9/10mm would get it but I wanted to check. Also, is it the same size for the front and rear lines?

    Yea, I should buy a set but the budget does not currently allow for it

    Thanks!

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    tee-boy
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    Re: What flare nut wrench size for brake hose removal?

    never used a flare nut wrench to remove a brake line.
    94 Silverado 2WD; 284K miles; Built 4L60E

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    Re: What flare nut wrench size for brake hose removal?

    Yeah technically it isn't necessary but I heard those brake line nuts are real easy to round off with an open-ended wrench.

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    Registered User Bob T's Avatar
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    Re: What flare nut wrench size for brake hose removal?

    How about you see what size open end wrench fits, then buy the same size flare nut wrench?
    '04 Silverado 1/2 ton 2WD ext. cab dk. grey. 5.3 liter, locking diff. XLerator exhaust - offbrand but throaty. Borgeson intermediate shaft, Bilstein HD shocks.

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    Re: What flare nut wrench size for brake hose removal?

    I think it's a 10mm, but why don't you check it with an open ended wrench like was suggested?

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    Re: What flare nut wrench size for brake hose removal?

    Well, I was gonna go by the shop after work and didn't have my other wrenches to measure with...

    Turns out to be about 15mm for the flare nut. But I think it might actually be SAE?! The 15mm flare nut was just a hair too big, and the 14mm was too small to fit on. That works out to maybe a 9/16", haha I don't know for sure I didn't buy an SAE set. Ended up getting an el-cheapo set of metric flare nut wrenches on sale for like $7 from Harbor Freight.

    Some of the other sizes I can remember were (I was putting on the Russell braided lines)

    Rear brakes:
    stock bleeders: 10 mm
    Russell speed bleeders: 11 mm
    stock brake hose bolt @ caliper: 11 mm
    stock brake 'junction' box bolt @ rear axle: 13 mm

    Russell's directions are a little on the vague side. There is a cylinder washer which must be installed in the new brake junction box at the rear axle to give enough clearance to the two attached hard lines. No mention of it is made in the directions, though. I guess you're just supposed to look at the extra part and figure it out eventually, heh. Other than that the fit and finish of Russell's kit was excellent. Going to put on the front lines hopefully later today. I'll post if there's any more interesting issues.

    Oh yeah I had another question for you guys: the brake fluid at the reservoir under the hood is black, but the fluid I bled from the rear lines still looks relatively clear. What is the deal with that?

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    Registered User Bob T's Avatar
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    Re: What flare nut wrench size for brake hose removal?

    Quote Originally Posted by jimmyhc
    ...
    Oh yeah I had another question for you guys: the brake fluid at the reservoir under the hood is black, but the fluid I bled from the rear lines still looks relatively clear. What is the deal with that?
    I think the brake fluid is supposed to be clear. Brake fluid is hygroscopic (absorbs moisture) which is bad. If the moisture gets hot it can boil, and it contributes to corrosion. Also dirt & wear products build up. I suggest you flush with new fluid until it all looks new.

    As for measuring the nut with an open end wrench - I call that the "redneck micrometer."
    Last edited by Bob T; 01-21-2008 at 10:24 AM.
    '04 Silverado 1/2 ton 2WD ext. cab dk. grey. 5.3 liter, locking diff. XLerator exhaust - offbrand but throaty. Borgeson intermediate shaft, Bilstein HD shocks.

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    Driving 4x4's since 1973 Tom S.'s Avatar
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    Re: What flare nut wrench size for brake hose removal?

    Flare nut wrenches are not needed for the brake hoses, but I'm a firm believer in using them because they offer more support than a standard open end (which directly affects the skinned knuckle ratio). They are also a tool that with reasonable care, will last a lifetime. If you can't afford to buy a good set, at least buy a quality single wrench. Craftsman makes a good set for a reasonable price - or look on ebay and see what you can find. The only thing I buy at HF are gloves that I use and throw away.

    BTW, if you find a brake fitting that is stubborn - especially a bleeder, use a candle. Heat the fitting a little, then let the hot wax drip on it and wait a while.
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    tee-boy
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    Re: What flare nut wrench size for brake hose removal?

    candle??? Try a propane torch.
    94 Silverado 2WD; 284K miles; Built 4L60E

    98 Trans Am; TH 400; 4400 Stall; F.A.S.T. 90; SS Long Tubes; BMR rear adjustable suspension; Slicks and Skinnies on Bogarts; Electric Water Pump; 11.50 1/4 mile; 400 lbs weight reduction; Underdriven; Stock valvetrain (Always a Work in Progress)

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    Re: What flare nut wrench size for brake hose removal?

    While I also use the propane (mapp actually) torch, remember to be careful. Rubber hose can blow off the fittings and wheel cylinders can pop open. Also if you do heat it with a torch, heat it until it turns cherry red then walk away for 10 minutes, 9 time out of 10 it will come loose really easy afterwards.

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    Re: What flare nut wrench size for brake hose removal?

    So, the kit wasn't too specific about the front driver's side installation, but it seemed to work out alright having the ABS and stainless steel lines share the same stock mounting bolt.

    Have any of ya'll done this kit before? Does the pic look about right? Also, on the passenger side, which I haven't gotten to yet, it says you may need to tap that front hole. Is that really true? I guess I'll go buy the tap and die stuff and if I don't end up needing it I'll just return it.


    Last edited by jimmyhc; 01-22-2008 at 03:29 PM.

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    Driving 4x4's since 1973 Tom S.'s Avatar
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    Re: What flare nut wrench size for brake hose removal?

    Quote Originally Posted by tee-boy
    candle??? Try a propane torch.
    You're not heating it with a candle - use what ever you want to heat it - remembering that brake fluid does burn. After it's heated enough to melt the wax, then use the candle. The wax will suck up into the threads and make the fitting come off much easier. The process is similar to sweat soldering copper pipes.

    I would NOT heat it up cherry red!
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    Re: What flare nut wrench size for brake hose removal?

    Finished up installing the SS brakes hoses today. Well, by the fourth wheel you're getting pretty good at it, but then you're done!

    BTW, I ended up not needing to tap that front hole on the passenger side, it already had threads. Here's a pic of the finished passenger side, getting ready to bleed the lines. You can see where the brake hose and ABS are sharing the stock mounting bolt again.



    And just for grins, here's a pic of the rear brake line junction with the washer correctly installed so there's enough clearance to tighten the flarenuts on the hardline.


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