Old rubber brake line wont come off

[logan1]

Hey guy,

I'm trying to upgrade my old OEM rubber brake lines to SS brake lines. The problem is that the old rubber brake line just wont unscrew off the hard metal tube that comes form the master cylinder. I really don't want to damage the hard line or the little S- shaped hard line that are connected together using the rubber tube. I am scared that if i apply any more force i'll end up rounding out the little 10mm nut at on the hard line side.

What would be the best solution to get the little piece of flex runner tube out without damaging the hard lines.

Here are a few pictures of my brake lines:

[dclamm]

Do you have flare nut wrenches? (they go 3/4 around the hex head). You'll need those to keep from rounding the hexes. Soak the joints as long as you can with PB Blaster or similar. If you can get the one off on the firewall put the other S curve big hex in a vice. The S curve one does look tough.

[geezer]

The proper flare nut wrench is good advise. I also keep a small tin of valve grinding compound on hand. When applied to the nut or wrench, it provides an additional "bite" that will prevent rounding the nut. I've also alternated a little heat from a propane torch and a shot of PB Blaster as well in extreeme cases.

[Darrel]

Did you keep the hose fitting in the bracket while trying to remove the hard line?

Might be a stupid question but thought I would ask.

[logan1]

Well I got the 10mm flared nut wrench but still not luck with getting the coupling to break.

[Zed Head]

I have a flare wrench too but it has not always worked.

Looking at those pictures, it may be vise-grip time. Once the points of the nut are rounded the wrenches are less effective.

If you take great care in placing the vise-grips, and make sure the jaws still have good serrations, you can break those fittings loose with minimal damage. If you feel the grips slipping at all, stop and reset.

And before you start, you should file the twisted off points of the brake fitting nut down flat to give a good gripping surface. The actual twisting of the wrench or vise-grip is 5% of the time involved. Getting the grip set is the other 95%. I have actually filed new serrations on my old vise-grips to get them to do the job. Clean the vise-grip jaws and the nut of any oil, grease or fluid. Any slippage at all is bad. Get everything set, double-check, then apply twisting force. If they are that tight, you may also bust a knuckle when it lets go, so have a band-aid ready.

You can get pre-cut lines with the right fittings already flared on at most auto parts stores, for the short hard line. They are inexpensive. I made a bending jig with screws and wood but you can borrow real bending tools from the parts stores. Just take the old piece in to make sure you get the right style and length.

If you decide that the hose is coming off no matter what, you could use a torch. Put a torch on the big end, watch out for bubbling brake fluid. Of course, once you bake the rubber hose, there is no going back.

[JohnnyO]

Part number for pre-crimped AGS brake lines with correct M10 fittings:

BLJ-308 - 8" (you need this one for the S shaped line) Cost is about $3.00 at Napa.

They also make these lines up to 60" with the correct fittings. After that you have to bend and flare your own.

Get them at Napa. O'riellys are green coated and just don't match.

I wouldn't worry about the S shaped line. Throw that away with the hose. I would worry about the line at the frame. Mess that one up and you will have to bend and flare.

John

[spitz17]

I second vice grips, had the same problem. Put a wrech (C-Wrench? The one that goes all the way around with a small opening) on the hard line, and a vice grip on the soft. Came off with easy.

Good luck!

[a7dz]

Heat the joint and then use the flare wrench on it.

[mlc240z]

Soak the heck out of it over a couple of days with PBlaster or Kroil and be patient.

I've had better luck with a little pipe wrench (6" overall length) when the nut is rounded over. The more you turn, the tighter the grip. Never really used vise-grips on stubborn connectors.

One other thing to watch out for is if the hard line is "welded' to the flare nut.

Turning the rusted line/nut on my driver's side rear line wound up twisting and snapping the line. Keep a wrench on the other nut to make sure they don't twist in unison. If you can finally get the nut to move, only move it a little and then re-tighten. Loosen again while watching the hard line. If they move together keep working them back and forth while spraying more PBlaster on the connection until they free up. It'll save you from calling Roger at ZBarn and getting a replacement hard line.

You also might want to just replace the S-shaped tube bridge. I believe still available from Nissan, remember paying about $12 per to replace.

[bpilati]

Drink a beer.

[logan1]

Thanx for all the help guys. I went to Wal-mart and bought a $15 propane torch and used it to heat the coupling. Once the metal was red hot; i use the flare nut wrench on the hard line side and a regular wrench on the rubber hose side and managed to get the threads to unbind.

Once again thanx for all the helpful tips.