Brake line replacement

Tiny
ANONYMOUS
  • MEMBER
  • 2000 DODGE DAKOTA
  • 173,000 MILES
I want to replace all the brake lines on my Dodge Dakota with nickel copper alloy lines. The existing lines are rusted and keep leaking. I tow a boat in launch it in salt water.

Should I use 1/4" line or 5/16"?
Monday, November 5th, 2012 AT 4:20 PM

6 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,864 POSTS
3/16" is standard line going to the wheels. There is no advantage or benefit to using a different diameter, and you'll have to use a bunch of adapter fittings. I don't know where you're going to find brake lines that are made from something different than the original ones. If you use some non-standard tubing you run the risk of getting lawyers and insurance investigators involved. I can share that copper tubing will not hold up to normal brake fluid pressure. You can easily reach over 2000 psi. Copper tubing will explode on power steering systems that only reach 1100 psi.

Copper tubing is normally only flared for plumbing uses. Brake lines need double flares to seal against their seats. Copper is softer than steel and will crush when trying to make a double-flare. Harder metals will crack on the final step or the first step of the double flare won't form properly. The tube will kink instead of making a nice symmetrical bulge.

If you're worried about ocean salt, which is no more destructive than driving in winter in Wisconsin, the road salt capital of the world, spray rust-proofing on the lines once they're bolted in place, especially around the fittings behind the doors. That's where salt tends to collect, at least from road salt. Unless you accidentally drown your truck, in which case you have bigger problems than rusty brake lines, salt water shouldn't reach any lines or fittings road salt wouldn't reach.

I sprayed 14 quarts of rust proofing on my '93 Dynasty before it ever left the dealer's parking lot, and there is not a spot of rust on that car anywhere. Of course it only has 4,200 miles and was never driven in winter, but I also have an '88 Grand Caravan that is still driven daily in winter. It has never been parked in a garage since the day it was new. Only three brake lines have needed to be replaced about five years ago. The rest of the van is leaving me, one crumb of rust at a time, but all the other steel lines still look fine. What I'm saying is, stick with standard, pre-manufactured lines with the fittings already on them. You won't have to fight making the double flares and hope they'll seal.

I should probably mention too, for the benefit of anyone else reading this and contemplating using non-standard parts, compression fittings are absolutely never allowed on high-pressure brake lines. Nothing but double flares or is flares, as it came from the factory. Compression fittings WILL blow off since they're not designed for such high pressures.

Please let us know if you need anything else to get the problem fixed.
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Tuesday, November 6th, 2012 AT 5:51 AM
Tiny
DACOLBERT
  • MEMBER
  • 1 POST
  • 1998 DODGE DAKOTA
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 75,000 MILES
My Dakota has developed a fluid leak somewhere in the brake system, one mechanic, who I don't trust, told me the brake pump needs to be replaced, another guy who I DO trust insists that the leak is in the part where the brake lines from the four wheels join up, where the fluid under pressure is divided and distributed to the four brakes. The truck and I are in Mexico (I bought the truck in Wisconsin and drove it down here), I am returning for the holidays and want to buy that piece of brake line, or brake fluid distributor, in the states and bring it down with me. What is the part number and what is it called?
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Thursday, May 30th, 2019 AT 3:08 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
If its actually leaking you should be losing pressure and fluid-I think you're talking about the pressure differential valve
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Thursday, May 30th, 2019 AT 3:08 PM (Merged)
Tiny
RUBIY669
  • MEMBER
  • 2 POSTS
  • 1997 DODGE DAKOTA
  • 6 CYL
  • 4WD
  • MANUAL
  • 7,700,000 MILES
My 1997 dodge dakota 4wd needs front brake line replaced. It leaked out all brake fluid
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Thursday, May 30th, 2019 AT 3:08 PM (Merged)
Tiny
RUBIY669
  • MEMBER
  • 2 POSTS
Mileage is 77, not 7,700, 00
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Thursday, May 30th, 2019 AT 3:08 PM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 33,864 POSTS
What's the question?
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Thursday, May 30th, 2019 AT 3:08 PM (Merged)

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