Brake line size

[Camdo]

I broke a rear brake line on my 2005 Envoy. The one that goes from the right rear to left rear wheel. The line is 1/4 tube but the fittings at the hose ends where they connect are 1/2-20 thread which is a 5/16 tube nut size. It seems that GM uses oversize flare nuts.

My repair possibilities are:

1. Cut back the broken 1/4 line and re-flare the end, add an inverted union and a new piece of 1/4 tube with an oversize nut. cons: tight space and need a double flare tool.

2. Re-pipe with a ready made 5/16 brake line that comes with 1/2-20 nuts as standard.

Method 2 seems quick and easy, but will 5/16 brake line fit the GM hoses fittings? I am concerned about the inverted flare inside the fitting. The small dome that mates with the flare was presumably sized for 1/4 tube.

Has anyone tried using 5/16 tube on these vehicles. What was the result?

 

[Camdo]

I broke a rear brake line on my 2005 Envoy. The one that goes from the right rear to left rear wheel. The line is 1/4 tube but the fittings at the hose ends where they connect are 1/2-20 thread which is a 5/16 tube nut size. It seems that GM uses oversize flare nuts.

My repair possibilities are:

1. Cut back the broken 1/4 line and re-flare the end, add an inverted union and a new piece of 1/4 tube with an oversize nut. cons: tight space and need a double flare tool.

2. Re-pipe with a ready made 5/16 brake line that comes with 1/2-20 nuts as standard.

Method 2 seems quick and easy, but will 5/16 brake line fit the GM hoses fittings? I am concerned about the inverted flare inside the fitting. The small dome that mates with the flare was presumably sized for 1/4 tube.

Has anyone tried using 5/16 tube on these vehicles. What was the result?

There are special flair nuts that are for 1/4 tube with 1/2-20 threads. Dorman sells them and are labeled for GM vehicles. To fix my problem I went with option 1. Doesn't look pretty but works. I purchased a double flair tool for $50, ouch. Overall, I spent about $100 fixing the broken line.

I am still wondering if ready made 5/16 brake line will work on the GM 1/4 tube system. If you try it please post back the results.