Flare nut wrench size?

You mean the brake line flare nuts on the end of the lines? I see nothing that looks like a 'plug'. You buy the lines ready made or you have them made a garage, using a brake line flare tool set. eBay sells them ready made.

https://www.google.com/search?q=2006+gmc+canyon+rear+brake+line+plug+from+master+cylinder

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U need what is called a flare wrench I have rounded nuts before and the flare wrench took them off in most cases. The wrench can be found at most auto parts stores I find autozone to be the best

You must make sure that (1)the line is tight but not over ightened if over ightened the flare has cracked and must be replaced (2)be sure you are flaring the tubing correctly that the tubing is sitting properly in the flaring block and that your are cutting the tubing evenly (3)inspect the fitting on the master cylinder and that the new line fitting is// the proper size////metric or sae/////and the master cylinder fitting is not cracked===== also the brass block is a union for both rear wheels you will see the other lines coming out to each wheel unless it' up front then that is a proportional valve ok but I think you have either a cracked line or fitting from over tightening or you are trying to mate an sae fitting with a metric one or improper flaring and crooked tube cutting good luck stephen

Hello my name is brad,3/16 brake line,brad

You can fix this but you need some specical tools You need a tubeing cutter and a flaring tool you can buy sections of brake line im not suppose to name stores but it begins with an N and ends with an A cut the line back to a point where its sound its easyer if you can remove the other end at a fitting then you;ll olny have to make one flare under the vehicle the flareing tool is about 30 dollars and the tubeing cutter is around 5 -10 dollars thr line is cheap You need to flare the old line to make it work with the new fitting you can;t use compression fittngs there not legal and won;t work if you have a problem getting the fitting end of at the rear wheel try hitting it with a propane torch for a few seconds not to long don;t start a fire or melt your rear wheel cylinder The instructions for the flareing come with the tool don;t try to dubble flare its not nessary but this will be a perminate fix and all you have to do is bleed the rear drivers side wheel cyinder good luck

Don't do this unless you have skill at and tools to repair flair pipe. You will need the special tubing wrenches as well. The fittings/pipe are probably rusted and - frankly - it will be a night mare getting the repair done ... and then the 'fun' begins when you try to get the air out of the line.

I'm not aware of a particular Manual that specifically addresses Brake Line for your Specific Vehicle.
However I have replaced several "complete" and "partial" Brake Lines in my years of experience.
Specific/Pre-Contured Brake Lines for your Truck are available at most auto parts stores. Calt them for availability and prices.
However these are somewhat expensive. YOU CAN 'MAKE' YOUR OWN LINES!
Also available at these auto parts stores are two (2) tools you can buy.
1) A Brake Line Bending/Shaping Tool.
2) A Brake Line Cutting/Flaring Tool.
These tools are very easy (and fun) to use.
The auto parts stores carry "Straight" "Bulk" Brake Lines in different sizes (lenght and diameter). They also carry Brake Line "male" and "female" Brake Line Connectors. Make sure you purchase the correct diameter size Brake Line and the correct Connectors to fit these Brake Lines.
If the original Brake Line that you are replacing has viable (usable) sections and/or connectors you can use, then use them.
Take the old Brake Line off using a flare wrench.
Check your Brake Line Connectors to see if they will properly connect to your remain system.
Measure this piece with a material measuring tape (don't tell momma!). Measure the straight Brake Line and using the Brake Line Cutting Tool, cut the straight bulk Brake Line. Using the old Brake Line as a reference: use the Brake Line Bending Tool to shape the straight bulk Brake Line into the desired shape, matching as close as possible to the original Brake Line.
BEFORE USING THE BRAKE LINE FLARING TOOL:
Place the proper "male" or "female" connectors onto the line, FACING the proper directions.
Using the Brake Line Flaring Tool: Flare the ends of the Brake Line.
Connect the "new" Brake Line using the flare wrench.
Make sure you Bleed the entire Brake System.
Let me know if this helped, or if you have any additional information or questions. Feel free to contact me at FixYa.com!
ps: Make sure you clean, roll-up and put away that material measuring tape!!

Have you removed the Brake Line? If not: this must be removed in order to remove the cylinder. Use a flare-nut wrench. If you have removed the Brake Lines and Bolts, tap lightly with rubber mallet to loosen.

this is simpler than i thought.you just remove the plastic air filter housing,in order to have room to work.to remove,loosen the hoses going in and outof the filter housing.next,open and remove the top of the housing,then remove the air filter.at the bottom of the bottom half of the filter housing are 3 bolts,remove these,and the bottom section will slide right out of the hose.using an 11 mm flare nut wrench,gently loosen the brake line from the bottom of the front proportioning valve.it is essential to be careful with this step,as the nut will strip easily.i cannot stress enough the importance of the flare wrench,as it has better contact with the head.next,take either an adjustable wrench,or a deep socket 22mm ratchet head,and loosen the valve.on removal,repeat these steps with the rear brake line and valve,then place the new valve,turning just until tight(overtightening can damage the valve).replace the brake line nut at the bottom of the new valve.repeat this on the front valve.after this is through bleed your brakes as you normally would when change the brake pads.have plenty of brake fluid available,as it will almost all drain out during replacement of valves.have a drip pan on the ground under the master cylinder before removal of any brake components.

Depends on your mechanic ablilites. Steel brake line is basically 0.188 inch diameter line, and the metric 6mm line dia is very closely same.
Dodge uses ISO bubble flare , and not the American standard double flare at the end of the steel tube line. This ISO bubble flare on the steel line then fits into its mate female end which is the rubber hose connector end.
So, easiest way to get rid of the ISO bubble flare and change to American double flare end is:
Some automotive stores such as Parts Plus Auto Stores carry the brass brakeline adapter which has one end being the male end that fits nicely into the rubber hose with its ISO bubble female fitting, while the other end of the brass line adapter is the female end which has the double flare so you can then insert the steel line replacement with standard double flare into this end of the adapter.
Steel line , bungy brake line or equivalent is fine, and has the brake line nuts already on it, and is flared for you too. If you want to stay with ISO bubble line fittings you can get that in bungy brake line lengths too but it is less common for some stores to carry, and that is why the conversion brake line fitting adapter mentioned is so easy a way to change from ISO bubble flare to a double flare for easier use of all steel line being standard American double flared brake line. The brake lines come in straight lengths, 2ft 4ft, and 6ft, so you can use them to fit your necessary total length by connecting them with tubing couplers which the steel tube lines brake line nut gets threaded into.
My same year Durango had its rear line blow thru last year, due to the rusting of the steel brake line. I just got done last week, doing a entire steel line replacement myself. It was a medium sized effort for sure. You should check the other lines for the entire brake system to see if you need to replace more than just that section which failed for you, as my lines showed heavy corrosion at many other locations in the brake line system.
It is easy to double flare brake line tubing , and Sears sells its craftsman brand of brake line double flare tool kit for that purpose at about 60 bucks if I recall it right.
One thing you should do when doing your own double flaring, is to use a dial caliper to measure the diameter of the flare at its widest flared end, to insure you are within the required diameter of flare to insure proper sealing when you tighten down the tube flare nuts. I recall the flare diameter is supposed to be 0.272 inches , plus or minus 0.006 inches ( so range of dial caliper measuring of that formed flare should be between 0.266 inch and 0.278 inch) to insure the right diameter of flare for good sealing.
You can also get steel galvanized tubing line in coils of 20ft and more, with a bunch of brake line nuts ( all this is standard american brake line nuts, for double flared line fitting) from Inline Tube company; www.inlinetube.com.
Check out the great tech info from FEDHILL website, www.fedhillusa.com
Good luck, I did it so you can do it and feel satisfied and safe for the family with solid and sound steel line that is much better than chancing an accident via leaving the rusted line in place.