beasticles

Greasy - quick update for you - I installed the new rear brake line (that runs from the top right port on the ABS to the splitter above the rear diff in the back). Another forum member posted in this thread: http://www.gm-trucks.com/forums/topic/177718-best-way-to-remove-rear-brake-line-from-abs/page-2#entry1691258 thatthese AGS tube nuts are a perfect replacement for the ABS fittings - and he was correct: http://shop.advanceautoparts.com/p/american-grease-stick-co.-steel-tube-nut-5-per-card-1-4-in.-1-2-20-inverted-blf-44c-5/22190121-P . I actually could have salvaged my old fitting, but the new ones were a perfect fit (and at $2.50 for six nuts - why not!). I used a standard 1/4" tube and nut for the rear splitter - which I was able to source from Advance Auto as well. As I mentioned in my prior post - I used EasyBend brake line from Amazon.com https://www.amazon.com/gp/product/B0027ABNUC/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1which worked great for my application - no issues with simply bending by hand. Having never flared brake line before - I practiced on short pieces of line Saturday night before tackling the job Sunday. I was able to get decent double flares on both ends of the line (obviously don't forget to have your tube nuts already on the line and facing the correct direction before flaring). I had multiple flare nut wrench sets on hand - but in the end - due to the cramped space, I ended up using a small Craftsman 9/16" open-ended wrench to crack the ABS nut loose and remove (it was slow going as I had to turn it little by little due to the lack of clearance - damn you GM), and for the rear splitter I used a pipe cutter to snip the old line and was able to get a 1/2" (?) socket over the fitting to remove. The ABS fitting was on very tight as others have mentioned - and due to the lack of clearance I really had a heck of a time getting it to crack loose. It took all my strength with the small open-ended wrench to crack it loose - but once it is cracked - it will come off relatively easily. I left the old line in place (it was rusted to hell and I didn't want to deal with removing it), and simply threaded the new EasyBend line along the top of the frame rail. I connected the line to the rear splitter first - then slowly threaded the line all the way up to where the ABS unit is. It's a little trick to get the tube nuts initially threaded into the ABS and the splitter, because the brake line is fighting you from "squaring" it up, but once you have the first thread in it snugs right up. I still need to bleed my brakes tonight (was ready to retire for the night after getting the new line in) and check for leaks, but the hard part is now done! Timing wise I started around 5pm and finished around 7:30pm - just for removing the old line and getting the new line installed. Let me know if you have any questions. When my rear brake line started to weep I was doubting my ability to tackle this job, but it is certainly doable for the average shade tree. Another tip - removing my spare tire made it much easier to move around the rear, deal with the rear splitter fitting, and feed the line up the frame rail from the back. It's not necessary but gives you a bit more space.

Greasy - brucelimerick's longer post above is immensely helpful as he was kind enough to actually list out the sizes of each line along with the size of the fitting at each end: "The rear lines are conventional 3/16" after the splitter on the rear axle. The line running to the splitter is 1/4" line and a 1/4" fitting going into the splitter. Where this line goes into the ABS it is a 5/16" fitting taking a 1/4" line. The 2 lines coming from the master cylinder to the abs are 1/4" line with 5/16" fittings drilled out for 1/4" line. The 2 lines to the front cylinders are 1/4 " line with 1/4" fittings at the calipers and 5/16" fittings with 1/4" line at the ABS. You can't buy these lines. All the mechanics I talked to after making the assumption that the 1/4" line would have 1/4" fittings could buy the 5/16" fitting with the 1/4" bore and they made their own lines. I ended up getting 1/4" to 5/16" adapters for the connections to the ABS and ran 1/4" lines. The adapters are a problem, they have to have the small end on the 5/16" side. The big ended ones can be used on the master cylinder. The 5 on the ABS required me to phone and visit every automotive part store in 200 miles." Since I only plan to replace my ABS to rear-splitter line (which runs the length of the top of the driver's side frame rail), I went with 1/4" Easybend line from Amazon: https://www.amazon.com/gp/product/B0027ABNUC/ref=oh_aui_detailpage_o01_s01?ie=UTF8&psc=1 And plan to purchase a 1/4" x 1/4" fitting for the splitter end, and a 1/4" x 5/16" fitting for the end that ties into the ABS. I also purchased this https://www.amazon.com/gp/product/B007C6JZ6A/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1 flexing and ratcheting flare end wrench to hopefully help with the awkward angle of the fitting at the ABS pump (the one going to the rear splitter is the top right corner fitting). I will be making my own double flares on the Easybend line, and bending it into place by hand. The only thing that is unusual is that some of the fittings are 5/16" with a 1/4" bore, but if you Google you'll find many parts stores carry such a fitting. Will post up how things go.

I know this is an old thread - but it is one worth digging up since it deals with the notorious brake line rust that troubles most GMT-800 body trucks. About to tackle replacing the hard brake line that runs from the ABS module to the splitter at the rear of the truck feeding the two calipers. I joined this forum just to say thank you, particularly to brucelimerick, for all of the information posted about this job. Basically, my background story is that I bought a higher mileage (163,XXX) Z71 Suburban (2003) on Craigslist for below market price - the guy was just trying to get out of his loan payment. The body was clean and the interior in decent shape, but it had clearly been neglected. The suspension was original (shocks and everything) from the factory, and the underside has significant surface rust (not frame damage though) as the vehicle started its life in Michigan (I am in Virginia). I have been working through the vehicle, updating and replacing parts as needed, and it is shaping up to be a pretty decent car. I am still questioning whether or not I would buy another GM vehicle, as I have experienced now two inexcusable design failures - the transfer case pump rub issue (causes pin-sized holes in the t-case), and now the rusted to hell brake lines. **End rant** The other weekend I replaced all of my shocks and put new coil springs in the rear of the truck. Of course, after letting the axle droop I now have a brake line leak in the long line running from the ABS module to the rear splitter. Thanks to this forum I have already purchased EasyBend brake line (copper nickel) and a double flare tool - I plan to cut out the old line at the ABS module and the splitter, but otherwise leave the old line in place and simply bend into place a replacement line which I will secure to the existing line. I appreciate all of the information here - particularly on the fitting size/line sizes. I also have a Motive Speed Bleeder so hopefully that will help with the process. The only concerns I have about the job are creating my own flares, and tightening the new line to the ABS module where there is hardly any place to fit a wrench. Will post up how it goes for anyone else who might be up for tackling this job. After realizing how expensive it would be to have a shop do this job, I decided to tackle it myself even though I have never replaced a hard brake line before.