replacing brakeline

1997 Blazer 4X4 LT. I had to slam on the brakes and driver side brake line going to rear wheel burst around by the back door area. Looked at it and the entire length of brakeline looks rusted. How do you replace this? How do you get to it??? It is on top of the frame rail and looks very inaccesible. Any help is greatly appreciated.

My guess its probably has metric fittings. Many auto parts stores have brake lines in various lengths, complete with all flares and fittings on both ends. It's much easier to use such prefab lines rather than making your own. flaring your own lines is tricky to do, even for experienced mechanics.

I would suggest you carefully remove the line and take it to an auto parts store and get a new line of the same or slightly longer length and width, with matching fittings.

If you get the old line off without bending it, you can bend the new line to the same shape, so it takes the same routing. You can usually bend it with your hands, or bend it around some larger sockets to get a nice radius curve. Do not kink or crease the line. If you do, the line is ruined and you will have to start again with another line.

Then install it,(try to use the same clips and fittings) tighten the fittings ( a set of line wrenches would be an asset) and bleed the brakes.
Make sure the line is secure and does not rub on any sharp edges.

Note, if the old line is truly inaccessable, you can leave it in place and run the new line alongside. This may be a bit trickier because you would have to make sure the line is routed away from places where it can be damaged by a stone thrown up, or by off-roading damage.
You would also have to secure it properly, so it wont shake or vibrate and will not touch the car on any sharp edges.

If you must route a line in such a manner, its best to use an armored line, which is wrapped up in a wire housing.

thanks for the response. I have shaped brakelines in the past and have a couple tools for that purpose. I haven't flared any lines but have used compression fittings before. What is your experience and opinion on them? I like your suggestion of running the new lines next to the old ones. Like you said, I would have to run them where they wouldn't get damaged and attach them securely. I was first thinking I would have to remove old lines completely and run the new ones in the exact same place and that is where it seemed very difficult so I was really wondering was whether there was any proper, or easy, procedure for removing old lines from along the frame rail on the 97 blazer because I just couldn't see how to reach up there and disconnect and reconnect things; there just is not enough working room it seems. thanks again!!

DO NOT use compression fittings. Compression fittings are only rated to 170psi, not NEARLY enough for a brake line. Brake lines must use inverted flare or bubble flare. The OEM fittings on the vehicle are in fact metric. If it's a 4 door, you can remove the fuel tank and get right at the entire length of line.

1997 Blazer 4X4 LT. I had to slam on the brakes and driver side brake line going to rear wheel burst around by the back door area. Looked at it and the entire length of brakeline looks rusted. How do you replace this? How do you get to it??? It is on top of the frame rail and looks very inaccesible. Any help is greatly appreciated.

i would recomend using the black coated brake line they will not rust as bad.

Like Old Master said, NEVER use compression fittings.....

This vehicle uses a bubble flare......if you can find a good section of pipe, you cut it there, install nut and then make the bubble flare....then use a union and go new pipe the rest of the way(can measure this with a string alongside the old pipe, then measure the string itself)......then purchase pre-made sections and unions to make up the length....

thanks to all! That's exactly what I was looking for. Specific information. I'm gonna attempt this next week and I expect also to replace some other brakeline hardware which may be rusted, corroded or froze. I will update next weekend. It is a four door so I will first remove gas tank.:smokin:MERRY CHRISTMAS

thanks to all! That's exactly what I was looking for. Specific information. I'm gonna attempt this next week and I expect also to replace some other brakeline hardware which may be rusted, corroded or froze. I will update next weekend. It is a four door so I will first remove gas tank.:smokin:MERRY CHRISTMAS

I purchased a double flare tool at auto zone for 20.oo ..the flare fittings and brake lines are available in sizes with fittings and flares or get the 25ft roll and make exactly what you need.

thanks to everone for the good sound advice. I wasn't able to complete job yet; had family emergency. I got the side of truck up on jack stands and removed wheels and sprayed down brake line unions and fuel tank strap nuts with PB Blaster. That's as far as I got. I'll get back to you.

thanks to everone for the good sound advice. I wasn't able to complete job yet; had family emergency. I got the side of truck up on jack stands and removed wheels and sprayed down brake line unions and fuel tank strap nuts with PB Blaster. That's as far as I got. I'll get back to you.

use care to not get any oils into the brake system.

Pretty sure these are bubble flares, not double flares....

Pretty sure these are bubble flares, not double flares....

the double flare tool I use makes the same flare that the brake line fittings sold at the part stores sell. the replaement tubing sections sold as well.

I know british vehicles use the 37 deg bubble...

the double flare tool I use is 45deg and fits perfect with the new fittings.

I believe these vehicles do have the bubble 37 deg flare. that would be the ISO. I used SAE so I went with the double flare fittings.

Just to update... I haven't done much yet. As always, been too busy. The truck is in my garage with driver's side on jack stands and wheels removed. I guess I do have decent access to the old line and there doesn't seem to be any unions between the one behind the front wheel and the one near rear axle. I have pryed the old line from the plastic clips, sprayed fittings wih PB blaster and that's about it. someone said to cut the lines at the nut and then loosen it with six point socket, that it might be easier that way instead of using flare wrench. I really appreciate all the input from you all. I'll update again later.

well I did cut the lines at the nuts at both ends and used six point socket or wrench to loosen nuts. They came out easier than I anticipated but then they had been soaking in PB blaster for a month. Then I felt my way along the brake line on top of frame rail and felt the plastic clips and pried the brake line out with a flat scewdriver. There were four clips. Once the brakeline was loose, I pulled it out from the rear wheel well twisting and turning until it came right out. It was one piece ten feet long. I did not have to drop fuel tank thankfully. I plan to use 2 pieces of the AGS poly armour bendable pre flared lines with one union placed somewhere in between where it would be easy to get to, probably in rear wheel well area where there is enough open space to get wrenches in. Thanks for listening and thanks for all the advice, I used a lot of you guys knowledge and it got my old brain turning too! Does anyone have any experience with the AGS poly armour lines? Can they really be bent by hand without kinking?

well I did cut the lines at the nuts at both ends and used six point socket or wrench to loosen nuts. They came out easier than I anticipated but then they had been soaking in PB blaster for a month. Then I felt my way along the brake line on top of frame rail and felt the plastic clips and pried the brake line out with a flat scewdriver. There were four clips. Once the brakeline was loose, I pulled it out from the rear wheel well twisting and turning until it came right out. It was one piece ten feet long. I did not have to drop fuel tank thankfully. I plan to use 2 pieces of the AGS poly armour bendable pre flared lines with one union placed somewhere in between where it would be easy to get to, probably in rear wheel well area where there is enough open space to get wrenches in. Thanks for listening and thanks for all the advice, I used a lot of you guys knowledge and it got my old brain turning too! Does anyone have any experience with the AGS poly armour lines? Can they really be bent by hand without kinking?

allowing the penitrating oil to take hold after a few weeks is the way to go if you can wait. less damage .

two piece is what I did for this one . on the type lines you used I never used them , but using a tubing bender is a good idea especially on the abs pump bend area.

well I finally found time and got the brakeline installed. I used all you guys knowledge and it made job a lot easier, thanks a lot. I got the poly armour bendable line by hand and I got pretty close to original routing. As usual tho, there is something else. When I tried bleeding the line (left rear), no fluid came out of the bleeder screw. Wat up?? I tried about 6 different times with friend pumping and holding pedal to floor but nothing. No fluid, no pressure on pedal. I started vehicle and pumped brake pedal thinking it would build pressure but still nothing. I put a new bleeder scew in too. Do I need to bleed all four wheels? If so, I start with one furthest from master cylinder right? This model Blazer is ABS. Do you bleed them the same way? thanks again!

well I finally found time and got the brakeline installed. I used all you guys knowledge and it made job a lot easier, thanks a lot. I got the poly armour bendable line by hand and I got pretty close to original routing. As usual tho, there is something else. When I tried bleeding the line (left rear), no fluid came out of the bleeder screw. Wat up?? I tried about 6 different times with friend pumping and holding pedal to floor but nothing. No fluid, no pressure on pedal. I started vehicle and pumped brake pedal thinking it would build pressure but still nothing. I put a new bleeder scew in too. Do I need to bleed all four wheels? If so, I start with one furthest from master cylinder right? This model Blazer is ABS. Do you bleed them the same way? thanks again!

I think I mentioned before that you must not push the brake pedal to far down and bottom out the master cylinder. this can cause it to stick in the down position. if so you will get a dead brake pedal.

pushing the pedal about 3/4 down easy and not too hard so as to not cause this sticking.

with a helper I like to loosely hook up the down stream portion of the brake line at the junction fitting in the rear. bleed the line at that point /until fluid comes out then tighten the fitting. then go to the caliper/brake cyl. bleed screw.

well I finally found time and got the brakeline installed. I used all you guys knowledge and it made job a lot easier, thanks a lot. I got the poly armour bendable line by hand and I got pretty close to original routing. As usual tho, there is something else. When I tried bleeding the line (left rear), no fluid came out of the bleeder screw. Wat up?? I tried about 6 different times with friend pumping and holding pedal to floor but nothing. No fluid, no pressure on pedal. I started vehicle and pumped brake pedal thinking it would build pressure but still nothing. I put a new bleeder scew in too. Do I need to bleed all four wheels? If so, I start with one furthest from master cylinder right? This model Blazer is ABS. Do you bleed them the same way? thanks again!

suppose to start at right rear but i just do them anyway on bleeding and your fluid not coming out when you loosen bleeder take it all the way out see if fluid comes out if so you can try to clean bleeder but i'd go get a new one from parts store wont cost but about buck.

Will do! What's this I hear about the ABS pump needing special code reader or special tool to allow it to be bled?? Sorry dude but I forgot to mention a very important thing, when brake line burst, I had to drive about 6 miles home and pressed brakes along the way but tried to use emergency brakes the whole way and dumb ass me, did not stop to fill master cylinder with fluid along the way. Got home and it was not entirely empty but front resevior on master cylider was 90% empty. Shit!! So there might be air in ABS pump and could this prevent brakes from bleeding properly?

Will do! What's this I hear about the ABS pump needing special code reader or special tool to allow it to be bled?? Sorry dude but I forgot to mention a very important thing, when brake line burst, I had to drive about 6 miles home and pressed brakes along the way but tried to use emergency brakes the whole way and dumb ass me, did not stop to fill master cylinder with fluid along the way. Got home and it was not entirely empty but front resevior on master cylider was 90% empty. Shit!! So there might be air in ABS pump and could this prevent brakes from bleeding properly?

this is when the ABS valve body I believe for sure will require the GM ABS bleeding equipment. these valves must be commanded to operate as the bleed process is being done. air will be traped in this module.

If you ran the master dry this can cause the master to stick. If so then you will get no pedal resistance / pressure created.

do the master cylinder bleed proceedure then see if you can do some bleeding. then if you find that the ABS valve body is causing brake issues you will require the GM bleed process.

I lucked out. I found an electrical connector unplugged from ABS pump and plugged it back in and ABS light turned off. I really dont know how it came unplugged. I then sucked out all old fluid with baster and wiped out master cylinder with clean rag (it was all black). I refilled with fresh fluid and started blazer up and I got some good pressure on brake pedal. I drove around for 3 blocks and checked and no leaks. Brakes feel OK but still not as firm as normal. I did not try bleeding yet but I noticed brake light on. Will this go out when I bleed brakes and what might cause light to be on? Thanks again for listening and advising.

Sounds like you still have air in there somewhere. This procedure will remove all air that is trapped in the system. Remove the master cylinder cover, fill the master cylinder, leave the cover off, open a bleeder, let it drain for maybe 10 minutes, make sure the stream is clear, (no bubbles) keep the master full. Repeat this for each wheel, doesn't matter what order. Then perform the automated bleed, this will force any trapped air in the ABS unit into the brake lines. Do not open any bleeders while the automated bleed is in progress. When the automated bleed is complete, then use the two person bleed procedure, (not vacuum, not gravity) until no bubbles are present at any of the wheels. By the time it's all said and done, it's not unusual to use a pint of fluid at each wheel.

The parking brake and the proportioning (centering) valve can turn the red "BRAKE" light on. After the system is bled properly, and the proportioning (centering) valve is centered, the light should go off.

with what you just stated now and before why did you not bleed the brakes? the red brake light should reset when this is done.

jc AT, you are right, Why didn't I bleed them right away. Guess I was just too anxious to get back on the road and get the thing out of my garage and the brakes were pretty decent. I just got done bleeding them and it took a while but air started coming out then fluid and pedal got more firmed up. I drove around and within 2 minutes, the brake light reset and went out just like you said. I want to thank you and oldmaster and scrapper and everyone else who listened and helped me out. This site is great. Now on to replacing driver side fender, grill and bumper. Thanks again!

jc AT, you are right, Why didn't I bleed them right away. Guess I was just too anxious to get back on the road and get the thing out of my garage and the brakes were pretty decent. I just got done bleeding them and it took a while but air started coming out then fluid and pedal got more firmed up. I drove around and within 2 minutes, the brake light reset and went out just like you said. I want to thank you and oldmaster and scrapper and everyone else who listened and helped me out. This site is great. Now on to replacing driver side fender, grill and bumper. Thanks again!


so the brakes are complete . the ABS/brake fluid issues can be confusing at times. contamination usually causes the braking components to act up. bleeding the system at the pad/shoe replacing helps remove the bad fluid from the system. air has water in it this then creates pitting and corrosion in the brake system.

brake fluid according to GM lasts forever. this is not correct. many vehicles have recommended brake fluid replacement intervals to ensure correct ABS operation.

good luck with your vehicle repairs.