brake lines

i've been searching - anyone know of a good tech writeup to changing the steel brake lines on an XJ?

on my DD, they look like they are about rusted through - the elbows look like they are going to snap.

on a scale of 1 to emergency, i'd say i'm at a 7.5.

anyone bend their own lines?

I bought a few feet of line at Autozone and made one line to replace one that corroded/split on me. I rented their flaring tool and had to practice a lil to get the flare right.

how expensive was the line? I need to replace the entire two lines that go along the driver's side frame rail.

also - what kind and how many fittings should i pick up? can fittings be reused? where do you drain the brake fluid? i'm like a lost child in a grocery store.

When your draining the brake fluid, it's best to plug up the line someplace before the master cylinder, if the master cylinder runs empty, you may have to prime it again. Sometimes they prime easy, sometimes they are a pain.
Brake line in a roll shouldn't be too hard to find, it's been awhile, but I bought enough on line for $20 to do two XJ's or more. Flaring takes some pratice. All brake lines aren't created equal , some are *harder* and harder to flare.
There aren't two brake lines running along the frame rail to the rear. One is a brake line, the other is the fuel return line from your fuel rail or possibly the gas tank vent to the charcoal canister.
Many of the fittings for the XJ are kind of specialty items. The local Auto zone may or may not have them.
One trick I learned is to cut the line a little long, you can always put an extra bend in there to take up the extra line, but you can't add any line if you mess up a flare or two.
While you have the line out, it is a good time to replace the rear wheel brake cylinders.
The T fitting at on the rear axle is the only one I've ever replced. Not because it was bad, but the rubber line fitting was all but welded on there. They can be hard to disassemble.

bacelaw said:

also - what kind and how many fittings should i pick up? can fittings be reused? where do you drain the brake fluid? i'm like a lost child in a grocery store.

Click to expand...

I am 98% sure that I reused the old fittings. Make sure you slide the fitting over the line before you flare it though. (ask me how i know..lol) You'll also need a tubing cutter that can be rented at the parts store.

I was doing the pass. front line so I can't comment about how the line(s) are routed/configured to the back of the jeep.

There are numerous methods to brake fluid bleeding, I did a "gravity bleed". You just open the bleeder valves one at a time and put a catch pan under it. It takes about 20-30 minutes for each wheel but I find it is the easiest way. Keep an eye on the reservoir and add a little fluid periodically so it doesn't run dry.

Be sure to mount the line well. If it's aloud to move it will often rub a hole after some time.





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It's hard to find a good bud.
It's even harder to lose one.
WORK SAFE

i just did this on the weekend, and there is only one brake line on the frame rail fyi. just remove thge old one from the proportioning valve, you will need to reuse that fitting and get some preflared lines with connectos 3/16 from parts shop and bend them to the shape of the one you removed, from the combo, then add the one to the rear rubber line from the diff and join the two together.

For a New England vehicle that's going to see future rust, consider getting shorter pieces of line for the main one that goes along the frame, joined by connectors. The cost won't be that great, and in addition to making it easier to get the length right, you can then replace individual sections later when they rust again. The couplers are brass, and can be disassembled and reused even when the rest of the line and fittings have turned to a glob of unrecognizable rust.

Start measuring at the rear, and work your way forward, trying to arrange it so that there will be a separate line from the proportioning valve down to a little above the point where the line starts up from the horizontal frame run. the number of pieces on the straight run is optional, but if you put a coupler more or less in the middle it makes things a little easier. This gives you the option later of replacing the bottom part or parts without redoing the part in the engine compartment, which rarely rusts. If you get the pieces with a little extra length, it's easy to loop the piece that goes up to the proportioning valve to take up the slack.

I have done this on my Chevy truck, which loses at least one brake line a year. It saves a lot of time.

great advice people - when i remove the old rusted line from the rubber one in the rear -will brake fluid spray everywhere?

do you drain the entire system and replace the fluid?

This is worth a look http://www.classictrucks.com/tech/0501cl_brake_line_basics/

Whichever section you decide to replace, make a plug, so the master cylinder doesn't run empty. It won't spray unless you push the brake pedal. But it will slowly drain, often until the master cylinder is empty. Search brake bleeding, ABS is a whole nother can of worms.
I've found vice lock pliers, adjusted so they are very firm but don't crush the fitting, about the surest way to remove a fitting, I wiggle the flare nut back and forth, until the bond breaks, then switch to a flare nut wrench. A good set of flare nut (or line wrenches) is a must, regular end wrenches won't get it. It is easy to round off the flare nuts. Sometimes you get lucky and can loosen the flare nut with a flare nut wrench, you have to know when to guit, so you don't damage the nut.
New flare nuts, don't have to be tightened that tight, the flare is actually the seal and overtightening can crush the flare and cause cracks.
Making a good double flare takes some practice. Make sure the flaring tool fits the brake line well. Sears brake line flaring tool is what I use, I have half a dozen different types to choose from in my shop.
Some of the brake lines in later model XJ's are millimeter, most are SAE. Not much difference in 5 mm and 3/16", a micrometer might come in handy. A good thread gauge might also be usefull, assuming can get you in trouble.

Well I never did lines before and even I managed to do it. The generic brake line comes in various lengths with the fitting on each end (yours has the same fitting on each end while some vehicles vary). I used a small common tubing cutter and bought a cheapo flaring tool that could do double flares (brake-lines use a double flare). Anyhow the line is a few dollars and the tool kit about 25 bucks. Not big money for sure. Buy an extra piece of line to practice on.
I bought a fancy bending tool but found that the line bent easier and more accurately by hand using the old line I removed as a guide. Once it was bent to shape I cut off the extra, slipped on the fitting and used my flaring tool...done...30 minutes tops.
Buy a line wrench to make tightening the soft brass fittings easier without damage.
I did lose brake fluid so a quart would be useful to have on hand. My ABS brakes were unaffected by the installation although the light turned on for about 30 seconds until the fluid circulated throughout the system.
Finally, don't waste the money a one man bleeder kit if you have a friend and a pair of safety glasses.