Brake line replacement.

[71T Targa]

Well, I’ve just opened my box from Pelican with a few brake goodies. I’ve got shiny new brake lines, new bleeder valves and caps, a liter of ATE Superblue, and a Motive Power Bleeder.

My plan is to drain the fluid and replace the lines, then use something ‘cheap’ to flush the system with.

Are there any ‘gotcha’s’ I should watch out for? I know getting the old lines out may be a bear, but is there anything else? Anything I’ve forgotten?

And finally, can I just go to Wal-Mart and get the cheapest brake fluid they have? I’ll just be using it to flush the system, then replacing it with the ATE.

[turbo dave]

Make sure you use a wrench that wraps around the bolt (don't remember what it is called), not just a regular wrench, when loosening the lines. You run a real risk of stripping your nut heads (ask me how I know...)

[scphelps1]

I believe it is called a flare nut wrench.

[Don Plumley]

It's called a Flare Nut wrench, important to use on brake fittings.

Don't forget to clamp the overflow line shut first, or you will make a big mess.

Brake fluid eats paint, so be very careful. I'm going to have a bucket of water standing by just in case.

Otherwise, I'm doing the very same tomorrow (flush and fill) and am very interested in any tips or hints.

Don

[Jim Sims]

The wrenches are called tube wrenches or flare nut wrenches; one can get a reasonable set at Sears.

Use a compatible DOT-4 brake fluid for your flush; see:

http://members.rennlist.com/911pcars/brakefluid.htm

The rubber gromments on the top of the master cylinder that seal the lines coming down from the brake fluid reservoir become brittle with time and can blow out and leak when using the Motive presssure bleeder; Pelican sells replacement gromments if this happens to you. Also if you end up damaging a metal "hard brake line" Pelican also sells replacements.

Cheers, Jim

[cary]

Don't forget to clamp the overflow line shut first, or you will make a big mess.

Comes out, up front behind the valance. #2 pencil works great for a plug.

[Jim Sims]

Sometime ago I wrote this essay on the topic:


Here's what I do (for cars with each caliper having a single bleeder valve):

Gather tools and materials: floor jack (with wood piece on lift pad), jack stands(4), soft socket for wheel nuts, 100 ft-lb torque wrench, 1 liter
Ate brake fluid (in a different color than currently in car), Motive pressure bleeder, small 7 mm and 8 (or 9?) mm box end wrenches, 8-10 "
length of clear hose to fit over bleeder valve nipples, rubber cap or bit of rubber or plastic hose with one end plugged (golf tee, etc.), container
to receive old brake fluid (small glass jar), metal can for old brake fluid disposal, cardboard box lined with plastic trash bag sufficient to hold
motive bleeder, small stand or box to set glass jar on, old newspapers, paper towels and hand wipes. One may also consider having a spare
bleeder valve available (some car use two sizes - front and rear can be different) and new rubber bleeder valve dust caps.

Place car with adequate space to work around vehicle (no tight garages). Loosen wheel nuts. Jack car up, place on jack stands and remove
wheels. Put newspapers under each wheel position. Remove bleeder valve rubber dust covers and clean if reusing. Clean dirt off bleeder valves
as required. Open front hood.

Brake fluid will be handled after this point; DONT GET IT ON YOUR PAINT! It will damage the paint and attempting to wipe it off will make the
damage worse. Some attempt to blot or wash it off but the damage will still occur. Take your time. Wipe up spills (on floor, non-painted car
chassis surfaces and tools) immediately and thoroughly. Watch your hands, clothes and shoes. Clean your hands often and don't touch or lean
on the car (the reason for not having a tight garage).

Remove MC reservoir cap (debris screen under cap may be left in place) and vent hose (take care that you don't snap off the integrally molded
hose barb) and install vent cap or bit of hose with gold tee or other plug. Place Motive pressure bleeder (PB) tank in plastic trash bag lined box and place in front trunk area next to MC reservoir and attach Motive PB cap to MC reservoir. Pump up PB (follow
instructions on PB) to around 10 psi (higher pressures may run the risk of blowing out the rubber bushings which seal the plastic lines from the
MC reservoir to the MC. If you can't hold pressure check for a leak (MC reservoir cap, vent line hose barb plug, PB tank lid). Look for leak from
MC area; if the plastic line to MC joint rubber bushings are bad there can be a leak from MC.

After proving that hookup holds pressure; release pressure by unscrewing the pump lid of the PB, not the connection at the MC reservoir! Then disconnect at the MC reservoir and remove the PB from car. Fill the PB with brake fluid and put back into plastic trash bag lined box and hook up to MC again. Pump up PB (follow
instructions on PB) to around 10 psi. Starting at the wheel position furtherest from MC (RR in LH drive cars) place wrench over bleeder valve hex and attach clear hose to bleeder
valve nipple. Place hose in jar (I sit the jar on a box or stand of some kind so it is at a convenient height). Open bleeder valve (take care to
pull the wrench in the correct direction; the bleeder valves are on the inside of the calipers so one can get mixed up). If bleeder valve won't
open and shows rust or corrosion spray the base of it where is screws into the caliper with "Kroil" or other penetrating oil (not WD-40) and wait
15 minutes and try again. The hose will want to twist as the bleeder valve is opened so take care that it stays in the jar and doesn't tip the jar
over. Allow the brake fluid to flow until one obtains a full transition to the new brake fluid color. Close the bleeder valve; don't over tighten - I
use small combination wrenches to limit my ability to over torque. Remove hose and wipe up any spilled fluid. Look for leaks from bleeder valve;
if leaking tighten a bit more. If no leaks, install cleaned or new dust cap onto bleeder valve. Repeat at other wheel postions working towards
MC (LR, RF and finally LF). I empty the jar of old brake fluid after each wheel position. If you put the full liter of brake fluid in the pressure
bleeder you should have plenty of fluid to bleed the entire system but check that you always have enough fluid in the PB tank to keep its
intake well covered (one can tilt and shim up the cardboard box to force the fluid to the intake side of the tank). Also check PB pressure; my
experience is that I don't have to repump it much if at all. I usually make a second pass around the wheel positions to ensure I have exchanged
as much fluid as possible in the wheel calipers.

When finished with all wheel positions depressurize the Motive PB by unscrewing ITS lid (follow instructions). DON'T UNSCREW THE MC LID
FITTING FROM THE MC UNDER PRESSURE! Check brake pedal for firmness (CLEAN HANDS, CLOTHES AND SHOES! Wife or girlfriend in clean attire
is useful for this task if they know what the brake pedal should feel like). Check all wheel positions for leaks. If needed add fluid to MC
reservoir, replace MC reservoir cap (check cap for cracks and gasket if equipped with one). Remove vent cap or plugged hose piece and
reinstall vent line. Remove Motive PB from trunk and remove surplus brake fluid from Motive PB and wipe it out with clean paper towels. Secure
old brake fluid and surplus new brake fluid. Pick up newspapers under wheels. WASH HANDS!

Close front hood. Remount wheels, install lug nuts by hand and seat them well by hand using soft socket and using the cross-wheel tightening
pattern. Lower car and torque wheel lug nuts to 50 ft-lbs using cross-wheel tightening pattern, repeat but torque to to 94 ft-lbs.

Test drive, starting out carefully as if you have no brakes. Test brakes with a gentle stop in driveway. After test drive look for leaks. Good
Luck! Jim

[71T Targa]

WOW, Jim this is great info. Where is the tech. article?

[pbs911]

My plan is to drain the fluid and replace the lines, then use something ‘cheap’ to flush the system with.


Are you replacing all the lines or just the flex lines? Personally I would flush the old system with cheap brake fluid to remove any contaminates in the lines that come before the lines you are replacing, install the new lines and bleeder valves, flush again with cheap brake fluid and then go with the Blue.

Either way is probably the same, but I wouldn't want to flush the old junk through the new lines.

[71T Targa]

Good point, I’m just planning on replacing the flexible lines. So a flush before and after could be in order.
How much of the cheap stuff will I need for this job? Or is there anything else I could/should use for the first flush?

[dtfastbear]

Three small pieces of advice that I wish I had before I did the same task. They might seem very obvious, but those are usually the things that bite you!

1) Make sure you use the correct lines on the front and back! I accidentally put the shorter lines up front. They fit, but I'm sure that if I'd put the car down and driven it, they probably would have ripped out when the suspension went through its full range of movement, like at the end of a straight at the track

2) Make sure that you do NOT twist the fittings on the lines or the lines themselves! They must remain absolutely still as you screw the hard line's fitting INTO the flexible line. Make sure you use a wrench to isolate the fitting on the flexible line.

3) Several people have already said that you should be sure to clamp the overflow hose. I thought I had, but it wasn't securely clamped and fluid was able to make its way through once the system was pressurized. The result is a mess that no one would want to deal with.

Good luck!

Dean

[71T Targa]

Originally posted by dtfastbear

2) Make sure that you do NOT twist the fittings on the lines or the lines themselves! They must remain absolutely still as you screw the hard line's fitting INTO the flexible line. Make sure you use a wrench to isolate the fitting on the flexible line.


Dean

So when I remove the old lines, I should hold the flexible line in place and turn the nut on the hard line? I probably would have done the opposite of that.

[KTL]

That's right, you counterhold the flex line end and do the turning on the hard line end.

I soaked my lines with PB B'lasta a few times before (read: days) actually turning the wrenches on the lines. Some of the lines still didn't come off cleanly and twisted the hard line. The hard line fitting didn't want to spin on the line itself. Mostly boogered up with that annoying sealant that's on virtually everything underneath the newer cars. My car has only 65k mi. on it so i'd expect the same results on other, older car's brake line removal jobs too?

I'd recommend a little wire brushing beforehand and count on having to replace at least one hard line (if your flex lines are still the originals as mine were).

Just my $.02

[71T Targa]

Do I need to use any lube or loctite on the threads?

I was thinking teflon tape would be a good idea here

[Jim Sims]

Use neither (certainly not loctite); these threads do not make a seal but instead push the shaped end of the hard brake line tightly against a sealing surface inside the hose. I would use nothing on the threads but a very small amount of "neverseze" or similar compound on the nut threads might make it easier to get them off in the year 2012 when they're replaced again. Just don't get the neverseze on the sealing surface on the end the brake line and don't overtighten as the neverseze will reduce the thread friction. Cheers.

Don't buy a cheap flair nut wrench spend the extra bucks on a SnapOn.

The torque on the the brake lines is 14Nm or about 10 lb-ft or 120 lb-in. Depending upon model of course.

So at the same time buy a 3/8 drive 11mm flair crows foot wrench and borrow or buy a torque wrench that covers the 14Nm range.

You will also have to compensate for the added length or get an offset extension when torqueing.

Also before putting the wheels back on, very carefully clean all the points where brake fluid can leak from (all the connections you opened up) with brake clean. As always read and understand the directions.

The above is after the brakes are blead of course. Then have someone step on the brakes and check for leaks at any of the points in the brake system that you opened to air. After the m/c that is.

[turbo dave]

Wow, that's the last time I post a massively lame response to a question! Well, at least I'll attempt to be less massively lame...


Anyway, it wasn't that hard to do, and it helps firm up the pedal- you'll be happy you did it-

[vesnyder]

I just did mine last month. The only issue I ran into was on one of the wheels I could not get the nut to spin free of the line that went from the brake to the SS hose! I just put that end of the SS brake line on first and no problems. The bleeding went very easily - I used the vacuum pump and probably should have had someone help me pump them to finish them off but they are firm and seem very good!

[phaques]

What is the expected life of stainless brake lines (non-dot)? A mechanic recently told me that if I am using these for track use, I should expect to replace them every few years..is that right? BTW, it appears that some sort of rubber substance appears to be pushing through the stainless jacket on my lines - what is this?

[KTL]

That's the rubber hose that carries the fluid. The braided shielding is merely that- shielding. Kinda like sheathing on wire?

The braiding is to provide abrasion resistance.