DIY brake lines change ?

[asylum]

I searched the forum but did not find a complete procedure to change the 4 brake lines.

Will it be ok if I procede like this :

- unscrew the brake line and put the new one (will there be brake fluid leaking ?)
- open the brake fluid reservoir
- bleed the brakes like this to throw away the air in the brake lines : http://www.danoland.com/nsxgarage/brakes/bleed/bleed.html

Or do I need to totaly empty the brake circuit before unscrewing the old lines ?

 

[MvM]

I recently replaced both my front brake lines. One was because it was damaged and leaking. I replaced the other one just as a precautionary measure.

The procedure you describe is basically it.

• Unscrew the brake line fasteners that hold the line correctly aligned.
• Unscrew the old brakeline from the caliper. And yes, there will be fluid leaking but not too much.
• Clean the other end of the brakeline from the dirt and rust that will probably have accumulated there with a flat bladed screwdriver.
• Make sure you use wrenches which both have a good grip on both parts of the screws. Hold the lower end firmly fixed and turn only the upper part of the brake line. This is the screw that fits inside the brakeline. If it is too tight, you can use some creeping oil to get it loose but make sure your wrench will not slip.
• Once you have the upper bolt out, remove the holding clip with a pair of pliers.
• Clean the attaching surfaces.
• But the new brake line in place, clip in place with the holding clip and but the top bolt back in.
• Align the brake line correctly with the caliper and fasten in to the caliper loosely with the banjo bolt using two new washers.
• Put the brake line alignment stuff back in place.
• Then tighten the banjo bolts.
• Bleed your brakes and make sure there is no sign of any leaking.
• Do a few test-runs with your car and check again for any signs of leaking.

In the end, the hardest part was getting the old top bolt loose without destroying the threads. It was very tight in my case.
I would definately NOT empty the brake system, that might introduce air into the system in places it might to be easy to get it out off again.

 

[goldNSX]

In the end, the hardest part was getting the old top bolt loose without destroying the threads. It was very tight in my case.
I would definately NOT empty the brake system, that might introduce air into the system in places it might to be easy to get it out off again.

There's a special wrench to loose the upper screw. Buy it before you mess up the screw, it's worth the $10 or so. :wink:

Empty the system is way over-shot. Please remind the torque of the banjo bolt of the caliper: 35 Nm. Do NOT overtorque!

 

[asylum]

Done ! Let see on the first curve if I did it right :biggrin:

My girlfriend's uncle gave me cap I tighten on the brake tank and on which I connect a compressor to put ~1 bar. This pushes the liquid out when bleeding.

 

[Nero Tenebre]

There's a special wrench to loose the upper screw. Buy it before you mess up the screw, it's worth the $10 or so. :wink:

So what if you mess that top hex screw up... it is very soft. Now it's just round and I can't get it off. I used the appropriate tool and it still rounded the corners.