Brake Lines

[aston]

I am in the process of ordering new stainless braided brake lines.

Apparently they are made in various sizes AN3, AN4 and AN5. I am assuming these are industry standards for inside diameter.

What's the difference in brake performance with the different sizes?

[Chris_L]

The best way to order them is with -3 fittings on each end, that way they are easily replacable and if you need one on the trail it is more likely that someone else would be carring one that would work on your rig. I get them made at earls for $24 bucks each.

[aston]

The best way to order them is with -3 fittings on each end, that way they are easily replacable and if you need one on the trail it is more likely that someone else would be carring one that would work on your rig. I get them made at earls for $24 bucks each.

Good point

I decided to go with AN3. Apparently AN4 is more suited to clutch lines and can cause brakes to feel spongy.

[mrblaine]

Good point

I decided to go with AN3. Apparently AN4 is more suited to clutch lines and can cause brakes to feel spongy.

Why would that be?

[blkTJ]

Why would that be?

maybe the same reason we don't use -10 hose from the pump to the ps gear??? :confused: (just guessing )

[Matt Pascoe]

The best way to order them is with -3 fittings on each end, that way they are easily replacable and if you need one on the trail it is more likely that someone else would be carring one that would work on your rig. I get them made at earls for $24 bucks each.

How do you adapt -3 fittings to the calipers? is there a banjo to -3 adapter? I will have 6 pieces of flex line and it would be great if I could carry 1 generic spare.

MP

[mrblaine]

maybe the same reason we don't use -10 hose from the pump to the ps gear??? :confused: (just guessing )

Once the line was filled and if it was rated for the pressure, what difference would it make?

[mrblaine]

How do you adapt -3 fittings to the calipers? is there a banjo to -3 adapter? I will have 6 pieces of flex line and it would be great if I could carry 1 generic spare.

MP

Yes, there are -3 to banjo and -3 to frame adapters for the hard line transition. If you get them, make sure they supply the correct crush washers for your particular banjo adapter.

[aston]

Why would that be?

I am not an expert but I found a couple of credible references:

This is the braided steel hose I used to replace the restricted stock rubber hose. It's a little hard to see, but on the right you can see that it fits in the stock rubber grommet just fine. Initially someone on-line suggested AN-4 size line, but Dick Walkush at W. M. Engineering where I purchased the hose said that AN-4 was only used on race car applications that had true hydraulic throw out bearings, not your usual hydraulic master/slave arrangement.

· It is recommended that rigid lines with an ID of 3/16" be used throughout the chassis because of their resistance to flex.
· AN-3 stainless steel braid Teflon should be used from the chassis out to the calipers and rear axle.
· Flex lines in AN-2 will restrict fluid flow and lines in AN-4 will increase displacement with the possibility of a spongy pedal feel. AN-4 is good for the clutch line.

[aston]

How do you adapt -3 fittings to the calipers? is there a banjo to -3 adapter? I will have 6 pieces of flex line and it would be great if I could carry 1 generic spare.

MP

My local Hot Rod shop had a good collection of Earl's fittings. They had to order one fitting but the rest they had in stock.

Go here to see the full range of goodies:

http://www.holley.com/earlsplumbing/index.html

Earl's assemble-it-yourself system worked great for me.

[aston]

Once the line was filled and if it was rated for the pressure, what difference would it make?

I might have known the answer if I hadn't slept through Fluid Dynamics at engineering school

[mrblaine]

I might have known the answer if I hadn't slept through Fluid Dynamics at engineering school

It won't make any difference. Other that requiring larger amounts of fluid at fill time, the rest is just displacement and not fluid pumping like you would have in a hydraulic fluid system such as a power steering pump and gear.

With the pump you have to be careful not to have the lines too small for the flow rate as the fluid is being circulated.

In a brake system, you are only moving the amount of fluid being displaced by the movement the piston in the bore of the master.

Theoretically, you could have a brake line 20 inches in diameter and as long as it didn't flex under pressure and had no air in it, you would still only or exactly displace the amount of fluid moved by the master.

I struggled with this concept at one point and the only way I could visualize it was to imagine a scuba tank filled with brake fluid, perfectly bled and a master cylinder ported into it at the top and a caliper with a short line at the bottom. If you move the piston in the master, the caliper will respond exactly as if it were in a car's brake system.

The gentleman with the spongy brake pedal comment is dead wrong unless the line can't handle the pressure.

[irishjeeper]

ive got a question.is there anyway to not use steel hard lines on the frame and use a braided stainless throughout the system,i really dont feel much like bending and flaring.