brake lines and hardware 14bff disc swap-AFCO racing products?

[mostwanted]

I have an 86 K5, so whatever lines that were stock off of the frame. I need part numbers or information for the flexible line that comes off the frame rails, the tee, a reel short flexible line like 12" and a way to couple the hardlines to the flexible. Tell me what you done if you think you have a better way.

 

[txfiremank5]

Front brake hoses for a 1979 Chevette will work for the soft lines.

 

[mostwanted]

Thanks for the info txfiremank5

Another question- Has anyone around here used afco racing products? Here is a link to their circle track brake page. I am impressed with their pricing. 30" braided hose (#4) for $13.95. Am I missing something or are we on the take from the offroad retail industry?

 

[ntsqd]

If I understand "#4" correctly that's a -4 sized AN hose, which you do not want in a brake system. Clutches are OK with -4 but not brakes. Use -3 only in brakes.

I do not like pre-made SS brake hoses. They aren't field repairable like those you can make yourself. And unless you buy those with the anti-whip feature they all have a tiny, tiny tube that connects the hose to the rest of the fitting. It is very easy to break those off with a rock or over-extension of the suspension.
I buy my hose, hose ends, and adapter fittings from Orme Bros and I always buy enough extra hose to replace the longest hose on the vehicle, and at least one extra of each unique type of hose end. That way the spares box has enough bits to make up any of the brake hoses on the rig.

 

[mostwanted]

I am not sure what a -4an would hurt. At their price of lines, I wouldn't have any proble,s carrying spares either. I plan to hardline it off of a tee along the axle up to about 5 or 6 inches from the end, then softline it up to the caliper in case of caliper flex.

 

[ntsqd]

The problem with a -4 line is that the interior surface area is greatly increased. That means more change in volume for a given pressure, which translates into a more mushy pedal. I know of no racing brake mfg who would recommend anything other than -3 or 3/16"

In one foot of -3 or 3/16" tube there is 4.8 square inches of surface area. In a -4 or 1/4" tube there is 9.4 square inches of surface area. Almost double the surface area.
Pressure is pounds per square inch, so more surface area means more stress on the tube since the force on the tube is the pressure times the area. Same thing as with putting on calipers with larger pistons to get more clamping force. This is why as the diameter goes up in any hydraulic tube type it's working max pressure goes down. The tube used in brake lines is only .030" thick. At 1200 psi the 3/16 only has to deal with 5,760 lbs-force while the 1/4 has to deal with 11,280 lbs-force.

 

[mostwanted]

The problem with a -4 line is that the interior surface area is greatly increased. That means more change in volume for a given pressure, which translates into a more mushy pedal. I know of no racing brake mfg who would recommend anything other than -3 or 3/16"

In one foot of -3 or 3/16" tube there is 4.8 square inches of surface area. In a -4 or 1/4" tube there is 9.4 square inches of surface area. Almost double the surface area.
Pressure is pounds per square inch, so more surface area means more stress on the tube since the force on the tube is the pressure times the area. Same thing as with putting on calipers with larger pistons to get more clamping force. This is why as the diameter goes up in any hydraulic tube type it's working max pressure goes down. The tube used in brake lines is only .030" thick. At 1200 psi the 3/16 only has to deal with 5,760 lbs-force while the 1/4 has to deal with 11,280 lbs-force.

Wow, well put. I fully understand. I was reading some of their discriptions, and it does look as if you can buy their lines in a -3 size. I did some figuring the other day, and I would have less than $90 in plumbing my rear axle by using their parts. I will look furthar into Orme Bros before making any purchases.