Thread: Big or small line to the front brakes? (3/16 or 1/4")

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Most cars use 3/16 line front and back. Some use 1/4 to the back. The master has two different size fittings so the guys who put the car together don't mix the brake lines up. Lots of time the brake line is the same size(usually 3/16) and only the fitting itself is larger. Adapters, 3/16 brake lines with the larger fitting and the fitting only (for 3/16) are usually available. Check with NAPA or other parts house.

would a smaller brake line cause more breaking pressure?

Thanks paul. I found a shop just around the corner from my shop that makes all the racecar brake lines in the county. This is after spending days and days trying to answer my questions and find parts. I had my lines with fittings made while I waited. Duh.

Bigtruck, there is something like that going on. Someone who know should try and explane it though.

Jim

The reason hydraulic brakes work so well is because the pressure at any point in the whole system is always the same! Big line, small line, it makes no difference. If the brakes wear some, the pressure is still the same at all places. If the brakes get hot, the pressure is still the same. If this weren't true, the car would swerve left or right when you stepped on the brakes, depending on which side of the car the sun was shining on!

When you plumb the master cylinder, you need to determine how the tubes were arranged in the car the master came out of. It makes a difference because of the balance spring inside the master cylinder, that's located between the front piston and the rear piston. You can usually tell by the size of the reservoirs. If a master cylinder is from a car with front disc brakes, the reservoir for the front wheels will be larger than the reservoir for the rear wheels. This is because disc brakes draw more fluid from the reservoir as the brake pads wear, but drum brakes do not draw more fluid as they wear. The automatic adjusters in drum brakes make up for the wear, rather than the wheel cylinders. Master cylinders from cars with 4 wheel drum brakes have equal size reservoirs, so it's harder to figure out.

Originally Posted by BigTruckDriver

would a smaller brake line cause more breaking pressure?

Short answer . . . nope.

"would a smaller brake line cause more breaking pressure?"


a smaller wheel cylinder will.