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Demco Hydraulic Brake Line Kit Installation

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How to Install the Demco Hydraulic Brake Line Kit


Today on our boat trailer, we'll be installing the Den-co hydraulic brake line kit for tandem axles, part number Dm5425. To begin our install, we'll first need to remove the older manufacturer's lines. Now before we install the new line, we'll go ahead and drill a hole here in the frame so that we can run our line directly out of the frame and into the back of the coupler at the massive cylinder, instead of going out the frame and around the coupler. Now, with the hole drilled out, we'll go ahead and install the hose, take the long steel lines provided with our install kit, we'll straighten it out, run into the frame. Now we've got the hose pulled up into position. It'll go into the back of the master cylinder here at the coupler. As we thread into the master cylinder, we'll also twist the line with an extra set of hands as it goes into the frame so that we don't twist or pinch the hose or line as we're tightening it down. Quick tech tip: We'll make sure that the hose is centered of the hole so it doesn't wear against the outer edge and create a hole in our hose. I'll go ahead and move back to the frame of our trailer, start routing and securing the steel line, following the manufacturer's route along the driver's side frame rail. Keep in mind when bending your lines, that you don't want to make any sharp corners.

Make slow, easy bends so that we don't kink the line. We'll use the new hold down and self-tabbing screws to secure the line to the frame. Now, because of the excess length of this trailer, were going to need to modify our install kit. We'll take the thirty-inch piece of steel line and add it to the main line coming back from the coupler, using the tightened hydraulic brake unit, part number T1287900 to connect the two steel lines together. This will allow us to come back in between the two rear axles. From there, we'll add the T block, provided with the install kit, out of the block to the front axle. We'll use one of the hydraulic brake hoses, provided with the install kit.

Go into a T block on the axle and steel lines out of the block to both wheel cylinders. Our second output going to the rear axle, we're going to use the Kodiak hydraulic brake hose, part number BH-3MFS-3-5, to take the length from the first T block on the frame back to the second axle we'll install another T block to go off the both wheel cylinders. We're going to use a wing clamp to secure the line to the frame. We'll be using the field line coming out of the block to both wheel cylinders. We'll use the new hold down, self-tapping screw and secure the field lines coming out of the block to both wheel cylinders. Now to bleed out your brake system, it's recommended that you build the master cylinder, open up the bleeder and allow it to gravity bleed first and the fluid will dribble out. When you're ready to apply some pressure, you get an extra set of hands to actuate the brake mechanism and it will push fluid out. We'll do that ten to twelve times, making sure we get straight fluid each time, to make sure we get all the air out of the system. Quick tech tip: Make sure you keep the master cylinder full as you're bleeding the brakes. Now that we have the system completely bled out and the master cylinder cap back on, this will complete the install of our Den-co hydraulic brake line kit for tandem axle, part number DM5425. .


Info for this part was:

Employee Jeff D
Installed by:
Jeff D
Employee Dustin K
Video Edited:
Dustin K

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