Cylinder pump removal

[jetstream87]

As the time goes by the cylinder pump tends to get a bit worse and worse in which I have just placed the order, I seen some youtube videos in which they explain the removal process for the master cylinder in which one of them showed how to bench bleed the pump without having to remove the wheels. What do I need to removed the pump? Also I see the the pump has a low level indicator sensor connected to it, will I have to disconnect the negative post when changing it? If anyone has done this please guide me (1997 Nissan Pathfinder SE)

[smj999smj]

I believe what you refer to as a "pump" is what many of us refer to as a "brake master cylinder." Most times when you get a new or rebuilt master cylinder, it will often basic instructions on how to bench bleed the master cylinder before installing it and will typically come with some fittings and hoses to do this. Most of the time, people will put the bench in a vise, install the fittings on the master cylinder, install the hoses on the fitting and route them to the reservoir. Brake fluid is poured into the reservoir and the end of the hoses should be placed below the fluid line so it will not suck air into the system. A blunt tool is used to push the cylinder repeatedly at a depth of about an inch to an inch and a half, which will work the air bubbles out of the system.

As far as the R&R, the battery does not have to be removed. Unplug the level sensor harness, use line wrenches to loosen the brake lines and unscrew the fittings and unbolt the master cylinder from the brake booster and remove. Reverse to install. Finally, the fluid should be topped off and the brake system should be bled at the wheels using the proper bleeding procedure. The brake section of the Nissan factory service manual will have all the information you need, and you can download a copy of it from this site:

http://x.nissanhelp.com/forums/Knowledgebase/links/66/

[jetstream87]

I believe what you refer to as a "pump" is what many of us refer to as a "brake master cylinder." Most times when you get a new or rebuilt master cylinder, it will often basic instructions on how to bench bleed the master cylinder before installing it and will typically come with some fittings and hoses to do this. Most of the time, people will put the bench in a vise, install the fittings on the master cylinder, install the hoses on the fitting and route them to the reservoir. Brake fluid is poured into the reservoir and the end of the hoses should be placed below the fluid line so it will not suck air into the system. A blunt tool is used to push the cylinder repeatedly at a depth of about an inch to an inch and a half, which will work the air bubbles out of the system.

As far as the R&R, the battery does not have to be removed. Unplug the level sensor harness, use line wrenches to loosen the brake lines and unscrew the fittings and unbolt the master cylinder from the brake booster and remove. Reverse to install. Finally, the fluid should be topped off and the brake system should be bled at the wheels using the proper bleeding procedure. The brake section of the Nissan factory service manual will have all the information you need, and you can download a copy of it from this site:

http://x.nissanhelp.com/forums/Knowledgebase/links/66/

I got the master cylinder yesterday just the fact that I am thrown off is that I am unsure if I am not pressing the cylinder all the way properly or if I should remove the back cap that it has. The actual image is the second one on the list.

https://www.autopartskart.com/part_sear ... uct=Search

[smj999smj]

You shouldn't have to remove any cap. There should be a small hole in the back where you can insert a rod to push the piston; you'll need to secure the master cylinder in a vise when you do this. If you don't have a vise, then you can install the part and have someone slowly operate the brake pedal by hand while you bleed the master cylinder using the bleeder kit.

[jetstream87]

You shouldn't have to remove any cap. There should be a small hole in the back where you can insert a rod to push the piston; you'll need to secure the master cylinder in a vise when you do this. If you don't have a vise, then you can install the part and have someone slowly operate the brake pedal by hand while you bleed the master cylinder using the bleeder kit.

I haven't removed the cap at all, I am going to throw it in and bleed it with the car.

[jetstream87]

You shouldn't have to remove any cap. There should be a small hole in the back where you can insert a rod to push the piston; you'll need to secure the master cylinder in a vise when you do this. If you don't have a vise, then you can install the part and have someone slowly operate the brake pedal by hand while you bleed the master cylinder using the bleeder kit.

I bought a small set of flare wrenches in which I cannot remove the bolt of the lines from the line but it is either too big or small, what size can I use for the bolts and also for the bleed valve?

Wrench set:
7/16 x 3/8, 9/16 x 1/2, 11/16 x 5/8 in. and 9 x 11, 10 x 12, 13 x 14 mm

[smj999smj]

Smaller sizes on Nissans are typically "even-numbered" metric sizes. The bleeder screws are likely 10MM. Brake line nuts are usually 10MM, but you might run into 12MM or 14MM on a master cylinder or an ABS actuator.