My son’s car had brake problems and we had to change the master cylinder. My son has an 1994 Ford Explorer, and the master cylinder went bad on the brakes. Here’s how we saved money by doing it ourselves.
Supplies we needed:
New or re-built master cylinder for the make and model of your car
Wrenches/Ratchet and sockets
Liquid wrench
One quart of brake fluid and funnel
Rags
Eye dropper type of device to remove excess oil from reservoir.
Container for used brake fluid
Preparations:
We gathered the new part and the supplies we needed. The first step was to use the liquid wrench on the the bleeder valves on the calipers/wheel cylinders. This will give the liquid wrench time to work penetrating the rust and road grime that may have been on them, also we sprayed the bolts on the master cylinder itself to make them easier for us to remove later. For safety precautions we then disconnected the negative battery terminal and wrapped it in a towel so it wouldn’t make a connection.
Changing out the Master Cylinder:
After the preparations we began by starting this job by removing the cap and taking some of the oil out of the reservoir with the eyedropper that way the oil wouldn’t spill out on the engine as easy, we used a plastic disposable cup to put the used oil in. We also cleaned the access cap off thoroughly with a paper towel and wiped the complete reservoir unit on the outside as to not get any grime inside the reservoir that may later clog the unit.
Our master cylinder for our car has a fluid level sensor wire on the bottom and we had to remove this next. Then we loosened the break line screws that attach to the right side of the unit. Next we took out the bolts that hold the master cylinder in place. On the left side is one bolt and the unit was free and on the right side when we got the bolt off, there was a bracket we needed to remove that holds the break lines steady.
After that the unit was free from the engine. We removed the loosened break line screws and the unit was free from the car altogether. We had to watch because there was oil spilling from where the break lines had been connected. We then dumped this oil into the cup for later disposal.
Taking the oil reservoir off of the master cylinder was a job. We had to rock the reservoir back and forth sideways, we knew not do it front to back as this could damage the unit. It took several minutes to get this free. We will re-use this reservoir on the new master cylinder as the new one didn’t come with it. We installed the reservoir onto the new master cylinder after pouring all the used oil into our cup.
Then we placed the master cylinder into a vise and did what my husband called a “bench bleed” this gets the air out of the master cylinder and makes less air in the lines. We did this after we added the oil by using an attachment and tubes on the holes where the break lines come into the unit, the other end of the tube goes into the reservoir, when he manually pushes the piston in and out that gets the excess air out of the cylinder.
After the bench bleed was done we installed the unit back onto the car. We started by re-attaching in the reverse steps that we used to take it off. The break lines on the right side of the unit were first. After that we installed the right side bolt making sure to replace the bracket and when the left bolt was back in place, we re-clipped the fluid level sensor wire. Having tightened both bolts and the break lines we then topped off the oil level in the reservoir to the fill line indicator and replaced the cap.
Getting the air out of the lines:
After the new master cylinder was in place we then had to get the old fluid out of the break lines as well as any air that was left. Starting with the farthest break line from the master cylinder my husband loosened the bleeder valve and let the dirty oil drip into our cup until it was a steady flow of clean oil and had no air pockets. He then proceeded to the next bleeder valve until all four were all done. While he did this it was my job to watch the level of the fluid in the reservoir to assure that the oil level didn’t drop below the level indicator which would have made more air get into the line.
The clean up:
When we were sure the job was finished we re-attached the battery terminal and cleaned up our mess of tools. My neighbor down the road is a mechanic and he has a recycle bin for oil and car fluids so we were able to dump the oil there and not get it into the environment. That is important to us.
We purchased the re-built master cylinder at the local auto parts store for $39. We called our neighbor and asked a price for the break job and he said it would cost $69.80 for the part and $79.20 labor!! We saved a bundle just by doing it ourselves!