How to Bleed a Master Cylinder
Gather your supplies., Remove your master cylinder from the packaging., Mount your master cylinder in the vise., Prepare the bleeding kit., Screw the inserts into the outputs of your cylinder., Insert the rubber hoses., Place the ends of the rubber...
Step-by-Step Guide
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Step 1: Gather your supplies.
Bleeding from the bench is much easier than bleeding using the pump method, which takes a very long time and may not work.
It is also much less expensive than taking your master cylinder into a mechanic, who will quickly (and expensively) do it with vacuum pumps.
It is also necessary if you are installing a new master cylinder.
To bleed your master cylinder from the bench, gather the following supplies:
Your master cylinder with bleed kid Fresh brake fluid A workbench or table with a fixed vise.
If you have neither of these, it will be more cost-effective to go to the next method, which does not require a specialized workspace.
A wooden or plastic dowel.
Make sure this is strong, because you don't want it to snap while you're working. -
Step 2: Remove your master cylinder from the packaging.
Set aside the bleed kit that comes with the cylinder, as you will need it later.
If the new part didn't come with a reservoir, be sure to remove the one from the old part. , Steadiness is key when bleeding your master cylinder in this way.
Before doing anything else, mount your master cylinder in the vise on your workbench or table, and make sure it is level.
Hold the master cylinder by its flared mount, and make sure it is level.
This way, the air will leave properly, and it will fill with brake fluid evenly without gaps.
It needs to be firmly secured, but not so tight you crush or damage cast aluminum parts.
Make sure the plastic fittings are not crushed or blocked when putting the cylinder in the vise.
If your table does not have a pre-installed vise clamp, you can buy a separate vise that clamps on to the table if you do not have one pre-installed.
If you like the appearance of this table, it might be best not to use it, as vise clamps leave a mark on wood or metal.
If you have no other usable tables, wedge a rag in between the vise clamps to avoid leaving a mark.
This may not work, so proceed at your own risk. , This should come with your master cylinder, and consists of two rubber hoses and two plastic threaded inserts.
The inserts will be threaded on one side, and the other will be a smooth adapter for taking the hose.
Check the color of your hose, too.
If you have opaque hose, you might want to replace it with clear hose, because then you can see the air bubbles passing through the fluid more easily.
You can also opt not to use the bleeding kit, as it isn't necessary.
However, this guide will assume that you are using the bleeding kit. , These are located on the side of the cylinder past the flared mount.
Install these into the bosses (the threaded holes) without cross threading them.
Make sure they are finger tight. , Once you have attached the inserts into the cylinder, you can attach the rubber hoses to these inserts. , This container will be used for catching the excess brake fluid, so make sure you don't mind that it gets dirty.
Consider attaching the hoses to the container in some way.
Once you begin pumping, they will begin flailing about and spray blake fluid everywhere if they are not anchored down in some way.
An old coffee can works especially well for this, as does any cylindrical container with a wide, flared opening. , If your reservoir runs out of brake fluid at any time during your bleed, you'll have to start from the beginning.
You should only put clean brake fluid that is less than two years old into the reservoir.
Make sure it's in between the "max" and "min" marks and covers the ends of the hoses.
Brake fluid is very hygroscopic, which means it absorbs moisture and will degrade, and this damages the seals.
Do not reuse brake fluid , Make sure you do this slowly to avoid allowing air into the apparatus, or allowing the wooden dowel to snap.
Don't bottom out the piston, otherwise this might allow the entrance of air.
You have to pinch the rubber hoses closed each and every time you release pressure on the cylinder. , This will compress the brake fluid, so it will shoot out when you release the hoses.
This also prevents air from entering the master cylinder by not providing a vacuum for it to fill. ,, You will know you're finished pumping when there are no more air bubbles rising in the reservoir or present in the container of spent brake fluid. ,, When installing it in the vehicle, keep it level and remove the bleeding kit as you install the lines.
If you did this right, you shouldn't need to bleed the entire system, but you may want to to flush the system of old fluid. , These should have come with the cylinder, and will prevent leakage. , Otherwise brake fluid will leak out from the reservoir. , You need to make sure that your brakes actually work before you begin driving your car.
If you've done it right, the brakes should feel clean and crisp when you pump them.
If you've done it wrong, the brakes will feel "squishy" when you pump them from your car, indicating there is still air in the master cylinder -
Step 3: Mount your master cylinder in the vise.
-
Step 4: Prepare the bleeding kit.
-
Step 5: Screw the inserts into the outputs of your cylinder.
-
Step 6: Insert the rubber hoses.
-
Step 7: Place the ends of the rubber hoses into a container.
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Step 8: Fill the attached reservoir with brake fluid.
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Step 9: Begin pumping the master cylinder.
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Step 10: Push in the cylinder and pinch the hoses.
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Step 11: Release the hoses and let the brake fluid out of the master cylinder
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Step 12: then immediately pinch the hoses again.
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Step 13: Repeat this until there is no more air in the fluid.
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Step 14: Remove the master cylinder from the vise with the bleeding kit still attached.
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Step 15: Begin installing the master cylinder in your vehicle.
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Step 16: Remove the inserts and hoses
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Step 17: then place the caps on your master cylinder.
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Step 18: Replace the cap on the master cylinder's reservoir.
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Step 19: Test the brakes before returning the vehicle to service.
Detailed Guide
Bleeding from the bench is much easier than bleeding using the pump method, which takes a very long time and may not work.
It is also much less expensive than taking your master cylinder into a mechanic, who will quickly (and expensively) do it with vacuum pumps.
It is also necessary if you are installing a new master cylinder.
To bleed your master cylinder from the bench, gather the following supplies:
Your master cylinder with bleed kid Fresh brake fluid A workbench or table with a fixed vise.
If you have neither of these, it will be more cost-effective to go to the next method, which does not require a specialized workspace.
A wooden or plastic dowel.
Make sure this is strong, because you don't want it to snap while you're working.
Set aside the bleed kit that comes with the cylinder, as you will need it later.
If the new part didn't come with a reservoir, be sure to remove the one from the old part. , Steadiness is key when bleeding your master cylinder in this way.
Before doing anything else, mount your master cylinder in the vise on your workbench or table, and make sure it is level.
Hold the master cylinder by its flared mount, and make sure it is level.
This way, the air will leave properly, and it will fill with brake fluid evenly without gaps.
It needs to be firmly secured, but not so tight you crush or damage cast aluminum parts.
Make sure the plastic fittings are not crushed or blocked when putting the cylinder in the vise.
If your table does not have a pre-installed vise clamp, you can buy a separate vise that clamps on to the table if you do not have one pre-installed.
If you like the appearance of this table, it might be best not to use it, as vise clamps leave a mark on wood or metal.
If you have no other usable tables, wedge a rag in between the vise clamps to avoid leaving a mark.
This may not work, so proceed at your own risk. , This should come with your master cylinder, and consists of two rubber hoses and two plastic threaded inserts.
The inserts will be threaded on one side, and the other will be a smooth adapter for taking the hose.
Check the color of your hose, too.
If you have opaque hose, you might want to replace it with clear hose, because then you can see the air bubbles passing through the fluid more easily.
You can also opt not to use the bleeding kit, as it isn't necessary.
However, this guide will assume that you are using the bleeding kit. , These are located on the side of the cylinder past the flared mount.
Install these into the bosses (the threaded holes) without cross threading them.
Make sure they are finger tight. , Once you have attached the inserts into the cylinder, you can attach the rubber hoses to these inserts. , This container will be used for catching the excess brake fluid, so make sure you don't mind that it gets dirty.
Consider attaching the hoses to the container in some way.
Once you begin pumping, they will begin flailing about and spray blake fluid everywhere if they are not anchored down in some way.
An old coffee can works especially well for this, as does any cylindrical container with a wide, flared opening. , If your reservoir runs out of brake fluid at any time during your bleed, you'll have to start from the beginning.
You should only put clean brake fluid that is less than two years old into the reservoir.
Make sure it's in between the "max" and "min" marks and covers the ends of the hoses.
Brake fluid is very hygroscopic, which means it absorbs moisture and will degrade, and this damages the seals.
Do not reuse brake fluid , Make sure you do this slowly to avoid allowing air into the apparatus, or allowing the wooden dowel to snap.
Don't bottom out the piston, otherwise this might allow the entrance of air.
You have to pinch the rubber hoses closed each and every time you release pressure on the cylinder. , This will compress the brake fluid, so it will shoot out when you release the hoses.
This also prevents air from entering the master cylinder by not providing a vacuum for it to fill. ,, You will know you're finished pumping when there are no more air bubbles rising in the reservoir or present in the container of spent brake fluid. ,, When installing it in the vehicle, keep it level and remove the bleeding kit as you install the lines.
If you did this right, you shouldn't need to bleed the entire system, but you may want to to flush the system of old fluid. , These should have come with the cylinder, and will prevent leakage. , Otherwise brake fluid will leak out from the reservoir. , You need to make sure that your brakes actually work before you begin driving your car.
If you've done it right, the brakes should feel clean and crisp when you pump them.
If you've done it wrong, the brakes will feel "squishy" when you pump them from your car, indicating there is still air in the master cylinder
About the Author
Frances Ross
Dedicated to helping readers learn new skills in cooking and beyond.
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