Bleeder Valve Leaking? Learn About Sources and Solutions

Have you noticed a brake fluid leak coming from your vehicle’s bleeder valve and want to know how to fix it? There are various reasons that a bleeder valve may develop a leak and, luckily, some practical ways to fix a leak. 

Some of the common reasons that brake bleeder valves begin to leak include incorrect bleeder screws, a faulty o-ring, cracked or defective seals, a broken brake line, or a bleeder valve that’s broken outright.

In this guide, we’re highlighting the main causes for bleeder valve leaks, ways to fix these leaks, how to replace a broken bleeder valve, and how to seal a brake bleeder valve. To learn about the above topics and get answers to frequently asked questions, keep reading!

Reasons for Bleeder Valve Leaking

In order to decide how you’re going to fix a bleeder valve leak, you first need to find the source of the leak. The following parts and problems are common causes of leaking brake bleeder valves. 

Bad O-Ring

The o-ring that accompanies your bleeder screw is an important seal required to prevent bleeder valve leaks. But if this seal is cracked, faulty, or even too old to work properly, it fails to do its job and you might detect a leak.

You can determine if this might be the source of your leak by examining the o-ring and checking for:

  • Cuts
  • Cracks
  • Holes
  • Pock marks
  • Signs of disintegration 

Broken Brake Line

While it may not seem so obvious at first, a broken or malfunctioning brake line can cause the brake bleed valve to develop a leak. You may need to visit a mechanic to inspect your brake system in order to determine whether or not this is the source of your leak problem. 

Broken Bleeder Valve

This is one of the more obvious reasons your brake bleeder valve might leak. If the bleeder valve itself is broken, it won’t be able to properly control the outwards passage of fluid as it’s intended to. 

This is a common cause of brake bleeder valve leaks, and a mechanic can confirm for you if this is the source of your problem.

Incorrect Bleeder Screws

You should also check to see if your bleeder screws are in good working order, broken, or screwed in too loosely or too tightly. If they’ve been screwed in such a way that they’ve stripped the thread or some other misalignment, then the valve could develop a leak. 

Cracked Seals/Gaskets

In addition to a bad o-ring seal, you might also have a leak due to problems with another seal or gasket in the bleeder valve system. 

This is a really common cause of leaks, especially if the gasket or seal has deteriorated over time, become dry, developed cracks, or fallen out of alignment.

Sealing a Brake Bleeder Valve?

There are a few ways to seal a brake bleeder valve in the case that it is leaking. You can use a thread sealant to effectively seal the bleeder valve screws if that is the source of the brake fluid leak. 

To do so, you need to first properly clean out the valve and remove fluid and debris from the parts, including the screws. Then, you can seal the screws so that the valve is protected against leaks. 

Replacing a Broken Bleeder Valve

In worst-case scenarios, you may need to replace your bleeder valve altogether. If the valve part itself is shot and that’s why it’s leaking, you can find a replacement part to DIY install or have a mechanic put in place. 

New brake bleeder valve kits typically don’t cost too much money – they usually range between $25-$50. It’s worth it to buy quality parts from a good manufacturer, since you need this essential part to safely drive your car. 

Ways to Fix Bleeder Valve Leak

The method of fixing a bleeder valve leak depends on the source of the leak. For example, if you have one or more faulty seals/gaskets, it’s best to remove and replace them with new ones. If the leak is coming from a bad bleeder screw, you should replace that screw. 

Sometimes, the problem is with the brake line, in which case you’d likely need to get a mechanic to replace the brake line. 

In most cases, you will need to replace parts entirely, rather than repair them, since the parts in this auto system are so small. 

Final Thoughts

Has your car’s bleeder valve started to leak? There are several causes that lead to a brake bleeder valve leak, including bad o-rings, broken gaskets and seals, a faulty valve, and a broken/misaligned bleeder screw.

Assess your bleeder valve system to find the source of the leak (with the help of a mechanic if necessary), and replace the appropriate parts when needed.


How do you seal brake bleeder screws?

Make sure that your brake bleeder screws are completely clean, free of brake fluid, and dry first. Use an automotive thread sealant and apply it to the threads of the bleeder screws. Allow the sealant to fully dry before threading the screw into place again.

Can you use Teflon tape on brake bleeder valve?

No, you should never use Teflon tape on a brake bleeder valve because it is highly reactive when it comes in contact with brake fluid. Some people mistakenly apply Teflon tape to bleed nipple threads as a seal, but it will have the opposite effect over time as the fluid eats away at the tape.

How do you clean a bleeder valve?

Brake bleeder valves can become clogged, and when they do, you should unscrew the bleeder screw. Then, you can get inside the valve and use a drill bit to unclog and clean it out (using the drill bit by hand and not with the motor on).  

How tight should a bleeder valve be?

A common misconception about bleeder valves is that they need to be super tight to work properly and contain fluid when you aren’t bleeding. But they shouldn’t be too tight or you could damage parts. Tighten the bleeder valve’s screws by hand until they’re “finger tight”. Any tighter, and you run the risk of breaking the screw while driving.

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