The hydraulic fluid in our clutch system often traps air in it. When that happens, the clutch will lose pressure. And the only feasible solution to this problem is to bleed the clutch. I have experienced situations where there’s no pressure in clutch after bleeding several times.
In this article, I’ll explain the possible reasons why there is no pressure in clutch pedal even after bleeding the clutch. I’ll also explain how to fix this problem.
Why is my clutch not building pressure?
We often assume that our clutch only loses pressure when it needs bleeding. That’s why most folks are disappointed to see their clutch pedal still doesn’t have pressure even after bleeding it. So, if you are wondering why my clutch has no pressure and won’t go into gear even after bleeding, here are the possible causes;
Typically, if there’s no pressure in a clutch after bleeding, you had incorrect bleeding, clutch fluid leaks, faulty slave cylinder, throw-out bearing issues, or clutch master cylinder issues. The only way to regain pressure is to diagnose and resolve the underlying problems.
Let’s have an in-depth look at these possible causes and how they can cause no pressure in the system.
The most common reason your clutch has no pressure, but returns is incorrect bleeding. The truth is, not everyone knows how to bleed a clutch. Even with the right guide, you may have to make a couple of trials and errors. That’s normal.
You don’t learn how to ride a bicycle by just reading a book. You have to practice it. While this theory doesn’t apply to everything in life, you have to religiously follow the specified bleeding approach for your vehicle if you haven’t bled a clutch before. If not, you may not have the desired result.
Even the slightest mistake when bleeding a clutch can trap air in the system. If your assistant doesn’t hold the clutch pedal down when you ask him to, air will get stuck into the system. You also need to educate your assistant before bleeding the clutch. If he doesn’t depress the pedal down to the floor, you won’t remove all the trapped air in the system.
Clutch fluid leaks
A fluid leak is another common reason for no pressure in the clutch, even after bleeding the system. If there’s a leak somewhere in the system, no amount of bleeding will restore pressure to the clutch. You have to track where the leak is coming from and fix it before bleeding the clutch. So, if you are wondering why is my clutch not building pressure, it could be there’s a leak somewhere in the system.
The faulty clutch slave cylinder
A faulty clutch slave cylinder may be the root cause of your problem. I have experienced this a couple of times. In most cases, all you need to do is to replace the clutch slave cylinder. A defective clutch slave cylinder usually leaks fluid, making it easier to diagnose.
Unfortunately, this clutch component can also fail without any leakage. In any of these cases, the clutch won’t have pressure. So, if your clutch is losing pressure, there is no leak; check the clutch slave cylinder and confirm it is still okay.
Issues with the master cylinder
As the name indicates, the master clutch cylinder is an essential clutch system component. It converts the clutch pedal mechanical movement into a hydraulic pressure needed for optimal clutch operation. It is connected to the clutch pedal via a pin.
If the master cylinder fails or leaks, the clutch won’t have pressure. In this case, bleeding the clutch won’t restore the lost pressure.
Low clutch fluid
I said earlier that the clutch master cylinder converts the pedal’s movement to hydraulic pressure. It does this with the help of the clutch fluid.
If the fluid in the fluid reservoir on top of the master cylinder is low, it’ll cause low or no pressure on the pedal. It could be that you did not top up the fluid during or after bleeding the clutch. If there’s no fluid in the reservoir, the clutch pedal will stay on the floor due to no pressure.
Damaged throw-out bearing
The throwout bearing is an essential clutch component that helps temporarily disengage the engine from the transmission as you depress the clutch pedal. If the throwout bearing becomes faulty, the clutch won’t function as it should.
Here are signs of a bad clutch throwout bearing.
Entire clutch failure
If the throwout bearing, clutch plate, or disc are damaged, the clutch won’t hold pressure when you depress it. Keep in mind that the clutch system components work in harmony. Damage in one part can affect other system components if ignored for an extended period.
For instance, a worn clutch plate will wear out the disc if not changed on time.
Now that we have seen why the clutch pedal loses pressure overnight or even after bleeding, let’s explore how to get pressure back in clutch.
How to fix if there is no pressure in the clutch after bleeding
You have seen several reasons for a clutch to lose pressure after bleeding. The best way to fix it is to identify and rectify the root cause of the problem. You need one or more of the following to fix the problem.
Top the clutch fluid.
Open the fluid reservoir and check the level. If the fluid is below the minimum line, it is the root cause of the problem. All you have to do is to top up the fluid and rebleed the clutch.
Bleed the clutch properly.
If you did not bleed the clutch properly, the only solution is to rebleed it. And this time, you must get it right. If not, the problem will still be there.
Bleeding clutch cap on or off? If this is your contemplation, you have nothing to worry about. You can bleed the clutch with the cap off or on. However, I recommend removing the cap to monitor the fluid level as you bleed.
Don’t allow the fluid to drop below the minimum mark while bleeding. If it does, air will get trapped in the system.
Replace the slave and the master cylinder.
Check the slave cylinder to see if it is working properly. If it is damaged, replace the lousy parts and service it. However, I recommend changing the entire unit for a better result.
Inspect the master cylinder to see if it is okay. Check for leaks around or have a certified mechanic inspect it. Even the smallest leak anywhere in the system will cause pressure loss.
Check and replace the damaged clutch assembly.
Inspect the clutch assembly and replace damaged components. You’ll have to drop the transmission before assessing the clutch assembly. A worn-out clutch plate, worn-out or broken clutch disc, or damaged throw-out bearing can cause the problem.
A certified mechanic should be able to tell when any of these clutch components are bad. If you suspect any of these components are bad, drive to your mechanic and have them take a look. They will be able to identify and replace the faulty part as needed.
Trust me, having no pressure in clutch after bleeding is quite unnerving and frustrating. It’ll make you feel like you don’t know how to bleed a clutch. But knowing the possible causes and how to address them will ease the frustration. Of course, if you have been reading to this point, you will have learned the possible reasons and how to rectify them.