I heard that you need to ensure when bleeding clutch fluid the reservoir needs to be full otherwise you will have to start again.lbdue to air getting in.

Is this true and if so Does this mean as you see it go down just before it become empty you should add more?

Isn’t there a concern that when the clutch is depressed and the fluid goes up again it would push any newly added fluid above the max line.

I have also seen people close the cap straight after adding fluid so how will you see how much is left or can you do it with the cap open?

1 Answer 1


Yes this is true. If the fluid gets low enough, it will reintroduce air into the system which defeats the purpose of what you are trying to do in the first place.

There are two ways to do ensure this doesn't happen.

  • Have someone watching the reservoir during the procedure and have them refill it as needed.
  • You can get a bleeding kit, which has what I'll call a "hamster water bottle" (well, they be have the same as one, lol) included. It's a bottle you tip upside down with the nose of it in the fluid. As the system is bled and the fluid goes down, it automatically dumps more fluid in, keeping it at just the right level. Here in the States you can get one of these kits from places like Harbor Freight for under $20 (well worth the $$).

You can close the cap straight away. Most of the reservoirs are made of translucent plastic which allows you to see the level without taking the cap off. When the fluid is low, you refill.

  • If the fluid level is difficult to see despite it being transclucent, is it ok to leave the cap open and add as needed or will leaving the cap open introduce more problems? Thanks. Oct 9, 2020 at 13:38
  • @JamesWilson - Absolutely. That's the way I'd do it. Just check it regularly while you're bleeding it. Oct 9, 2020 at 15:06

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