Bench bleeding master cylinder

[Jeff10]

Hey Guys,

Thanks for the comments.

I guess what I don't understand is the need to bench bleed on a bench versus bolted up to the hydroboost unit. By operating the brake pedal the rod moves to operate the master cylinder piston. How much different is that than using a tool to depress the piston. Maybe a difference in travel? If there's no real difference, I'd prefer to bolt it in and do a 'bench bleed" without the hard lines installed. What am I missing?

The reason I'm asking questions is that I want to do it right. If that means a bench bleed off the vehicle... I'll do it. Otherwise, on the vehicle will simplify things.

Thanks,

Jeff

 

[Apogee]

You can do a bench bleed on the car, there's just more play in the system between any slop in the pedal linkage and clearance between the pushrod and MC. That said, if you find that the MC has an issue during bleeding, like internally bypassing fluid, then you get to uninstall it, but that's simple.

 

[suthernboy]

I believe the bench-bleed is recommended because it sort of pre-bleeds the MC and saves time and effort when doing the final wheel-bleeding (in theory, with a bench-bled MC, it should take fewer pumps and bleeding cycles at each wheel). Folks do it in a vise because one person can do it by themselves and it keeps any mess out of the engine compartment.

You don't HAVE to bench bleed. I never have. I prefer a vacuum bleeder at each wheel.

 

[bronconut73]

I do not bench bleed either but the theory is that you can perform more complete strokes of the piston and if you are having trouble getting those last few bubbles out of the mc then the longer travel strokes could be advantageous. A little tilting of the mc can help too.
But having said that I haven't bench bled one in years. I still use the little hoses and clips but I do so bolted to the eb.

 

[Jeff10]

Hi Guys,

Thanks for the advice.

Take Care,

Jeff

 

[miikee73]

I do not bench bleed either but the theory is that you can perform more complete strokes of the piston and if you are having trouble getting those last few bubbles out of the mc then the longer travel strokes could be advantageous. A little tilting of the mc can help too.
But having said that I haven't bench bled one in years. I still use the little hoses and clips but I do so bolted to the eb.

^^^x2^^^^