I'd like to get your opinion on this. I am replacing the master cylinder and the new part came with 2 adapter fittings and clear plastic tubes for bench bleeding. You know the type for squirting the fluid back in to the top of the resevoir.

My problem is that the directions that also came with the new MC refer to plugs for completely blocking off the brake line ports, not adapters and tubes.

To make things worse, the plastic tube adapters do not have the same thread size as the MC so when bench bleeding and I release the piston, air sucks back into the adapter. Also, no matter how long I pump the piston, I can't get any fluid to flow out of the port closest to the firewall.

Should I be blocking one port completely while using the tube on the other port? I don't think I got the correct plugs with the new MC. I can make the fittings I need. Just wanted to understand the correct process I should be following for bench bleeding.

 

Bench bleeding generally requires pulling the fluid out of the brake line ports with a hand vacuum pump, like the Mi-T-Vac.

 

Thanks Fred. I just bought a HELP! products bleeder kit that includes fittings for master cylinders. I was able to bleed it with this kit since I was able to get a good seal by just pumping the MC.

I also bought the Speed Bleeder bleed screws with check valve. Boy does that make it easy. I'll be installing them in all my cars.

I have never had good results using the MighytVac at the wheel cylinders. It always seems to get air in the line. I think I need to put teflon tape on the threads of the bleeder screw to make the vacuum method work.

I never thought of using at the master cylinder. That is a good idea. I have another vehicle I need to bleed and I am going to try that. Thanks for the tip.

 

Be careful with the Teflon tape on brake fittings - you don't want to get pieces of it in the lines.

 

Thanks. I was careful. I ordered 2 more Speed Bleeders for the ones I used teflon on so I can replace them.