Sure: I don't have a sheet from A1 Cardone to scan, but I get one in every master cylinder I have ever gotten from them. From a GOOGLE search, slightly different than the previous one I linked. This one is also hyperlinked if you care to check. Speedway PDF I get similar instructions from TCI/Heidt's/Classic Performance Products etc. After research I have found a few sources that do say to fully stroke the master cylinder during bleeding. Usually for stepped bore master cylinders. However, if you get into the technical data from Willwood/CNC/Tilton/US Brake etc. they all mention a positive stop in their instructions. Floor, usually a good and very inexpensive positive stop... This I wholeheartedly agree with. Thank you.
So are we saying that if it is not bench bled, air will be stuck in the master? On a system with no fluid in it whatsoever, what is the benefit of getting the air out of the master before getting the air out of the lines. Would make sense if you were replacing a master in a car that had full brake lines, would make bleeding the rest of the system much easier. If I am using a pressure bleeder/flushing machine, I am filling a new master with fluid, then providing pressure and fluid to replace the fluid that travels through the system pushing the air out ahead of it, so how could air stay in the master if not bench bled?
I think bench bleeding is one of those habits that die hard. Maybe that was standard operating procedure before they started using vacuum/pressure bleeders. I agree 100% with you that no air should be left when you pressure bleed.
You got me on this one, but I admit I'm not familiar with, nor do I remember ever installing new or rebuilt single system master cylinders, or seeing similar instructions with any others. All of the masters I've worked with and tested are post '66 dual/tandem. Curious though how damage could occur only during bench bleeding.
I sense that you feel this is new information you are seeing here. You and I have been thru this very discussion & several times I believe you know what you've been exposed too very well, I also believe that you think you can apply that specific knowledge to everything you have never seen. It just doesn't work like that.
That's how I do it. I've never had any problems doing it that way on the car or in a vice. I've never blown any seals either. Just don't slam the MC piston to the bottom of the bore with any force.
Hi Bob, This has been Wagners position on single bore masters for many years, but defitely not on the dual bore masters. PS, I worked for these guys for 20 years and sold them for 8 years before that. I follow and appreciate your posts on brake problem, you know your stuff, that's for sure.
you won't over stroke useing pedal but bench bleeding with a screwdriver or whatever you can, don't beleive me next time you do a mc take a screwdriver and shove piston all the way down till it bottoms out and see what happens there's no reason to sroke it that far anyhow your just gettin the air out
I no longer bench bleed!!!!!!! i just put the new master in and hook it up. now i use a LARGE syringe i bought from the vet supply, short piece of hose and presure the lines from the 4 wheel cyl. no more pumping!! no more yell'n at the wife, and very little mess!!! any one want a peice of shit mighty vac??????? the syringe and hose cost $7 and mighty vac $70. i had HAMBer roughidal come over to help me. he's like why are you making so much work out of it?? and he got out his syringe
https://www.youtube.com/watch?v=-f0hioL6fuo&feature=youtube_gdata_player You can't stop till she's "sassified"
The Jalopy Journal
