I just installed a new brake system on my 70 GTX (4 wheel drum non power) I haven't put fluid in yet, but I didn't bench bleed the master. Is it absolutely necessary? can I do it in the car? what are the ramifications. I don't want to take the master back out if I don't have to.

 

If you have a mityvac you can suck fluid from the master to each bleed screw or reverse fill the brake system from the bleeders up. But I don't think you have to bench bleed, it will just take a little longer the usual way. Welcome to the forum.

 

you can also bleed the master cylinder by unscrewing the brake lines then having somebody push it in in case you dont have the bleeder.i always force fluid up from the bleeders that way it pushes out all air in the system.

 

You can bleed the master while it is int he car like the guys said. After that, you can gravity bleed the rest, just keep an eye on the level of the fluid.

 

welcome to the forum
you do not have to bench bleed, but it'll make the process go quicker if you do

 

Not to mention easier because it only takes one person, not two.

 

bench bleeding is advisable. But I have a question. I am installing a disc brake kit w/power booster in my 1969 Coronet. Between the booster and master cyl. there is a rubber conical-shaped insert that seems to fit the opening. Does this stay in place or was it just for shipping purposes? Also the new proportioning valve is not exactly identical to the old one. Pretty close tho'. If it is not exact do I need to re-plumb or call the manufacturer and find out if it the correct one?

 

Yes and Yes