Master Cylinder Bleeding

[u118224]

I'm replacing some brake lines on a Honda and I removed the master cylinder to make life easier. I have a Motive power bleeder so I don't see a need to bench bleed the master cylinder. Agree or disagree? FYI, this is a non ABS system.

 

[kamesama980]

You're putting in the old and fully functioning MC back in and asking if you will need to bench bleed it?

How you bleed (old school, vacuum, pressure, etc) doesn't matter. If you kept the master wet you might get away without bleeding it but I'd bleed it again just to make sure.

 

[u118224]

The master cylinder is dry and needs to be bled. My question is do I have to bench bleed it before I re-install it on the car. With the Motive bleeder I should be able to bleed it after it's back on the car. That's my position, I'm just wondering if anyone disagrees.

 

[66HertzClone]

I would bench bleed it just to be sure, nothing like spending a lot of time bleeding at each wheel only to have to remove the master and start all over again. That being said, if you were careful and plugged the ports, kept it reasonable level, it might be okay.

 

[ChevyEFI]

Bolt it into the car.

Use bleeder fittings, routing them up into the reservoir so they will be submerged. If you have a spare cap you can drill a couple hols into and prevent splash, great. Else, pump slowly to avoid splash.

Pump slowly. Tap on it. Pump some more slowly. Keep enough fluid in the res. to keep the lines submerged.

It's bench bled.

Then bleed the system as normal.

1 man job.

 

[928'er]

Should be no problem with the Motiv. I've done it without bench bleeding.

One trick I've seen with hard to bleed clutch MC's is to use a (new) pump type oiler and reverse bleed it by pumping fluid up through the slave cylinder. Forces any air out the top.

 

[oldtools]

Bench bleed.

 

[u118224]

Thanks for the replies, I appreciate it. It's easy enough to bench bleed it so I'll just do that to be sure.

 

[joe_padavano]

I've replaced many a master cylinder without bench bleeding. I use a Vacuula vacuum bleeder and never had a problem. The pressure bleeder essentially works the same way - the pressure at the MC is higher than pressure at the bleeder screw. Doesn't matter if it's 14 psi at the MC and zero at the screw or 28 psi at the MC and 14 at the screw, the result is the same.

It certainly doesn't hurt to bench bleed, just more work and messier.

 

[devoncoolman]

They are all different. Ive seen some that were a bear to bleed and some not. Ive had cars that ive gravity bled and were ok. Just bench bleed it. In the end ull save urself time and aggravation.