Bench Bleeding a new Brake Master Cylinder
 

Does anyone know how to do this? My ASE Certified Brother-in-Law (Who Hates Me) said that I have to "Bench bleed" my new brake master cylinder before I install it into my '80 RX-7. He says that if I don't, installation is a royal pain in the ass... Anyone have a clue as to how to do this? :wallbash:

Thanks in advance!

if its brand new it should come with some plastic caps with a nipple on the end and a couple peices of rubber hose, basicly u screw the caps in and conect hoses ,run the hoses into the resivour, fill the resivour, then use like a screw driver and push in the piston on the master cylander ( pump it) it will circuilate fluid and when u release it it will suck fluid in and get the air out of it. ( make sure hte lil rubber hoses stay submerged in the resivour

http://www.diynetwork.com/diy/ab_bra...278197,00.html


This is a nice article with pictures.

Yeah it is a bitch to get out all the air in the master cylinder if you don't bench bleed it first. Just buy a bleeder kit from NAPA, it comes with a couple of fittings and some tubing. Hook it up to a vise and go to town on it.

Man, i must be getting old. I never worried about bench bleading mine. :) I've done them on my ol' 79 and 81. Even the 90 Rx-7 was'nt a very big deal imop. CJ

Hmmm, I never bench bleed :|

I just slap it on, fill up with fluid, and bleed through the brake lines. Of course I always did it when I had the lines off or was swapping the lines anyways, so I had to bleed the system no matter what. Still wasn't hard to get the air out through the lines, though.

I believe it might possibly have to do with which type of Master Cylinder you are dealing with. I've read where people have a hard time getting all the air out of their Master Cylinders when not Bench Bleeding first.

I could be reading totally wrong tech write-ups but i'm glad I bench bleeded my 95 Honda Accord's MS. There was alot of air even after 15 cycles. However there was a lack of back pressure so that might have something to do with it. But again, there are alot of folks who swear by bench bleeding, so take it for what it's worth. :bigthumb:

Bench bleeding is always a good idea. It cuts about half the time off of initial bleeding and gives you a nice hard pedal every time. Without bench bleeding, once in a while you get a bubble that is a real PITA. Cars with ABS are the worst.

While you can do it fancy, running lines back to the reservoir, etc. I just block off all the ports but one (in turn) and cycle the piston with my finger over the remaining port. As I press in, I lift my finger to expell air and (when it draws) shoot the stream of brake fluid into a container and then hold my finger over the port as I release the piston to get it to draw from the reservoir. Block that one off and move onto the next one. Takes all of 2 minutes, if that. So easy, I almost couldn't not do it if I tried....like popping the transmission into 5th before reverse to stop the countershaft so reverse (non synchro) does not grind. It's a habbit.

I tried bench-bleeding my new MC and ran into some problems. There are three outlets that I plugged with nipples and then ran the hose from them. For whatever reason I can't get fuid to come out of the front-side plug. Is something wrong with the rebuilt master cylinder I have? Am I possibly doing something wrong?


DB