Brake Master Cylinder New Install. Bench Bleed?

Hi all.

I'm going to install a new master cylinder on my Tacoma. The new one came with a bleed kit.
The instructions and all how to's say to bench bleed the new master cylinder before you install it.
Then bleed again after the lines are connected. This may be a dumb question but is there any reason you cannot install it in the firewall, attach the bleed kit and bleed it then? It seems much easier especially if you dont have a vise to clamp it into.

Thanks
Mike

 

because you want as little air introduced into the system as possible.

Not all manufacturers have the master cylinder as the "high point" of the hydraulic system. If have ever had to run gallons of fluid through a system trying to bleed trapped air out...

Do not forget to bleed the load sensing valve over the rear axle, start with the longest brake line first, usually the passenger side rear. If you have ABS you "might" create your own problem by NOT bench bleeding.

 

Hi and thanks. I understand that it needs be purged of air. I was simply wondering if the initial purge could be done after its installed, before you connect the brake lines?
Seems much easier than clamping it in a vise and pushing the actuator with a screw driver. Thanks for the tip about load sensing valve.

 

If I bleed new Master Cylinders at all it is with them already bolted to the booster .

I must have installed a few dozen in my youth before I ever heard of bench bleeding a Master Cylinder

My one attempt at bleeding a LSPV till it was finished cost a few hundred $$ never again

 

Thanks: Forgive me, but what is an LSPV?

 

The Load Sense proportioning valve

Living in the liquid brine belt everything rusts

Changing Calipers and Wheel cylinders for broken bleeders happens quite often

 

yes you can bleed the master as you described this has 2 issues as I can see. The first is this requires a second person to pump the pedal and the second is any brake fluid on the paint is going to ruin the paint.

 

Yes you can bench bleed it while bolted to the booster on the firewall. Actually easier. I do both methods depending what I want to do or my situation

All it needs is for the air to be bled and the fluid is just recycled back into the reservoir

 

Thanks Makes sense.

 

Thanks. My new master came with a bleed kit, so that should handle the majority of the fluid for the initial bleed.

 

Can you elaborate? What happened to cost you $$$ when you bled the LSPV?

 

Everything broke I had to buy a new valve list is around $250.00 replace all the brake lines to the valve .

If it was mine I would have left the darn thing off.

 

all you have to do is bench bleed the master, you have these hose kits that connect at each port and it recycles back into the reservoir whether you are pumping it by hand or by the pedal with it on the booster already.

after youre done, you reconnect all your master brake lines and rebleed again, this is to purge the air from the actual brake lines that connect all the way to your calipers/slave cylinder.

is there any part you are confused about? I bleed all my brakes fairly fast, maybe about 30 minutes or less depending on the method i use and by myself.