Filling and Bleeding New Brake System

[RRoller123]

Question for the assembled masses, who may have done this before:

I have replaced the Vacuum Booster, Master Cylinder and both front Left and Right brake lines; only the rear brake line/s remain from before.

So I am curious as to the best method to fill the new lines and Master Cylinder. Fill the MC separately, before hooking up the lines? Hook it all up and fill the reservoir and just pump everything through? The rear lines still have fluid in them, so start with the front Right, then Left then Rear?

I bet there is a preferred method to fill and bleed a mostly brand new system. I will go out and get a powered vacuum bleeder if that is the way to go?

Any insights into the best way to accomplish this are appreciated.

Pete

[kilrwail]

Having just replaced my master cylinder, I can attest to the value of bench bleeding it - but better to do it in the car because it's almost impossible to carry it from the bench and put in the car without spillage. Without bench bleeding it, you'll spend a lot of time and energy trying to get air out of it and all the way to the wheels. Then connect all the lines at the M/C, fill the reservoir and start bleeding in the normal way, i.e. RR then LR then front. Fill the reservoir often. Buy lots of brake fluid - it's cheap. Get a friend and a case of beer, or a power bleeder Good luck!

[nelsonj]

I replaced my M/C about two years ago. I made no attempt to bench bleed - I just took off the old (it was leaking so my reservoir was already empty) and put in the new (after getting things adjusted on that needle from booster). My advice: Make sure you have a lot of break fluid, and Get help pumping the breaks!!! I enlisted my son and we wound up pumping for hours - no exaggeration - before I was satisfied.

I've heard/read that some people attach a vacuum at the bleed screw and "suck out" fluid until there are no bubbles. I really couldn't figure out how to hook up a pump/vacuum, but it sounds like a good idea to try. Perhaps others could sharer their technique/ setup.

Otherwise, gets a good pumper or two! Good luck.

[vandor]

I've never bench bled a master cylinder in my life, and have installed dozens. Easiest way is to fill the reservoir and open the right bleed screw, then put a pan under it. In a few minutes (maybe even 10-15) gravity should pull the brake fluid through and it will start dripping out. Then bleed right side (farther away), then left side.
There are gizmos that can pressurize the reservoir so the fluid goes faster. If you use SpeedBleeders at the calipers then it can be a one person job, as the SpeedBleeders have a checkvalve in them that only lets fluid out, but nothing in.

[RRoller123]

Thanks all for your help, looks like it will be a breeze! Just some patience and lots of fluid. I will do the Fronts first, since those lines are completely empty, and the rear afterwards, then repeat the fronts. And get some of those speed bleeder one-way flow gizmos, since I am doing all this work by myself. Taking the RV out to North Truro today for the season, and there is a HF in Hyannis. Perfect!

Pete

[samakijoe]

I have used this tool with good results. Makes it really easy. Have speed bleeders installed.

http://www.speedwaymotors.com/Motive-Pr ... ,5790.html

[DieselSpider]

The Spider has been one of the easiest cars I have dealt with to gravity bleed or vacuum bleed with the only real gotcha being that you need to have the rear axle supported to keep the rear compensator valve opened or the fluid will not flow through to the rear wheels.

[RRoller123]

I've never bench bled a master cylinder in my life, and have installed dozens. Easiest way is to fill the reservoir and open the right bleed screw, then put a pan under it. In a few minutes (maybe even 10-15) gravity should pull the brake fluid through and it will start dripping out. Then bleed right side (farther away), then left side.
There are gizmos that can pressurize the reservoir so the fluid goes faster. If you use SpeedBleeders at the calipers then it can be a one person job, as the SpeedBleeders have a checkvalve in them that only lets fluid out, but nothing in.

Can you put a pan under all four and save some time by letting them all gravity drain simultaneously?

[jlw35]

Vandor,
Can you clarify for me, maybe I'm not reading your reply correctly as I get ready to do my brakes.
I first fill the reservoir, then open the left front bleed screw and wait until fluid runs out the bleeder, then followed by the right front etc? Do I have that correct?

Thanks
Jeff Whitney

[vandor]

Vandor,
Can you clarify for me, maybe I'm not reading your reply correctly as I get ready to do my brakes.
I first fill the reservoir, then open the left front bleed screw and wait until fluid runs out the bleeder, then followed by the right front etc? Do I have that correct?

I think the OP said he was only doing the front brakes. One should always start with the caliper farthest from the master cylinder, so if doing all 4 then start with the right rear. When bleeding rear brakes make sure the axle is supported on jackstands. If it's hanging down with no weight on it then the compensator (proportioning valve) will close the fluid path to the rear brakes.
With the rear brakes being father away it may take a while for fluid to reach back there by the gravity method alone, as it's pretty long path back to the compensator the forward again to the center hose, etc.

[DRUMMOND]

I have used both a pressure and a vacuum method. Vacuum was the easiest to use. sure as hell better than the pumping method with helpers. you also have the added benefit = don't have to give away your beer

[jlw35]

Thanks, just finished the front brakes. Worked fine.

Jeff

[RRoller123]

Bought a vacuum assist bleed system on Monday at HF, will use that and maybe post a few pics and comments on the results. I didn't see the one-way valve type speed bleeders there, maybe I missed them or they were not a store item in Hyannis.

Pete

[aj81spider]

The speed bleeders replace the bleed valve on your caliper, so they are 124 specific.

https://autoricambi.us/products/brake-s ... erformance

[jwldane]

I did the same job not long ago.

I bled the MC first by bleeding to the left front first to pull fluid through the MC. Once that was done the SOP from right rear to left front with jack stands under the rear axle.

Gravity works well if your patient. The vacuum help but is a pain to keep on the bleeder screw.

Hope this help. Good luck.