Brake bleeding sequence contradiction

Buick manual says closest wheel cylinder first (drivers side front), and just about every other guide I have read says do the opposite (rear passenger)! I also see some member recommend that as well. Which one is it and why is one better than the other? I could see how you could argue either way is better.

 

I think the real trick is to pick one and stick with it. Air will go where air goes. For the rear it makes no difference. The line drops in the center and pretty equal wheel to wheel.

For the fronts, they are separate from the rear so there's not cross-air. Passenger front is farther but if air gets in the lines, it will likely be in both. You're going to bleed them all any way.

 

I was taught to start with the right rear, but that was back when most cars had a single reservoir master cylinder. In all honestly, I don't think it makes any difference where you start, at least I've never noticed any difference. As already stated, you're going to do them all anyway.

 

^^^X's2

 

I've noticed a contradiction with the manual vs other publications as well and often wondered how much it really matters. My personal experience has been that is doesn't matter.
I've done it both ways and everyway in between and never had a problem. Of course there could always be an exception because of several other variables depending on the specific job.

 

I used to worry about following the manual to the letter. Than I realized after doing enough brake repairs that with a dual reservior master the fronts and rears have almost no effect on each other (other than the notch to allow one reservior top off the other in the event of a leak).

I'm at a point where I only bleed the end that I worked on. No need to bleed the fronts after replacing the rear hardline. No need to bleed the rears after replacing a front caliper. Just top it off after bleeding and everything is good to go.

 

..and I've even gone a couple of weeks before bleeding after a master changeout. I ran short of time that day and the system worked fine.

 

Got the MC installed. Started to bleed the system at the right rear wheel first using those nifty speed bleeders. At first things went well, as old fluid and air came out into the jar partially filled with clean fluid. Then I noticed that the aft MC chamber line was leaking a tad, so I tightened it up and resumed pumping. Some more air came out, but now nothing seems to happen at all. When I pump, no air or fluid comes out, in fact the fluid in the line started to rise up a centimeter or so above the fluid level in the jar. I tried closing and opening the speed bleeder a bit, but to no avail. Is this thing sucking air somehow or what? I hate brakes!

 

Tried the left rear wheel and nothing comes out. I even tried taking the speed bleeders out. The mc must be pumping if the line was leaking until tightened. Blockage maybe?

 

Do you have a firm pedal as in its not going to the floor? If a firm pedal, start loosening lines working backwards from the wheel cylinder, or just try the right rear. If same thing happens on right rear its possible the flex hose to axle is at fault. If the pedal continually is going to the floor and you aren't moving fluid, there may be another problem at the master.

Actually, if you fill the master and open the bleeders, the fluid should "eventually" gravity flow to each wheel but that can take 15 min to an hour.

If the master cyl has been sucked dry, I like to start by removing it for bench bleeding. It makes the wheel bleeding process go much quicker.

To bench bleed the master you'll need the plastic fittings and short hose that typically come with a new master or you can make them if you have some old lines that fit the master.

 

MC was bench bled prior to install. Pedal is firm, but can be pushed all the way down. If rear line is loosened at MC and pedal pushed, fluid cones out. Looks like an issue somewhere down stream. I will try opening both bleeders to see if anything will gravity bleed out.

 

Are you sure a piece of crud didnt get lodged in the wheel cyl in front of the bleeder? Ive seen bleeders get plugged up in the past. If all 4 wheels are stopping and the peddle is where you want Id say drive it and see how it goes.

 

Yeah but nothing came out with the bleeders removed...

 

Holy smokes can anyone recommend a bleeder screw tool for the front drum brakes? I can't find anything (including the brake bleeder tool I found at AdvanceAuto) that can get in there.

EDIT: I managed to remove one with a vise grip (gasp!), but found yet another issue. The front bleeder screws are not the same as the rear! They are longer and wider (look like a 9mm hex). Maybe the wheel cylinders are aftermarket? I thought the drum brake setups used the same bleeders at all 4 corners....

 

Ryall, I know this may set you back and you might not want to do it but Id say pull the wheel cyl's out and rebuild/replace them. Its not hard or expencive and will give you a fresh start and piece of mind. Again, I have everything here to do the job if you want any help.

 

I was thinking the same thing about pulling the wheel cylinders.... probably would be a good idea to do all 4 corners and just be done with it. I will probably replace the rear flex line, it looks old, the front lines are new.

 

Sure did

Ooo those are nice. I must have bleeders that are too long though. There is no way to get a closed wrench around them due to the proximity of the spindles.

Anyways, I went ahead and attempted a gravity bleed on the front brakes and it seemed to go without a hitch. I flushed out all the old fluid and really let them sit and bleed for a while. Pedal feels good, with about 2" of travel (I believe the book calls for no more than 2.5" or so for a power drum car). I am going to replace that rear flex line. It is pretty fugly. Hopefully that is the cause of the blockage.

Possibly related question: Would rear brakes that don't function cause the tires to sometimes chirp (eps. in the garage) when going from park to reverse or drive? Sometimes the car shifts really firmly into drive or reverse, but shifts really nice through 1,2, and 3 while driving (nice quick firm shifts). I was thinking maybe if the rear brakes weren't holding it might allow things to pop a little bit like that.

 

You know something is rusted up when a line wrench rounds a brake nut...