Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

[Mark E.]

Since I was a kid, I was taught to bleed brakes in wheel sequence from furthest to closest to the master cylinder (presumably RR first, LF last. (Although from a brake line perspective, is RR really further than LR? Ditto for RF and LF).

Explanations why goes something like "to get the gross fluid in the furthest reaches of the system out first". But I never understood why this mattered.

I'm about to change the fluid in the Corvette, so I thought I'd check the service manual procedure. Guess what? No mention of which order to bleed the calipers (1969/70 CSM).

[Don H.]

Re: Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

That is the way I have always done it. Why? Because I was told to! Don H.

[Larry M.]

Re: Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

The truth be told, the brakes probably don't care. They will be fine when all the air the air is gone.......however it occurs.

That being said, many many shop manuals have stated the sequence that you described. And it is likely the best way to do it. But, again, the primary intent is to finally get all the air out.........whatever sequence you use.

Larry

[Bill M.]

Re: Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

Funny thing is when I rotate tires I start at right rear as well

[Jim L.]

Re: Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

The truth be told, the brakes probably don't care. They will be fine when all the air the air is gone.......however it occurs.

Larry

In my not always humble opinion, this is the essence of the matter.

As a point in fact, when I bleed brakes, I begin with the wheel cylinder closest to the master cylinder and work my way to the most distant cylinder. Why? Well, my reasoning is that I don't want to have push air bubbles all the way to the back before getting them out; I want them out at the earliest opportunity.

Is my way any better? I dunno. But it works.

[Duke W.]

Re: Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

I agree with Jim. Consider a single circuit system. If you do a flush, siphon out the old fluid from the reservoir, clean out any sludge, and fill with fresh fluid. If you are installing a new master cylinder or starting with a dry system bench bleed the master and install.

So the line from the master to the junction block is either full of old fluid or air, and the shortest path to purging is to the left front. Does it make any logical sense to push it all the way through the system to the most distance exit? Not in my universe.

For a dual circuit system thoroughly bleed the front starting with the LF, then do the rear starting with the LR. Actually you can do the rear first and front last... doesn't really make any difference.

Duke

[Frank D.]

Re: Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

While we're on the topic I wish somebody would explain to me why I can never "gravity bleed" my original 63 drum brakes...
I've tried it 1/2 dozen times and the fluid just flat out stops running; bleeder valve wide open and top off the master cylinder.
I don't get it.

[Harry S.]

Re: Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

While we're on the topic I wish somebody would explain to me why I can never "gravity bleed" my original 63 drum brakes...
I've tried it 1/2 dozen times and the fluid just flat out stops running; bleeder valve wide open and top off the master cylinder.
I don't get it.

Frank, loosen the two nuts on the MC and pull it away from the booster. The piston will retract and this should open the hole from the top of the MC to the lower area. Sometime, due to the unique 63 booster, the adjustment pushes the piston in too far and closed the hole, thus stopping the fluid from flowing.

[Jim L.]

Re: Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

My hunch, Frank, is the difference in height between the MC and the WCs of a '63 is insufficient to create any meaningful pressure, and in any event not enough pressure to overcome the viscosity of the brake fluid.

The last time I bled the brakes on my '57 Shev-a-lay, I accidentally gravity bled the brakes. I opened the bleeders just to get some fluid moving, fully intending to bleed the brakes the old fashioned way. In short order, though, the fluid ran clear and to my surprise, I had a high, firm pedal. I think it's worth noting the height of the brake fluid column in a Shev-a-lay is much greater than in a Corvette, thus there was greater pressure available to move the fluid.

That's my theory and I'm stickin' to it.

[Frank D.]

Re: Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

I was actually thinking along those same lines Jim; however I'll try Harry's trick and if it works, well I'll be both happy and pizzed off at once.
Too simple.

[Timothy B.]

Re: Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

When I assembled the brake lines, brake cylinders etc. on my 63 chassis I used silicone dot 5 fluid and gravity bleed without any issues. With the cap removed you have atmospheric pressure helping.

If Harry's suggestion actually works you may want to investigate your pedal rod adjustment. There is a valve in the M/C that allows pressure on the drum brake system according to John Z which keeps the shoes just off the pin, maybe someone can expand on this.

[Duke W.]

Re: Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

It's called a residual valve, which keeps about 5 psi in the lines, so nothing can get in like water or dirt, but such valves cannot be used on disk brake systems that have constant contact pads.

...don't know about the gravity bleeding... never used that method... always use the two person (helper on the pedal me on the bleeder valve) command and response method.

Push down...

Down...

Let up...

Up...

Push down...

Down...

...

Duke

[Timothy B.]

Re: Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

There is a certain beauty to the gravity bleed method. Ever try the Pump up - Hold - Down - OK Hold - Let up - method with your wife inside the car... :-)

Do I need to explain further...

[Jim L.]

Re: Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

There is a certain beauty to the gravity bleed method. Ever try the Pump up - Hold - Down - OK Hold - Let up - method with your wife inside the car... :-)

Do I need to explain further...

Why, yes I have and it worked perfectly.

Maybe my bride was exceptional (heck, I know she was). I could show you pictures of her pounding on a pickle fork to get a tie rod end to turn loose, a picture of her with a breaker bar loosening the head stud nuts on my racing engine, and pictures of her working on her '59 when she did the body-off restoration.

[Timothy B.]

Re: Proper Wheel Sequence While Bleeding Brakes... Old Wives' Tale?

Jim,

I Love my wife but I can't say the same..