These brake bleeding threads just amaze me, they should read how can I make brake bleeding painful. This is one of the simplest procedures on a vintage GM product.

 

Watch one, do one, teach one. It's tough to teach one with a keyboard. That's what YouTube excels at, though.

 

I guess, I have done so many it just comes natural. Not knocking anyone's abilities.

 

Bleed brakes. Tools needed: 3/8"(?) wrench.

 

It takes more than a bleeder wrench to bleed C3 brakes properly.... The most important 'item' is your brain and a good 'working' knowledge of the bleeding process. If you have THAT and the properly sized bleeder wrench (and a bottle...and a hose...and some brake fluid), you might be able to get the job done right.

 

^Bingo!

 

NO NO NO!!!!!

As noted by informed folks here^^^^, bleeding the brakes on a C3 is NOT difficult and simply because the car has 4 wheel fixed racing style calipers with 4 pistons per wheel does NOT make the procedure materially different than just about any car either today or yesterday. If you cannot bleed the brakes easily with gravity with or without the 2 rear caliper bleed screws (I do not use both BTW), then the system inherently is not operating correctly and the issue lies with having the brakes system correctly sealed and operating. I have been bleeding my C3s brakes every few years since 1985 and I spend about 1 hour start to finish with a helper stepping on the brake pad with no operating issues afterwards, ever. HOLY smokes!!!!!

I think I will add the brake bleed topic to the C3 junk heap forum discussions including roller cam conversions including a roller cam walking without cam buttons since a double roller timing chain flexes, pushrod measuring for a roller cam install, 383 conversions creating monster torque over a 355 everywhere, aftermarket intake manifolds adding 20+ HP alone, and on and on......

 

No it doesn't. Any open/box wrench works. The only other thing needed is someone to pump and apply the brake. It will be messy from fluid spurting out but the brakes will be bled. To keep the fluid from spurting a tube can be used and a jar. But that does not affect the bleeding process nor end result. Anyone who can't successfully bleed their brakes using the simple pedal method, see post #19.

 

You are taking that position either because you have bled brake systems correctly for years and you consider the task "simple", or because you have NO knowledge of bleeding brakes and just want to troll this thread.

I highly suspect that you know how to bleed them and can do it in your sleep. But, what eludes you is that there IS some amount of understanding of the bleeding 'process' that is required...and a novice has NO KNOWLEDGE WHATSOEVER of it until his/her hands are on the bleeder wrench. There IS technique involved. Your long-term knowledge and experience has left you without any perspective of how a novice sees it. I.e. If you were to write down the process for bleeding brakes, what steps would you put on paper?? ---other that "It is simple....just do it."

 

Exactly, one wrench. 5/16ths maybe. Let gravity do the work...

 

I have always used the gravity bleeding method and it has worked very well. however it seems every few weeks or months someone is on here that can't get a hard peddle no matter what they do and i will admit it concerns me that one day it will be me that is having the problem. i've read threads were someone has changed almost every part of the brake system and can't get a hard peddle no matter what. seems like it is only a matter of time before it's me with the problem. LOL

 

The procedure is simple! But people want to do shortcuts, throw instruction sheets in the garbage, depend too much on the internet and get lots of misinformation leading to confusion. Why do you need a Motive bleeder? Because those that think they know tell others its the best thing since sliced bread and nothing else will work as good. It ain't! Using a Motive bleeder won't make your brakes any better or worse, so why waste your money unless you own a brake shop and can save time/money. But spend your money as you please. Now debate this pedal method as you wish but here it is for anyone who doesn't want to waste their money buying pressure or vacuum bleeder kits:

Top up m/c
Replace lid so brake fluid doesn't spurt out
Start at the furthest bleeder away from m/c or using the Chevrolet service manual for 1974, start at the bleeder nearest the m/c.
With engine off, tell helper to pump brake pedal until hard (several pumps of pedal) and then to hold pedal down until you tell them to release pedal
Place a length of clear plastic tubing of a size that will fit snugly over the bleeder outlet hole and not over the hex where you need to use your wrench
Run the tube into a clear plastic quart container like a water bottle that is 1/8-1/4 full of clean brake fluid (this will help suck back fluid vice air if you screw up by not following the procedure) and capture used fluid
Crack open bleeder about a 1/4 turn or whatever it takes to get a flow of brake fluid for about a second and re-tighten
Tell helper to release brake pedal
Tell helper again to pump up brake pedal until hard and hold it down
Crack bleeder again for about a second and re-tighten
Tell helper again to release pedal
After every three or four complete bleeding cycles described above, check m/c and add fluid to prevent m/c from going dry
Keep repeating (it may take 10 or more attempts per caliper bleeder) until there is absolutely no air bubbles coming out
Move on to next bleeder and repeat the whole process

This is the standard procedure I learned at an early age observing mechanics and read in factory service manuals on every vehicle and Harley I've ever owned in the past +40 years. So, which part of the process above is too difficult for any forum members? But don't try this if your not comfortable with your skill level. If it does appear too difficult for anyone, please see post #19. Don't jeopardize your life or others by working on your brake system. And DO NOT bubba your brake system!!!

BUT, it only works on a proper functioning brake system. If the brake system requires new parts (READ the installation instructions and follow accordingly when replacing parts) then it goes without saying that no bleeding techniques or pressure/ vacuum tools will work.

 

I would tell them to go out to eBay and buy a 1973 Chevrolet Service Manual ($17) and read Section 5. No need for anyone to write down the process, GM already did that.

 

Yes they have. And I didn't see that anyone bother to direct the OP to that document until you just did....

BTW.... The procedure listed above wouldn't seem all that "simple" if I had never bled a brake system before. Once you've done it, you know it. But, before you've done it, it's a bit intimidating with all the brake problem threads that cross this Forum.

 

(Pages of text instructions deleted)

Really? If your helper is someone who has done it before, fine. Every mechanic I have ever seen bleed brakes in person, did it by themselves, with the car suspended on a lift with all 4 tires removed, and did the bleeding with a pressure-assist device similar to (but much more expensive than) the Motive bleeder.

All these other methods may work just fine for you and others. I've wasted many hours trying them. I can get a hard pedal, first try, in 30 minutes with the Motive bleeder by myself. That's $60- well spent.

 

Hell, a 12 year old girl can pump the brake and hold it to the floor. Anyway, changing the spark plugs on a C3 is a challenge doing it the first time. Or use a wrench and a screwdriver. Changing a flat tire too. Operating a gas pump when gas stations went to self-serve. I guess working on our cars is not for everyone but anyone can do simple tasks if they choose to with the right tools, a shop manual and this forum. But if one does not try, one will never learn. I admire the folks who come in here and admit they are rookies but are eager to learn. No need to go pay a mechanic for a lot of maintenance items on our cars. Save the labour charges and buy tools and do the work yourself. Many here have done this. I know I did. But you gotta start somewhere. The only thing I won't do is paint and body work. I couldn't be bothered as its a whole new skill set. But bleeding brakes on a vette is a low difficulty level but you gotta follow the procedure to a tee. Failure to bleed the brakes using the pedal method means you did something wrong because all a motive bleeder does is eliminate the helper who pumps up the brake.

 

Both of the above method is exactly the method I have used. Motive and pump pump pump. Neither one that difficult. And both will work. The C3 does have a few issues that makes bleeding ALL the air out a challenge. The angle of the MC as it's mounted on the car. The angle of the calipers as mounted. The construction of the calipers. Air will always be at the top of any space, fluid can and will be pushed out past the trapped air. Watch the air in the clear tube you use from the bleeder to the bottle, if there is a loop in the tube, an air bubble can stay at the top of the loop while fluid flows past it. All the issues can be mitigated.

 

This is the bore of your master cylinder. The reservoir is feeding it fluid from the top edge. The two brake lines feed from the bottom. Use your imagination. You can just see the two dark vertical lines that represent the seal pistons at about 1/3 and 2/3. You can see the air bubble on the upper left corner. Which method will bleed the air from this MC. Motive with fluid pressure into the reservoir, Motive with the MC reservoir full and just air pressure, gravity bleeding at the wheels,,,,,, or other. It's tilted front upwards, just like on the car.

 

Fluid, pumped under pressure and being much denser than air, will purge or bleed the brake components of all the air in the system without any need to tilt the vehicle at different angles. I and a few others in here, as well as GM previously mentioned, do not tilt the vehicle. Why? Because its not necessary. I guess I can repeat this a million times but those who choose not to believe in physics can do so but you can't change the laws of physics.

 

So you are saying a Motive bleeder pumped up to pressure would do the trick? Would 15 psi work?