shotgun_000

I recently had to change a caliper, due to a broken bleeder screw. I used various methods to bleed the air, such as gravity bleed, and the old fashioned two person method. Also, I have used the vacuum pumps in the past. These methods are ok, but can take quite a bit of time, and may not be the best method.

I have heard of pressure bleeders, that attach somehow to the master cylinder, and force brake fluid under pressure through the system, purging the air out of the system. The result is a nice firm pedal with minimal time and work. Does anyone have experience with these systems? Where can I learn more?

Is this the method used during assembly of new cars, or do the factories use another method of bleeding after assembly of the brake system?

Thanks! :seeya

Larry B.

I actually have the best results gravity bleeding. This method seems to work when others fail. For some reason C-3's can be a real pian to bleed.

Jvette73

I learned from other forum members to tap on caliper with hammer while gravity bleeding to help dis-lodge trapped air. I tried this and it helped alot. I first saw the fluid running steady with no air, then tapped the caliper and saw more air come out.

shotgun_000

The only problem that I have with the gravity bleed method is that the front calipers also have broken bleeder screws. I guess this is the result of the car setting for about 10 years :( So, gravity bleeding didn't work too good, since the flow keeps stopping, and it's a pain to keep replacing the master cylinder cover, close the bleeder screw, and then climb in and pump. Then, restart the process for a few minutes until the flow stops again. If only I could open a front caliper bleeder screw:(

As soon as I have the money, I am going to replace all the lines, and install O-ring calipers. I'm hoping at that point, I can use a faster method. If not, I'll try gravity bleeding again :cheers:

shotgun_000

I spent nearly an hour doing this, and still had occasional pockets of air. I started wondering if air was just entering around where the hose went over the bleeder screw. If it was actually trapped air, it was a lot :yesnod:

joeveto

Here is my method. I have great success with it. I did it with the Vette last week and my truck this weekend...Both vehicle's brakes have never felt better.

Get a mason jar and partially fill it with clean brake fluid. Then pick up a few feet of clear tubing/hose of a diameter that will allow it to tightly fit over the bleeder screw. You may need to ream one end of the hose out, or stretch it with the end of a phillips screw driver, to get the end of the hose to fit tightly. But once the hose is stretched, it will stay that way, and will become an important tool in your garage. I have my bleeder kit nearby in the garage, and ready to go.

Now once the hose is attached, open the bleeder, and pump the brakes to fill the hose with brake fluid. In a sense, you're priming the clear hose with brake fluid. Then close the bleeder. Now raise the jar, with one end of the hose in it, above the bleeder. Any air in the hose, at the bleeder, will rise up toward the jar. This is good. We don't want any air near the bleeder. Once the air is up near the jar, lower the jar to about the level of the bleeder. This should keep fluid by the bleeder, and the air in the hose towards the jar.

I use an old recycling bin as my bleeder station. It's tall enough to place the mason jar and hose almost equal with the bleeder. Plus, it's a nice place to put the rubber bleeder caps and my wrench. A box will also work.

Now, open the bleeder and go pump the brakes. There is a rhythm to doing this. Slow and steady down, lift up quickly. Slow and steady down, quick up. While you're doing this, it doesn't hurt to completely flush the system, if you haven't done so in awhile.

At any rate, it will only take a few pumps before you can close the bleeder and move onto the next. Because the hose is primed, moving to the next bleeder is a simple matter of attaching the hose to the bleeder, raising the jar to move the air bubble up towards the jar and away from the bleeder, and then opening the bleeder and pumping the brakes. If there is air in the system, the moment you crack the bleeder, you'll see it come out. Raise the jar and let it rise to the top. Then go to work pumping.

Of course, keep a close eye on the master cylinder, and make sure it doesn't go low on fluid. Also, watch the mason jar to make sure it doesn't overflow. I always keep old brake fluid containers nearby to empty the old fluid into.

Try this method, and you'll never go back. You can do the whole car in less than a half hour, and you won't need a helper.

:cheers:

pws69

Pressure Bleeding is the ONLY way in my book! I restored an old pressure bleeder and after trying all the other methods (gravity, vacuum, "2 person") - it by far the best, fastest, and most reliable.

Rockn-Roll

:iagree:

This is how brake bleeding wass described in the California Bureau of Automitive Repair Brake Inspection and Repair Manual when I first started as an automotive fleet mechanic. The only other step listed in the manual is to hold down the brake pedal after the last pump, just before tightening the bleeder valve...I use a 2' 2x4 and a towel to wedge against the seat to hold the pedal down. This extra step eliminates any possibility of air coming in around the hose that's attached to the bleeder. It's also a good idea to situate the jar and hose so you can see it while pumping to watch for clear bubble-free fluid coming out of the caliper before the final pump and going around to close the bleeder.

gliot1

I replaced all of my bleeder valves with "Speed Bleeders" These things make bleeding much easier. It is just a bleeder with a check valve, so pressure pushed out, but when releasing the brakes air will nto be sucked in. You can order them from most all catalogs, or even Pep Boys or AutoZone now have them. Any time I have my wheels off for any reason a bleed the brakes, because its so easy. I just connect a clear hose to the bleeder and the other end is into a clear Gatorade sport bottle. Pump the brakes a few times; inspect the host for bubbles; if there are none, you're done.

shotgun_000

I forgot all about those :thumbs:

thejaf

IMHO, the best tool for bleeding brakes is a patient wife

Touringpro

I used a pressure bleeder made from a garden sprayer along with SpeedBleeders. The idea for the sprayer/bleeder came from: http://www.bmw-m.net/TechProc/bleeder.htm. The plate that fits on top of the master cylinder is a modified version of this: http://www.corvettefaq.com/c3/brakebleeding.jpg. The modification was to replace the compressed air fitting with a simple brass fitting with a barbed hose end: www.geneandpam.com/images/bleeder_plate.jpg . Clear vinyl tubing connects the plate to the sprayer.

I just dumped a couple of quarts of DOT3 in the sprayer, clamped the plate to the M/C, cracked the SpeedBleeders, and started pumping. It took less than 15 minutes to bleed all 4 calipers, and the brakes are great.

norvalwilhelm

I'm also a fan of pressure bleeding. I have a very profession vacuum system but only use it to suck fluid out of the master cylinder, I don't like it for bleeding the brakes. I have tried gavity and it is too slow. The 2 person deal is ok but requries 2 people.
I got an old master cylinder cover plate and installed a air fitting. I set the shop regulator to 10 psi, fill the resovior, install the cover and plug the air line in. I bleed one back and one front then refill the resovior.
Takes me only a few minutes and I can do it alone.
I have never had a problem bleeding brakes since I removed the proportioning/warning light switch on both my cars.

Koz

Sure, but where can you find one.. These specialty tools are hard to impossible to find. :jester

NHvette

True - but you can use an impatient wife to rear young boys that are pleased
to help bleed them with you. I once bled the vette brakes with my 5YO son
turning the wrench. Worked like a charm.

When alone I prefer the method outlined by joeveto.

Koz

I tried this with my 7yr old daughter but I had her pump the pedal. She quit.. It was hard for her with her short legs to reach the pedal. :lol: Maybe I'll try her on the bleeder end this time..

VegasJen

see my tech tip under the 'tools' section. takes a little longer but the wife will be happier. :cheers:

JB

:withstupid: Clutchdust, that's one of the most useful tech tips I've gotten off the forum. It works perfectly and is far, far better than having to depend on the wife, who not only gets bitchy about it, but doesn't have the patience to do it right. That piece of PVC is now a permanent part of my toolkit. Here's the link, folks: https://www.corvetteforum.com/techti...=132&TopicID=3

JB

BB68Vett

I have a pressure bleeder but it could only be used on European cars. Now the company has come out with an adapter for our Corvettes. Since I already have a bleeder all I need is the adapter ($25.00). I'll post my results after I use it. A pressure bleeder is great for locating brake fluid leaks, in addition to bleeding the brakes. If anyone wants the name of the company that sells the pressure bleeder then email me.

Koz

Last night I put both rear calipers back onto the car. Since I had rebuilt the back end I needed to fill the rear lines as well as the calipers. I started out with the gravity feed method but it was taking too long. I found a piece of 3/4 PVC and figured I'd give it a shot. I'm sure the pressure type bleeders are much easier since once you set them up you just play by the caliper until no more air bubbles BUT I was impressed on how easy it was using just a piece of PVC. Thanks for the tip. :cheers: