Best approach to bleeding brakes - Part 2
 

First attempt at filling and bleeding went about as expected - not well. I found several fittings I thought I had previously snugged tight but leaks showed I did a half-azzed job. The rear brakes seemed to gravity fill and flush most air out as far as I could tell. But the front Camaro brakes are giving me fits. One of them just runs continuous air. I spent probably 2 hours watching air bubble through the line from somewhere. There are no leaks that I can find. I suspect the bleeder screws. These first two are video clips.

http://i125.photobucket.com/albums/p...ps7ef4f1dd.jpg

I tried coating the bleeder to caliper area with dielectric grease in an attempt to cut off air from being drawn back around the bleeder. I tried pumping the pedal slowly to know effect - it just forced brake fluid out around the bleeder screw.

http://i125.photobucket.com/albums/p...ps3270e674.jpg

Ever see anything like that? Air bubbles never let up.

I did notice that the pistons in the Camaro units are still withdrawn and the pads are not close to the rotors. I'm wondering if this air could be coming around a cocked piston and seal. You can see the gap in this photo.

http://i125.photobucket.com/albums/p...pscdb4819f.jpg

I didn't see Kevin2's response about raising the front of the car way up, but I think I have some other problem. It may just be a real loose bleeder screw, I don't know. I gave up after about 5 hours. I think I sweated off about 5 lbs today. I will probably wait for cooler weather and put my wife in the seat for the old stroke-hold - loosen bleeder - tighten bleeder - release brake - etc.

I hate brake bleeding.

Red Rubber Grease
 

OK, now it's not a big deal, but in the future, when working on brakes and clutches, only use red rubber grease, not your dielectric or petroleum based stuff. I don't know why I didn't mention that in the previous thread. Sorry.:(

Dan,
I'll put this as politely as possible. Your simply killing yourself for no reason. It ain't that hard.
Here's what worked for me for 3 decades-and yes-even starting with an empty system.
As I said in the other thread, get speed bleeders. There's NO reason not to have them. You will thank me. Open once and close when finished. They're tons cheaper than all the other stuff you put on the car. Order them and take a break 'til they come.
While waiting for them, order a vacuum bleeder set. Pick your favorite and just do it. Mine came from Griots 2 decades ago and is still perfect. Made in Switzerland. Get what ever one he offers now.
Then-forget jacking a mile high and forget pedal-pumping. With the car up but level-open your new speed bleeders and fill the reservoir. Let it gravity feed and run out the open bleeders, checking the reservoir. If none runs out-don't sweat it.
Close the bleeders and one at a time, put the fitting from your new bleed hose on the 1st open bleeder with some antiseize-not dielectric.
Connect your compressor hose to the vac canister and (with a full reservoir) begin to pull fluid through the line. Have your helper watch the reservoir and add fluid as needed. NO PUMPING.
Do this 3 more times and you have a rock hard pedal and no air. And it won't take more than a pint of fluid since you already have fluid in system. Then do the clutch bleeder the same way.
Think your pads are away from the rotor because there's no fluid pushing them out or the pistons are corroded to the bores.

Yes, I think I have. Long ago on a new system with the old style master cylinder that had not been bench bled. But, you say the perpetual bubbles only appear on one of the front Camaro brakes, correct? If so, an unbled-MC problem would do the same for both brakes (somehow sucking air in on the pump stroke). If the perpetual bubbles only occurs on one caliper, then I say there is a problem with that caliper itself.

Unless you have a serious leak in the line/caliper (which you would have seen fluid leaking from by now) the source of your bubbles are the threads on the bleeder itself................I've seen this a hundred times...
It will not hurt anything,once you get fresh fluid coming out, then have someone in the car manually pumping the brake pedal and do the last bleed the old fashion way with 2 people and be done with it..........

If you really want to get rid of the bubbles, the only thing I've seen work is to remove the bleeder it self from the caliper (you can use vice grips to pinch off the soft line while you do this) and wrap the threads with Teflon tape and re-install, no more air bubbles................

speed bleeders already come with thread sealer applied-yes i'm shouting. PICTURE THIS IN ALL CAPS BUT THE SITE GESTAPO CENSORED ME DOWN TO LOWER CASE.

I'd just go ahead and buy the damn speed bleeders. But it looks like the thread sealant is ten bucks extra. Speed Bleeder Installation


EDIT -- and when you break one off in the caliper, go here: http://www.speedbleeder.com/News.htm and make sure you video tape it so we can all watch....

yes i know that,but he doesn't have speed bleeders and wanted to know how to stop the air bubbles with what he has on there now............

Oh stop it Patty-
http://www.summitracing.com/search?S...0BLEEDER&dds=1

David,
He fretted over getting a 'correct' washer bottle and covers for the tunnel tubes..........
Getting effective brake tools should be a much higher priority.

That's all beside the point,he asked how to stop the air bubbles with his present set-up and bleeders and I told him where his air bubbles were coming from,he DIDN'T ask what bleeders he should be using..........

David

[quote=DAVID GAGNARD;1256949]Unless you have a serious leak in the line/caliper (which you would have seen fluid leaking from by now) the source of your bubbles are the threads on the bleeder itself................I've seen this a hundred times...
It will not hurt anything,once you get fresh fluid coming out, then have someone in the car manually pumping the brake pedal and do the last bleed the old fashion way with 2 people and be done with it..........QUOTE]

After reflection this has got to be the issue and I think where I'm going with it. Even just barely cracking the bleeder until fluid movement is barely noticeable and coating around the base of the bleeder screw with grease it still pulls air into the line. It's surprising but it only starts after the syphon column reaches maximum head and then the dam breaks and here come the bubbles. It's got to still be pulling air around the bleeder in these old, rebuilt calipers. My wife has been put on notice for brake bleeding duty when the weather cools a little. Speed bleeders is another upgrade I can work on once I get this thing together and running.

I tried pressure bleeding the one bad caliper but it just caused brake fluid to run out around the bleeder screw even with it barely cracked open.

Kevins2's comment about raising the nose to get air out of the master cylinders does kind of concern me. I don't think it's practical to bleed these things separate from the rest of the system - at least that I know about. Guess I'll give that a try and rap them with a wooden dowel to try to move the air along.

You got it David - thanks.

Dan

Dan:
Now I'll put in my whole 2 cents worth having just flushed out the entire brake system on a 65 Fastback and starting from scratch,both rear caliper (Versaille disc brakes in the rear) were rebuilt and fluid was old and black,so a flush was in order.......

What I did was put the car level as I could on 4 jack stands and starting on the passenger rear took my little el cheapo Harbor Freight vacuum pump and hooked to the bleeder,after cracking the bleeder I began pumping to get the old fluid out until nothing would come anymore and yes I DID get air bubbles the whole time......once I had no more fluid coming out, I took the bleeder out and wrapped the threads with Teflon tape and re-installed it,then did the same on the driver side rear caliper... so now both bleeders have been wrapped with Teflon tape and the master cylinder and brake lines should be all but empty of fluid...filled up the master cylinder and began pumping again on the passenger side bleeder until I got nice/clean fluid,had to re-fill the master cylinder a couple of times....then on to the drivers side, doing the same thing.....once I got all nice clean fluid I moved to the front calipers (factory front 65 Mustang disc brakes), doing basically the same thing starting on the passenger side and then to the drivers side, re-filling the master cylinder as needed..........
Once all the lines and calipers were bled and everything was full of fresh fluid, I then got my wife to pump the brakes and do the final bleed the old fashion way, I did three pump/bleed sequences per caliper and got no air and all clean fresh fluid..........
then took it out for a test ride, everything worked as it was supposed to... and the owner commented that he couldn't remember when the brakes were that good!!!!!!!!!!!!! I also suggested doing one more manual/pedal bleed after about 50 to 100 miles,can't hurt anything...........

It's not hard to do, just take your time and be careful......even if you do not wrap the bleeder threads with Teflon tape, you CAN still bleed the system just fine and it WILL work...........

David

On the one really bad front caliper I may just have to bite the bullet and pull the bleeder and stop up the caliper hole with a rubber plug so I can wrap some teflon tape around the bleeder screw and reinstall it. I can also measure it to see what size speed bleeders I may need to order for the future.

Thanks

Hi Dan,

The method of raising the front of the car as much as possible is what Doug at ERA has been doing for countless cars, so in the absence of speed bleeders, etc. is worth a try. Also, I replaced one of my front bleeders with the nose of the car jacked up with minimal fluid leaking out in the process.

That said, I have no bubbles, no leaks - did a pressure test by pressing on the pedal for over a minute as hard as I can - and I'm still not happy with the pedal firmness. It's been many years since I've had a car with manual brakes so not sure if it is really soft or just me not used to that feel. Lastly, if you do try raising the nose and very slowly pumping the pedal, do so with it quiet and you'll hear some gurgling (again, this is done with all bleeders closed - then lower the car to level and bleed). I was able to get to the point where I no longer hear any.

Regards,

Kevin

I have bled brakes thousands of times and rarely if ever have I seen gravity bleeding that didn't have the air bubbles you are experiencing. There is not pressure on the brake hose from the bleeder to your can, so the air bubbles are walking themselves up the hose.

Did you pump up the pedal before you started to bleed? If not, that is the gap you are seeing between the pad and rotor. Even if you gravity bleed, you still need to pump up the brakes a bit. Bleed some, then pump them up again.

I use the stick method. Grab a broomstick and wrap a lot of tape around the end. Get int he car and pump the pedal. While holding the pedal down, put the stick between the pedal and the seat. Get out, open bleeder. That was before I bought the Speed Bleeders...but it still didn't take me 5 hours.

When starting from "dry" calipers, one thing that I do after the initial bleed is to gently tap the calipers with a soft mallet. Sometimes micro-bubbles of air stick to the corners that need to be dislodged. Wait at least a half-hour to do the final bleed.

Thanks Bob - I used the wooden handle from a trim hammer to tap on the calipers. It did shake loose a couple of bubbles.

Kevin - any idea as too how high? I had the nose elevated probably about 7 to 8 inches in order to pull the front tires. No need to remove the rear due to the inboard calipers.