We just got our master cyl. and booster back from being redone and we are having problems getting the air out of the system. The m/c was sleeved with a stainless sleeve and the booster was rebuilt to spec. The m/c is the original mast. cyl. that has the bleeder screws on the side of it and with the reservoirs filled, we are not getting any fluid out of the bleeder holes with someone operating the brake pedal. The bleeder screws are bone dry. What would cause this? I tried to open the right rear wheel cylinder to get the air out that way. Still nothing. Any helpful hints? The car is a 70 Elky SS 396 with power brakes and disc fronts. We completely replaced the whole brake lines with stainless steel lines and replaced the rubber lines as well. Would renting a pressure bleeder be the answer to my problems? I need to get this done soon so I can get the car mobile to get some very minor repaint work done to it before my first show on May 2nd. Thanks for the suggestions in advance.

Brian

You may need to pull a vacuum at the bleeders to get the fluid to move that far. One of them little "solo bleeder" hand pumps will probably do the trick. :wink:

I have one of those one handed vacuum pumps however it is being very elusive to me in my shed. I am sure it is out in the open and I cant see it. I was also thinking about renting one of those pressure bleeders that you attach to the master cylinder and then go to each wheel and bleed out the air. Has anyone ever used this before and if so, how well did it work?

Did you bench bleed the MC before you installed it?

Did you bench bleed the MC before you installed it?Ditto. Did you also reset the proportioning valve?

I've used pressure bleeders, gravity, doing the procedure by the book and it all works some better than others. I went through 3 mastercylenders trying to get a good one from the autoparts place.

Lots if ssues. Its moot at this point but always do a bench bleed on the MC before you install it then you can work the bubbles, if there are some in the lines out to the wheels. However if you've replaced all the lines or a lot of them then reverse the bleeder.

Reverse the vacuum bleeder at the wheels, pump the fluid back into the system. Have someone stand at the MC to look for airbubbles and help drain it as it fills up. Do all wheels then check.

Sounds stupid but it works also. Its tough getting all the air from the proportioning valve if it has air in it. Also look around at the lines make sure none of them are bent or kinked. You have to re-fill the lines and then bleed. Its just going to be a lot of work at this point.

I think I was told once that with a lot of air in the lines, like having new lines, you've got trapped air that is very hard to get going with fluid. I tried the reverse fluid fill when I replaced my lines in the front of my 76 and it wen't ok. It took a while to get use to the idea in my head, I am kinda one way about some things, but it turns out the advices wasn't as lame as it sounded.

I had a l large bottle of fluid ran a line into it had a friend watch the MC so it wouldn't run over. Its an open systrem when your not on the pedal. Just figured I'd throw that in.

Good luck.

Elky pete,

never heard of that being done before. sounds like a good idea. I did not bench bleed the m/c cause i figured the bleeder screws would be able to bleed it out. I will try to bench bleed the m/c tonight and if that doesnt work, try the reverse fill system.

Also, how do you reset the proportioning valve? I thought that was just a junction block to equalize the distribution of the pressure going to all 4 wheels. I know it has switch that when it goes bad or if there is a leak in the line, it will sense it and light something up. At least that is what it does on my 69 Charger.

Thanks for the info.

Brian

I've sold and used all kinds of presure and vacumn bleeders and I know the vacumn brake bleeder made by VACULA (http://www.toolsource.com/ost1/product.asp?sourceid=http%3A%2F%2Fdpxml%2Everizon% 2Enet%2F%5F1%5F29epu9203depe8k%5F%5Fvzn%2Eisp%2Fdo g%2Fresults%253fotmpl%3Ddog%2Fwebresults%2Ehtm%252 6qcat%3Dweb%2526qkw%3Dvacula%2Bbrake%2Bbleeder%252 6top%3D1%2526start%3D%2526ver%3D24863&dept%5Fid=500&pf%5Fid=52661&mscssid=L7RX0642408W9HBLKFQ1UP6DC78R98G5) works the best. A few months ago I replaced the master cylinder, both front calipers and both rear wheel cylinders. I did not bench bleed the MC but within 20 minutes I had bleed the brakes all by myself.

The Vacula bleeder is excellent it has a reservior of fluid you invert in the master cylinder so you don't run it dry only thing you will need is compressed air and it only takes one person to use.

I really like my Mityvac pump. It's so easy to use, but can be used for different things beside brake bleeding. It is best to bench bleed the master cylinder first.

I will try to bench bleed the m/c tonight and if that doesnt work, try the reverse fill system.



So how'd things go? Get things worked out? Inquiring minds wanna know! http://www.websmileys.com/sm/happy/1203.gif

Its been a whie but I am thinking that proportioning valve GM uses on the Elky, and I think most older cars, the light gets triggered by an unequal pressure. Its also re-set by proportional pressure when both sides (Front and back) have the correct pressure/fuid in them. So I don't believe you have to re-set the valve.

I usderstand some vehicles have a valve that shuts of the offending cirsuit for safety or some reson. Perhaps their thoughs are if a leak is present then shutting down that circuit will keep your brakes longer or keep you from leaking out all the fluid through that faulty circuit.

But as best I can remember you don't have to re-set the valve as soon as normal pressure is restored it re-sets its self. I could be wrong about that but I don't think I am.

The Service manual seems to agree. It also says there are no repairs that can be made to the "Combination Valve" and no reset procedure other than being properly filled & operating correctly.