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Discussion Starter · #1 ·
I have a 1973 pontiac ventura that came with disc/drum brakes. When I bought the car it had been switched to disc/disc, but they didn't change anything except the brakes themselves. I have since purchased and installed a disc/disc master cylinder, all the brake lines, and bled them repeatedly! I was told by a rod shop that my only problem would be that I might have too much pressure to the rear. Well, I don't seem to be getting enough pressure to anywhere. They won't pump up very much at all and they don't seem to be catching in the rear at all. I don't know if it matters or not, but it has power brakes, should I be bleeding the brakes with it running because the brake booster? I would really like to drive this car before winter, so any help would be appreciated. :confused:
 

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I had the same problem. Does your brake caliper have 2 bleed valves on top and 2 bleed valves on the bottom? Describe the caliper you have. On most dics brake calipers there are 4 bleed valves, 2 on 2 on bottom. You only bleed the top. You also bleed the outboard first, and the inboard second. Give us more info. If you can take a photo of your caliper, it would help.

The next thing I do is disconnect the lines at the master and adapt a air fitting to the line and run an air pressure test. This will let you know if there is any leaks. I use a spray bottle with a drop a dawn to detect leaks. Give us more info and we will figure this out.

Kirk :cool:
 

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Discussion Starter · #3 ·
I appreciate your help on this. The calipers on the front are new, but just factory equipment. On the rear it looks like they are an aftermarket kit that had brackets that were welded to the rearend housing and the calipers were bolted on. They don't look like anything fancy. The rear also has hook-ups for an emergency brake. As far as I know there is only one bleeder on the top of each caliper. Before I got everything to hook up the rear calipers, i had only the front hooked up and they bled out fine. That was before I knew I needed a disc/disc master cylinder. At that point I bought one from speedway motors, removed the proportioning valve, and put a "T" on the two front lines and ran the rear right to the master cylinder. When I bleed them I get clear, air free fluid coming out. I'm just getting to the end of my patience with the knowledge that I have. So, anything you can teach me is great.
 

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Two things; You say it is a new master cylinder. If the master cylinder is not level while it is in the car, then you will need to bench bleed the master first. My master was level in the truck and I bleed it bolted in place. There can be air in the master that you are not getting out. Go to You Tube on the net and watch a veiw of those videos.

Second; pull the wheel off so you can see the caliper without anything in the way. be sure there is only one bleed valve. I had 2 on top and did not see the second one :smash:

You must have air in the master. You Tube is very helpful,

Kirk
 

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I have had brakes that were a bear to bleed by conventional methods (pump up, open bleeder, close bleeder, pump up again and so on). Are you bleeding the passenger side rear first? Always start with the farthest one away from the master cylinder and work you way to the master cylinder. One way I have found that works when all else fails is to just open up the bleeders and let it gravity bleed itself. After you start seeing fluid dripping out of all bleeders, let it drip for a good long time (hour?). Keep an eye on the fluid level and keep it full. Close the bleeders and pump the pedal a few times to see if it helped.
 

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Discussion Starter · #6 ·
Well, I pulled my master cylinder off and bled it in a vice as opposed to on the vehicle because it wasn't level. I haven't bled the brakes yet, but right away the pedal seemed to feel better than it has before. I will bleed the brakes tomorrow and keep you posted. Yhanks for all the advice and help :thumbup:
 
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