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Discussion Starter #1
I've been trying to get a firm pedal and after researching past posts here I found some older posts that stated that while slowly pressing the brake pedal and watching the open master cylinder that if you see jets of fluid rising in the bowl it means that you still have air somewhere in the system. Is that accurate?

Thanks.
 

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You will need to verify this information.
As I understand it, when you suddenly release the compressed brake pedal the fluid returning from the caliper/wheel cylinder will create a geyser in the reservoir. If there are no bubbles in the geyser it is normal. If there are bubbles you still have air in the system. Maybe if your helper slowly releases the pedal you can watch the MC for bubbles in the returning fluid.
 

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There are usually a few specific reasons for not having a firm pedal and they are:

Air in the system
A leak in the system
Wrong size MC (this sometimes happens to people who upgrade calipers and rotors but not MC and the MC size is just inappropriate for the new volume of the system)
Bad MC

I say bleed bleed bleed and bleed some more. Once you feel that is exhausted you may need to move down the list. But usually it's air in the system.
 

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Spammer Hammer
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What of brake system do you have? Disc/Drum, Drum//Drum, Disc/Disc?

If you have drums anywhere in the system, they HAVE to be adjusted properly. They need a light drag on them with no pedal pressure. It makes a HUGE difference.
 

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Sort of a sidebar... but speaking of bleeding brakes, I watched an episode of RoadKill Garage where they mentioned gravity bleeding. Basically you open the valve a little and leave it overnight and the fluid eventually pushes all the air out. Sounds crazy to me. I could see it working OK on a motorcycle with one front disc. Anyone ever hear of anything like this? Maybe they were joking.
 

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Sort of a sidebar... but peaking of bleeding brakes, I watched an episode of RoadKill Garage where they mentioned gravity bleeding. Basically you open the valve a little and leave it overnight and the fluid eventually pushes all the air out. Sounds crazy to me. I could see it working OK on a motorcycle with one front disc. Anyone ever hear of anything like this? Maybe they were joking.
Yes I've read of lots of folks doing this on other car forums, but don't recall if they were doing all at once or one at a time. Don't want the MC to drain too far, of course.
 

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Dimples
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Sort of a sidebar... but peaking of bleeding brakes, I watched an episode of RoadKill Garage where they mentioned gravity bleeding. Basically you open the valve a little and leave it overnight and the fluid eventually pushes all the air out. Sounds crazy to me. I could see it working OK on a motorcycle with one front disc. Anyone ever hear of anything like this? Maybe they were joking.
Gravity bleeding is real and it works. I found this out accidentally, when I didn't tighten the valve enough and went and had lunch or something. My reservoir on the end of the tube had gathered quite a bit of fluid. I was on the passenger rear wheel, so I did the rest that way and I feel confident that there was no air in the system afterwards. I don't think I would leave it over night though, as it would likely drain the MC and you'd have to start over.

Basically, it takes longer, is more do-able with one person and is therefore less "work". You'll also likely run through more brake fluid in the process. I've since done it both ways with good results.
 

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1966 Mustang Hardtop 289 4 Speed
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I tried gravity bleeding a few times on my new system. Had very little success with it. Made a jar with a gatorade bottle and hose. Did it alone. I set the laptop next to each wheel and initiated facetime on my phone. Pumped my pedal 6 times and topped up my master each time. Worked like a charm. Took the car for a test ride and no pedal issues. Sometimes we try to complicate the easiest tasks. If I were to do it again I also wouldn't waste my time on bench bleeding either.
 

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I have bled my brakes from dry many times. I have never bench-bled a master Cylinder. I just assemble everything dry and add brake fluid.

I do some pumps of the brake pedal and bubbles will come out in the master reservoir. Adding more fluid as needed.

I then bleed each wheel using a cheap handheld vacuum pump. This is done via a container with brake fluid in it, so the bleed screw cannot suck air back in. A second person is handy to monitor the master reservoir level and top it up when needed. Sometimes I wrap some PTFE tape around bleed screw threads to stop air being sucked back in around them.

This has never failed me and it always gives me a nice firm pedal. The total time is about 15 - 20 minutes from dry to working brakes. The only time I have had a problem was when I could not get any brake fluid to the rear wheels. The rear brake hose going to the axle had collapsed internally.

I have used the vacuum pump method to bleed my hydraulic clutch as well.
 

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I've had good luck using a Motive pressure bleeder. You do have to buy an adapter cap for your brake reservoir so the bleeder can pressurize the system. The pressure bleeder will force all the air out of the brake system using a minimum of fluid, usually in around 30 minutes for the complete brake system. You can get them at Summit, Amazon or direct from Motive.
 

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Discussion Starter #11
Im using one of those I borrowed from my-son-law and I just got the adapter so hopefully I’ll be back on the road soon.
 

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Original poster: If you are still having problems I think more information may be helpful. As has been said there are many ways to bleed the brakes but technique is not always the problem. In our cars when people replace the brakes with non-stock combos sometimes other issues arise. I bled my brakes until I thought I would go mad and it turned out I needed an adjustable master cylinder push rod. Let use know what your working with.
 

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Discussion Starter #13
Original poster: If you are still having problems I think more information may be helpful. As has been said there are many ways to bleed the brakes but technique is not always the problem. In our cars when people replace the brakes with non-stock combos sometimes other issues arise. I bled my brakes until I thought I would go mad and it turned out I needed an adjustable master cylinder push rod. Let use know what your working with.
I'm using CSRP booster, master cylinder, calipers and rotors. I've added a combination valve and new rear wheel cylinders. I'm using a Motive pressure bleeder. I've been in touch with Dennis at CSRP and he has offered some advice.

I'll be removing the rear wheels next to insure that all is good back there. They have been adjusted to where there is a lot of drag, probably too much but I'll take care of that while i'm back there.

Also considering the master cylinder push rod. Dennis at CSRP is pretty confident that it is correctly adjusted but if I can't make any progress elsewhere I'll try that.
 
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