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Re: Bleeding Brakes, without a helper [Re: Cab_Burge] #2778965
05/28/20 02:29 AM
05/28/20 02:29 AM
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Grizzly Offline
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Originally Posted by Cab_Burge
Why do you wire it above the brakes, gravity doesn't flow well uphilll work grin


Go back and read what I typed.

The way kentj340 and andy has it, as soon as you let off the pedal the air bubble will go up into the system by the time you get your 4ss back there to tighten the bleed screw.

Re: Bleeding Brakes, without a helper [Re: Mr. Potatohead] #2778968
05/28/20 04:59 AM
05/28/20 04:59 AM
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in a cattle trailer down by th...
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in a cattle trailer down by th...
Originally Posted by Mr. Potatohead

But yet ya cant easily change a cam in a 40 year old rig, what the hell.


Originally Posted by Guitar Jones
I use a vacuum bleeder. But I rarely ever do one and I don't sell them. I spend my days doing major engine repair and replacement.


What are you talking about? I had trouble finding a cam with the duration and LSA that I wanted that didn't have lift figures that would smash the valve seal without machining the head or crashing the pistons into the valves. That was a function of time and money, not ability to do the work.


I never learned to count my blessings, I choose instead to live inside my disasters.

The Scamp is sold, now just two old trucks and one new one.
'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion.
'74 W200 Crew Cab 360, NP435, D44, D60 and NP205 divorced transfer case. NV4500 coming soon.
2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
Re: Bleeding Brakes, without a helper [Re: Grizzly] #2779026
05/28/20 11:07 AM
05/28/20 11:07 AM
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Caracas, Venezuela, SouthAmeri...
NachoRT74 Offline
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Originally Posted by Grizzly


I'm not a Mechanic by any stretch of the imagination, but, you Dummies do know that the reservoir that is capturing the brake fluid is supposed to be ABOVE the caliper? An air bubble always rises UP. It can't be forced DOWN if the reservoir is above the bleed screw. LOL. tonguue



yes but no... the bubbles are also pushed out no matter if recipient is above or below the caliper or cylinder. If you pump out the brake fluid enough with hose sunk into the brake fluid, will be eventually blown from the line, included the hose up to recipient, and bubble will be free to go up into the recipient, but not in to the line while you are pumping fluid with the pedal. The lines along the car also makes some ups and downs and the air is allways pushed out no matter what.

anyway, still with recipient above the caliper or cylinder, hose allways goes down again, getting sunk into the brake fluid at recipient, so, will be the same

Re: Bleeding Brakes, without a helper [Re: Grizzly] #2779052
05/28/20 12:39 PM
05/28/20 12:39 PM
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Bend,OR USA
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If you use a hose that is submerge in the fluid how can it suck air back into the system, especially uphill, instead of having the container above the bleeder screw where air can get back into the hose from above?
Theory is one thing, reality is another work
I wish I had a old time pressure bleeder now instead of using a vacuum bleeder like I do now whiney


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Bleeding Brakes, without a helper [Re: Cab_Burge] #2779124
05/28/20 03:16 PM
05/28/20 03:16 PM
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Rittman Ohio
fourgearsavoy Offline
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I think this thread needs to be split into 2 parts: Gravity or pressure bleeding because there seems to be confusion as to how air goes down and fluid goes up. Gravity fluid container goes below the caliper,pressure, container goes above the caliper shruggy Right?

Gus beer


64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60
Re: Bleeding Brakes, without a helper [Re: fourgearsavoy] #2779284
05/28/20 10:30 PM
05/28/20 10:30 PM
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Grizzly Offline
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Cab and Nacho, on a ONE MAN bleeder, if you hit the end of the stroke and an air bubble is:

halfway between the caliper and oil catch can

and the catch can is BELOW the bleed,

that air bubble rises and goes back into the system.

If the catch can is ABOVE the bleed screw, then the air bubble travels UP to the catch can where it belongs and fluid drains down to the bleed screw.

This is Grade 2 Science, air rises in fluid.

Get a Helper next time and watch it, and you'll see what I mean. It's way faster and you use way less fluid my way.

Re: Bleeding Brakes, without a helper [Re: Grizzly] #2779336
05/29/20 06:54 AM
05/29/20 06:54 AM
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NachoRT74 Offline
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Grizzly... yes as far the air bubble is still on the line it can return by the returning pedal action, including the hose to the recipient. But once the air bubble is out of the line it won't return no matter if is above or below the bleeder ( just like the ohms law on electricity ) Air won't retunr to the full line because the MC gets easier to get filled by its bowl than get back all the fluid from the line with its air bubbles and the hose is sunk,. That is pumping the system with the recipient,. Some air will return as far is on the line but keeping the pumping action several times with hose into brake fluid will eventually expel the air no matter where is the recipient.

Now about the gravity ( actually together with athmospheric pressure ). The recipient is still below the MC bowls, so no matter if the hose/recipient is above or below the Caliper or rear cylinders. Gravity/athmospheric pressure will still push out the bubble because MC bowl is still above the full system.

it happens the same when you extracts gas from your tank, once the line goes below the actual gas tank level, the gas will flow alone no matter if goes up first or how many turns makes before the final recipient... Is an athmospheric pressure principle.



Last edited by NachoRT74; 05/29/20 07:07 AM.
Re: Bleeding Brakes, without a helper [Re: Grizzly] #2779337
05/29/20 06:54 AM
05/29/20 06:54 AM
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new berlin wisconsin
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Mr T2U Offline
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you are correct. air bubbles will rise, basic science.

why this is irrelevant is the next pump of the brake pedal 10 seconds later this air bubble will be pushed out before it has time to rise naturally to cause problems. also when you bleed like this the line is curved above the bleeder before it goes into the bottle. the air bubble will stay in the middle of the line and not go back into the bottle, also basic science. the only way it can rise back up into the caliper is if the bleeder is at the bottom of the caliper, and you don't want that.

i have bled a lot of brakes with a hose attached to the bleeder and the other end is submerged in brake fluid in a bottle. it's irrelevant weather the bottle is above or below the bleeder. it's more important that the hose stays submerged in the brake fluid than weather the bottle is above or below the bottle.
some people argue that it's better to have it below the bleeder. this way you can see air bubbles trapped in the line to know if the air has been pushed out. others argue that it's better above for the reason why you stated.
i say it's irrelevant. hook the bottle in the easiest way you can as long as it doesn't fall exposing air to the line that should be submerged.


perception is 90% of reality
Re: Bleeding Brakes, without a helper [Re: Mr T2U] #2779341
05/29/20 07:01 AM
05/29/20 07:01 AM
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NachoRT74 Offline
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Originally Posted by Mr T2U
it's irrelevant weather the bottle is above or below the bleeder. it's more important that the hose stays submerged in the brake fluid than weather the bottle is above or below the bottle.
some people argue that it's better to have it below the bleeder. this way you can see air bubbles trapped in the line to know if the air has been pushed out. others argue that it's better above for the reason why you stated.
i say it's irrelevant. hook the bottle in the easiest way you can as long as it doesn't fall exposing air to the line that should be submerged.


iagree

as far is allways below the MC bowls if making it at least by gravity/athmospheric pressure


anyway. I never have used a final recipient or hose... mostly of times I just let it drop to the floor. I just loose maybe 1 or 1.5 fluid ounces bleeding by gravity on my car without pump the pedal. Then clean with water and done. Never have got a problem.

Last edited by NachoRT74; 05/29/20 07:12 AM.
Re: Bleeding Brakes, without a helper [Re: Mr T2U] #2779355
05/29/20 08:25 AM
05/29/20 08:25 AM
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Grizzly Offline
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Originally Posted by Mr T2U


why this is irrelevant is the next pump of the brake pedal


Yes, and I found I have to make numerous trips to refill the master (sometimes running it out mad) and pump a gallon of CLEAN brake fluid into the catch can which gets wasted by being contaminated by the dirty stuff.

With the catch can above the caliper, less pumps, I only have to fill the master once, maybe twice and use about a 1/10 th of my clean fluid compared to chasing air bubbles.

Also, if you are doing it yourself, when you turn your back on the catch can and go back to the pedal, you have no way of knowing if an air bubble is working it's way back to the system. And it DOES happen.



Re: Bleeding Brakes, without a helper [Re: Grizzly] #2779358
05/29/20 08:37 AM
05/29/20 08:37 AM
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Rittman Ohio
fourgearsavoy Offline
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This is why I like to pressurize the master cylinder instead of pressing the brake pedal. You just pump the handle, attach the hose, crack the bleeder, then watch until you get clean fluid with no bubbles. Job done then move to the next wheel shruggy

Gus beer


64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60
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