brake pedal no resistance

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jdflight
Posts: 110
Joined: Sat Aug 22, 2015 12:37 pm

brake pedal no resistance

Post by jdflight »

Good afternoon need a little help

back ground info: Last couple of months I have rebuilt my rear suspension. I installed my wheel cylinders and backing plate then got this idea it would be easier to bleed them before installing shoes and springs.

During installation on passenger side there was a lot of pressure and the metal pieces that go in the cylinders and attached the to the shoes, they would not retract and even popped off one of the dust covers on the wheel cylinders. I finally have everything put together and have bleed the brakes with a pressure bleeder. I know there is no air in the system, I pumped it up to 25 lbs of pressure and have bleed them three times not counting the original time. I still don't feel like the pedal is firm enough so I am looking for suggestions.

One thing I did read is that I should loosen the emergency brake before adjusting the brakes, so I am going to do that. I have included some pictures to of the spring set up just to make sure I have it right. You can see on the passenger side the adjuster is adjust out pretty good distance not to adjust the breaks but not to fall out if that makes sense.
Attachments
driver side brake
driver side brake
driver side brake adjuster
driver side brake adjuster
passenger side emergency brake bar
passenger side emergency brake bar
passenger side brake adjuster
passenger side brake adjuster
jdflight
61Monza aka Wilma
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64powerglide
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Re: brake pedal no resistance

Post by 64powerglide »

If you don't have the drums on all you are going to do is blow out the wheel cylinder pistons & cups. You need vacuum to draw out the wheel cylinder & line air not pressure.
64Powerglide, Jeff Phillips

Kalamazoo, Mi..
jdflight
Posts: 110
Joined: Sat Aug 22, 2015 12:37 pm

Re: brake pedal no resistance

Post by jdflight »

64powerglide wrote:If you don't have the drums on all you are going to do is blow out the wheel cylinder pistons & cups. You need vacuum to draw out the wheel cylinder & line air not pressure.[/




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jdflight
61Monza aka Wilma
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jdflight
Posts: 110
Joined: Sat Aug 22, 2015 12:37 pm

brake pedal no resistance

Post by jdflight »

I am using a pressure bleeder not the pedal method since it is only me. I did have the drums on when I did the last few bleeds though


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jdflight
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terribleted
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Re: brake pedal no resistance

Post by terribleted »

Were the brakes adjusted manually for a firm drag before bleeding? First step is adjust all brakes to a firm drag against the drums, then proceed to bleed regardless of what method you are using. And yes e-brake cable should be fully loose before any of this. E-brake is adjusted after the brakes are all at a firm drag and the brakes have been fully bled. E-brake should be adjusted so that pulling the handle fully up makes 5-7 clicks only. No pressure once there is for sure no air in the system and the adjusters set for a firm drag indicates another issue such as a bad master cylinder or improper master cylinder push rod length perhaps.

You talk about the rear brakes. You are bleeding all 4 brakes yes? Low or no pressure could be an issue in the front brakes as well. If you have a single master cylinder it is very possible that there is air in the front part of the system. Even if the master cylinder is a dual unit it is still possible to get air in the front system if the master cylinder has been over pushed with air in the system. I would start at the beginning and do it again adjusting and bleeding all 4 brakes going as directed from the longest line to the shortest. Go around at least 2 times watching for air. An empty system can take considerable bleeding to get just right.
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
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jdflight
Posts: 110
Joined: Sat Aug 22, 2015 12:37 pm

Re: brake pedal no resistance

Post by jdflight »

Thanks for the information. I have adjusted all brakes before bleeding and have started at the passenger rears, then driver rear, then passenger front the driver front. I will do it again, I have readjusted the rear drums after losening the parking brake to make sure I did it correct. Might be improper push rod adjustment but it was fine before this. HMMM

I cant see why the master cylinder would take a dump from just sitting three month though.
jdflight
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Re: brake pedal no resistance

Post by terribleted »

You just never know /shrug. If there are no leaks anywhere there is either air in the system or something else is wrong with parts or adjustment...it is after all a pretty simple hydraulic system. I have had a couple give me fits after total system rebuild even with all new parts. Perseverance and perhaps a little cussing and eventually an issue was found OR they just finally got where they were happy:)
Corvair guy since 1982. I have personally restored at least 20 Vairs, many of them restored ground up.
Currently working full time repairing Corvairs and restoring old cars.
https://www.facebook.com/tedsautorestoration/

Located in Snellville, Georgia
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