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12-14-2014, 02:31 PM | #1 |
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Soft Brakes (pedal to floor)
Hello - Been working on this a month and have exhausted all the options I have found in these forums. 1975 Chevy blazer disc front, drum rear.
My brake pedal travels to the floor before stopping. Slamming the brake pedal to the floor at about 30 MPH takes about 30-40 yards to come to a complete stop. The pedal also returns slowly after being applied. Done so far: Overall System:
Front brakes:
Rear brakes:
General notes
Any help or direction would be greatly appreciated. Minus the hard lines, and Combination/Prop valve almost everything has been replaced. |
12-14-2014, 04:15 PM | #2 |
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Re: Soft Brakes (pedal to floor)
Seems to me that there's either more air or a leak. Loosing any fluid?
If using a helper, only push the brake pedal once, then while they're holding it down, crack the bleeder. Pushing the pedal 5 times may be aerating the fluid. I usually do it myself, but I have a small bottle (brake bleeder kit) Tubing goes from the bleeder screw, under the fluid level in the small bottle. That way your pushing out air, and not taking the chance of introducing air in through the bleeder screw.
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'86 C-30 dually, 454/tbh400 '73 K-20 350/350/205 (sold ) I'm kinda like duct tape- no real purpose, but handy to have around. |
12-14-2014, 07:39 PM | #3 |
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Re: Soft Brakes (pedal to floor)
Don't pump the pedal between opening the bleeders it aerates the fluid making air pockets that will not work out.
Push the pedal down with the bleeder open and then close the bleeder before the assistant lets off the pedal. You can build one of these or buy one. I built one and bought a Master Cylinder cover from Motive Power. Makes one man bleed jobs a piece of cake. http://www.amazon.com/Motive-Products-105-System-B... Use a C-Clamp to hold the cover on, if you can find a place to put it, rather than the Rube Goldberg J-Hook and Chain arrangement that comes with the Motive Power cover.
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1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. Last edited by hatzie; 12-14-2014 at 07:44 PM. |
12-14-2014, 08:00 PM | #4 |
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Re: Soft Brakes (pedal to floor)
sounds like the ford i had. try bleeding with it running
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1986 c20 "the hillbilly" 350 sm465 3.42gears 21mpg at 70mph 1985 k30 "the ice cream truck from hell" no rust az truck 197-8??? c30 "ramp truck" 454 1978 monte carlo 350 350th with 2.73 gears. no rust. sc car |
12-14-2014, 09:16 PM | #5 |
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Re: Soft Brakes (pedal to floor)
One thing nobody usually mentions is to start with the longest tube run first and work your way to the shortest.
On the squares this is usually the Left Rear Wheel Cylinder and then RR then RF caliper then LF...
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1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. |
12-14-2014, 10:10 PM | #6 |
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Re: Soft Brakes (pedal to floor)
I thought the procedure was push the pedal down, open the bleeder, close the bleeder, then release the pedal? That's how I always did it...
Wouldn't opening the bleeder with the pedal not depressed allow air in?
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'84 K20 350/465/208 |
12-14-2014, 10:23 PM | #7 | |
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Re: Soft Brakes (pedal to floor)
Quote:
When you do push the pedal, do it slowly and to its full stroke.
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72 GMC C2500 402/Th400 first truck (still have) 77 GMC C3500 CC dually Sold 70 C50 dump truck "Rusty" 87 K10 Suburban Sold 93 K2500 xcab 6.5TD 96 GMC K2500 Suburban 6.5 TD |
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12-14-2014, 10:45 PM | #8 |
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Re: Soft Brakes (pedal to floor)
had similar issue with my suburban last year, one of my lines to the prop. valve had just a slight leak(bad flare job) had no visible air when I bled the system but wasn't getting a lot of pressure when I opened the bleeders up.
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12-15-2014, 08:57 AM | #9 |
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Re: Soft Brakes (pedal to floor)
Is there such a thing as a pressure gauge that screws into the bleed valve spot?
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12-15-2014, 09:14 AM | #10 |
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Re: Soft Brakes (pedal to floor)
When was the last time the master cylinder was changed out? My pedal goes right to the floor and I know for fact my master cylinder is to blame.
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12-15-2014, 07:30 PM | #11 |
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Re: Soft Brakes (pedal to floor)
MC has been changed twice in the last 30 days. MC testest to be working well.
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12-15-2014, 10:09 PM | #12 |
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Re: Soft Brakes (pedal to floor)
I should've added "Only open the bleeder after you tell your assistant to push the pedal down." I mistakenly figured that was self explanatory.
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1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. |
12-16-2014, 05:34 AM | #13 |
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Re: Soft Brakes (pedal to floor)
Not self explanatory, but I did mention it. However, I didn't mention to close it again before you release the pedal...
Of course the OP didn't ask for a step by step procedure.
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'86 C-30 dually, 454/tbh400 '73 K-20 350/350/205 (sold ) I'm kinda like duct tape- no real purpose, but handy to have around. |
06-14-2019, 12:43 AM | #14 |
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Re: Soft Brakes (pedal to floor)
tube on bleeder
"Quick Bleed" between the 2 hoses usually seen on race bikes it IS a 1 way check valve but IS a bleeder valve also u can do like we do in VW put valve stem like a tire(one with threads and O rings) and place it In the top then pressurize |
06-14-2019, 09:28 PM | #15 |
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Re: Soft Brakes (pedal to floor)
Does the pedal feel harder with the engine off?
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06-15-2019, 06:21 AM | #16 |
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Re: Soft Brakes (pedal to floor)
I don't know if a GM booster has an adjustable push rod, but this would be worth looking into: https://www.google.com/amp/s/techtal...%3fhs_amp=true
If the booster push rod is too long or too short (very possible in today's low standards of manufacturing) you'll never get get a hard pedal with the engine running. If you have no air in your system, and still have a soft pedal, this is a likely culprit. |
06-15-2019, 01:37 PM | #17 | |
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Re: Soft Brakes (pedal to floor)
Quote:
If you want a real exercise in futility... Try buying ball joints and tie rod ends that last more than 5,000-10,000 miles. Wheel bearings are another fun excursion into pulling out gobs of your hair.
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1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. |
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06-15-2019, 01:54 PM | #18 |
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Re: Soft Brakes (pedal to floor)
Still bleeding the brakes after 5 years..??? damn
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06-15-2019, 02:04 PM | #19 |
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Re: Soft Brakes (pedal to floor)
Oops, did not realize I posted in a zombie thread. I hope OP got his brakes to work.
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06-15-2019, 02:26 PM | #20 |
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Re: Soft Brakes (pedal to floor)
You posted useful relevant information on the thread subject. Don't feel too bad.
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1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
And please let us know if and how your repairs were successful. |
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