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Old 03-30-2011, 11:20 AM   #1
Mattman2010
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Brake Issue

My 1980 K10 is starting to have a brake issue. When you put your foot on the brake it is solid and when you let off the brake you have to push the pedal even farther down to get it to brake, but it is still solid not spongy like air in the lines. Also when you have the truck in gear and have your foot on the brake it will "bleed off" and the pedal goes farther to the floor. When it does this and you push your foot down with it it will hit solid.

So to me it doesn't seem like it needs the brake lines bled, and I am not sure how to test the booster or anything else on the system. What do you think the problem could be?

Matt
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Old 03-30-2011, 12:13 PM   #2
Jonboy
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Re: Brake Issue

Sounds like your master cylinder is shot. It will hold pressure for a little bit, but fluid will begin to bypass the seals as you hold it.
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Old 03-30-2011, 01:29 PM   #3
inovermyhead
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Re: Brake Issue

I agree Jonboy, my brother had the same problem on his a few years back.
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Old 03-30-2011, 01:36 PM   #4
Mattman2010
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Re: Brake Issue

Thanks guys, Looks like I can get one from Oreillys for $15.
Matt
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1980 K10 - 6.2L Diesel/SM465/NP205
Build Thread

1984 K30 CC Dually - "The Tank"
12V Cummins/Nv4500/Np205/D60/D70HD 4" lift & 37's
Build Thread

1960 C-60 Dump Truck
Make it road worthy!
Thread

Last edited by Mattman2010; 03-30-2011 at 01:36 PM.
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Old 03-30-2011, 08:06 PM   #5
kcackler
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Re: Brake Issue

Agreed with the above. I had the same issue and it was the master cylinder. Quick fix, though, luckily...
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Old 03-30-2011, 10:11 PM   #6
Mattman2010
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Re: Brake Issue

Yeah, that was the problem. I went out to my truck and the brakes didnt work at all, so I got it down to the shop and replaced it with one off of my k20 cab that I have setting around. It fixed it!
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1980 K10 - 6.2L Diesel/SM465/NP205
Build Thread

1984 K30 CC Dually - "The Tank"
12V Cummins/Nv4500/Np205/D60/D70HD 4" lift & 37's
Build Thread

1960 C-60 Dump Truck
Make it road worthy!
Thread
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