something wrong with breaks not sure what?

[jsleeper81]

alright guys I have a 2000 k3500 and I have been driving the truck short distances due to when breaking it seemed to pull to the left, the harder I applied the break the more it pulled to the left along with there feeling like air in the system.
I first thought maybe breaks where not bled properly until a couple nights ago I had to slam on the brakes it pulled like usual but it just did not feel like there was getting enough pressure to stop the truck so I pressed as hard as possible out of reaction and out of no where the truck started to pull to the right now, when the truck finally came to a stop the right front brake had locked up completely after waiting a few minutes seemed like the pressure released and I was able to get it home.
so at this point I knew the caliper had to be bad so I went ahead and bought 2 new front calipers to replace as a pair along with new pads and this is what I pulled off.

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so as you can see the piston basically blew the the pad which I have never seen before.
I replace with 2 rebuilt calipers I went ahead and painted them made them look nicer since I am trying to fix it up right and cleaner. here is some with the other caliper on.
and to anyone that notices yes I know I need new discs I plan to replace those next.

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so now that I have replaced both calipers I was thinking all would be good to go so had my wife pump the breaks to bleed them and was not getting pressure to the passenger side so pulled the feed line off the back of the caliper and asked my wife to hold and watch while I pumped well fluid came out but in order for any to come out I had to bury my foot into it which felt like I was trying to reach the radiator with my foot lol.
so bled it the best I could and tested the stopping force the pedal had and with light pressure the left break grabs good put not the right however with excessive force on the pedal the right side begins to grab.
decided to put it all back together and take it out on the road for a test and same as before except now I have much better response to stopping but still pulls to the left, and it feels like if I press hard enough it tries to even out the breaking pressure but only barely at slow speeds.
to me it seems like maybe the master cylinder may be bad but not sure I would checks the brake lines but there seem to be so many all around the abs module which I would like to remove all together but needing to find a how-to article on this first.
any input would be appretiated thanks everyone.

 

[Black_cirrus]

Simplest check would make sure the line isn't restricted. check for hard line pinched or crimped. And make sure the brake hose hasn't collapsed internally (never seen it but have heard of it). take the hose off the hard line and check for flow.

 

[jsleeper81]

okay I'll do that first thing tomorrow i do know both rubber lines on front appear to be newer not that, that means anything I do know the hard lines look a little rusted so am even considering replacing all of those as well

 

[Ironhead]

I just want to second the opinion that the rubber flex line may have deteriorated internally, causing swelling, which causes a blockage under pressure. If the lines are original, I think it would be wise to replace them, two at the front, and I guess one at the rear. Cheap insurance.

 

[east302]

to me it seems like maybe the master cylinder may be bad but not sure I would checks the brake lines but there seem to be so many all around the abs module which I would like to remove all together but needing to find a how-to article on this first.
any input would be appretiated thanks everyone.

I doubt that it's your master cylinder. It only sends fluid through two lines...one to the rear and one to the front. The hydraulic circuit only splits to the two front lines when it exits the ABS module and brake pressure modulating valve.

Like others said, the front brake hoses are the likely culprits. As a quick test, remove the rubber line where it connects to the hard line at the frame and press the brake pedal. If you get fluid out of the hard line then the rubber line is probably damaged internally and restricting flow. If not, then you know the problem is upstream. You would then disconnect it at the abs unit and see if you get flow, but I really think you've just got a bad flexible line at the caliper.




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[jsleeper81]

I doubt that it's your master cylinder. It only sends fluid through two lines...one to the rear and one to the front. The hydraulic circuit only splits to the two front lines when it exits the ABS module and brake pressure modulating valve.

Like others said, the front brake hoses are the likely culprits. As a quick test, remove the rubber line where it connects to the hard line at the frame and press the brake pedal. If you get fluid out of the hard line then the rubber line is probably damaged internally and restricting flow. If not, then you know the problem is upstream. You would then disconnect it at the abs unit and see if you get flow, but I really think you've just got a bad flexible line at the caliper.




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hello, to all those that have helped with this I pulled the passenger rubber line and sure enough that was the problem.
I replaced it and now seems that all 4 breaks are working now " Thanks everyone ".
the only thing left is it still feels like there might be some air in the lines but it might just be me I'm only used to driving small cars like hondas mostly 06 and newer cars and the break pedal is very senitive exp. on my wifes 2014 civic, I'm going to assume it will never be like that.
there is a slight 1/2 an in or so play from top of pedal to when break react to pressure and the return seem much slower than that I'm used to driving.
but its all a work in progress thanks again guys.

 

[Nathaniel2g]

hello, to all those that have helped with this I pulled the passenger rubber line and sure enough that was the problem.
I replaced it and now seems that all 4 breaks are working now " Thanks everyone ".
the only thing left is it still feels like there might be some air in the lines but it might just be me I'm only used to driving small cars like hondas mostly 06 and newer cars and the break pedal is very senitive exp. on my wifes 2014 civic, I'm going to assume it will never be like that.
there is a slight 1/2 an in or so play from top of pedal to when break react to pressure and the return seem much slower than that I'm used to driving.
but its all a work in progress thanks again guys.

Its a 20 year old truck. The pedal on these trucks always had play, even from the factory. My dad had a 94 K1500 Z71 and he told me his pedal at brand new feels the exact same as the pedal in my 96 does.

 

[jsleeper81]

Its a 20 year old truck. The pedal on these trucks always had play, even from the factory. My dad had a 94 K1500 Z71 and he told me his pedal at brand new feels the exact same as the pedal in my 96 does.

okay, this is something I figured.
it would be nice if I could get it to be more responsive in the future.
I'll do some research cause there has to be some possibility somehow, I work at fedex as a courier and drive a ws900 freightliner this thing is ancient but I have to be careful with the breaks because of how sensitive they are.
but overall the truck stops way better than it did.

 

[jsleeper81]

Okay, Guys I have continued trying to bleed thinking that maybe there was air because I test felt another truck simular too mine except it was a 98 1 ton but brake system was the same.
and his had a much much stiffer and solid feel to the pedal was also far more responsive during breaking.
I also notice when returning to mine, compared to his when I shut his truck off his brake pedal got stiffer and stiffer while pumping, mine however I can keep pushing when the truck is off but does not get any stiffer just continues with the same pressure and continues to stop in the same position no matter how much I try and input of why the difference thank.

 

[east302]

I believe the 3/4 and 1 tons used a different system (hydraulic vs vacuum) so that's probably not a good comparison. There are some that have swapped to that system to get better braking performance.

I'm pretty sure the pedal should firm up with the engine off, but a bad booster usually makes the pedal harder to push with the engine on since vacuum assist is lost. Others can probably elaborate on that.

I'd get a shop to run the automated bleed and bleed out the lines a few times. I hear that it can take several attempts sometimes to get all of the air out.


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