Front Brake Question re: Youth driver (1 Viewer)

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I have searched this board for the last 4 days reading posts regarding brakes, brakes, brakes…
I need some opinions/insight. My LC is a '92 w/ ~ 218 on the clock. It has rotors in the front and drums in the rear. Last week I replaced all four corners. I have done this many times, well with the rotors.

Our 16 year old is driving the truck when we permit it :) He seems to be trying to go 0-60 from stop sign to stop sign (not good and thats a whole other story). So hard baking on a 22 year old truck… Could this cause caliper to get stuck (the front passenger side)? He called and said that the pedal would go to the floor w/ very little braking power (also said that that front side was smoking a bit). I picked up the car checked fluids and drove home, no problem. I have checked for leaks, pulled wheels etc. and test drove with no additional issues. Anyone ever have an issue like this? I am very apprehensive about allowing him to continue to drive the LC due to well where should I start…

Any/all insight is very, very much appreciated.

Cheers, Jake
 
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It's possible you have a caliper that is partially hanging or only one side of it is working, thus causing more pressure on one side of the pads (not both pads on the same caliper)

I have also seen lots of kids drive with one foot on the brake and one on the gas, because they are afraid of it. Even if they are only resting their toe on the pedal, it's enough to put fluid pressure on it and slightly "ride" the brakes. Follow him when he drives (hopefully without him knowing) and watch the brake lights.

The pedal going to the floor could be a couple things. However, if there is smoke at the wheel, he is probably boiling the brake fluid by riding the brakes, that puts gas bubbles in the brake fluid and the master cylinder will compress the bubbles instead of solid fluid pressure. If the problems goes away after it cools down, then that is likely the cause.

Another possibility is the master cylinder starting to go and will allow fluid past the seals internally (no external leaks) and will allow the pedal to go to the floor. Sometimes this can be diagnosed with pumping the brakes and the pedal will get harder.
 
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I agree w/ re: to the pedal going to the floor. When I got to the destination, all was working properly (everything obviously cooled down).
The great thing about our truck is it is not the ubiquitous vehicle on the road that blends in well. I have explained this to our son so he understands that driving behavior can easily be seen/monitored.
 
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I have a 14 YO that I'm doing this with right now. Next week he will get his school permit. I have him help me do all our work so he understands what happens and how it works so he doesn't do some of those things. I have also taught him how to drift in figure 8's in the snow with our 95 Jeep GC. I'm sure he will wreck something at some point or get it stuck, but at least I will have my LC to go get him. I would rather he know HOW to handle the car/truck than to get into a situation and not know how to react. We go out and drive in really bad weather conditions real late at night so there is less traffic and we can introduce "semi-controlled conditions". I have him intentionally try to lose control so he can regain it.
 
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I'd suggest driving the truck a few miles without using the brakes, or at least minimally.
Then stop and feel the temperature at each wheel. If one is really hot, it probably isn't your kid's fault.

When you did the brakes, what all did you replace? Did you bleed it afterwards? If you opened the bleeder to push the pistons back in (the proper way), you may have gotten some air in there. A little air becomes a big air bubble when it gets hot.
 
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Did the drive and checked rotor temp, was the same as the drivers side and minimal if any heat from non braking… Changed pads, rotors, and shoes in the rear. Readjusted the shoes according to the service manual. I did bleed the brakes but what you mentioned makes sense w/ the air bubble.
 
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Check your brake lines or better yet just replace them. If your calipers got to hot then yes they can definitely sieze. But rubber brake lines as they go through their wear life can have sections of rubber flake away from the line itself causing blockages and if the brake pressure cant bleed off youll get a hot caliper that will ultimately sieze itself. Happened on my old wrx and went through 4 sets of calipers until i switched to stoptech brake lines then i never had an issue again.
 
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Biggest thing to stress obviously is that 6000 plus pounds doesn't like to be raced from stop sign to stop sign. :beer:
 
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As part of this I would inspect the brake lines for any sign of a leak, crack, heavy corrosion, etc... My '92 went up on stands 1.5 years ago to replace lines that were rusted through and gave out. check it all out real carefully. Most of the lines are available, some are not.
 
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Definitely make sure all the air is bled out of the lines. If you see no issues there, take a hard look at the master.

I've also had issues with the Calipers on my Cruiser. I would recommend rebuilding them just to make sure they check out. You'll generally be able to tell that a caliper is sticking because you'll get vibrations in the steering wheel(for the fronts) or feel it in the pedal(for the rear).
 
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Jake,

I see the 92 is loaded up very well according to your signature. Have you adjusted the LSPV? This helps a lot with lifted and/or heavy vehicles. I see you changed the rotors/drums. Are you using OEM pads and shoes? Those two things: adjusting the LSPV and using OEM pads/shoes have helped our less than desirable braking issues. New rotors/drums, which you have and stainless steel braided lines also help.

Steve
 
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I agree w/ all the comments and very much appreciate the insight. I do need to change out my lines and adjust the LSPV as suggested by Steve (thank you). As we are in the process of allowing our older son (new driver) to use the truck I am feeling some anxiety. He is very involved with the maintenance when I am working on the truck so he is getting in tune with it. Wish I had a LC when I was 16 :)

Thanks to everyone who has chimed in!
 
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IMO, which is pretty worthless, the pedal going to the floor could be:

1). Master cylinder dying
2). Leak in a line
3). Not properly bled brakes

The strange thing is that you haven't been able to reproduce it....

What happens if you are parked and pump the brake pedal? It should firm up.

What procedure did you use to bleed.....2 person? "Power bleeder?"

As mentioned in one of the posts, you should adjust and have bled your LSPV, however to my knowledge, that would not affect the pedal going to the floor.

The LSPV distributes the braking force to the front and rear. If lifted and not adjusted, more brake force is sent to the rear, and with drums brakes that is definitely not a good deal....

I don't think you would have a stuck caliper....I guess that could explain the smoke...but again it wouldn't affect the play in the pedal.

Could there be more to the story than your son is telling you....?? We have all been 16 once ;)
 
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084runnerltd, I also thought about the 3 you mentioned above. I don't think I can reproduce it because I have not been going through the hard braking (fast go fast stop). I am planning on changing out lines. I think something released inside one of the lines creating a clot like scenario (atherosclerosis brakes). The lines look great exterior but I have a feeling the interior is degrading. I am not an expert but I am OK with turning wrenches…
 

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