Everyone please read...Can you figure out this Brake problem?

GI Joe

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OK I have a problem that started about 2 weeks ago and I cant figure it out.
He's whats up. When the car is in reverse the brakes work normal. In forward gears they work fine some times and other times its like I'm standing on a brick...hard as a rock and car wont hardly stop.
I'll list some things that are happening that I have considered but that I think just add conjecture; I dont really think they are realted.
1. My line lock stopped working during a rewire job and I never found the bad wire so I re wired it and this time (unlike the way its been for 2 years) I added a relay to the linelock setup. When I was done the relay and line locks worked but I had this problem that I mentioned in the opening of the post. I assumed I had a wire grouding intermitently causing the line lock to close and not allowing the fluid past thus explaining hard pedal.
So this weekend I replace both line locks, the relay, and all the wiring. Still does the same crap! I'm using the cruise control button of course ( I'm the inventer of that..lol) so to make sure some was not bad in the button/steering wheel, today I unplugged the realy completely giving no power at all to the solenoids to make sure there was not a grounding issue going on inside the wheel there and still the same problem even with them completely unplugged. Remember these are 2 new solenoids too.
2. My tune has traction controll turned off yet for some reason the traction "little car" shows up in the dash all the time . But this tune has been on the car for a few weeks and the brakes have been fine.
3. Cam lowered vacuum to 11-9" of vacuum...but again they have been working fine with the cams and the tune.
4. I ammue if I had pinched a line the braked would be hard or soft all the time.
5. I assume if the booster was going out the pedal would be soft...or is that wrong...maybe hard..
6. I hard checked vaccum lines to the booster and the seem fine.
Fluid is fine.
7. Brake were bleed even thought they really did not need it.
Its a dang trip guys....I wont drive the car on the highway...just down the street...go 5 mph...push the brakes works fine...30 seconds later do the same thing...and its like a rock and I almost hit the neighbors mail box...
This one has me stumped guys.
...and why would it work fine in reverse and intermittent in forward...
I have an idea what could be up but waiting to hear from others that might know.
An intermittent brake problem is not something I look forward to at 135 mph.:thud:
 

05stroker

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A bad booster will make the pedal hard and not soft (no power brakes) . Also ck the vac line to the booster from the intake to see that it is connected and not kinked. My sons F150 just had a recall done for the booster line to add a clamp at the intake becouse they were coming of and causing a similar issue when the line came loose. Good luck .
 

GI Joe

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A bad booster will make the pedal hard and not soft (no power brakes) . Also ck the vac line to the booster from the intake to see that it is connected and not kinked. My sons F150 just had a recall done for the booster line to add a clamp at the intake becouse they were coming of and causing a similar issue when the line came loose. Good luck .

I will check it...but I would know if its that because everything it tied to that...the boost gauge, the fuel pressure rail sensor, ect is all tied to that line...The line does feel soft. Perhaps its collapsing...
 

thump_rrr

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I will check it...but I would know if its that because everything it tied to that...the boost gauge, the fuel pressure rail sensor, ect is all tied to that line...The line does feel soft. Perhaps its collapsing...
unplug your vac hose and cap it towards the engine.
Use a manual vac pump to bring the booster under 20-24"hg and try it several times with only a single brake application to see if it helps.
 

94tbird

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the little car icon on the dash will always be there when traction control is turned off in the tune
 

GI Joe

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the little car icon on the dash will always be there when traction control is turned off in the tune

well it was not in my JDM tune...maybe he knew a trick...but thanks though that eliminates that as an issue...
 

GI Joe

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what I was wondering is if a brake caliper could be freezing...
 

ZmanM3

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what I was wondering is if a brake caliper could be freezing...

I was kind of wondering if something like as small pebble or something got into one of the calipers and is moving around in there, sometimes its in the way and doesn't allow the caliper to close and some times its rolled out of the way and allows the caliper to close. Just a thought, although it wouldn't explain why the breaks always work in reverse.
 

SoundGuyDave

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If you had a sticky caliper, you would see massively unequal pad wear... Either the inside or outside pad would wear considerably faster than the other, and if you warped your caliper (I've done it!) you'll see a tapered wear on the pads, where the top of the pad wears quicker than the bottom.

For a quick test, spray some water on your front rotors, both sides, let it sit overnight so that you get a fine sheen of rust, then take it for a QUICK spin, not too far, and look for where the rust is worn off. It should look equal on both sides of the rotor, and on both sides of the car in front. Any real difference will indicate something is amiss. Does the car pull under very light braking, just caressing the pedal? If no, you probably don't have sticky slides or piston bores.
 

GI Joe

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unplug your vac hose and cap it towards the engine.
Use a manual vac pump to bring the booster under 20-24"hg and try it several times with only a single brake application to see if it helps.

Where do i get a manual vacuum pump that will work while the car is running
 

SoundGuyDave

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Any vacuum pump will work... Once you disconnect the manifold line (and cap the nipple at the manifold), your booster is isolated from engine vacuum, so the pump becomes the source.
 

GI Joe

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problem is idle is too low. at 800 rpms the cams only make 6" vacuum. at 900 they make 10" and 10 " is fine for everything...
It had been idling at 875 and was fine and I made some changes on the car that lowered the idle and that was the entire problem.
 

KIMMER

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That's very good to know Dave! Hopefully this will help someone else in the future.
 

Vapour Trails

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This is sort of related.

Does anybody notice that after returning to your car after being parked for several hours that the pedal (before start up) is rock hard? This is a sign that all the vacuum has bled off.

I took it into Ford and they said it is normal for that to occur after a couple hours, but every other vehicle I've driven has a soft pedal, indicating the vacuum has been maintained. There is obviously a leak somewhere and that concerns me.
 
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