Breaks don't grab after boosting

[daelv]

So I've noticed after hard acceleration or burnouts/ donuts in my truck, when I try to apply the breaks right after they pulsate and seem weak. Yesterday we had an open skid pad event at the local Harley dealership in Vacaville CA. And I went in and did two or three donuts. I started with a break stand and then went on to do the donuts using no breaks. So after I decided to stop, I put my foot on the break and all it did was pulse and kept rolling at like 5mph. It stopped shortly after by hitting a small tree that was in the parking lot.

Besides the small dent in the bumper I was pretty pissed that 200+ people now think I'm an idiot. I've been drifting/ and doing controlled slides ever since I got my first car 11 years ago and I've never done anything like that. I've looked high and low in every forum but I can't find any similar cases or anyone that has diagnosed the same thing unless I'm not searching correctly. Any info would be greatly appreciated. -Elvis


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[daelv]

Oh and my truck is a 05 crew cab 4x4 with a 4in rancho lift on 33" tires. I have a sct x4 with the hottest canned tune. I'm not sure if that would mess with the ABS system at all, thanks


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[sootie]

its pretty normal if you go from unequal wheel speeds to cramming on the brakes, the ABS freaks out. To avoid it in the future, disconnect an abs sensor.

 

[daelv]

Thanks for the reply sootie. That makes sense to me but what doesn't make sense is getting on the freeway full throttle or racing someone with no wheel spin, and then applying the breaks and they pulse and feel real weak. I'm wondering if it has something to do with boost pressure going up and messing with some sensor or a bad vaccum pump.


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[Zmann]

your brakes are not controlled by a vacuum pump
nor effected by boost psi

 

[Zmann]

you may want to pull codes with a scanner capable of reading them all

you may have an ABS or hydro boost issue

although the pulse after getting on it then breaking is common it should still stop

 

[daelv]

Ok I'll try getting it on a scanner today. My girlfriends dad is a mobile mechanic and has a fancy scanner that he used to check my truck before I bought it. I'm leaning towards an abs issue, ever since I bought the truck in August of 15' when I turn full lock sometimes the abs light comes on.


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