IBC need more braking force

[username taken]

Okay, I have the IBC on my truck, but with the Weekend Warrior in tow, the brakes seem to be getting weaker as the miles rack up.

When I first started, I had the IBC at 6 empty, 7 loaded (trailer weights 12k and 15k respectively) now with the IBC maxed out at 10 it seems like it barely applies the brakes enough empty.

When I apply the trailer brakes manually, it nearly puts me through the windshield. I have cleaned and adjusted the trailer drums, with no change. Is there a way to adjust the braking force relative to the pedal travel? Could a sensor be out of adjustment?

Right now truck brakes are doing most of the work, which gets scary running down hills with 15k in tow.

 

[LBZ]

Not sure what an IBC is but it sounds like a GM warranty related problem to me.

 

[Darius6t9]

Not sure what an IBC is but it sounds like a GM warranty related problem to me.

Integrated Brake Controller.

 

[dmaxfireman]

first thing i would check is put a voltmeter on the brake terminal of your trailer plug and measure how much output you are getting when somebody else steps on the brakes

 

[dmaxfireman]

then compare it to how much output you are getting when that person hits the trolly brake

 

[ffden]

Username Taken
I see they pulled your thread on dp. Could you let me know if the piston cooling jet caused the problem? Good Luck buddy!:thumb:

 

[username taken]

GM says this is non adjustable except with the gain adjustment. Panic braking (standing on the pedal with my 275 lbs) only produces maybe 30% on the IBC bar graph.

Does anyone know how this system is modulated? Mechanically, electrically, or hydraulically? EG - how does it know how much voltage to send to the trailer brakes? There has to be a way to adjust this. GM techs apparently don't know what the secret is, and claim if there were a problem it would throw a code. They blame the trailer, but other trucks can lock my trailer's brakes with the pedal.

Trolley brakes will lock all 6 wheels on gain 10 easily. Pedal barely makes a difference - truck is doing 90% of the braking. Help! Am I going to have to install an aftermarket BC?

 

[username taken]

FFden, piston went south because of porosity in the casting/ forging. Piston jet may have contributed but was not primary cause - can't prove for certain if the jet was working or not.

Let's just say this - when I build a bottom end, it will have a HVHP oil pump, not this 30psi @ 3000 rpm bull$hit.

 

[Chris611]

I see this thead is about 7 months old, but figured I'd post. I don't have an IBC as I have an '05, but when I bought a Hayes G2 brake controller it would act very simlar to what yours did. I would hit the brakes and would only see about 30% braking. It was a solid state controller. All the bells and whistles. I talked with Hayes and they sent me a new controller that had an updated firmware in it. Still didn't help. I ended up pulling a 5 year old controller out of one of the truck that is mechanical. Has a swinging pundulum in it, etc.. t has worked good. I felt like with the new solid state controller and the transmission downshifting and the crappy brakes on the chevy's it just wouldn't trigger the controller to start braking. I ended up using the manual override for the first two trips. I pull an 8000lb pulling truck on a 14k (rated load) trailer. So about 13k lbs total.

 

[Ron Nielson]

NO doubt the problem has been solved now, one way or the other. As far as the ITBC goes, when it's working correctly, it's a great controller.

One thing of note is that there is a pressure sensor in the master cylinder (on the engine side) that sends signals based on the brake line pressure to the brake controller as an indication of how much braking the truck is doing i.e. the more brake line pressure, the more braking is needed at the trailer. It COULD BE that this sensor is not functioning correctly and therefore not sending the appropriate signal. From the description of the problem, the trailer brakes do work, and the ITBC will (manually) work, so must be something in the circuit that senses how much braking is needed. From my memory they are about $75 and would be very easy to replace.

 

[username taken]

NO doubt the problem has been solved now, one way or the other. As far as the ITBC goes, when it's working correctly, it's a great controller.

One thing of note is that there is a pressure sensor in the master cylinder (on the engine side) that sends signals based on the brake line pressure to the brake controller as an indication of how much braking the truck is doing i.e. the more brake line pressure, the more braking is needed at the trailer. It COULD BE that this sensor is not functioning correctly and therefore not sending the appropriate signal. From the description of the problem, the trailer brakes do work, and the ITBC will (manually) work, so must be something in the circuit that senses how much braking is needed. From my memory they are about $75 and would be very easy to replace.

You nailed it - I replaced the pressure switch on the MC and now the IBC works like it is supposed to.