rear brake problems

[Zozma]

How much should the rear brakes grab? Every time i brake hard it seems like just the front brakes are working and my truck is trying to nose diveand the rear brakes aren't doing anything and I even bypassed the rabs which I'm pretty sure is dead and I've looked at the rear brakes and bleeded them. at this point I have no idea

 

[ab_slack]

Front brakes do most of your braking by far. 75% to 80%. The weight shifts forwards. The most obvious proof is that rear brakes can last a long time while front pads need regular replacement.

They contribute a bit, perhaps mostly keep the rear well...in the rear.

A simple test if RABS is disabled is find a gravel parking lot. Again at a fairly low speed, find a spot that isn't too heavily traveled and stomp on the brake pedal as much as you can to lock up your brakes. You want to be going fast enough to skid maybe a foot or two. After doing this, get out and look. Did all four wheels show skid marks in the dirt? Any that don't which look like it just rolled over the gravel (or dragged much less than others) wasn't getting enough force to lockup. If result is ambiguous try a few times in different spots because sometimes the surface just isn't uniform so a spot might not show as much as others just because of how the surface is.

With RABS working a simple test, on a wet day doing a fairly low speed 20 to 30 MPH slam on your brakes. Front wheels should lock and if your rear brakes (and RABS) are working you should feel the brake pedal pulsate as the RABS kick in to prevent lockup. That however will only tell you that at least one is working, can't be sure about both. This can't be done with four wheel ABS as you don't know which is pulsating.

 

[Zozma]

Rabs is bypasse . On gravel the front digs trenches but both back tires look like they just rolled

 

[adsm08]

Put some weight in the bed and try again. Brakes do more work when there is weight over their axle (go figure, right?). Since a pickup bed weighs almost noting compared to the front of the vehicle it is not surprising that the rear won't lock up and skid.

If you want to test them jack up the rear, hold the brakes, and try to turn the wheels.