front/rear braking bias

[henrym]

I have my 81/84 K20, and I have changed the brake proportioning valve hoping to have better braking, with no change. I have the metic 14 bolt with the 13" brake at the rear. My problem is the system is heavily biased to the rear, which is fine if I have a ton of weight at the back, BUT,,,,,,my fronts don't really engage, meaning: the fronts never really clamp down and aid in braking as much as I think they should be doing. A simple test of hard braking, or trying to do a burn out, the rears are so lock down, they won's spin with out stalling. In a panic stop, there will be only the rears locking up, and the fronts are still rolling. I was wondering if anyone else is having this issue, and what you have done to get a more even 4 wheel brake force. I am contemplating forking over the cash for a disc brake proportioning valve, where there is no bias to the rears, just equal pressure to all 4 wheels. Any info greatly appreciated

 

[R Carnella]

I'm having the same problem with my v2500 suburban. light stoping from any speed is fine but emergency stopping is scary, rears lock way to soon and fronts don't really bite or really engage at all. My entire brake system is new and I have big bear drilled/slotted rotor brake kit from summit racing on the front.I was hoping to improve front stopping power but pretty much the same.

 

[R Carnella]

Different proportioning valve sounds like a plan to me what year truck should I look up?

 

[Frankenchevy]

I got the disc/disc prop valve from summit. I think it was only $60ish. Also pulled off the load sensing valve at the same time above the rear axle. Never had the issues you guys were having before the change though. Just did it because I converted the rear to disc. My truck stops pretty damn good considering the era and weight.

You could also install a valve on the hardline for the rear brakes and turn it down until the lockup goes away. Most people dial in this method on gravel.

 

[Blue Ox]

That load sending valve was critical to control rear lockup on my trucks with the 13" drums. I know GM said to eliminate it, but my 'burb was a disaster without it.

The only substitute I can think of would be an aftermarket adjustible proportioning valve for the rears.