Brakes won't lock up

[K5Silverado]

Hello,
Long time viewer and first time poster here. My '87 K5 won't lock the brakes, and as far as I can remember, it hasn't since I've owned it - several years now. Does anyone have a stock, or nearly stock K5 or truck that has brakes that will lock up easily?

I don't have any stopping problems but have always wondered

[Gene]

Ive got differentials out of a 91 and as much as ive tried they wont lock up either.

[K5Silverado]

Thanks for the reply Gene. I had an '83 2wd long bed truck years ago that would lock up, so I found it odd that this won't.

By the way, I just went through your entire build thread - very nice truck you have built!

[BigRed76]

I've got a '76 K10 with stock brakes all around and if I step on the peddle hard enough it'll lock up the rear brakes...

[K5Silverado]

Thanks for the reply. That's good to know. I wonder if it has anything to do with truck vs. blazer, weight on rear-end, etc.

[OrrieG]

Stock tires and wheels? Bigger tires and wheels add rotating mass that is harder to stop. I've heard stories of guys lifting and putting big tires on small foreign trucks, then not being able to stop them or destoying the brakes in the process. Assuming front discs, you might look at the adjustment of the rear drum shoes. The front brakes do most of the braking and may limit pedal travel, therefore drum shoe travel (discs are fully engaged before shoe can travel the full distance to stop the rear wheel). If you are really worried about it you can get an adjustable proportioning valve to adjust the front back bias to your liking.

[K5Silverado]

Thanks OrrieG. Funny you should mention the proportioning valve. I just installed a new one, the original one was leaving a small puddle of brake fluid everywhere I parked - bad leak. That's what motivated me to post my original question. I suppose I was expecting the performance of the new valve to help the brakes lock up, but evidently the old original valve performed just fine as there's no difference in performance between the new and the original. No more leaks on driveways luckily with the new one.

I'm running 32" tires on stock 15"x8" ralleys. Slightly bigger than stock but probably not enough to make a differnce. I'll adjust the rear brakes some, but I think I'm ok with how the truck stops. It just kind of struck me as odd that the brakes never really locked up. I'll see how a rear brake adjustment helps.

Thanks!

[BigRed76]

Well mine's running 35's & it'll still lock up the rears, so maybe something isn't right with my brakes

[rpatowers]

I had the same problem with my 72 4 x 4. I installed a hydroboost brake system and they will now lock up.