I was wondering what is causing my brakes to feel like they aren't grabbing good. I have already redone the rear brakes with all new drums, shoes, wheel cylinder, and spring kit. The only thing I have done to the front so far is just new pads. I didn't even turn the rotors. I also installed a new master cylinder.

Ok what is happening is when I push the brakes they don't really have a gradual brake it is just stopping and if I need to stop faster I have to push much harder. It is kinda hard to explain on the internet, but the brakes don't lock up or anything. It just seems like they are weak.

The front calipers boots around the pistons are already dry rotting and the boots are falling apart. The vacuum to the brake booster I assume is good. Only vacuum hooked up is the distributor and transmission. The booster has a separate vac line on the back of the intake. I have no idea how to tell if the booster is working or not.

I don't know if the rotors are worn down either, but I can take them to the store and see if they can mic them.

I hopefully can narrow down what the problem is so I hopefully won't replace something that doesn't really need to be. I am sure at some point I plan to redo all of the brake system but I need to fix only what is needed so I can get the truck dependable enough to go a 100 mile trip.

Thanks for any suggestions or help
Larry

 

Basic booster check would be: Pump the pedal several times with the truck 'off'. This will use up any vacuum being stored in the booster. While holding the pedal down, start the truck. The pedal should go down a noticeable amount.

Are you sure the rear brakes are correctly adjusted? My ol' rule of thumb used to be to run the self adjusters up until you had a light 'drag' while turning the drum. Once that happens, have a helper (or yourself) apply the brakes several times and recheck the drums again.

Brake shoes need to be 'centered' when replaced, and the easy way is to adjust to that very light drag--have a helper hit the brakes several times--and re-adjust to a very light drag. You really should only have to do this a couple/three times before things are good. The drag upon final adjustment should be extremely light. However the brake pedal travel should not be that much. The rear brakes control the pedal height via the combo valve (that valve prevents the front calipers from engaging until the rear brakes start to kick 'on'...rear brakes out of adjustment= pedal has to travel more before the calipers kick 'on' and results in a lower then normal pedal)

Normally after a brake job is done, and you are used to how things "used to be" with the old parts? The system will seem a bit different, but it's probably acting like it is supposed to. Of course if it seems to be just flat out wrong? There could be an issue not figured out yet.

S-

 

The way I adjusted the rear brakes was... I had it on the lift and after I put the drum back on I would spin the drum and listen for the rubbing sound the shoes made. Once I started to notice a little bit of rub and a constant sound I backed the shoes off just a bit. I have never heard of doing it your way but I am willing to check it.

I will go try the booster test now and see what happens.

 

Tedybear is right they must be centered. I always tightened the adjuster till it stopped (brake locked up) this centers the shoes then back off till it just starts turning free. The only trick is once the adjuster is tight you will have to stick a small screwdriver through the hole to push the self adjusting lever off the spur so that it can be turned backwards.

 

LOL, Actually I do it that way for the reason that I stink at getting the small screwdriver in the exact right spot to release the star wheel.

Many ways to do the job, provided you get quality results? That's what matters.

S-

 

I always had trouble getting that darn screwdriver in there to release that spur.

I cured the problem, I took the drums off and took a metal rod and determined the exact spot where a pin could be inserted to release that darn thing. I drilled a hole there large enough for a 1/8" drill bit to go through. Now when I adjust the brakes I tighten them up until they are seized and then I stick a 1/8" drill bit through the hole, the spur releases and I back the adjuster off until the drum just starts to drag.

 

Were your brakes like this before your brake job? If not you might check and make sure the shoes are not on backwards. Otherwise your calipers might be hanging up inside.

 

Well actually I haven't spent enough time in the truck to know how the brakes were before. Before I done the brake job the brakes were bad. The pedal would go almost to the floor before any braking would happen. When I was getting ready to bring the truck home after buying it I had to put a new master cylinder in just to get it to stop. Long story but I didn't have much driving time in it to get a feel for the brakes.

 

I can relate. With ours? Once we got it into the garage to give it an 'eval' it was like a slap in the face. Master Cylinder was caked with rust, and the lines replaced at one time didn't use the union fittings. Brakes pretty much not there....

Found heavy grooves in the rotors which someone slapped a set of pads onto 'em. Pads take time to wear into the rotors when recycling used parts..Our pads had a 1/8" matching groove into the rotor. And the right caliper was partly locked up-Piston was not releasing the full amount causing heavy drag. (wheel still turned, but it took a lot of effort)

Went to the rear brakes--One drum worn out beyond any hope, Blown wheel cylinder (it had black garbage built up IN the cylinder part)..Hardware was toasted, self adjusters rusted into a massive heap.

We bench bled out the master cylinder, replaced it...replaced both calipers/rotors/pads..both wheel cylinders/both drums/shoes/all hardware. Thankfully with shopping around I found the parts to be "fair" in price. Autozone actually had the drums for about $36 a shot, and the other stores listed them for over $70 a shot each! We also did the parking brake cables (all 3) at the same time for inspection (NYS is a pain with inspections). New bearings as well on all 4 wheels.

Basically we had 2 brakes dragging all the time (right front and left rear) So when we tested everything afterwards? It takes getting used to how the system should work when all parts work in concert together.

Given the condition of the calipers? They are not expensive for rebuilt..and if the dust seals are shot? Just replace 'em. Any deep grooves in the rotors will also cause slightly decreased brake action due to the friction contact area being a bit less then ideal. (just a bit...but not to much normally) Brake drums are also suspect to other issues such as cracking and warping..

Might be a good idea to get the calipers replaced, and really flush the heck out of the brake system with fresh fluid. As mentioned? If it does not feel "Right"? It probably has some hidden problems not found yet. And yeah--ours does the neat effect of having the pedal go down about 1 1/2"...and the pedal gets pretty hard, without a lot of "mushy" some new cars have. But it stops on a dime, and gives ya change.

S-