While I had the front end up on jackstands replacing the tie rods, I noticed the front brakes drag. Bad. Hard to get even a full turn spinning by hand.

Rechecked the bearings, and recleaned and relubricated the caliper slides.

Still drags after the pedal is depressed.

My calipers have the V notch slides. Do the later model pin style calipers slide easier? Can the pin calipers be retrofitted to my kingpin knuckles?

 

Are you sure there is not residual brake pressue in the caliper? You can test this by opening the bleeder on the caliper when the brake is dragging and see if it frees up. Is this problem just one wheel (did you check both sides)?

 

+1 Bumpkin. Assuming they're fairly new to be dragging without hung pistons- did you remove fluid when compressing them to replace the old pads? Or do you have a bad pressure valve of some sort.

 

Stang, don't know about the retrofit, but my 76 was dragging a little and I drained and flushed the old brake fluid out and put fresh fluid back in.

I was going to install new calipers, but after that I haven't had any trouble for over 9k miles.

Hope this helps..Trav..

 

What usually happens, the truck is run a long time on the front pads, and they wear and the pistons in the front are extended in the caliper bore for a long period, with the old fluid behind them. This leads to rust forming behind the pistons. Then you put new pads on, and when you compress them with the c-clamp, it pushes the piston over the rusted area, and they get sticky. Rebuilt calipers will usually fix this.

 

I thought about this all day.

Then I looked under the truck again. For some reason I thought the part the caliper rides on was bolted to the knuckle. It is one piece. So much for retrofit.

I was wondering on the bleeders. The brakes were fully bled just after I got the truck(had to put in new master cylinder before I could even drive it). It does act like there is residual pressure in there. Might not have gotten all the air out. The truck did sit for 5 years give or take before I got it, and with the blown master cylinder probably got water in the fluid side. The old fluid was rust colored....

The pads were new just after the master cylinder was replaced, 2 years ago. No issues with the brakes till recently.

The dragging may be the reason my mileage recently dropped 2 mpg....

About $42 each for the calipers from Oreillys....
and $39 each at Autozone....

Going to try rebleeding them before replacing.

 

Update. not good.

It almost feels worse, as in the rotor is even harder to turn. Didn't get any air. Fluid that came out was light brown.

Interesting thing while pressing the brake pedal with the master cylinder cap off. Fluid shot out of the rear brake section and coated the underside of the hood. Front brake section showed no change in the fluid level while pumping the pedal.

My Light Truck Shop Manual says to replace the master cylinder due to an internal leak. This master cylinder is only 2 years old.... Fine. Will pick it up tomorrow.

It also says to check for open compensator ports. Since the front brake reservoir level did not change, the port is either plugged or the piston is not moving back far enough. I pulled the two master cylinder nuts and rechecked the brake booster pushrod length. Good. And with the master cylinder off the booster, pressure is still there. No change.

The LTSM also says check for seized wheel cylinder or calipers. I took clamps and pushed the pistons back and they moved back about 1/8". Rotor spins easy. Press pedal one time and damn near locked again.

Both front brakes are the same which makes me think there is residual pressure holding the brakes. As in if the compensator port is blocked, the hydraulic pressure cannot release.

Anybody have any other ideas?

 

Stang, Have you replaced the rubber brake lines on your front calipers?
They may be collapsing on you.
I had to change mine because it set for a few years.
They get soft on the inside and won't let fluid travel through.

Just a suggestion.......Trav..

 

Not yet, but will be picking them up tomorrow with the master cylinder.

Might go ahead and order the calipers too....

 

Sounds like a plan!!
It should put you back in action again...Good luck..Trav.

 

So much for the plan.

They have the hoses in stock, but the master cylinder and calipers have to come from the warehouse.

Will have them Friday and they will pricematch the lower prices I found at Autozone...

 

Oh Well, Even the best laid plans.......
I had to wait on my calipers and master cylinder too.
At least they are still available.(I hate to hear OBSOLETE)

Gotta catch a nap....Later.

 

Picked up the master cylinder and front hoses. Wanted to do them first and see if there was a difference. Well....

Pulled the master cylinder. Then since there was no pressure on the brakes, I tried to turn the rotor. Same stiff drag.

Pulled the passenger side hose off the caliper. Now definitely no backpressure. Still same drag.

Pulled pass side caliper and pads. Spins free, but I hear the bearings. Ugh.

Just for S+G, I put my dial indicator on the rotor and have about 5 thousandths runout. Not enough to pulse the pedal, but should have been able to push the pads back. Nope.

Heading back to pick up new calipers, pads, and bearings/seals then get the rotors surfaced. They don't have the rotors, even at the warehouse.

I should be putting all this into the Dana 44/50 that should be there......

 

Sounds like me. I was having similar problems on my 85.
I finally replaced everything: Rotors,calipers,hoses,MC and booster.
While I had the front end apart, I checked and repacked bearings,checked all the joints,etc.
Needless to say, I am ELATED over the difference.
In the long run, It was WELL worth the work and expense.
Good Luck....Trav..

 

I had just replaced the booster and master cylinder 2 years ago. Dang it.

Oh, and when I thought it was going good, proceeded to twist off the end of the brake line to the drivers side hose. It was the fitting behind the shock tower. Thought I was spinning the nut, but the line snapped. Like I needed more to fix....

Another observation. The brake pads were not wearing evenly. I should say the outers were, but the inners were mostly wearing at the bottom, ie: the leading edge of the pad. Looks like the upper piston was not pushing very hard since it was stuck....

And Oreillys does not have the bearings in a set. You have to buy the bearings and races separate. At least they are in stock. Not Timkens, but National/BCA.