Front Disc Brake Dragging

[Dylan Thomas]

My truck is an early 1998 with a 12v Cummins. This truck has a history of front disc brake dragging. I've learned to periodically remove the brake caliper pins and apply disc brake grease to them. I also periodically replace the brake fluid.

The truck doesn't get used a whole lot so when it exhibited pull-to-the-right during braking a month ago, I naturally assumed that the brake pins (especially the left front caliper) needed greasing and the fluid needed to be changed again. However, the problem persisted to the extent that the left fron wheel became really hot and I could smell burned brake pads.

I removed the LF disc brake caliper from its mount, turned it horizontal and stepped on the brake pedal until the caliper piston popped out of the cylinder. A caliper rebuild kit - consisting of an internal seal ring (square cross-section and an accordian boot - was sourced for < $7 from O'Reilly's Auto Parts.

The piston was not corroded but the seal ring in the caliper bore was replaced. There was some loose corrosion particles collected on the old seal ring which may have contributed to the piston not retracting after the brake pedal is released. The old accordian boot looked good so I didn't replace it. The brake fluid was replaced again because of all the air introduces and because fluid was dark amber color.

 

[Signal73]

Make sure the rubber hoses haven’t swollen internally. I found that problem once after replacing a caliper only to have the pads stick again.

 

[Dylan Thomas]

Thanks for that tip. It's probably the next item to replace if this brake dragging problem persists.

I too have experienced an internally swollen rubber brake line on the LF wheel of my 1996 Dodge B2500 cargo van. That condition was evidenced by an initial pulls-to-the-right braking action immediately followed by normal (no pulls-to-the-right) braking action. As a work-around (prior to LF brake hose replacement), I'd learned to step on the brake pedal twice for every braking maneuver in order to compensate for the left caliper's delayed pressurization due to the hydraulic flow restriction.

Make sure the rubber hoses haven’t swollen internally. I found that problem once after replacing a caliper only to have the pads stick again.

 

[GAmes]

The hoses will sometimes fail and not allow flow when the pedal is released. Visually they look to be good. I suggest you replace both hoses. Also, what type of lube are you using on the pins?

 

[Dylan Thomas]

The hoses will sometimes fail and not allow flow when the pedal is released. Visually they look to be good. I suggest you replace both hoses. Also, what type of lube are you using on the pins?

 

[GAmes]

Good choice. Are you also lubing the flat surfaces where the caliper rides on the piston housing?

 

[Dylan Thomas]

I apply grease onto the flat surfaces of the front wheel steering knuckle which interface with corresponding flat surfaces on the brake caliper. These surfaces are exposed to road spray and, therefore, don't remain greased for very long...

Good choice. Are you also lubing the flat surfaces where the caliper rides on the piston housing?

 

[GAmes]

Those are the only two places that I apply lube to. I only lube them during the bearing repack process, every 50-60k miles.

 

[Dylan Thomas]

My understanding is the caliper casting should be free to move/slide laterally on its slider pins and along the interfacing (flat) surfaces of the caliper and the steering knuckle.

The slider pins have bushings and I apply the grease between the pins/bushings as well as between the caliper/knuckle.

 

[GAmes]

By two places I meant the pins/bushings and the flat surfaces.

 

[Cummins12V98]

Brake hoses can be the cause of sticking caliper pistons.

 

[JMcCoy]

If it persists, and it will, usa air to remove the pistons and emery the surface. DO NOT have your fingers in there when the pistons pop out!

Went to Ford calipers and never had a problem since!

 

[Ozymandias]

I'd never use shop air to pop a piston out that is connected to a perfectly safe hydraulic system to pop it out.

 

[Joe Mc]

Went to Ford calipers and never had a problem since!

Please explain how you did this.