Ford van brake problem

ford
brakes
van

#1

I?ve got a 1989 Ford E350 Conversion van that has a strange problem I haven?t been able to figure out.

The left front brake caliper seems to be dragging to the point of getting very hot. If I continue to drive it, it will get so hat that it will smoke and the van will pull to the left. Eventually the pedal will go soft as the fluid boils.

This is what I?ve done and I?ll also explain the brake system.

I?ve replaced both front calipers with remanufactured units. I?ve replace the front brake pads with heavy service pads. I cleaned the slider area well and greased the pins (which are also new). I replaced both front rubber brake lines between the hard line and the caliper. I?ve cleaned and repacked both front wheel bearings. They where both in great shape, so no need to replace. I?ve also replaced the brake fluid and bleed the system

The brake system has a master cylinder off the vacuum booster, and two ports off the master cylinder. The rear port has a large brass cylinder (1? diameter by 3? long) in which the rear brake line is attached. I assume this to be a pressure limiter of some sort. The rear line runs down to the chassis and to the rear axle where it enters a distribution block and is split out to each wheel cylinder. The front port of the master cylinder runs down and into a distribution block. One line goes to each caliper. As you can see this is not a diagonal brake system.

Could there be a problem with the master cylinder possibly not allowing fluid to flow back and release pressure? If that?s the case, why only the left front and not both the left and the right?

This is driving me nuts!


#2

That hose you installed might be defective. Or you may have twisted it or bent it in a way that broke the inner lining. What happens is a flap of the lining hangs out into the passage, and creates a sort of check valve, not allowing all fluid to return to the master.

If that’s not the problem, then you’ve either got a seized/seizing caliper, or a bad distribution block. Rebuilt units are rebuilt incredibly cheap, things can and do go wrong. I heard figures saying 1 in every 100 rebuilds, on average, have some kind of problematic defect.

-Matt