993 EFI brakes seized on.

Hi everyone.Never a dull moment with a Hijet! The brakes have locked on a few times in the last couple of days.When the brakes start to bind you have about half a mile before they are so tight you can't move the vehicle.When this happens the brake pedal becomes solid,no play.both front wheels are locking they get hot.I'm not sure about the rear wheels,it hasn't happened in a safe enough spot to jack all wheels to find out.After about 20min half hour the pressure on the brake pedal eases and off you go.What could be going on??

Had similar on my old Bedford cf2 350cwt, turned out to be the servo plunger into the master cylinder.
Could be a few things, iffy brake hoses or possibly the caliper sliders not moving freely?
Sure someone more in the know will be along soon and put you right

Have you changed the servo/ m/cyl unit? There is adjustment on the servo rod, try backing it off a bit. Mine had a similar prob after I replaced the unit, didnt know wtf was up, kept locking on. Thats when I found out you can adjust the pedal travel to the servo, mine was on a wee bit heated up, locked up the brakes.

yeah, the guy who had my bedford before me changed the servo to one from an automatic gearbox type, bigger unit giving more power.
Turns out that the plunger was not actually going into the bore of the master and hitting on the shoulder. this meant that after braking say in traffic it was causing the system to pump up and lock the brakes on.

If it not the servo reckon it could be a collapsing brake hose?