what would cause the brakes to lock up when driving along it seems to happen after the truck warms up and will not be a problem after it sits and cools down
We need a little more info. Do the brakes lock up when you step on the brake pedal? Do they lock up on their own? Front brakes or rear or both.
thanks for the reply. here’s more info:
the car starts shuttering very subtly before it happens. then when it has to work harder, like when we get to a hill, the brakes start working against the car without me pressing on them. I’ll be flooring it and going very slowly, sometimes to the point where the car completely stops. A heinous smoke smell comes out of the car. if i can burn through it without stopping the brakes sometimes release back up (evidenced by cruising instead of stalling when i am shifting gears). Also going into this problem, and coming out of it the pressure under the break pedal is huge. When i leave the car by the side of the road for a while and come back to it later the brake pedal has a normal pressure and the car drives great. last year this problem was happening and the mechanic replaced the front brakes, callipers and lines. i was away for the winter and barely drove the car, but now that i am using it for work again it is basically acting the same as it was.
It could be a clogged brake line, to find out next time it does it stop and feel each wheel to see the one that is dragging.
A good repair guy can bleed that brake and see it is not squirting as much-clogged.
Also could be disc or drum hanging up.
The rubber brake lines to each wheel can cause this condition. When the rubber line breaks down internally it will let pressure in but not back out. Over time they will release the brake. You just need to find out which brake(s) are locking up.
Are all 4 wheels dragging? One dragging more than the others? Or possibly only one dragging? Have you pulled the wheels off the offending brake and inspected?
This truck probably has rear anti-lock brakes. The anti-lock hardware clogs up badly if the brake fluid is not changed periodically. When this happens the rear brakes stay applied. Over time they may bleed back down enough to move the truck again, but the first time you step on the brake they’ll stay applied again.
The anti-lock valve is underneath the truck, about under the driver’s seat as I recall. Temporariliy opening the brake line behind this valve to release the pressure once the brakes are stuck will confirm the valve is bad.
Pretty pricey, unfortunately. Something like $300 for the part as I recall.
I’m leaning towards old brake fluid. When the calipers were changed the brake fluid should have also been changed at that time.
Old brake fluid has a much lower boiling point than fresh fluid. This means it expands more and when that happens the brakes may lock.
Back in the 70s there were some problems with Harley Davidson rear brake calipers seizing at speed and the brake fluid was a major factor in this.
I will go with the old fluid,followed by the hoses. I had a 88 Ranger 4 cyl 5 speed. This truck was so underpowered I have a hard time justifying 5th gear. I really disliked this truck and gave it to a nephew. Lets see him speed in this thing. Only vehicle I ever had to replace the steel brake lines on, they actually riusted through.Elissa after the brakes getting so hot and smoking you want to inspect the linings for physical damage.
Which parts have been repaired / replaced to correct the error