# 87 2WD Brakes Locking Up



## thorn87d21 (Jun 2, 2007)

I just recentally started having a problem where when im driving I can feel the front brakes out of nowhere lockup for a split second then release without me even touching the brake? I have had for awhile a leak in my left front brake hose but my fluid is up to top. Today on my way into work the truck actually locked so bad for a 2nd or two that I went to give the truck gas and it just reved up and went nowhere. Brake pedal pressure feels normal and the truck stops like it should without any sponge feel to the pedal.

Im going to put the truck on a battery tester machine today to check battery and alternator output to make sure it doesnt have to do with this and then Im going to run this tank of gas fully out to make sure im not getting mixed up with an engine miss.


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## Fred S (Aug 26, 2006)

Your explanation doesn't make sense to me. If your brakes are locking up, the last thing you'd be doing is giving the truck more gas. You'd be too busy trying to keep from crashing. And when a brake caliper locks up, it usually stays locked. I think the problem is something else.

The battery and alternator won't be related to this problem, but it's good to test them anyway.

My first guess was an automatic transmission that was going out of gear momentarily, but I see that you have a manual trans.

With a manual, if the engine's revving and you're in gear and you are not moving, either your clutch is worn out, or the transmission has MAJOR problems. Hopefully it's just the clutch.

Can you answer the following questions? It'll help.

When you say that the brakes lock up, do the wheels skid? Which wheels?
Does this problem happen at any particular speed or RPM?
Can you make the problem happen? How?
What's the mileage on the truck?

Fred


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## thorn87d21 (Jun 2, 2007)

Fred S said:


> Your explanation doesn't make sense to me. If your brakes are locking up, the last thing you'd be doing is giving the truck more gas. You'd be too busy trying to keep from crashing. And when a brake caliper locks up, it usually stays locked. I think the problem is something else.
> 
> The battery and alternator won't be related to this problem, but it's good to test them anyway.
> 
> ...



The truck will run fine driving down the road when its cold or warm but out of nowhere without any warning the truck will feel like the brakes are being applied but short of locking up for a split second then releasing. Yesterday when it happened I heard a quick chirp from the front tire. Now this morning the truck actually slowed down for over 2 sec as if I hit the brakes but it still doesnt fully lock up. It seems to happen at any rpm and speed. 

The problem best explained is if you were driving along at 50mph and you tapped the front brake really hard really fast for a split second in a panic situation to avoid a animal but short of locking them and holding them down for over a sec. Its enough to make me go forward in the seat and make my seatbelt catch. 

I cant make this happen and it seems as if my gas mileage on this tank of gas is alot lower then normal.

Im going to pull the line going into the brake booster today and look for any signs of fluid etc..


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## Fred S (Aug 26, 2006)

That's a really odd problem. The fact that it's intermittent like that is worriesome.

It's a 2wd, so it's not drivetrain related if the front wheel is chirping.

An 87 probably doesn't have ABS on the front wheels. I don't think it was even an option in that year.

I'm still not convinved that it's the brakes, because it's just so strange for them to grab and release on their own like that. I can't think of a failure mode that would cause that.

I'd have a good look at your wheel bearings. If they're failing they may be locking up momentarily. It's pretty easy to just pop off the dust cap and eyeball the outer bearings. You can also jack up the front end of the truck and spin the wheels. Do they spin smoothly? Does the wheel have any side play?

Let me know what you find.


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## wessass (May 20, 2006)

Your front brake rotor is locking up. I have a 5 speed and it did the same thing. It was wear in the side of the caliper where the piston moves back and fourth. The piston cocks in the hole and sticks. It will get worse. if it totally freezes you can take a 10mm wrench and slowly pop the bleeder open on the caliper. Just enough to let some fluid out. Then tighten it back down. The brake fluid boils past a certain point of the rotor getting hot from dragging and creating pressure. This is not a fix by any means, have some professional technicians look at this for you. You should replace the rotor, caliper, pads, wheel bearings and seal. have your ball joints looked at while you have it apart. There is a great deal of heat that has been through all those components safety should always be first.


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## thorn87d21 (Jun 2, 2007)

wessass said:


> Your front brake rotor is locking up. I have a 5 speed and it did the same thing. It was wear in the side of the caliper where the piston moves back and fourth. The piston cocks in the hole and sticks. It will get worse. if it totally freezes you can take a 10mm wrench and slowly pop the bleeder open on the caliper. Just enough to let some fluid out. Then tighten it back down. The brake fluid boils past a certain point of the rotor getting hot from dragging and creating pressure. This is not a fix by any means, have some professional technicians look at this for you. You should replace the rotor, caliper, pads, wheel bearings and seal. have your ball joints looked at while you have it apart. There is a great deal of heat that has been through all those components safety should always be first.


Exactly what my friends father told me about the piston grabbing from too much pressure buildup in the fluid. I went today and got in new calipers, pads and hoses to replace while im down there. If I feel the rotors look burnt or damaged I will have them replaced and the bearings. The rotors do not have any warping or vibration and the problem only started mainly yesterday so I dont think I have done damage to the rotor but I will know come tomorrow. My friends father also warned me not to keep driving or I would damage the rotors.

I will keep an update on this post come tomorrow and let everyone know the outcome and hopefully this post and the other comments on here will help those in the future that may run into this same problem.


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## 88pathoffroad (Jun 6, 2004)

You're seriously driving around with a leaking brake line? Are you suicidal?


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