What up!! 89 F150 Supercab, 4X2. Hopefully this will be an easy question. I don't think that I have ABS brake system, especially 4wheel ABS. But here is my dilema. How sensitive are the brakes on this model truck supposed to be? I can pull out of my driveway less than 20 feet going no more thatn 5mph and barely press the brake and it skids like I was doing 100mph. I am worried that when I am driving on the road doing normal speed and need to stop, especially suddenly, I will skid right into the vehicle in front of me. It will be even worse on a wet road and terrible on a icy one. Is there a way to decrease the sensitivity level on the breaks. I haven't checked the pads or shoes, because the brakes work. The problem is working they seem to work too well. I don't think that they have LOCKED but the skidding is scary. I scared my neighbors stopping in the driveway.

 

Is it only the back brakes or all 4, the back breaks could be from sticking calipers, worn shoes, or out of round drums. My truck also does this at low speeds on the back brakes only, if I travel faster or warm up the brakes it will brake normally. This condition gets worse when it is wet.

 

I only notice it in the rear because that is where the skid comes from, or at least where I seem to feel the skid. So are you saying that the brakes shouldn't be that sensitive because the front brakes should equalize the force and make it less likely to skid when depressed? I will check the brakes on tomorrow to see if anything has fozen or is sticking. Would the size of the tires make a difference in the braking power: I have 31x10.50R15LT on all four?

 

Your truck should have at least rear wheel anti-lock brakes, although they don't work very well. I have never felt the RW anti-lock work on my '87. When you turn the ignition key forward you should see the anti-lock light come on. If you follow the rear line from the master cylinder to the frame you will see the anti-lock brake control module. You really need to determine which are locking up, the front or rears. On a truck the rears are supposed to be more likely to lock up because there is not much weight on the rear end, but my rears have never locked up. I have locked up my fronts many times without the rears locking. There may be a problem with the proportioning valve. It balances out the front and rear brakes. It looks like a nut that is bolted to the master cylinder inline of one of the brake lines, I think the line that goes to the rear.

 

I will check it tomorrow, because I wouldn't say it is locking up, but maybe they are. It is definitely the rear. I would think that the fronts would pull the truck downward when I break if it was them especially by themselves. I will eventually have to look into getting a brake job, oh bother!

 

Suggest to inspect the rear shoes. Had an occurence where the rear axle seals were leaking that caused the brakes to grab HARD, causing a situation similar to what you describe.

 

My father's '88 F150 I6 does this... especially when it isn't driven. Also if it's raining, be sure to ease to a stop instead of last-minute braking. I'm going to ask if the truck has been driven daily, or if it is a "need to haul something" truck, because if you only use it 1 time a month: It's normal (according to the '88 I've experienced).

 

I have 31 10.50R15 LT on my truck, when it is wet my back brakes lock at slow speeds with little brake input after they warm up or at a higher speed above 15 mph they brake normally. I have checked and my drums are round and there is no grease or other liquid on my shoes, there is a lot of brake dust though.

 

Perhaps something to consider - the front brakes aren't doing their job??? Just have a hard time believing that this is 'normal'. Something has to not be operating right.

 

My front brakes lock up on my truck. They're very sensitive. When it warms up it's better, but they still seem grabby. I'm towing my GN about 100 miles on Tuesday and would like to fix this. The trailer has brakes, but I'd rather have the truck in tip-top shape for such a trip.

I thought maybe the rear shoes weren't adjusted right, but the e-brake works just fine - not much pedal travel and they work great.

I noticed that the rear lines have been replaced very recently (I've only had the truck a few weeks). Maybe it needs bled?

Mine's a '95 XL. Should it have ABS? I don't have an ABS light (I don't think) and there's definitely no anti-lock action going on.

Is the proportioning valve adjustable?

Thanks, and sorry to thread-jack. This seemed like an appropriate place to continue the discussion.

Jim