Vibrations 1994 f150 4x4

Does it go away once you go faster than 30mph? Is it in the steering wheel, or in the seat? Is it worse with the brakes applied?

Have you had your tires balanced? Checked for a bent wheel?

Just some Questions and Ideas.

Spdloader

Once I hit 30 it starts, and then it gets heavier once I get to about 60. After that it isnt as bad, but def still there. I thought it was my rear wheel, had it balanced and everything is fine. Then I thought it might be something in the front end, but everything is tight and there is no play in anything. I feel it in the seat and in the steering wheel. Now that you mention brakes, I have a problem with those. When I apply the brakes, the pedal stays where i push down to. When I need to back off the brake, I have to lift it up with my foot to release the brakes. When I step on the gas, the brakes seem to release a bit. Hope this helps because the manual I bought is crap when it comes to troubleshooting this. I also don't have the budget to bring it somewhere to get it fixed.

Thank you

Eureka! <lightbulb=on>

haha, I feel dumb now. I wasnt even thinking of that. Thats Matt!

I believe you have answered your own question. Brakes. Calipers or wheel cylinders or both sticking.

You must find out why.

Bad master cylinder? Bad hoses? Bad calipers/wheel cylinders?

Spdloader

If you have to pull the pedal up, it is in the master cylinder or the vac boost unit, not at the wheels (this is not to say that there may not be a caliper problem too)

----------------- The SnoMan

(this is not to say that there may

Which is why I suggested he check the entire system. Spdloader

Yes but I would check master cylnder and vac boost first because brakes will not work properly until this is resolved and it is hard to trouble shoot the reat of the systems when there are seriuos issues at its heart.

----------------- The SnoMan

Again, which is why I said, in order:

Spdloader

Or vacum booster

Neither of these would cause the brake pedal to need to be pulled back up.

THere is the return spring that assits pedel return too.

----------------- The SnoMan

">>>>>Bad master cylinder? (That would be first)

SnoMan, Why are you trying to confuse this poor guy?

Based on the OP's information, it's a bad master cylinder, but, the square-cut Kalrez seal on the caliper piston is what returns the pistons in the calipers to neutral, thus forcing the fluid back up toward the master cylinder, which moves back to the neutral position with the aid of an internal spring in the bore of the master cylinder. If this seal hangs, the brakes will overheat, warping the rotors, causing a shake. In the rear, the springs on the shoes do the job of returning the system to neutral, forcing the fluid back up the line to the master until it is needed again. If they fail to do their job, then overheating is the result and the drums will warp, causing a shake.

Also, the emergency brake cables can be stuck holding the rear brakes where they drag, creating the overheating and shaking symptom.

All those things should be checked, overheating brakes have a domino effect on the entire system.

The vacuum booster won't hang the system when it fails, it'll simply create a "hard" pedal. A failed booster won't hold the brakes "on". It also has an assist spring to return the shaft to neutral, or "off".

The pedal return spring under the dash simply keeps the pedal from activating the brake light switch.

The OP has enough information to accurately track down his problem now.

Spdloader

Okay, enough you two. Spd, what you've posted here is completely, totally wrong. It was childish and stupid of you to try to "defend" yourself against a simple bit of correct advice that was useful to the OP. Any reasonable person would have said "oh, yes, that's good advice," but instead, you acted as a needy idiot. This post (which is totally wrong) is beyond that. It's one thing to be a prissy crybaby, but it's another to post something that defies a correct understanding of such a simple system.

Now, I realize you're going to respond to this pretending what you've posted is true, and tell how what you meant is correct all the time, and blah blah blah. But I hope the OP will be smart enough to see that your needs as displayed here aren't going to fix his brakes and he can ignore that.

The OP needs to get his brake pedal returning. After that is fixed, then it will be possible to determine whether there are any other problems in the system. The reason for this is obvious, but I'll state it here for folks that would appreciate the discussion. *The brakes are not supposed to release when the piston isn't all the way back.* Simple, really, and obvious to anybody who's ever had to stop a car, I would think. There are holes in the master cylinder body that allow each circuit to exchange fliud in or out with the reservior as needed. That could be fluid coming back from the release of brakes, or fluid keeping the system full as brakes wear. That allows the brakes to return to whatever physical state that they are supposed to when you're not braking. This hole only works when the master cylinder comes all the way back.

So, just to clarify for the OP, this thread has gone beyond fixing your brakes and it has entered into the realm of proving somebody is right by lying about how your brakes work. You'll need to use some discernment with the answers.

You have the right to say whatever you wish. I was a professional trainer of brakes, steering and suspension, and front end for 14 years, for a major manufacturer. I've never lied about anything so trivial in my life and have nothing to gain by misleading anyone here I post to. I don't post about what I don't know, like transmissions, and some electrical problems. Obviously you don't have any experience with SnoMan and how he continually jumps in and confuses things, and you have little understanding of how a braking system works. You are stating what you think, I was stating what I was trained to teach. If what I said makes no sense to you, then you have revealed you limited knowledge.

Your personal insults are insignificant Joe, just like last time you personally attacked me.

Spdloader

.....and just to clarify, I don't think SnoMan is a bad guy, I just think he's so smart that he isn't able to relay his thoughts in laymen's terminology. He usually restates what has already been said, only in terminology that an engineer or professor would use. SnoMan is a grown man and can take care of himself, he doesn't need some kid with an agenda taking up for him.

By the way, Joe, I'm not sure why you came back out of your hole to attack me again, just don't make it personal like last time and send me private emails to my home.

Spdloader

I appreciate all the help. I replaced the master cylinder, wheel cylinders and rear drums. I checked the front rotors, and they were ok. The brakes did the same thing, when I pushed onthe brake, it stayed where I left it, and to release I had to again put my foot under the brake and pull it up with my foot. I unplugged the vacuum hose to the brake booster, and plugged it up with a bolt. The brakes do require more power to stop of course, the the pedal returns to the correct spot. THey work a hell of alot better so next weekend I will replace the booster.

As for the vibrations, it is still there, not as bad. it starts at 40 mph, and stays hard untill 65, then it isnt as bad. I checked the front steering components and there is a little bit of play in the pitman arm, but I don't think that would make all those vibrations. I changed the front driver tire because it seemed like it was out of round. That helped a little bit more. The caliper on the front drivers rotor is sticking, and i think that might cause the vibration. Other than that, I am not sure what else it could be. I purchased this truck last summer around august, drove it untill october and then let it sit over the winter untill last month. Any other suggestions or idea's? I would really appreciate it.

Thank you

Aside from checking the other tires / wheels I don't have any other ideas for the vibration.

Spdloader

Warped brake rotors can cause vibration, if you have a ball joint gauge available, which is nothing more than a pair of vise grips with a flexible arm holding a dial indicator you can check for run out on the vehicle. Given that the power booster has been causing the brakes to drag, there's a good chance there is some warpage. Not to mention the seals on the calipers may have been cooked a bit as well. Does it have plastic pistons or steel ones? The plastics gave lots of problems. If the rig uses hat style rotors, sometimes you get rust build up between the rotor and the spindle and it can cause vibration.

Whitelightning

That makes pretty good sense. The booster I suppose was the root problem.

It sounds an awful lot like a tire. If your front brake is sticking all the time, it ought to get blazing hot. Drive it and then let it coast down to a stop and see. If you stop it with the brakes you won't really learn anything from that.