Front Wheel "Hop"

[OCBob]

I'm having a big issue with my old GMC pickup and was just hoping that someone here might be able to point me in the right direction.

When applying the brakes the front end shakes something terrible. The whole truck slams back and forth and it sounds like it's all about to just come apart. Under 25 mph or so it's not so bad, but at regular speeds it's unbelievable. I've been told by someone that it is the brake rotors. Anybody know if that sounds right? Don't have the money to play hit and miss trying to figure it out.

 

[trubuilt]

you could try and have the rotors turned that is fairly cost effective

 

[Silverback]

The most obvious thing would be the rotors being warped.

I'm assuming it's a 2 wheel drive, so the other possible cause could be ball joints. If they are bad enough they will allow the spindle to jump around.

Do you have any signs of abnormal tire wear? If not, then it's probably the rotors.

 

[bigredv10]

If the rotors warped it would shake take the wheel off give it a visual look over if you have a micro-ohmeter or and kind of gauge check it that way,straight edge whatever or take it to the allingment shop thell tell you within minutes if its fugged if not maybe suspension..??

 

[OCBob]

The most obvious thing would be the rotors being warped.

I'm assuming it's a 2 wheel drive, so the other possible cause could be ball joints. If they are bad enough they will allow the spindle to jump around.

Do you have any signs of abnormal tire wear? If not, then it's probably the rotors.

Yeah, it's 2 wheel drive.

Abnormal tire wear? hehehe. The front end of this thing is jacked. This is the same truck that I had pics of when the ball joint snapped on one side. But we did an alignment, at least by eye, and it seems to ride pretty straight now.

Guess it's time to see if I can find some rotors at the junkyard.

 

[RB04]

I would bet warped rotor, best off replacing it, not to expensive either between 30-50 bucks, you'll need to replace the pads at the same time

 

[Azmotorhead]

I'll gaurantee it"s a warpped rotor I had a old (81) GMC that would shake violently under certain conditions. Problem solved with new rotors

 

[scoobert]

i just hope the 2WD does not trap the rotors like the 4WD. best off with new rotors. hit and miss as the junk yard, and for a common 5 bolt gmc they should be VERY cheap.

and yes 90% chance its the rotors. they might even be cracked (common problem with some GMC trucks)
i would also put 5% chance of idlerarm/tie rod end,
and 5% bad tire.

also be ready with an extra $20 for new calipers, and also $50 for new pads. don't go cheap on safety.

 

[stanssrt10]

upper lower control arms tie rods. steering bars . rotors usually only shake when you push on the brakes., but then not always thecase. you said violently to me its the susp.

 

[Begood]

Another way to check the rotors is to jack the front end up in the air (with the engine turned off). Then press the brake pedal down hard and release. Now with your hand spin each front wheel (one at a time) slowly and see if you feel any tight spots. You can also have someone put a small amount of pressure on the brake pedal while you spin each wheel. You should be able to tell if they rotate smoothly, or bind in some areas.

Bill.

 

[VENOMOUS1 RACING]

Noone has mentioned this but I have had shocks be gone completely and do the same thing. I agree on the rotors as well but if not check the shocks for leaking and most likely need replace. I've seen a wheel bounce off the ground a foot due to a bad shock.

 

[ZCx]

should get feed back through the pedal if its the rotor.

might sound silly, but might try gettin in an open area & drive her backwards & see if it smooths out.
had a '57 ford wagon that would act bout the same. drive her backwards & smooth as silk. can't remember what part of the front suspiontion was the prob

 

[scoobert]

i have a warped rotor in my car and cannot feel it in the peddle.
would not describe it as a hopping thou.

 

[JTS VENOM PERFORMANCE]

I'm having a big issue with my old GMC pickup and was just hoping that someone here might be able to point me in the right direction.

When applying the brakes the front end shakes something terrible. The whole truck slams back and forth and it sounds like it's all about to just come apart. Under 25 mph or so it's not so bad, but at regular speeds it's unbelievable. I've been told by someone that it is the brake rotors. Anybody know if that sounds right? Don't have the money to play hit and miss trying to figure it out.

you have warped rotors, but most likely some of the suspension parts are worn, depends on the year, alot of the older trucks the lower balljoints wear badly as well as the upper control arm bushings, and those upper control are bushings are really the ones most people overlook and think its the ball joints, but agin depends on the year