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'67 Frt Brake shake

KBMWRS

KBMWRS

Welcome truth back
Donator
Under heavy braking at speed my front end shakes bad.

reason?

rotors?...fix?...need to get re-machined?

Plan on replacing front brake hose and pads so should I also get the rotor/discs turned at the same time?
 
Could be rotor out of balance, bad pads, pucks not retracting which would keep them applied, which would cause heat, which would cause vibration.

Did it just start? Do you have an adj brake rod?
 
"6t6red" said:
Can a bad outer tie rod cause this under heavy braking?
Click to expand...

Good question, I've yet to experience that one.
 
I had the same thing when I over adjusted my front drums, backed off the adjusters and fixed so I would think sticking pucks could do the same thing as stated above.
Jon
 
"silverblueBP" said:
Could be rotor out of balance, bad pads, pucks not retracting which would keep them applied, which would cause heat, which would cause vibration.

Did it just start? Do you have an adj brake rod?
Click to expand...

No its done this since I've owned it...7 years but now going to change pads so just asking.
Adj Rod???? Not sure what you mean.

My guess is rotors need turning/machining.

I'll be repacing the pads and checking the pistons.
 
Most of what people believe is 'rotor warpage' is actually a build up of pad material. Deposits of pad material get left on the rotor especially when the rotor has gotten very hot. By turning the rotors you make them thinner and more prone to pad transfer again.

Personally I wouldn't waste time with turning the rotors, If they look worn I'd ditch them and start with new ones. If your pads need replacing do that at the same time. Make sure you bed them in correctly!
 
"Shaun" said:
Most of what people believe is 'rotor warpage' is actually a build up of pad material. Deposits of pad material get left on the rotor all the time but especially in one spot when the rotor has gotten very hot. By turning the rotors you make them thinner and more prone to pad transfer build up again.

Personally I wouldn't waste time with turning the rotors, If they look worn I'd ditch them and start with new ones. If your pads need replacing do that at the same time. Make sure you bed them in correctly!
Click to expand...
 
"KBMWRS" said:
Adj Rod???? Not sure what you mean.
Click to expand...

The prop rod that goes from the brake pedal to master cylinder, if it's adjustable, it could be too far out which would keep pressure on the front brakes.
 
Thanks guys.

Craig and I will be getting into this in November. Just getting ready.
 
I kinda agree with Shaun.

Brake pulsating/shaking is most often caused by two things: rotor thickness variation, or excessive runout that leads to pad buildup on the rotors and eventually thickness variation. Either way, turning the rotors (if they're above minimum thickness) will solve the problem. With quality rotors, there's no problem turning them, especially with an older car that gets driven on the street. When you get to newer, heavier, and higher performance vehicles, it becomes a problem. It's also a problem with cheap rotors that have much less material to start with.

You should never install pads on used, unturned rotors. Pads need a very flat rotor surface with a non-directional finish on them in order to function properly. If possible, I'd even try to machine the rotors on the car (the new ProCut on-car brake lathes are very, very nice) to minimize any stacked-tolerance runout. Not that that's really an option for you, but it's one of the best ways to do it.

If you replace the rotors, make sure they're true. Many brand new rotors will have as much as .003" runout from the factory, which is too much. Some parts stores (like our local Kragen) will even store them on edge, which can cause excessive runout. Many shops will check new rotors for runout before installation and machine them if necessary.
 
On the back of the rotors is usually stamped what the minimum thickness is. If you have enough meat, you can have them shaved to remove any warpage. If you go below the minimum thickness, you'll need new rotors. I believe most NAPA stores can cut rotors. Certainly, any decent auto machine shop can do it. Probably run you $50 for both rotors.
 
Mike, as mentioned just take the rotors and have 'em checked. If they're within spec you can have 'em turned with no problem. Sounds like they're just "out of round" so to speak. A NAPA or any mechanic shop can do it.
 
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