I’m having problems isolating a wicked vibration that randomly occurs when driving anywhere between 45 mph and 65 mph. (if the vibration starts it usually continues up past 65 and if i stop the car then start up again the car usually still shakes even at 35 or so) The steering column and gear shift shakes violently. If I take it out of gear, I don’t notice a change in vibration. The vibration would only change if I slowed down. Pushing on the brakes causes the brake pedal to vibrate really bad. It occurs randomly so it doesn’t seem to indicate an issue with the tires (otherwise it would happen consistently). I took the car to Discount Tires and had them check all of the tires and rotate and balance them. I inspected the motor mounts and transmission mounts and nothing appears wrong there when revving the engine. Jacked up the rear end of the car and ran it up to 70 mph and no vibration would occur. Inspected the driveshaft at all speeds and not the slightest wobble there (I was hoping for a driveshaft imbalance so that maybe I could balance it with some hose clamps). The problem started a year ago and only happened a handful of times, then started back up off and on throughout the past month or 2.
Replacements made so far with no change to the issue:
Struts and shocks have been replaced. I replaced the lower control arms, upper ball joint, idle arm bushing, tie rod end, sway bar end links, wheel bearings, and sway bar bushings. (Transmission was rebuilt recently and it seems like if there was an issue with the transmission mounts, they would have noticed). I also had the wheel alignment done about a month ago.
Could be a problem with the rotors?
Does anyone have some ideas to check out?
Check front wheel bearings and front brakes. Maybe a anti rattle kit if you have discs: http://www2.cougarpartscatalog.com/c8zz-2b120-1-hk.html.
If the rubber insulatorns in the kit is worn, front end behaves strange.
Check also that the brake pistons moves smooth in/ out.
If the caliper bushings are shot, then I would expect chatter, rattling sound that can be localized pretty well if you drive with the windows down and have a passenger to listen from that side. That’s what mine did, it was like that when I bought it actually, it was the first automotive repair I ever did by myself. The “don’t do” I learned from that one was that there is a specific type of grease for brakes, and if you use the wrong kind of grease it can result in the caliper bushing being melted into a tar-like mess.
I would focus on whether it happens only when moving. If it’s only while moving, that really makes it seem like something to do with the brakes or the wheel bearings, something right there at the wheels. If I didn’t already have a vacuum gauge installed where the clock was, I would run a long hose from a manifold vac to a mityvac inside the passenger compartment. If the manifold vacuum is steady when the vibration is happening, I would be comfortable ruling out anything to do with the engine at that point.
If you take off the front wheels you can get some pics of the rotors. And measure their thickness too. You can also try rattling the calipers around, and see how much play they have. I would think with that info, people here could do a bit of diagnostics
I noticed, in your list of items repaired, that the lower control arm ball joints are not listed. Since the problem persists when you are slowing down and braking…and with steering column vibration. Have you ever owned a FWD vehicle with bad front struts?..similar symptoms. This is based on the assumption that you have a manual transmission… and If it were not for the fact that this also occurs while “slowing down and braking”…I’d then be thinking axle bearings, pilot bushing, u-joint or pinion angle.
Do you have an export brace installed? Lower front bar with the welded pieces too? I had a vibration around 45 MPH and it sooo much better now since I just did this install a few days ago. It was not easy to get the export brace but I got it there with some help from a buddy.
I also just got new styled steel wheels and new BFG radial TAs. Love them too.
Just a thought.
TomSwede - The wheel bearings were replaced with new ones and repacked. I’ll have to check into an anti-rattle kit though. I’m not sure about where the rubber insulators are located.
tmh - My dad hung his head out both sides of the car to listen for any noises and we couldn’t hear any chatter or localized sounds coming from any direction. The vibration only happen when driving and usually kicks in around 45-65 mph. I’m not sure where manifold vac connection is, but I do know there are two on the Edlebrock carburetor. There does seem to be a slight loss in power when the vibration occurs. I’ll see what I can do about getting some rotor pics and measurements too.
67.5xr7 - The ball joints were included with the replacement of the lower A-arms. It seemed just like an issue with the struts being bad and vibrating like that, but we replaced the struts and it didn’t change anything. The car is an automatic and the issue occurs when accelerating and/or braking or even just holding speed. I’ll have to do more research on the pilot bushing too.
sweetair - I’m not aware of any export brace being installed. It was pretty much stock when I bought it. Unfortunately, I don’t have a way to verify if the front rims are good, but I figure Discount Tires would have told me if there was a problem during the rebalance.
Looks like I have lots of things to check out and I’ll update this post when I get more information.
sixty8cougar, if you look at the link i posted, black rubber insulators.
Remove the wheel grab the brake caliber and move it forward and back in and out. If you hear clonking noise the rubber insulators for the brake calipers is worn out, you would hardly be able to move the caliper at all if the insulatorns is ok.
The insulators is fitted with the bolts creating the calipers to float, so the pads wear equals both sides.
Edit: If your brake hoses is old it could be that they are swollen internally and creating/acts like a check valve when braking and not letting the brake fluid back to the master brake cylinder when you step of the brakes.
I have finally gotten away from work enough to get back to my car and the forum with an update. I replaced the one brake hose that looked quite worn in fear of it acting like the check valve as posted by tomswede. I had to take it to brakesplus to get the fitting fixed so that it would seat correctly from the brake line into the hose. Only the front passenger hose looked bad at all. The front passenger looked like it had been replaced a few years ago and the rear brakes are drum brakes. I also went and bought new calipers and all of the hardware that had the rubber insulators and anti rattle kit, but the car still shakes violently and sometimes smells like brakes. I was hoping the anti rattle kit and the hose would fix it. My brakes also will NOT release properly. I replaced the brake-booster and the master cylinder about 2 years ago and now the calipers and pads and the bad hose. What else could be causing them to not release? Today I got my new rotors (slotted and drilled ) and another set of pads for these rotors. I was going to replace the rotors and pads today but realized the brakes dragging is still an issue. And is there anyway the heavy vibration could be coming simply from non completely releasing brakes? I can still turn the rotor, but certainly not with ease it is a tough struggle. Supposedly brakesplus bled my brakes when they did the lines. Is the brakes not releasing due to them simply not being bled thoroughly? I’m simply out of ideas on all of this. I noticed the brakes smell only once or twice before when it shook but not the rest of the shaking times. But now it stinks like brakes with nearly every drive whether it shakes or not even on the 7 mile drive to work.
If the rotors are warped wouldn’t that lead to the brakes not fully disengaging? Sorta pulsating, like what happens with a warped bicycle tire knocking the break pad in one spot every time it spins around?
Check the length of the adjustable rod between the master cylinder & the power brake booster. My car 68 XR7 390 X code was doing much of the same. The rod was adjusted to long the brakes then got to hot and expanded the frond end would shake violently.
cougarrand
I replaced the rotors and will certainly check that rod. I was unaware that there was an adjustable rod it certainly sounds like it may be the issue! For that adjusting rod, is it internal then? inside between the master cylinder and the brake booster? Or would it be the rod that goes from the brakebooster through the firewall to the brakepedal? How is it adjusted? Should a mechanic do it or is it easily adjustable for a DIY job to get it done correctly?
Also (likely unrelated but worth mentioning) 2 days ago I had difficulty going up hills at 50 mph. It acted more like a fuel issue and has happened none of the other times than 2 days ago and today. I would be at 50 going up a hill and the car would bog down to 40 and it would sound low and then would sorta pulsate from pushing me back in my seat to losing its power and letting me fall forward again. it was at about 2 seconds of being pushed back then 2 seconds of power loss and it did the bucking front to back power issue. My fuel filter was nasty 2 days ago so I figured the fuel was just having trouble since it was quite nasty. However it did it again today and the fuel filter is clear.
You can find the instructions for the rod adjustment in the 68 repair manual. There is a template to use to adjust the rod. I made mine out of stiff piece of cardboard. You will find the rod by taking off the master cylinder from the power break booster. It is between the two parts.
) and another set of pads for these rotors. I was going to replace the rotors and pads today but realized the brakes dragging is still an issue. And is there anyway the heavy vibration could be coming simply from non completely releasing brakes? I can still turn the rotor, but certainly not with ease it is a tough struggle. Supposedly brakesplus bled my brakes when they did the lines. Is the brakes not releasing due to them simply not being bled thoroughly? I’m simply out of ideas on all of this. I noticed the brakes smell only once or twice before when it shook but not the rest of the shaking times. But now it stinks like brakes with nearly every drive whether it shakes or not even on the 7 mile drive to work.