The steering wheel shakes when I'm going at about 55mph. It doesn't shake or vibrate when i'm driving slower or faster just right around 55 in any gear. Any ideas or suggestions? Thanks.

 

Sounds like you your car might have a slight alignment issue and is causing the tires to wear unevenly. I had this problem a long while back and it was due to the Z pulling to the right and wearing the inside of the tread. The vibration was noticeable at 60mph for me.

John 82ZXT

 

First, check the balance on your wheels, both front and back.

If that's not it, have the alignment checked.

If these are good, it may be a bad tire. If a belt is separated in the tire, it will give inconsistent balance results and will start shaking again shortly after the balance.

 

Yes that was most of my vibration problem a while back. Even after my tires were balanced the vibration was still there. Then I decided to have my tires rotated front to back. The steering vibration was gone so I knew the messed up tire was on the back now. (later I got new wheels and tires) Also, my brake rotors were warped a little. After they were resurfaced, the warp wasn't fixed. Had to repalce those.

 

This goes for everyone and I should probably post it to a broader forum.

You should NEVER have your rotors re-surfaced! This is an old solution to an old problem that doesn't exist anymore. Back when new drums and rotors were WAY more expensive, this was a viable option.

First, you'll find out the cost of a new rotor is about $10 more than the $50 to $70 they'll want to charge you for the 're-surface'. Brembo replacment front rotors from TireRack.com for the 280ZX are $48/ea. Rear rotors are only $31/ea.!

Second, you'll remove the superior temper from the outside of the rotor which will increase the probability of warping it again. This guarantees the shop will see more of your business.

Thirdly, even if you ran your brakes down to the rivets and cut a groove in your rotor (like I did), as long as the thickness of the rotor from the bottom of the groove is within spec, there's no need to thin out the rest of the rotor to match it. This will greatly reduce the mass in the rotor and it's cooling capacity, again, greatly increasing the probability of warping it REAL soon also guaranteeing the shop will see more of your business.

The whole 're-surfacing' business is a farce that's been going on so long, many(most) shops and tech's believe it's true.

As an anecdote, about three years ago I got into a heated 'discussion' with a dealer 'technician' at a dealership that wanted to resurface my rotors. When I told him I didn't want them re-surfaced, I just wanted new pads installed, he replied that it was a safety issue and therefore required by the manufacturer and that he couldn't release the car to me unless it was done.

The service manager was out all morning and wasn't available.

He stood fast in his position.

That's when I kindly told him I would rather have new rotors installed than re-surface my old ones and that I wanted three things when I came to pick the car up:

1. I wanted him to save my old rotors
2. I wanted to speak to the service manager when I arrived
3. I wanted him to show me where in the factory service manual it was required

About 4 hours later, I got a call to let me know the work was completed and an apology for the mistake and wanting to know what they could do to make it up to me.

I asked him how much it would cost to have the new rotors removed and the old rotors re-installed ($250 at dealership rates). I told him I wanted $230 off my service, which he grudgingly agreed. So, for $20 I got new rotors and I have my old rotors I can put back on for when these need replaced!

Fortunately, my job has slowed down considerably and I have time to do this work myself so I won't have to "out-source" this work anymore!

Cheers,
LWW

 

hahha..
anyways i also had the shakes long ago untill i replaced my tie-rod ends.
so might check those for play too.

 

Hmmm... interesting. All the shops around here will turn rotors for $10-12 each if you remove them and bring them in. That's what I had done because it was so cheap. My new slotted rotors were only $60 each for the front.

 

Wow, It's amazing how so many people who aren't in the busniess "seem" to know so much about it... Some of your argument against resurfacing rotors is true, but only slightly. First off, many newer European cars (and a few domestics) have gone to what is known as a "composite" brake rotor. THese rotors are not machineable due to the various metal content in them. That content is intended to be softer and more heat resistant than a standard steel rotor and thereby, they wear much faster. The various automakers will be the first to tell you that these rotors Must Not Be Machined! In many cases thes soft composite rotors wear out faster than the actual brake pads. In the case of the 280zx, the factory rotors as well as virtually all of the aftermarket rotors are steel. They are given a minimum thickness tolerance before warping is imminient. The thinner the rotor gets, the less heat it can disiopate... therby encouraging warpage. However, it is not only acceptable to machine them, it is absoulutely necassary if the rotor is not perfectly flat and true (without measurable run-out) upon installation of new pads. If, as you say "even if you worn the pads to the rivets..." Only a complete fool would put a brand new set of pads against a grooved rotor. Soon, that groove in the rotor will make an opposite groove in your new pads... and in the meantime, you will not have anywhere near a reasonably good mating surface between the two. That means simply that by lessing the contact area between pad and rotor you A. have less material meeting to stop the car, B. will prematurely wera the new pads, and C. create hot spots and further warping to an already damaged rotor... which can lead to cracking... even breakage in extreme scenarios. Finally as for installing a new rotor... Even that rotor needs to be checked for run-out and machined if necassary before installation. Most of these rotors (even Brembos) are machined prior to shipping to U.S., But, if they are stacked incorrectly during shipping or even place improperly on a store shelf for any period of time, THEY WILL BE WARPED! So, while I don't encourage over-paying you local repair shop... please be educated enough to do the right thing when it comes to your brakes.

Rod.

 

Wow. Two really good arguments. I didn't know there was such debate on this ... I've only turned drums or had mine resurfaced, but I've always bought new rotors - of course, every rotor I've bought was an aftermarket upgrade

Just as long as nobody tries to resurface a slotted or cross-drilled rotor (I can see the mechanics of that disaster ...)

 

Just a couple more cents worth... Cross drilled or slotted rotors are also machineable with the right lathe bit. They are also more likely than a solid rotor to warp. A "dimpled" or just "slotted" rotor is preferable to a cross drilled rotor because they allow for the gases that build between the pad and rotor a place escape... therby greatly reducing brake fade. Cross drilled rotors (although the look really cool!) tend to cool faster immediately surrounding the holes than they do on the solid parts. So much so, that they create hot-spots near the holes (changes in composition), that ultimately result in pulsation (vibration through the steering wheel or brake pedal upon braking).

Rod.

 

Fortunately, we're not talking about European or domestic cars with composite rotors on this board and, fortunately, I know what "composite" means. I may have inappropriately assumed the readers would understand I was referring to steel rotors.

Agreed

Uhh... Isn't that by definition warped?

You got me... I agree, if it's seriously grooved, it's definitely a bad/dangerous thing. I was speaking, although not very clearly, of a slight groove that is the result of slight rivet contact. If you drive it for an extended period on that rivet the damage will create a safety issue, it's better to replace the rotor. If it's within spec, then you can resurface it, but I was advocating replacement because I believe the additional removal of material from resurfacing is worse.

Thank you for your input. When I'm wrong I try to admit it as soon as I can overcome my id. In this case, I don't believe I was wrong, since you kind of agreed with me until you told me I was wrong... sorta...

When in doubt, be safe.

Cheers,
LWW

P.S.
You're right, I'm not in the auto industry except as a consumer, but a significant portion of my immediate family is and I didn't mention my cousin has been a Materials Engineer / Metalurgist for GM in Detriot for the last 10 or so years. This is where I obtained my information, although it is second hand and has the potential for error, I think your salient points confirm my original conclusion.

 

Sorry IWW,
I didn't mean to sound condescening... You make some interesting points. When I read the line "you should never have your rotors resurfaced" I had to reply with what I know from 17 years in the business to be the truth about brake rotors. I was also trying in a way to help you make your point when it comes to certain types of rotors or in certain situations that don't allow for resurfacing. I think what upset me was the implication that the business of resurfacing rotors was a scam. Contrary to popular belief... not all shops are out to screw everyone that walks through the doors. However, it is also true that some do... and, that not everyone in the industry is well educated in their field. I know plenty of crooks and/or morons that do what I do for a living. Simply opting for a new rotor when the old one is thin, or warped, or grooved however, is not the answer. As I stated... even the best new brake rotors are more often than not, somewhat warped right out of the box. I stock about 200 brake rotors in my shop, all of which are high quality (usually brembo or the equivalant), and all are sworn by the manufacturer to be "true" upon removal from the box. In a perfect world, I suppose they would be. But, by the time they get to me, 9 out of 10 need to be machined slightly to correct run-out. All of these rotors are factory machined before shipping, and most need to be re-machined before installation. I notify my customers of this going in. I let them know that the minimum of surface loss was needed to make sure that they would not experience rotor related vibration in their cars. From time to time, I get Mr. back-yard-mechanic-know-it-all in here telling me that that is simply not acceptable, and against my better judgement, we put new rotors in without machining them. This almost always ends up with the customer coming back with a problem that I told them would occur, and now one of my technicians has to spend part of their day re-doing work for free (and not getting paid for it) to apease that customer and correct the problem. I guess my point is, that sweeping generalizations are never correct in every situation. I appreciate what you were saying, and I know you were trying to help other drivers to not get ripped off... Point well taken. I just wanted to put the whole enchilada on the plate before we all said grace... Sorry again if I sounded condescending. I hope all is cleared up.

Rod.

 

uuuh... I've never heard of turning new rotors. I also thought that I couldn't turn my slotted rotors. I installed them new and they seem fine so I guess those were ok.

 

Dude, no sweat. Like I said, you made some good points and clarified some of the muddy water I left laying around. Your direct experience in the 'biz' combined with your sincerity is appreciated and gives your observations merit.

Like I've said in other posts, when I'm wrong, I want to know about it so I can get my shiite straight!

Cheers,
LWW