So my long neglected car got new brakes last week. The mechanic suggests I need new struts, an alignment, and new tires.
I believe it - the car has a wicked vibration above 55 miles/hr.
I asked if just getting an alignment would be of any value with the current bad struts in it. He said probably not. I think he may have been trying to get me to buy new struts rather than a simple $60 alignment. I told him I’d be putting it off until a different paycheck.
So - question to you auto folks - what’s the relationship between my car’s alignment and the struts. What the heck is a strut anyway?
By the way, the car is a 94 Mercury sable with 112K miles on it. It barely goes anywhere so I’m only putting a couple hundred miles a month on it. I think last year I did just under 4000 miles. I’m not too willing to toss a bunch of money at it. I just want to putter back-and-forth between the bus depot, the grocery store, and home.
What I’d like to do is put a $60 alignment into it and get the 4 tires for $100 deal from the local discount place and call it good.
Macpherson struts are basically shock absorbers; they’re part of the Macpherson suspension system. However, shock absorbers are just there to dampen…er, shocks; the load-bearing members are the springs. Struts, OTOH, have springs integrated, so they bear load AND dampen at the same time.
Since bad struts are going to encourage your car to bottom out and bob around, I’d replace 'em. They’re what, about $250?
There’s no sensation of bobbing and weaving right now. I’m aware of the old shock-absorber test where you jump off the rear bumper and watch the car bounce. Is there a similar test to see if my struts are still good?
Also, will the quality of my struts affect my tire alignment?
Yes, the quality of the struts can affect the alignment, among other things.
Worn struts are “bouncier” since they don’t do as good a job of damping the vibration and movement caused by hitting bumps in the road. This will cause your tires to move up and down more often and over a larger distance than they would if you had good, firm struts.
This movement can cause premature tire wear and mess up your alignment when the tires rebound back to the pavement.
Have a pal drive next to you on the highway, and have him look at the tires. If one or more tires is bouncing around wildly it is probably just a case of the tires needing balancing. $30. I can think of nothing associatiated with a strut that would cause a wicked vibration at high speed.
I suspect my tires are so badly worn from the alignment problem that they need replacement. The vibration feels like high-speed distortion of the tire itself but checking the tire weights is a good idea - I’ve thrown them off before.
Replacing the tires soon is necessary - just look at them to see that - but I don’t want to do that without getting an alignment or I’ll just ruin my new tires.
However, if the struts are so worn as to not make the alignment stick, then it’s just wasted money until the struts are replaced.
That’s why I was trying to find if the struts are really worn out and how dependent the tire alignment is on strut quality
I second NurseCarmen’s advice. Vibration at high speed is much more likely to be a matter of tire balance than than wheel alignment. As new tires normally are balanced during the mounting process, the vibration should reduce considerably.
To determine whether alignment is necessary:
– Does the car tend to ‘pull’ to one side or another when tracking down a straight road?
– Are any of the current (worn) tires worn unevenly? That is, worn on one side, cupped or scalloped patterns visible in the tread?
If the above conditions do not exist, there is no particular reason to realign the wheels.
Re: the front struts, they may be probably past their useful life if the car has more than 100K on it and they have never been replaced. OTOH, since you are putting only about 4K/year on the car, you have plenty of time to decide whether the expense is worth it.
I’d say go ahead and replace the tires if they are worn to the wear indicators; rebalance if not. Only do the other work if you expect to drive the car another 30K miles or more.