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What's the Diff? Struts VS Shocks


Jackofalltradez's Avatar
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09-27-02, 10:31 AM   #1  
What's the Diff? Struts VS Shocks

Oops! Just realized that's the name of a 70s sitcom. But seriously, I have a hard time differentiating between how the two devices do the same job.

All I know is I had the rear struts replaced on my Contour, and the rear end is calmer, quieter, and the whole car rolls much longer and smoother.

thanks,

Jack

 
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09-27-02, 11:14 AM   #2  
Joe_F
A strut generally encompasses the spring with it (but is removable).

A shock is just a piston type valve and the spring is not encompassed by it.

For instance, my Saturn has front and rear struts. You use a spring compressor to hold the spring while you take the strut out (off the car).

My 84 Olds 88 and my 79 and 80 Trans Ams have shocks all the way around. A couple of bolts and they are out on the floor.

15 minutes on the old timers, one hour each on the Saturn.

Some cars have a combination (struts and shocks). My 89 Cavalier is such a vehicle. My friend's 1991 Dodge Shadow is another combo type car.

They serve the same purpose. The struts are more "responsive" being that the spring is encompassed in it and on a shock, the spring is located elsewhere in the suspension.

Does that help?

 
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09-27-02, 01:41 PM   #3  
Excellent. I also read somewhere that the intent of struts was to provide a "cushy" yet at same time firm ride in the waves of smaller cars coming from both Detroit and Japan in the 80s and 90s. This had to do something with less travel room?? for shocks in the smaller wells of these smaller vehicles??

-Jack

 
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09-27-02, 08:46 PM   #4  
Joe_F
Sure.

Less parts, "easier" to manufacture since most FWD cars are unibody (a few were body on frame), and a tighter ride in most cases. Also, in theory, less to "wear out".

If you look at a 3rd generation (82 to 92) Firebird or Camaro, you'll see struts in the front to my knowledge. But, the lower control arm actually has slots where a shock would go .

I can remember the dealer showing my dad the 1982 T/A pics in late 1980 when we were buying our 80 Turbo.

The dealer bragged about the new one having MacPherson struts, etc, etc.

My dad rolled his eyes and said, "I'll take that orange 1980 Trans Am instead".

Nice and old school

 
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09-28-02, 08:13 PM   #5  
knuckles
3rd Gen. F-bodies as well as Fox bodied Fords use what's called a "modified strut". The coil spring is located between the lower control arm and the frame. The strut attaches to the steering knuckle & the body of the car.

This system is less complicated (read cheaper to build) than a conventional SLA suspension, but not as cheap as a MacPherson Strut suspension. The upper control arm is eliminated, saving money & installation time during manufacture.

Replacing modified struts takes about 10 min. longer than replacing conventional shocks, but you'll need an alignment when you're done.

 
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10-01-02, 11:10 AM   #6  
Very Strange

Early Sep: Check & adjust tire pressure acc to Ford Contour sticker on door - psi 31Front, 34Rear.

Sept. 23: Check pressure because temps have cooled. Set to specs.

Sept. 26: Have rear struts/mounts replaced. I test car and ride and alignment are on point.

Sept. 30(yesterday): Checked tires again because they looked suspiciously low. Fronts were 30(morning was cool), but here's the weird thing: Rears were both exactly 31psi!! That's a drop of 3 pounds (which would result if the AM temperature went down 30 degrees!! And it sure wasn't 25 Fahrenheit yesterday AM - it was 60)

Judgement: Strut garage definitely lowered rear tire pressure, but why??

So I adjusted tires properly and the ride on this Europe-bred baby could not be schweeter!

But why the deflation by the strut place??

-JoaT

 
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10-01-02, 12:28 PM   #7  
Joe_F
Who knows why.....just fill 'em up to spec and go from there. If they leak, have it rectified.

 
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10-01-02, 01:26 PM   #8  
redneck
You had the struts replaced on a independent suspension car and did not have it aligned? A "test drive" will not tell you anything. Watch your tire wear closely as the miles pile up--I would bet $ that it needs an alignment!

 
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10-01-02, 01:55 PM   #9  
Of course a 4wh alignment was performed, and indicated by item on the invoice! I'm particularly anal retentive about so much as a hair of pull to one side and would have made a huge scene if it was at all off. Independent strut work without alignment? That's like landing a jumbo without gear down. (LOL)

What I'm concerned about here is why the garage took air out of the rear tires. I'm sure they both didn't suddenly develop leaks over last weekend(JoeF).

 
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10-01-02, 08:39 PM   #10  
Alignment:step 1 check for worn,bent,damaged or misaligned component in steering and suspension/repair as required. Step 2 check air pressure and inflate to manufacturers specs.Step 3 entails step 2 check ride height(if tires are low ride height is affected)repair ride height.Step 4 align vehicle to manufacturers specs.If above are not followed alignment may not be correct.I have aligned cars and trucks for 25 years this is and will be my policy on alignments.So if you think they altered your air pressure have them recheck your alignment,be there and watch,if need be from outside the garage.You may be ok 3 psi isn't a lot.

 
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10-02-02, 02:29 PM   #11  
That will be FINE!!!

I think the strut place knows how to perform alignments, but I do appreciate the step-by-step.

It was the technician, not the owner who I paid the bill to, who took the car for a test drive. So it is possible that depending on how many miles the tech road tested the car, that the tire pressures probably went up due to heat, maybe even to 37 or 38 psi.

Because he needed spec height then and there, he probably bled the rears(and rears only since no work was done on fronts) to get the 34psi he needed to properly adjust the car.

Now that's 34psi of relatively HOT air, which would explain why, when the tires cooled off, they only tested 31psi! Not to mention it was 70 degrees out the day of the repairs, and only 50 Monday morning.

Case solved.


(whew....)I shoulda' been a detective.

-Jack

 
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