Unobtanium254

Greetings, all,

I've got a bad right rear F55 shock -- a definite leaker. I have my 2003 50th Annie convertible up on jack stands, and removed both rear shocks. The bad one is definitely trashed; you can barely compress it, and it was filthy with new and old oil.

The other shock still looks fine. Underneath the boot, the piston is clean, there is no oil or grease, and just a little bit of dust on the inside of the boot.

I also inspected the 2 front shocks, without removing them. Both still look good, too.

Some car history:
The car is 11 years old, and only has 38,000 mi. I'm the 2nd owner and bought it when it had 21,000 miles. It's not my daily driver. I also don't race or abuse the car. I like to drive it in the Texas Hill Country on winding roads where its great handling makes it fun to drive. I don't recall hitting any pot holes crazy hard (although our urban roads in San Antonio really suck).

So, the car is not abused in any way. Conversely, could this leaking shock have been from a LACK of driving?

Given the car's history, and the shocks age and mileage, should I:

A.) Just replace the bad right rear, and re-install the left rear?
B.) Replace the bad right rear and the good left rear (the theory being that you need to replace in pairs -- but I don't really know if you have to or not).
C.) Replace all 4 because once one goes, the others are not far behind.

BTW, I do plan to replace with new F55's to keep it original and avoid having to re-program the car.

Any thoughts or opinions or experiences are much appreciated !
Thanks !

U

Smoken1

Replace at least both rear but thats just my 2cents

bjones7131

I agree with 8vettez

Smoken1

I have an 02 and dumped my F45's to go with the C6 Z06 shocks. The ride is MUCH BETTER and alot more comfortable on short and long drives

Unobtanium254

Thanks for the responses, all.

Let's narrow this down a bit. I like the performance and ride of my factory equipment F55 shocks, so I do intend on replacing in-kind.

Yep, I know they're ridiculously expensive, but that's not an issue for me. The wife says I'm ridiculous and expensive, anyway.

BTW, I can get new F55 rears for $488.23 at gmpartsdirect.com, and for $633.76 at gmpartshouse.com.

I've convinced myself NOT to replace the 2 good fronts, as it it is not all that difficult to jack up the car and remove the shocks, so I can do that in the future, if needed.

So, I've narrowed it down to:

A) Replace only the bad right rear
B) Replace both the back shocks in a pair (and either keep or sell the older good one.)

Smoken1 responded to replace the pair, (thanx, Smoken) and that was my first thought, too, but if anyone has comments about long term reliability history of these F55's, I'd like to hear them. I'm a big believer of "If It Ain't Broke, Don't Fix It", and would tend to leave the left rear shock on there, but if the new ones perform "differently" than the old ones, then replacement in pairs makes sense.

Thanks again, gang!
Unobtanium

racebum

judgement call. back when i worked in a shop. if a car came in with one leaking shock it left with one new shock unless the customer wanted both or all 4 repaired

Unobtanium254

Ooops....sorry. Just noticed that 8Vette7 also advised to replace both, if I'm going to stay with the F55's.

So we got 2 "votes" for replacing the pair, plus my original gut feel to do the same.

Any other thoughts?

Thanks again !

Un-Ob

Unobtanium254

Thanks Racebum! Appreciate the response.

Now we've got one vote for just replacing the bad one.

Decisions, decisions.

BTW, this was my first intensive weekend with my car up on jack stands since I've owned it. I used the Corvette Forum to build my wooden ramps and load lifting crossbeams, and also saw the procedure to remove shocks. All of this really made the job a lot easier.

I just hope someday I can contribute back to the Forum with as much as I've learned !!

Cliff8928

For what it's worth, RockAuto has rear F55 shocks advertised for $477 each. They don't list the fronts for some reason.

I would think the MagneRide shocks would be fairly resilient if there are no leaks. If i had them, I'd probably just replace them both, but keep the good one on the shelf.

racebum

it's half a vote. i replace shocks on my own cars at 10 years of age, all 4, regardless.

i'm just saying in most auto repair environments replacing one is very common

JrRifleCoach

Consider replacing shocks like you do tires.
One rear worn/damaged? Replace both.

All four 10 years old with 38k miles? Replace all four.
Enjoy your new found ride

RBbugBITme

There is no need to replace the good shock. You're not matching their curves on a dyno so there is no point.

etekberg

If it were me, I'd replace all 4. But I'd also ditch the F45.

Unobtanium254

Hey guys,

Thanks for all the helpful responses. I've decided to buy 2 new F55 shocks for the rear, and keep the old good one "just in case".

Once I get them in hand and replace them, I'll give you a report on how they work.

As I removed the right rear, the electrical connector at the top of the shock also was cracked and the plastic was quite brittle, so I'm replacing that component too. The grainyness (graininess?) of the fracture surface makes this look like a particulate-reinforced plastic. They often use tiny silica ("industrial sand") particles to strengthen injection molded plastics.

You'll see the fractures from 6:30 to 8:30, and from 10:30 to 12, plus a single crack at 4:00. I guess the metal spring clip held the piece to the top of topof the shock.

I'm a materials engineer, and you wouldn't think this plastic would embrittle so badly, since it's shielded from the sun and UV rays, and here in Texas has never seen salt or road chemicals of any kind. Sheesh.

Happy Labor Day to all !
UnOb

RBbugBITme

Replace the one bad one and then go for a drive. Then replace the good one if you feel the need, otherwise return it.

Corvette_Ed

For the cost of replacing one shock the OP can buy a whole brand new set of Bilstein or comparable high performance shocks, have the F55 tuned out of the PCM, and never have to worry about them again.

JrRifleCoach

Would you also recommend to replace one piston if that cylinder is low on compression?

RBbugBITme

By your logic then all 4 shocks should be replaced. Most people would recognize that that makes no sense. Like I said before, these shocks are not being dyno matched. So you don't even know what your starting point is on the old shock or the new shock. You're just throwing money at something you know works well from the feeling the driver has. But if after replacing one bad one, you notice the other doesn't feel right either then replace the other one too.

Corvette_Ed

The shocks are over a decade old. The new shock will have a higher ride height and react differently during use than a worn shock would; this is a 100% certainty so yes, you do know well enough what the starting point is. This is why you replace both of them.

RBbugBITme

Shocks don't determine ride height.