jmgtp

How long can the C4 suspension tolerate being fully extended without causing harm to stressed rubber bushings or shocks? My car is in winter storage and I have 2 things on my agenda, fixing a problem with the exhaust and replacing the Teflon washers. I only have a few hours each weekend to work, which over the course of the remainder of winter storage is ample time. However, that also means the car would reside on jack stands, suspension fully extended for probably 6-8 weeks. Am I asking for trouble? The rubber bushings are already showing their age with ample surface cracking and the current shocks (Monroe senselesstracs) are about 5 yrs old (replaced by previous owner). I’d like to see a few more seasons worth of use before replacing shocks and bushings.

Currently and in past years storage, the car has just sat parked in the garage. Every few weeks I check tire pressure and fill to max sidewall psi during storage.

Bobby Brewsky

YMMV

"We suggest that when people put their cars away for the winter months, they put the cars on stands and remove and bag the tires. This prevents any moisture from having harmful effects [on the tires]. Allowing the suspension to hang is really the least of their worries, and is not detrimental" said Dave Tillotson, Guldstrand's Operations Director.

http://www.corvetteactioncenter.com/...l#.UtbyQp5dXDs

zr1fred

Should be no problem to leave it on stands indefinitely.

jmgtp

Thanks guys, I guess I'm over thinking it a bit and a month or two in the air isnt going to make or break it. Have heard a lot of talk about blowing out shocks and ruining bushings but seems like a non issue.

WVZR-1

I'd have to disagree here I believe and I'd think it NOT wise to leave the suspension "just hanging" or "extended". Every component in the steering and suspension is engineered to be maintained in an "operational attitude". The tie rods, the tie rod ends, all ball joints, sway-bar bushings, shocks and all of the similar rear suspension components are now in a position that's "not intended".

Is there a reason that you can't/couldn't use the stands at the suspension locations? Rotate them to maybe a more desirable location when the maintenance procedure requires it.

volkswagens-for-life

I hang my snowmobiles up every single year so that the tracks are fully extended. Keeps the shocks, track, picks, and bogeys healthy.

Its actually preferred to leave the suspension hanging as opposed to compressed.

QCVette

Another vote for no problem.

The shock absorbers have a stop welded inside them to limit travel of the suspension and/or overextending the shocks. This should keep the suspension in a max drop condition that should not damage any components even though it is lower than a loaded at rest position. They are designed that way to avoid catastrophic failures in an extreme driving situation when the car takes a wheel off the ground.

If that weld inside the shock is bad, the suspension can hang very low and cause problems. When I was an engineer at a car assembly plant I worked with a shock manufacturer because their welds were failing and actually caused a vehicle line shut down because a weld broke and caused the wheel and suspension to hang too low so that it couldn't advance the line normally without lifting that wheel every time the line advanced. They were one of the first suppliers to cause a line stop and got charged back big money for the failure. I spent a few weeks at the supplier to get their process straightened out.

WVZR-1

You're assuming everything is in "optimal condition" - Are all shocks "created equal"? The OP also didn't mention that the wheels/tires were removed. Are they?

Not a "reasonable comparison" - a "tracked traction" piece of equipment not typical "control arm/sprung/shocked" piece of equipment. In an "operational attitude" the shock is neither compressed or extended fully.

Jack one up and just eye-ball the frame mounting bushings for the sway-bars and the new angles of everything. Way to many reasons NOT to than there can be arguments to just "let'r dangle"!

1991Z07

I had mine on the lift for 6 months...

It drives just fine. No problems.

Don't worry about it.

Of course...my bushings are all urethane and my entire rear end is heim-jointed (along with the front sway bar).

volkswagens-for-life

Well if the thugs in the city are comfortable enough to leave their vehicles on concrete blocks while changing tires, then thats good enough for me!

Just BOB

You are comparing apples to watermelons.

I haven't consulted the Corvette Factory Service Manual on this topic, but a number of GM and Ford FSMs that I have used in the past have specifically cautioned against torquing through bolts on conventional bushings without the full loaded weight on the vehicle. This is because the rubber bushing is bonded to the outer shell and the inner sleeve. Torquing the through bolt with the car at nominal ride height ensures that the bushing is not in torsional shear when the car is at rest. In contrast, torquing the bolts with the car on jackstands preloads shear in the bushings when the suspension is subsequently returned to normal ride height. Bushings preloaded in such a manner tend to creak and groan at cooler temperatures. Similarly, leaving a properly assembled suspension hanging for months or even weeks induces similar strains in the bonded joints in the bushing assembly and can lead to shortened bushing life.

MyOtherCar

[QUOTE=Bobby Brewsky;1585928653]YMMV

"We suggest that when people put their cars away for the winter months, they put the cars on stands and remove and bag the tires. This prevents any moisture from having harmful effects [on the tires]. Allowing the suspension to hang is really the least of their worries, and is not detrimental" said Dave Tillotson, Guldstrand's Operations Director.

so does this mean driving in the rain truly is bad for corvettes???

jmgtp

I wouldn't feel safe working under the car. If we had a solid rear axle that'd be a different story. But with the IRS and jack stands awkwardly placed on a loaded suspension I think it'd be risky.

jmgtp

So here is another thought. I've seen people use ratcheting tie downs to hunker down a lifted jeep suspension enough to clear a garage door frame. I have plenty of ratcheting tie downs. Would it be possible to have the C4 supported by jack stands and the suspension kept in compression using the tie downs? My only fear would be that one would let go when I am beneath the car working., that and it's on the side of redneck engineering that I try to stay away from.

volkswagens-for-life

Hell, I have a fear of working on any car on stands. If I dont have ramps, I dont feel safe.

Just BOB

When there is no way around using a stand, I always have multiple tires, wheels, cribbing or what ever that is at least two inches thicker than I am (Which is becoming an increasing challenge these days) under the car to catch it before it catches me!

volkswagens-for-life

I dont even feel safe using a jack plus 2 jack stands Thats the minimum I use when under a car.