Good Afternoon All,

I know there have been many, many threads on jacking C3s. While I've read every one of the threads that I could find, I didn't see anything about jacking on the "Frame Crossmember over Axle" (see diagram below). My spare tire assembly is currently removed, making the Frame Crossmember over Axle look like a great option. Is it acceptable to jack the vehicle on?

Thanks

 

 

 

Are you talking about this one marked "Rear End Crossmember" that is above the differential that the diff mounts to?

 

Hugie82 is talking about the crossmember that's labelled as Frame Crossmember , I use the outer areas where the arrow points to "body mount" and "set 3" to get a jack under . that area ,on both sides is very strong as it is gusseted as well .

 

Thanks everyone for you help. My ultimate goal was to lift the car entirely off the ground, and then work on the brakes. In the end, I decided just to use the factory jacking points listed in the owner's manual. First, I opened all doors and the hood and closed them one notch. Then, using two jacks, I lifted the front end, little by little to keep it level, all while watching the effect on the body of the car. All looked good. Once up high enough, I put the front wheels on my lift stands.






Then I did the same thing to get the rears up on the lift stands.






While the car was entirely on the lift stands, I was able to lift the front end even higher, to make room to put the jack stands where the jack had been, by inserting a jack inside the lift stand (example pic below of me testing it on the rear end).









Once front end was on jack stands, I came back to the front brakes to work on them. I ended up finding out that I needed a part that was going to cause the car to be in the air longer than I had planned. I didn't want to leave the front end "hinging" on the jack stands that long, so I ended up taking a page out of the book of DUB and used my other jack stands to support the front end under the rotors.









I then took a floor jack and jacked slightly up on the front cross member, using a short piece of 2x4 to distribute the load a bit. I just lifted it enough to take a little weight off the jack stands. (Pic below of me testing the "fit" of the jack to the crossmember.)






This was my first attempt at lifting the car. I read so many conflicting threads and posts about jacking up on the front cross member, that I decided to do the side-by-side jacking method for the front (and ultimately the rear). Once under the car however, I saw that my crossmember appeared to have been jacked on in the past, so I think from now on, I'll lift the front end using the 2x4 on the crossmember to get the front end on the lift stands or jack stands. For the rear, I'll continue with the side-by-side method.

 

Seems like you have found a method to work for you.

Also..you are aware that if you were doing the brakes in the front.. You could have raised the front end and put the jack stands under the shock absorber mounted in your lower control arm, and then set the car down on those jack stands. and not have to have the jack stand under the frame where GM has stated it will work.

I will pick up a Corvette at the center of the front lower cradle area all day long and not think twice about it. No damage occurs to it due to the obviously I have a way of doing it so it will not get damaged.

I pick up the rear under the differential/spring area

On some cars I have to drive it up on the four pieces of wood I have to raise it up so if the car is low to the ground...I can easily slide my floor jack under it.

Jacking up a convertible at the #3 body mount area can cause the door gap to WIDEN when it is raised...so keep an eye on it. Which is why I raise it up by going under the rear differential/spring area.

AND to see how bad your convertible is in regards to fatigue.....raise you car up by going under the rear differential...then put your jack stands under the #3 body mount areas and lower the floor jack and see how WIDE your door gap begins to grow.

So many people who own these cars take the effort to do like what 'ZRXGreen' has done. And I can say that if a person is serious about this...sometimes taking the time and money to custom fabricate up the provisions to attach to the floor jack or protect the cradle is what is needed if the person is worried about that.

DUB

 

Thanks, DUB. Much of what I did today was guided by advice you had given me in the past. In fact, I also had to drive one of the front tires up onto a makeshift wood ramp, as one of my jacks is higher profile than the other, and would'nt make it under the frame.




I remembered you talking about putting the jackstands under the control arms at the shock mount. Just so I make no mistake--you are saying to put the jack stand where I drew it in the below pic, correct? It's OK to turn the wheel from stop to stop while it's supported like that?




Your advice to me about the body and door gaps were ringing in my ears, as I lifted it up using the sid-by-side method in the front. I went very slowly, and kept going back and forth checking. If I had seen anything amiss, I would have immediately stopped.

As far as lifting by the front cradle, once I saw that someone else had done so in the past, I was much less reluctant. Did you think the use of the 2x4 was correctly positioned and the right size?

Thanks again.

 

YES...the curve in the top of my jack stand can cradle the curve in the lower shock and I also use some old carpet pieces I have out of a C4 that has the mass backing on them so I do not damage the shock in its appearance if the shock is on a really nice car.

AS for using a piece of 2x3 like you did. that is up to you due to I am more afraid of it slipping off. I use the really dense black Styrofoam that they use in shipping now-a-days that you can darn near stand on and not compress easily. This can allow the saddle of your floor jack to be positioned so two teeth are at the back edge and the dense black foam will protect the other two teeth from denting the cradle..but yet still grip.

I have also made a fixture that can go on top of the saddle for my one floor jack and it conform to the bottom of the cradle and it is lined with some dense rubber and NOT the black Styrofoam I mentioned earlier. But also keep in mind I have driven the car up on my wood ramps to raise it so I have easy access to jacking it up from the front and rear.

Keep in mind I work on just about every level of Corvette you can imagine....some that are ultra sweet...and others that have seen better days. So it all depends on what Io am working on and if damage to areas has already occurred...then whatever I choose to do it not going to make it any worse.

So...if you have concerns...then possibly making special fixtures that make it so when you go to jack the car up...you are not worrying about dong any damage to it and you are safe in doing it may be required.

I could comment further on how I do things when jacking these cars up...but the back lash from those people who would just have to put their 2 cents in and not UNDERSTAND I know what I am doing...because if I screw something up...guess who has to fix it. So... I am going to keep my mouth shut. Simply because it is the inherent nature of some people comment when they have no clue nor considered any of other things that come into play and worry about the smallest of things.

DUB

 

ZRX...what brand stands are they that you're using?

 

They are made by Lift Stands, inc. http://myliftstand.com/

I first learned about them when caskiguy talked about how much he likes them and posted a picture of them in use here: https://www.corvetteforum.com/forums...-question.html (8th post in the thread).

 

Ah...thanks!

 

Thanks DUB. It's too bad that you've experienced pushback to the point that it keeps you from fully sharing your knowledge... and I get it. Like I said earlier about the best way to jack the front, I read a lot of conflicting viewpoints. In the end, all that did was help me make the best decision I could make, weighing the pros and cons of how I was going to move forward to solve my problem.

 

Never lift by the front crossmember as it is easily damaged and will require a special tool to try and repair the damage. Lots of people do as someone did on mine. Whatever you do Scott always practice safety first. It is the main reason I bought 4 stands ( I know they ain't cheap. Built by a guy in Kankakee area no less, his part time gig. )

 

Much appreciated, thanks!

 

In the illustration above...my question is.

What is keeping the rear clip from sagging with no jack stand after the number 3 body mount jack stand area??

With ALL the weight of fuel and the rear differential, spare tire, etc...on a convertible especially...this added weight puts a lot of strain on the lock pillar area and can GREATLY cause the gap at the door to widen.

Then couple that with aged frames with rust and this is what can cause for problems.

Even when I have a car up on my lift. I have my two safety stands under the car to provide support under the cradle and also the differential spring mount area so the front clip and rear clip do not sag. I just do not put the car up on the lift and let it sit there without the added support of my safety stands.

DUB

 

DUB, This from GM. I see it as a guide for those that want to "know" the proper Jack points for supporting the car during minor work while on the ground and off the ground. Now knowing ones vehicles frame condition is a added plus. I get what your saying but just knowing "where" to put the jack to change the tire or brake work is a good and safe thing to know.

 

I agree to a point. Changing a tire is one thing...and that is also suspect to problems....but doing extended service work is entirely another.

I get that this is a guide but It also shows where there are issues in what GM provided. Because following this 'guide' can also get a person in trouble if they are not paying attention and use this 'guide' as the be all and end all of areas to support the car.

DUB

 

Just predrill a couple of small holes on the fat area of the dolly and use a deck screw to secure. I modified the top with 2X4 to hold the frame as I worked on the front and rear suspension. When done just undo them and there ready again. Sorry I some how missed your request.