C4 full front suspension rebuild and lowering kit

[69MyWay]

This thread will contain some usefull info for anybody considering a full front suspension rebuild.

I ordered a set of new poly bushings from VB&P, new bilstein shocks, I am getting new ball joints, wheel bearings, and converting up to 13" front rotors and stainless braided brake line.

The first pic here is what you usually see when the wheels come off, before you start the job.

First jack the car up really high and support it. I suggest throwing the tires and wheels under the car to support it incase you knock it off the jack stands while hammering around under there.

 

[69MyWay]

Now, removed the caliper, brake hose, anti lock brake sensor and wire, disconnect the upper sway bar mount, and remove the rotor. You can also go ahead and remove the shock.

 

[69MyWay]

Now removed the spindle by supporting the lower a frame with your rolling jack, remove the aluminum suppor that goes on the lower X member where the spring comes out of the frame, pull the pin and loosen the castle nut on the lower a frame ball joint. A ball joint fork works well here to snap it apart. Remove the upper splash shield from the inner fender and now you can grab the two 18mm nuts that hold the upper a frame to the car. Remove the nuts, slide the a frame out, and keep the shims in together as you will want to put them back the way they came out to drive it up to the alignment shop.

 

[69MyWay]

Now you are ready to yank the spring.

It is held in with four 15mm nuts that are part of long studs that have 13mm heads on them coming down through the frame. After you remove these nuts, wiggle and jiggle, and the spring will work out the open hole.

 

[69MyWay]

Ahhhhh, nice fresh front spring (actually I just cleaned the old one up). The spring looked great, no fractures, no splinters, and nothing unusual.

Now, for the lowering kit I will be shaving the upper part off the spring mount. This will raise the spring in the housing effectively lowering the whole car.

 

[69MyWay]

Now for the real fun stuff.

Pressing the old bushings out is a real pain no matter what you do (for the shade tree mechanic like myself). There are a number of ways: burn them out, drill them out, press them out, hammer them out, cuss them out (oops, that last one does not work).

I get creative as possible with all my tools. In the next picture you will see a gear puller that I have fashioned unto the bushing and am pressing it. It worked rather well. I have a 50,000 ton press in the shop, but the a frames are too akward to fit in the press.

You have to remove the ball joint in the press, drill and grind out the studs in the upper a frame ball joint, and press all these bushings.

 

[69MyWay]

You clean freaks will love this. I always pretty much thought the front suspension in this car looked pretty clean. Boy was I wrong. In this next pic you will see the passenger side parts all scrubbed up and ready to go in comparison with the left side.

Now, I first scrape off any excess goo, then I simply use warm water, a scotch brite pad, and plenty of dish soap to gently scrub the aluminum clean and fresh.

 

[69MyWay]

I ran out of time tonight and my back is killing me from lifting the transmission up earlier in the day.

Later I will press out all the bushings in the driver side, clean those parts, then reassemble.

The lowering kit ($30) included longer studs for the rear spring. When the car goes back together I will adjust the rear spring studs to get the perfect stance considering how the front will be sucking the road. I will take some after pictures as I have plenty before. The difference should be stunning.

 

[geekinavette]

Great stuff...keep it comin!

I'm hoping to "refresh" my '84 suspension, front and rear, this winter, IF I can convince the wife to spend x-mas money on the Vette (in addition to the engine rebuild).

What is VB&P? Do the prices compare with what Eckler's sells for suspension parts?

Thanks!

Bill

 

[Ken]

I have a 50,000 ton press in the shop...

I don't know squat about presses, but is that number realistic? You have the equivalent of the "largest forging press in the free world, the Loewy 50,000 ton press"? :confused

_ken

 

[69MyWay]

I don't know squat about presses, but is that number realistic? You have the equivalent of the "largest forging press in the free world, the Loewy 50,000 ton press"? :confused

_ken

Oooops, I stand corrected. It is only a whimpy 50 ton (I was thinking pounds tons, you know.......)

 

[Ken]

:L Sorry to be nit-picking, maybe I shoulda communicated in private eh?

 

[vms4evr]

Awesome Chris! I've been thinking about redoing the front end with all new ball joints, tie rods, etc. and poly bushings. I think I follow what you're doing but I also think you've convinced me not to do it myself. I've never gone beyond simply replacing shocks...

Great article though.

Graham

 

[69MyWay]

:L Sorry to be nit-picking, maybe I shoulda communicated in private eh?

Pick all you like, just keep the nit to a minimum :J

I was just taking a shower and realized what I meant to say anyway. If 2,000 lbs = 1 ton, then a 50 ton press would be 100,000 lbs of pressure....right? So, I got the 100,000 mixed up with the 50, and ta da! = 50,000. Of course, if you really believe that, then I should have come up with 500,000 ton press. Now that would be schweeeet.

 

[69MyWay]

Here is a pic showing how to remove the upper ball joint. I first center punched the rivet, then drilled the rivet out. This is a pain in the butt, however it yields quick quality results with a good sharp drill bit and a straight drive angle.

 

[69MyWay]

This next pic shows the stock front spring mount. In order to install the lowering wedge, I have to first cut off the upper portion of this mount. To gain another 1/4" to 1/2" after the 1" gained from the wedges, I will also discard the stock aluminum spacer that goes above this in the spring mount. This sucker is going to be low and tight.

 

[69MyWay]

This picture shows the VB&P lowering wedges now attached to the spring.

I must say that one of the most difficult parts of doing this job is cutting the stock rubber mount off the spring. You must be very careful not to knick, scrape, gouge the spring. However, a little scratch here or there is going to happen no matter what you do as you have to use extreme measures to get the old rubber off.

I have found a mitre box saw works very well. You can wrap duct tape around the bare spring and put the mitre saw on the horizontal plain of the spring and hand saw the majority off. Then, with a 60 grit grinding disc and a very careful hand you can basically shave the remaining rubber down to a micro thin layer. Then you can scrape, clean, etc. At that point you glue the lowering wedges on to the spring, and tape them in place so that the glue will set. After they are secure, you are now ready to slide it into the car.

Like I said before, I not only went with the lowering blocks, but I also yanked the aluminum shim plates to gain as much as 1.5" in drop.

 

[JT ZR-Won]

Chris,
Awesome write up! Very well documented. This procedure looks all to familiar. Fortunately I didn't have to replace any bushings but lowering the front was not fun. I remember jacking the car so far of the ground I thought it was going to fly away

I know there were two different front springs put in C4's. The "soft" spring and the "stiff" spring. I know my ZR-1 has the stiffer of the two. I have an old Corvette Fever article that explains step by step how to lower the front of a C4. The guy who wrote the article mentioned something interesting. He said that you might want to consider shaving the rubber underneath the spring on the very end of the spring. If you're going for the "slammed" look this little tip will do it. On my ZR-1 we didn't do this only because this was the first C4 I ever lowered the front on and we weren't sure how low it would make the car. After we completed the job, I now wish I would have shaved the ends of the spring. My car sits very nicely now but I think we could have dropped it another quarter inch in the front.

A few months later we dropped the front of my friends '96 CE and shaved the ends of the front spring. I believe his car had the "soft" spring. His car also had the look I was trying to achieve in the front. The only is I can't remember how we determined the which spring we had........I might go by year of the vehicle. Looking forward to reading the rest of the progress!

Jay

 

[69MyWay]

Just got back from the store

New front upper and lower ball joints and new front hub bearings.......$650!!!!!!!!!!!!!!!!!!!!!!

Updates and pics coming soon.

 

[69MyWay]

Okay, here is the newly rebuilt front suspension. What you are looking at here is:

1. new poly bushings complete
2. new Bilstien shocks
3. new wheel bearing hubs
4. new upper and lower ball joint
5. lowering wedges installed
6. Everything cleaned and detailed
7. coming soon, 13" rotors and calipers with stainless braided lines.

Looks nice, don't you think?