LD85

Well, in short, it looks like the 1985 Rear Upper Mount is not the same as the later years, so I can't weld a washer onto the mount plate and move it, I am not surprised really.

And to top it all off you can see that the mount hole is offset towards the edge of the frame (towards teh car center) and there is a rolled up edge there that prevents you from mounting anything flat on that edge.

It looks like I will have to weld up a mount bracket that replicates the factory mount,, then cut the factory mount off, and weld the new bracket on becasue I can't see how you can get into the boxed frame to put a nut on the mount bolts.

Spoke with QA1 tech today, their big issue with C4's and Coilovers is they say the mounting bracketsare flimsy,, well, I can take care of that, probably will use .250" thick CRS like I did on the front CO tower.

For you guys that have done this mod on later years,,,, do the pics look similar to the later years, except for the shock mount?

ALL PICS BELOW ARE OF THE PASS SIDE SHOCK

Lichen

I won't comment on the Gabriels. But, on early C4's, it is usually the front shock mounts that need beefing up. Why do only the rears? Exotic Muscle sells the whole 4 corners for under $1000. Add some Bilstein sports (I think that they come with the package) and you will be planted and cornering like you never thought possible.

LD85

Gonna put the same QA1's on the rear, HAL-DR5855B with 275# springs, you have to move the bracket for the Coil Springs to clear, likie in the latter years.

Front mod from my sig
http://forums.corvetteforum.com/show...light=coilover

LD85

Here is a pic of the new spherical bearings that came today, this will help with the apparent misalignment on the shock loop.

You press out the Poly bushing, then press the bearing in and install a snap ring on the ID of the loop on both sides of the bearing. Part # QA1 EMB8-102pk

rklessdriver

Any standard Heim type end coil over would work in that top mount.

To fix the mis-alignment you could either move the shock forward in the mount with a spacer. If you can't move it forward enough with a spacer, I would cut the mount off the car (looks like 1 bolt and 1 spot weld) and move it forward until the coilover is strait and clear of the half shaft.

Alternativly instead of re using that huge factory shock mount I would call up an oval track supplier and buy 2 of their small pre made coil over shock mounts and weld or bolt them on the car...

Like these:

http://www.daymotorsports.com/product/25/SHOCK-MOUNTS

http://www.southwestspeed.com/?sec=v...Shock%20Mounts

http://www.ubmachine.com/shock.html

PN 35-3310 and 35-3325 from UB Machine would probally work best and look the cleanest.

Will

LD85

Tonight I cut the Towers off both sides. They are only @ .110" thick so we'll heli-arc weld .125" thick SS to the sides of each tower which will make them @ .245" thick,, then stick weld them back to the car hopefully tmorrow night.

Mo_Bandy

Hi Indy,

No that mount is not even close to the later years.

Where you cut out the mount there is a plate that has two bolts that the "shaft" bolts too, at least on my 96.

If you movforward of the original mount about 3/4 of an inch and reweld your mount you should clear the half shafts if you do not "slam" the car too low. The 96 mount at the top is centerd on the frame rail.

Mo

LD85

Thanks MO, it looks like the 84-87 is different than the later years,

also the rear uses the same shock as the front the QA1- DR4855P.

The extended and compressed length is virtually identical for the stock shock and the QA1 mentioned above.

Gonna weld the reinforced brackets on tomorrow night, then post some pics.

Mo_Bandy

Yes actually the 96 does as well, the reason I am using a longer shock is I kept having issues where going over railroad tracks the tires were leaving the ground as if I was over extending the shock. So just beware

If you have any questions please let me know!


Mo

LD85

Interesting, with a compressed height of 11-5/8 for the 5855p as opposed to the 4855p's compressed length of 10-3/8's, how does the shock keep from from bottoming out?

Mo_Bandy

Hi Indy,
I understand the concern, like I said I have run the shorter shocks on the rear, it seemed to me they were over extending.

I just measured, the car has about 1/2 tank of fuel. The ride height is 27.5 inches from the floor to the fenferwell lip. The shock length is sitting right at 14 inches. I have exactly 2 inches to the rubber snubber leaving 2 inches to point the snubber contacts which puts the shock length at 12 inches, leaving another 3/8 of an inch to the shock fullt compressed. I have yet to hear it or feel it bottom out. I might add that when I just went out to measur this to double check my reasoning, there were no marks where the snubber contacts so I'm definately not bottoming out.

Notice it shows the 4855 as 14" extended... (Which where my ride height is. )

So the reason I chose the 5855 is the recommended height is 13.25- 14.25 which is about center shock.

Unless you are slamming the car about 2 inches, if so, then you can use the 4855 but you may need to take another look at length the front shocks to be sure you do not run into compression problems up front, to keep the stance you are looking for.. remember the front shock in the stock mounting position is about 3:1 the rear shock is almost right at 1:1 wheel to shock ratio.

Best regards,
MO

LD85

Thanks Mo, I will look into this some more.

Its a wrap,, I'll adjust the leveling Monday eve.

Well, we welded 1/8 thick SS to the side of the stock mount, it ain't pretty, but its pretty strong, it was .105" thick before, now its .235" thick afte rthe SS was added



We also welded a larger base to the mount in an effort to spread out the load, the base is 1/4" thick 1018 CRS


RJ welding the mount on last night @ midnight


Welded on and moved forward 1.250"


Painted and since I kept the factory mount in an effort to make this reversible in the future,, I put a rubber bushing in between the Spherical bushing and the mount wall, I will search out a better solution for this but with teh tires on, you dont see it.

BrianCunningham

Looking good LD

If you want, I've got pics of a beefed up front mount from the autox/RR section.

Mo_Bandy

Looks Great!!!

Mo

LD85

BC, I beefed mine up but I would like to see what the other guy did

AGENT 86

Another project on my list, that still isn't started.
I will be picking your brain, sometime down the road.

coupeguy2001

I would have thought that the fronts would get more benefit from this than the rears due to the friction of the spring tips sliding on the lower control arms.
It will be nice to get all 4 done, but the rears don't seem to have to overcome any static friction.

LD85

Well, in researching I noticed that most all aftermarket shock mount brackets are 3/16" (.187") thick, various widths but still thicker than stock, so I figured, why not beef up the stock mounts.


Also GM/Chevy made the mounts so they were below the seam of the tubular frame, so I did not want to change the geometry if this is what GM intended, this is why I stayed with the stock mounts,

I had CO's in the front with the stock mono-spring in the rear and it seemd that the rear was fighting with the front in terms of control... so I decided to install the rears.

BrianCunningham

I didn't realize it was your mount pics I was about to post LOL

Lookin' good!

You should market those front mounts!

LD85

Hilarious!

You know my motto,,,,,,

Half Right,, is ALL Wrong