Discovered yesterday that the ears on my rear differential housing are broken. Couple of questions:
How much time should it take a pro shop to replace the cover? I'd like to do it myself, but if it's a half hour job for them, it will take me 4 hours, and my garage floor is cold.
How do I know when my spring is shot? Should I get a comp spring? I do not want to mess with ride height issues at all.

Thanks

 

I have never timed this job but I would say it could take a couple hours IF that is all you were going to do. I end up painting something making it a longer job.

You have to remove the spare tire carrier, remove the spring and remove the snub bushing on the front of the rear. Remove the U bolts that connect the half shafts to the rear. Support the diifferietial (I use my floor jack). loosen the 2 bolts on the crossmember (do not remove the bolts). Using a 2 jaw puller, break the crossmember loose from the frame. Remove the crossmember bolts and lower the rear/crossmember. Remove the4 bolts connecting the rear to the crossmember. Then you can remove the bolts holding the cover tot he rear.

I have a fiberglass spring in all 3 of my Vettes. The ride is smoother in my opinion.

 

Thanks very much for the info, but since you have three Vettes I hate you

I think I will try this myself. I want to do poly/graphite bushings anyway. You had no height issues with your fiberglass springs?

 

Any time you swap springs,you will have to readjust your ride height. No biggie though. Just adjust the bolts at the end of the spring to get it where you want it. Before you remove old spring measure how much of the bolt protrudes beyond the nut. This should get you back to near level and then just adjust for height.
Sly

 

One advantage of doing the work yourself is you can clean and paint everything, check your drive axle's u-joint, plus save some labor costs. When you complete the job you will know you took your tie and did everyhting right.

 

I ourchased the spring from Muskegon Brakes andthe bolts that came with the spring worked perfect. I didn't have to "adjust" up or down.

Take your time - heck, where you going to go this time of the year anyway? Clean parts, paint, check or replace the U-joints.

I throw a couple furniture pads on the floor to lay on when I am working under the car.

 

That idea appeals to me. What's the best way to clean/paint? Please mention products you use. Thx

 

Sand off any rust you can get to, clean with lacquer thinner. Any areas that still have light rust spray with a rust converter and a good quality primer after it drys. Then paint with a good quality rattle can spray paint; Dupli-color, etc.

 

avoid trw springs...vbp is solid option...

 

i would guess that it would take you about the same time as a shop, after all, how often does a shop do this? they probably figure it out as they go along, unless they're vette specialists...

i've taken the pumpkin out more times than i care to count, and as the other say, it's worth it to take your time and examine everything along the way, clean, paint, replace, etc.

 

This isn't an uncommon issue on older C3's. Check your "D" height against the factory trim height specs (they're in the AIM) to see how bad your spring has sagged, and so you'll know where it ought to be should you decide to replace it and wish to restore your ride height to original. I'd post the specs, but 1968 is one of the years I don't have. BTW, the "D" and "Z" heights are the only reliable ride height specs to go by for maintaining designed suspension geometry, as non-original tires, worn out body mounts and such don't effect their accuracy.

Do note that 1963-1977 covers used 2.25" springs and 9/16" bolts while 1978-1979 covers used 2.5" springs and 7/16" bolts. Just speculation, but it could be that the detriment of having larger bolt holes outweighed any benefit of having larger bolts. I'd get an "HD" replacement cover. They're relatively inexpensive and readily available.

 

with everything else out of the way first, itll only take 10 mins or so to drop the diff if you use the gear puller.

careful working back there. things can get carried away before you even know it.

for example, i wanted to just replace some worn out bushings back there. but noooo.... this happened instead.



everything but the almost new Ujoints were replaced. i even rebuilt the trailing arms and pressed in new wheel bearings.

 

WOW nice! Really glad you posted these pictures, I need some inspiration. I must have some kind of mental disease. NO ONE but me will EVER see under this car...but I really want it to look like that.

Ordered the HD rear end cover, but really want to do the whole rear suspension. Waffling on the poly/rubber thing. Don't think I can do the trailing arms myself, at least not do them right. How important is it to replace the diff crossmember bushings?

 

When it comes to pulling the crossmember, what does the center screw of the puller bear on?? Or will this be obvious to me once I get started?

 

i actually did not replace the cross memeber bushings. 2 reasons for that. 1, they didnt look too bad, and 2. theyre ungodly expensive, about 100 bucks for the two of them.

as for the puller set up, it took me a moment to figure it out my self. youll leave the 2 bolts partially threaded in, for 2 reasons. those bolts will catch the Xmember when it pops off, so the whole thing doesnt come crashing down, and, thats what youll be pushing against.

a word of warning with the gear puller method for removing the Xmember. depending on how stuck your Xmember is, this may happen. we ended up heating it up and pulling it back straight, then welded it all up. and because i knew damn well that if i ever had to drop my diff again, i didnt want to go through that mess again, so i took a grease gun and filled the inside of the sombrero, greased all over the outer shaft, and filled the bushings up. if i have to do this again some time, the whole thing should just slide right off now.

 

Did anyone actually give you a time estimate?

You can get it done in one day, but it will be a pretty full day. Of course that is if you don't clean and paint everything. Personally I cleaned and painted everything.

 

First, when you say you want to "do the whole rear suspension", if you mean making real improvements I submit that you shouldn't make choices which may serve to compromise the end results. Of course, what are the right decisions depend on your ultimate goals.

With that thought in mind, consider that while poly is fine for control arms and anti-sway bars, it isn't best suited for applications where movement is in more than one plane during suspension travel, such as it is with camber struts and TA's. Heim-joints w/o zerks are the best call for the camber struts (NMB's preferred), with camber lock plates replacing the eccentric adjusters. Guldstrand, et al, have kits. IMHO, I'd stay with rubber if you're not prepared to step up to heim-jointed struts. Also, stay with rubber on the TA's if not at least going with sphericals, which is a major mod. Install a solid diff locating kit and you won't have to worry about the x-member going anywhere.

There's much, much more to ponder, again depending on your goals, but after addressing all suspension wear issues (including the steering box, etc.) the above are as good a place as any to start out back, followed up with a precision alignment using the appropriate settings.

 

I agree, use the rubber, the car will feel 100% better and you'll get a nice ride. If you do the frt suspension stay away from the kits, use MOOG only as they are the best parts. The kits usually have all or most imported parts. Be prepared though, a full MOOG setup is about
$400.
Do the work yourself if you can, no shop will put the detail into the work that you will.

 

I'm cleaning and painting, for sure. Need a recommendation for a spray-on rust converter -- hopefully one that acts just like a primer and that I can paint over.

Thanks for the advice, I've decided on rubber for the bushings--though at first I chose them mostly because I'd be contemplating suicide if my car started squeaking. Sounds like the camber rods are more important than I thought. Is "NMB" a manufacturer? I've looked at VBP's strut rods with Heim joints...? I could also use a good source for rubber bushings, esp. the diff tongue mount, only seem to be able to find poly. How important are the crossmember cushions? I don't want to skimp but another-user is right they are expensive.

I was actually planning on doing the front first, starting with the steering box, before I fopund the cracked diff cover. I'm hoping the results of my rear suspension work will inspire me to do the front as well, this winter. Oh, and it will also help if I'm not broke...

 

The one place I would,and am,using poly IS in the diff bushing. In my instance I needed to keep the rear end movement to a min. This is also the reason when I changed out my rear crossmember cushions,I went solid. Do a search on "solid crossmember mounts" and you should come up with something.
The rest of the applications,I went with rubber. I didn't see the need for poly in a street application,and I see you agree.
As far as a rust encapsulator goes,and I really don't know if it works in that way.......I think it is more of a rust neutralizer,anyway,POR 15 seems to be the "tool" of choice. Although I don't think it comes in a spray.
As far as the rest of your car goes,you will realize that you don't have to spend a ton of cash to get your car looking good. A good amount of elbow grease and some paint go a long way. I have found that if you take the time with the DETAILS,such as eliminating overspray and such,your efforts will pay off in spades! And you will have a car that will bring you a lot of compliments and will be a pleasure to drive.
Or you could do what I did. Start by convincing yourself that you are going to only do the "safety" items. The next thing I know I had Corvette parts all over the place. My Wife stated that she thought a 'Vette "exploded" in the garage.
So naturally I had to do a "nut and bolt" resto!!!!
So after about 2 hours of driving time,5 years ago,I think I will have my car back from the "final stage", paint. And man let me tell you ....5 years is a long time to have to wait for Christmas!!!!!!
Good Luck,
Sly