Hello,
Just want to introduce myself and my project.

Me.
Based in Brisbane Australia and 44 years old, I am far from being called a mechanic, but I am a mechanical fitter and machinist by trade. These days sees me as a Business Development Manager for Norbar Torque Tools - A subsidiary of Snap On Tools. Seeking some sort of a project and a feeling of accomplishment in my life, a spur of the moment decision was made a bit over a year ago to buy some ones unfinished project car and complete the jigsaw puzzle. I am really enjoying the project and the learning curve.

The car.
1977 C3. I don't know a lot of detail on the history other it was imported into Australia around 20 years ago. It was stripped and the bulk of a right hand drive conversion was done by a local company called Superformance. A mirror image firewall was put in place and the modifications for RHD was done to the steering using some parts from an older Australian Ford (common for the conversions here). The car is solid, straight and free from rust. It was sold a couple of times before I got hold of it, and as I am finding, a few bits have gone astray along the way. I have stripped all of the front end components and painted with 2 Pac gloss black. All pushes bearings etc have been replaced. I am now focusing on the rear end.

Diff Issues.
Wanting to simply change the seals I have found what seems to be a common problem from the era where I have excess float in both output shafts. I feel like this should be sorted out before putting it back in the car.
LHS has 0.024" of float - and 0.002" gap to the pin when closed, 0.030" when pushed away from the center pin.
RHS has 0.027" of float - and 0.02" gap to the pin when closed. 0.026" when pushed away from the center pin.
The shafts are not badly worn. I would like to fix utilising the hardened button method. I have access to an excellent machine shop with CNC lathes mills etc. They also have hardening capacity. Best bit is, these guys will do it for free....winning!!

Anyone out there able to assist with dimensions or tips to get this sorted?



Just got her home, in the garage


in my shed/workshop


workshop is 4m X 8m (Aussie lingo) or 13ft X 26ft. Heating is not required down here, cooling is key.


350 SBC. Not original motor


Spends most of its time like this now...up on stands.


Well if you have read this far, thanks and I look forward to chatting soon!

Jeff.

 

Welcome to the forum.

To see where you are at now, measure the distance between the axle tip and the face of the retaining clip. Typically, this dimension will be in the 0.185 - 0.200” range for a “normal” axle but can be far less (in some cases, the tip is worn down to the clip groove).

Your “play” can result from worn axles, spider gear wear (and setup - i.e. how the shimstacks were selected when built) and potentially cross shaft wear. In the simplest case, you could fab the button so the dimension from the button face to the retaining clip face is, say, 0.020” longer than what you have now but I would recommend you first investigate the spider gears (search YouTube for Tom’s Eaton Posi tuneup) and get your spiders down to zero lash, then remeasure your axle play.

 

Thanks I watch the video.
I will do a bit more investigating before going too far.
Much appreciated.

 

Pretty cool you can get buttons made! Love the silver..
agree with above.. i might change all your seals and tune up fix as needed then decide what size..

below may help you as i had no clue
https://www.corvetteforum.com/forums...ay-advice.html

 

Tune the posi,correctly, then all you may need to do is get the axles hardened

 

Thanks I will look at this ASAP.
Christmas may be an issue for any parts short term.

 

welcome to the money pit from a fellow ozzie, there's a few of us regularly on here putting our slant on how we do things upside-down.
I too am a fitter n turner / toolmaker, 34yrs same place working on plastic injection moulds.

If you have any carb problems, listen to Lar's, he's the expert with all things Quadrajet, i even sent mine over to him to work his magic on.
Any diff problems, GTR1999 (Gary) is the go to guy.

useful link
GM Heritage Archive Downloadable Vehicle Information Kits
there's also someone on here offering free wiring diagrams...

hint, fill your profile in on the side so people know where you are from, otherwise they say "oh, just buy it from your local (insert parts supplier here)", well we don't have them here...
and shipping can take ages from the US as you probably know.
there's a couple of vette parts stockists here, 1 in Qld ans another in Vic. can be pricey tho.

 

FYI GTR1999 looked in here already ...
and he is probably the singular world wide expert of these C3 diffs.

What he is saying is if you shim the spiders with Toms Diff "tuning" method, you will not only strengthen the rear, because it removes a lot of backlash in the spiders, but since it moves the spiders inward, closer to the yoke c-clips, it tightens up your yoke slop measurement as well. IIRC mine tightened up at least .015-.020".

Also most of the 73+ up axle yokes had below standard heat treatment and wore excessively from the factory after 60-90K+ miles. If the yoke end measurement is still respectable (.189" from c-clip to top of axle) find a place to get them properly hardened and you may be good to go with no new parts required. Probably easier than the buttons, unless you just like a challenge.

 

Welcome to the forum! Glad to see you posted. As I mentioned to you in the past, insufficient hardening of the yokes is very common on these cars. But others on here have more and very good advice as well.
bottom line. Listen to Gary.

 

Thanks for the tips. Good idea to add some more info.
The forum is a lot more help than the facebook sites....I guess they are an a]American car.

 

Thanls. I will be looking at this, this week. If all works out, i can have the parts hardened at a business I work with.

 

FYI...when you find info that interest you,either print the info and also save it on a disc.
OR you can write down the thread Title and make a note of the post # to help you (re)find the info faster.
Also...take pictures of the Pictures other members post which are included in the thread(s).

 

I find it easiest to simply "Subscribe" to the thread. Later you can click on the list of threads you have subscribed to and find it real quick.