Ok this is another one of my favorites. Not to sound arrogant but I build the best saginaw steering boxes on the market. Not because I'm a super genius but simply I put the time into them and the extra work requred to make them better then the day they were new and certainly better then some I've had shipped to me that were "professionally rebuilt" I have one coming in now out of a 63 SWC that was "done" by a vette shop. The guy is my brother in law so I know he had paid the shop big $$$ to go through the car yet it was all over the road.
What you need to know about these boxes:
1- Do not attempt to adjust the lash unless you have a dial in/lb wrench and the box is out of the car. I know there are guys who will tell you to use the fish scale procedure in the car, they will also tell you that vette boxes are NG and to buy a new one- big mistake.
2- Forget about adding grease as the book says, not accurate. If you overfill the boxes they will leak. They are not vented and heat will expand the grease and either blow out a seal or the oil in the grease will weep out. Even properly filled this may happen. Plus a lot of times you'll get a false reading as the old grease creates a caked up dam preventing the new grease from getting to the bearings. I believe I have some pictures of just this situation with a box sent to me.
3- The 63- 69(69 manual only) used a full 360* spline while the L69-82 used a coarse spline with a flat milled into it. The rag joints from 63-66 were the same and are $$$$ now, the Tele joints were different and I have not seen one. The 67-E69 rags are also different and the L69-82 are all the same. USE a GM rag if you need one. Pay the $100 or so and get it, forget about those repair kits I think they're junk. Remember I don't care what a vendor says this is coming from a restorer, owner, driver. NOTE:
I no longer recommend ANY Rag joint from ANY supplier. I found the current GM rags have changed. They no longer are grounded and material isn't the same. They are not as rigid as they were a year ago and I suspect the supplier is not making them in the good ole USA anymore- I could be wrong but the ones I got in from my local GM dealership are not the same anymore. If you can find a NOS GM rag look for the wire mesh molded into the rag and red ink on the material. Hopefully someone will come up with a quality rag joint like the GM rags I used to buy but I wouldn't count on it. I have a couple left but will be holding on to them.
4- The pitman arms for a power car are different then a manual car. The PS arms have 383 as the last 3 digits in the arm. The manual arms are 451.
Ok here we go:
This is what they look like when I get them in. Yours is probably the same. If your car has been sitting a long time then the grease get acidic and attacks the ball screw in the worm assembly. Be aware when looking it over.
The first thing you have to do is remove the pitman arm. Some of these suckers are on there pretty tight so I hit them with the propane then PB Blaster. I use a puller and spacer to protect the threads on the shaft. Use an impact gun to pop it off just be sure to have the arm turned in the right direction so it doesn't free wheel into the end of travel. Remove the lash nut and turn the lash screw out a little. Remove the 3 cover screws and screw the lash screw in to back off the cover. I have a 3/4 socket set that I use to loosen the side adjusting nut and lock ring.
Here is what an old box looks like with the nut off.
Here are the 2 inputs, full spline and the milled one.
Remove the parts and wash them. Here they are broken down.
I made some tools up to do these all the time but for you one timers here's the trick to removing the bushings. In the cover use a burr and once it cuts through the bushing will spin it out and you can use pliers to remove it. The 2 in the housing require a homemade tool. Get some washers the diamter of the bushings and bolt them together. Then grind a flat on one side so they can be fit into housing and lay flat on the bushing then you can drive them out one at a time. I made a tool to install them. They are soft so you need to radius the ID like you would a cam bearings and install the same way.
The kits sold are not all the same. The quality does vary now compared to a few years ago. They usually come with bushings and those are ok although I never use them. You can use them and have a vendor type build - BUT if you want the best built box you will have to machine up and fit your own like I do. This takes time and you need a lathe. Is it worth it for a 1 time job, that's your call.
Here is a stock bushing
If the gears are still good- they can be set to 11-12 in/lbs and there is no heavy pitting then you can rebuild them with 54 new balls. I take the shaft and polish it before fitting the bushings to it.
Here are those ball guides, follow the GM manual on rebuilding the box here.
Look at the ball screw for pitting. If bad then you have to replace the gear set. I can not get the parts separately.
When I get the gears back and new races in place I dry set the gears to see where they run.
This is another spec to check, the gap has to be between .0015-.002" Shims in the kits will get you there or you have to machine up some.
When all is good, preload set to 4-5 in/lbs, lash goes to 11 -12 in/lb ok then you can add grease, leave room for expansion. UPDATE 8/2010- I no longer use Mobil 1 grease. It's a good grease but had issues with the oil separation with it. It separates more then other greases and will sometimes lead to the oil from the grease weeping out past seals. Maybe only a tablespoon of oil will weep but there are other greases out there that work better. ALSO some rebuilders will not tell you want they use or will tell you they use a special grease. This is total BS they just want your cash and will use tactics to try and sell you something. Any quality grease will work, the key is using one that will not separate like the Mobil has. Even though the red grease weeps it will stop, all the grease is not going to leak out. On the other end of the spectum I found "rebuilt" boxes without any grease! No leakage there, a couple of new seals,a paint job, old bearings,bushings,and gears and they charged the guy $150-$200. Real nice.
Here it is, done and ready to bolt in. If you add the arm torque it to 150 ft/lbs. I also witness mark the set points so you can see if an alignment shop helped you out and adjusted it. Then you get to set it up all over again. This has happend more then a few times so pay attention.
This is more involved then it looks and it is not a ebay $150 special. It's your vette- do it right! If you want the best and don't want to do it let me know.