Wednesday, March 25, 2026

Two Years of Vette

It has been almost two years since I posted any updates on the progress of the blue '75 Vette. It hasn't been because there was no progress, but the entire process became so difficult that taking pictures to document everything became too tedious. The barn was better than being outside, but it was also not a great place to work. The continual sprinkling of debris from the loft left the floor constantly too dirty to sit anything down. There were always mice and spiders and bugs. While working at some points in the year I had to hang a fly swatter on a nail near me because of several wasp and hornets nests. They would constantly be flying over head and divebomb from time to time. At one point we had a 100 year flood and the barn flooded while all my tools happened to be on the concrete floor. None of them washed away, but I did have to disassemble my tool box and individually clean and oil every single tool. The summers were painfully hot in the barn, and the winters cold enough to prevent work all together. We no longer have our own cattle, but we do rent the fields out to beef cattle farmers. The cows are constantly wanting to come down and get into any and everything I'm up to. Licking or biting or otherwise dropping gifts right at the entrance. With all that, I'm still glad to have a place with a roof to do the work. This project was difficult, but not more so than several of the previous projects before, however I think I can say that this was the most difficult project, mentally. Most of the time it felt like no matter how much work I put into it the finish line never got closer. It was exceedingly difficult to become motived to go down and work on the car, especially in the harsher weather months. At times I had to break it down into the smallest tasks and only concentrate on those things. Sometimes as small as just going down to remove one part and then call that enough. The project did not have to take two years. Sometimes it would sit for a couple months with no progress. Other times, it would have to take a backseat to the many other things that have been going on in life. My mother died in 2025. We expanded our business where I took on the role of contractor for a massive construction project. Our newborn is now almost 3 years old, and April began homeschooling the children. There were times when someone might ask how close I was to being finished and I honestly could not give them an answer because so many of the steps were unknown to me I would only be thinking about how to finish the step I was on, and when that was finished I would have to take a step back and figure out what was next. In the end, what was a relatively small project by the standards of what I have tackled in the past ended up feeling like a massive victory of endurance and perseverance. I found paperwork on this car that showed the date my father purchased it. I can't remember the exact date, but it was somewhere around when the car was 4 or 5 years old. The vast majority of the parts on the car had never been off. Many of the parts were covered in grease, which aside from becoming a permanent part of all my clothing also protected the parts from rust very well. 

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I taped off and sanded the frame with scotch bright from in behind the jackstands to the back of the car. Then treated it with Ospho and then used a 2 stage epoxy primer and then painted the frame. I let my middle daughter do some of the painting. She really enjoyed getting to paint, but enjoyed most peeling away all of the tape. The goal is not to make a show car, but to make a presentable driver that is well protected. 

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Several of the parts were taken to be powercoated.

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Unfortunately, I cannot remember all the fine details as clearly as when they happened, but I remember the general details.  I generally detail every part, nut and bolt and write an explanation so that years later I can look back and remember what I did, but not this time.  I purchased two used half shafts and flanges in good shape. Removing the u-joints was a real torture test. I tried renting a tool and it destroyed the threads. Then I took it to a friend's house that was a mechanic in the 70s and has worked on cars for decades. He ended up breaking a tool he's had since back then that has taken apart countless u-joints. Finally I took it to another friend that had some magic method that got them removed. Reinstalling the new u-joints was difficult. They didn't want to compress properly to allow the c-clips to fit. I took it to a different mechanic that ended up ruining the u-joints so I had to purchase new ones. I finally figured out the right combination of efforts, forces and techniques to get them installed. 

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Getting everything primered and painted without cow snot ruining the job was a chore.

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After hanging in the sun a while, everything dried for a few days in the barn. I found out there is roof leak over the stairs so if I sat anything there it would get wet. 

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One of the leafspring mounting ears on the original differential cover was broken so I ordered a new HD unit and painted it black to match. This was the part that I found where the roof leak was. The roof leaked right where I had the new bare steel diff cover sitting and it rusted, which caused me to have to prep before primer and paint.

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 I lugged the differential up to the house so it could sit in the sun without the cows knocking it over. I prepped it with scotchbrite and Ospho.


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Ospho takes a while to cure and it needs to be well ventilated, but it works very well. I left the old diff cover on while prepping for paint.

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Two stage primer for the diff and axles. 

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 It was a longer step, but finally the diff and axles were done, along with the transmission yoke and a few other smaller pieces.

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Researching the correct way to get get the diff ready to reinstall took as long as doing the work itself. I painted the diff first so the process wouldn't possibly damage any new seals.

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Making sure everything is cleaned properly is tedious and can be tempting to hurry through, but these are the moments where taking the extra time prevents having to redo all the work later.

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New seals installed with the proper grey Permatex.

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Several years ago my friend's family business closed and they auctioned all of their things. Fortunately I was able to pick up this C-clip plier set, which made removing and installing the axles pretty easy.

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 I got the axles reinstalled and rechecked all the clearances.

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I cleaned the gasket surface as much as I could. I really missed having compressed air so I could use my gasket surface wheel. It makes this process effortless. Even though I would later clean out the inside of the diff with brake cleaner I still put paper towels down to catch debris. No need to take any unnecessary chances.

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It had been years since I'd changed a pinion seal, so I had to basically start from scratch in learning how to do it again. I marked the location of the pinion nut and staked it.

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When my father's dealership closed down years ago one of the tools I kept was the GM pinion tool. I almost never use it, but when I do it makes the job much easier.

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The pullers I'd bought for earlier parts of this project made short work on removing the yoke.

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 Installing the pinion seal is always a nervous moment.  There are many opportunities to mess things up here and there's a lot to be read about making sure this is done right so it can be done only once. Learning about speedy sleeves, which I did not require thankfully, and where to apply RTV is priceless information that the forums provided. 

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Another helpful lesson learned from the forums is to apply RTV to the splines on the yoke to prevent leaking. I would have never thought of this and I cannot imagine the disappointment of getting the car back together and having the pinion leak.

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Even things like installing the drain plug can become big issues that set you back several days. Since this was a new diff cover it left a lot of things uncertain. The drain plug didn't seem to want to thread correctly like all the other plugs I've worked with. It wouldn’t go in far enough to clamp down the posi-tag. Turns out, the plug is not straight tread and it is normal for it to not thread all the way in, leaving a few threads exposed and making it look like it is either cross threaded or that the plug doesn't fit. Fortunately the forums were able to help me learn this. Learning what type of gear oil and posi-additive also took some research. It's interesting how something so simple can take so long to figure out because of how many different opinions you can find from all over the internet. After getting everything installed and letting the Permatex dry I filled the diff with oil.  I remember waiting anxiously until the next day to check and see if the yoke or had leaked any oil. I left a paper towel under it so I could check. I left it several days and was relieved to find it dry. 

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Getting the differential and crossmemeber reinstalled felt like a milestone that was impossible to conquer. I ended up putting it off for a while for the dread of tackling it by myself. As it turned out, installing it really wasn't all that difficult. I ratchet strapped it to the floorjack and wrangled it in within a couple hours.

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Some small tricks from those that have blazed the trail before were very helpful. Like putting dental floss on the end of the trailing arm pivot bolt to pull it through the hole.

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After reading about the difficulty of rebuilding trailing arms, but more so weighing the odds of me damaging it, doing it incorrectly and the cost of tools to make it work, I opted to purchase rebuilt units.

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Getting them installed was another project that seemed like a huge challenge that was very intimidating, but once again this part wasn't actually that hard. In fact, I almost felt like I must have done something wrong because installing the trailing arms almost felt too easy, but only in comparison to what I was expecting. I suppose this may have been due in part to the fact that when I removed all of these parts they were welded together from age and it was extremely difficult, but when reinstalling everything was new and clean so it was much easier. 

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 It didn't take very long in the humid barn for the new calipers to rust. One by one I would research how to install each remaining piece of the rear suspension. I would print off guides at work and carry them with me to the barn.  At some point the cat that showed up at our house started following me to the barn and hanging out with me while I worked, acting like a dog. 

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It never at any point felt like the end was coming for some reason. I think because in order to get through this project I had to put the end goal out of mind and only concentrate on the job at hand.  This project always had to take a backseat to all the other responsibilities that happened in the last couple of years.  Then suddenly, one day, all the pieces were back in their place. Most things presented some form of challenge or problem, but a solution eventually made itself known.

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Finally, the car had a rear suspension again and sat on its own wheel for the first time in over 2 years.

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I torqued everything that should be torqued before the car was let down and only snugged the bolts that needed to be torqued with weight on the tires. I then drove it up to the house and onto some ramps so I could torque the remainder of the pieces. I found a shop in town that has an employee that used to work on Corvettes so he knows how to properly align the rear end. I installed new stainless steel shims and put an equal number of them on both sides of the trailing arms. This also exactly matches the way the shims were oriented before removing them, so it should be close. Since I had to cut my old strut rods I upgraded to new adjustable strut rods. Unfortunately the employee at the tire shop had a family emergency and is going to be out of work for a little while so I am currently awaiting his return before I can get the rear end aligned and finally go for a ride.

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Monday, July 1, 2024

Trailing Arm of Tears

 The next step was to remove both trailing arms.  I only have pictures of the passenger side, as I did it first, but both came off essentially the same.  The first steps are to remove the rotors, hard and soft brake lines, the caliper, the parking brake cable and the shock.  Fortunately, since I'd just had all new brakes put on, most of these came out easily.  The front fitting on the hard brake line was seized to the nut, so I had to loosen the rear and then bend it to spin it free.  I'll likely need to get new brake hard lines, and I already have new hoses ready to install.


 I'm not sure exactly how old these shocks are, but I'd say that "old" is a good description.  I know for a fact they are minimum of 45 years.

 I had been soaking these bolts for several days with penetrating oil and found that the nut came off relatively easy.  I left it in place while trying to hit the bolt loose.  I found that the cotter pin for the trailing arm nut was just slid into the hole and was never bent to lock it into the place.  I found the same thing on the cotter pin for the shims.  At least the driver's side cotter pins were installed correctly.

I hammered the fire out of this bolt, but it was absolutely not going to budge.  Protection on the dog log of the fender is definitely good insurance.

These were my weapons of choice.  I've had this upper control arm shaft for years.  I kept it when I replaced the suspension on some project years ago.  I put the nuts on the end and use it as a driver.  I don't use it often, but when I do need it it's often the only thing to get the job done.  It also allowed me to keep the hammer a good distance away from the fender.

Since the bolt wasn't moving, I proceeded to remove the shims.  They didn't pose too much trouble, and after removal I bound them together with tape and labeled their location.

After a lot of hammering I though the bolt finally came free, but as it turned out it was only moving back and forth with the control arm since the shims were now removed.  The bolt itself was very stuck to the bushing and arm, so I had to use a sawzall to cut it out.  It's good to remember that you can use a jack to raise and lower the control arm to allowed better reach of the sawzall, either from the top or bottom as needed.  I can't say that the job was easy, but considering how tight the spaces are I have to say cutting the bolt out wasn't as bad as I was expecting.  After removing the trailing arm assembly the piece of bolt left inside the bushing did not want to come out of the trailing arm at all.  I'm afraid trying anything further may damage the arm, and I don't want to do that because I'll need to exchange it as a core for the replacement.  From what I have read even if the bearings are good the original grease inside of them should be replaced.  In order to do that, the bearings need to be removed.  If they are removed, they should be replaced.  To replace them, special tools are needed and given the condition of the parking brake and the front bushings, which also require special tools to replace, the easiest solution seems to be replacement.  At least I can use my current arms as cores.  If I try to do the work myself and damage them, then I would have no core to exchange.

 

This is a close up of the control arm bushings. 


I was glad to find the control arm pocket appeared to be in good shape.


 Here's the empty cavity after everything was removed.  The driver side added one level of difficulty because the inside shim would not budge and I had to cut the bolt out with the shim in place.  I broke a blade on that side but eventually cut through it.  While I'm waiting on all of the new parts to come in I'll clean up all of the exposed frame areas and the control arm pocket.  Likely, I'll scuff all of the areas and then spray them down with Ospho, followed by primer and paint.  I've been keeping a list of parts but now it's time to go over it several times so hopefully I don't leave anything out and have to pay for shipping twice.

  

 

 

 

Wednesday, June 19, 2024

My Yoke is Easy

 Once again, the pictures belie the amount of time and work that went into the following steps.  This took place over the course of 2 and 1/2 weeks.  Among other things I've also been building sliding barn doors for the carports.  It has been hazardously hot and humid and the limited airflow in the barn has not been pleasant, but not as bad as working on the doors in the direct sunlight.  My friend Nick came over and helped me move the engine stand from one small barn room and into the tack room and install the differential on the engine stand.  It involved some careful maneuvering to make sure nothing was damaged during the move.  

 The scope of this entire project has seemed impossible, however with the help of the forums I just focus on how to make incremental progress and solve each new problem one step at a time, as it arises.  Despite having ridden and driven C3 Corvettes my entire life, I had no knowledge of their suspension until I began this project, so there has been a lot of learning in a short amount of time.  

I needed to figure out the condition of the side yokes, so I finally ordered a dial indicator and stand.  I've wanted one for quite a while and now was finally the time.  

After draining the oil overnight, the first thing to do was to measure the end play on the side yokes.  I found the driver side had .037" and the passenger side had .043".     


After opening up the differential I was very glad to see that the ends of the splines appeared to be in good shape at first glance.  When my mower broke the keyway on the wheel spindle I had to borrow a set of strong ring pliers.  When our friends that owned Branham's Trucking Co. sold out and closed their doors, Dad and I had gone to their auction at the end of 2021 and I picked up their shops C-ring pliers and this was the first chance I'd had to use them.

The yokes slid right out with no problem.  They had the slightest of resistance which gave way with a gentle tug.  The bearing surfaces appeared to be in good shape.

The tips of the splines also appeared to be in good order as well.  The measurement from the inside edge of the c-clip groove to the end of the spline was .186" on the driver side and .180" on the passenger side, which is within specs.  It was a big relief to find them in such good condition because remanufactured side yokes have become very difficult to source. 

Before taking everything apart I spun the rear end and it all moved freely and there was no feeling of bad bearings.  Visual inspection of the bearings didn't show any problems either.

The center pin did show some signs of wear, but nothing that was concerning.

Then I moved on to checking the backlash on the ring gear.  It measured .011", which thankfully was good.  I also tested the backlash on the pinion yoke and it has 0 endplay.

Even though the side yokes were in good condition, I still had a problem.  The u-bolt straps were all seized inside the holes and my drill press kicked the bucket a while back. These straps were the original cause for this quick u-joint replacement turning into a nightmare.  One of the nuts had also rounded off back when I was trying to remove it while on the car.  This step was extremely frustrating because no matter how I mounted the yoke in the vise it would not hold itself square.  I also did not want to clamp down too hard and risk breaking it.  First, I had to try to get the rounded nut off. I finally got a socket to bite it, but then the bolt began to turn.  I eventually had to grind down the backside and hammer it out with the nut still seized.

The process for the rest of them was similar.  I had to heat the yoke, then grab the stud with vice grips and try to work it back and forth.  I had been periodically soaking the studs with penetrating oil for several days.  Eventually after heating and working it back and forth I would be able to get the stud to twist back and forth just a little.

After it began to twist just a little bit I knew it had broken the rust bond, so I would use a punch and drive it out, which did not work well even when I supported the bottom of the yoke.  It was definitely an exercise in patience. 

After a whole lot of heating, and vice-gripping, and hammering, readjusting the vice and going to the house to get a flyswatter to kill the legion of hornets which were trying to build a nest next to the light bulb over my head, all 8 studs finally left home for the first time since 1975.

Finally, the differential inspection was complete.  I did accidentally hit the metal shield once with a hammer and bent it, but I was able to bend it back into shape so it will be usable.  I was really afraid of this step and afraid that I would not be able to remove the studs without damaging the yokes and I'm very thankful this is over.
 
The next steps will be checking the rear wheel bearings to see if they are good.  If they are, I hope to be able to only replace the trailing arm bushings, as I don't currently have the budget for this car to replace the entire trailing arm assembly.  Also, I will need to remove all 6 u-joints and replace them, hopefully without bending or breaking anything.  Until then, the '75 will have to hang out in the barn while summer continues to pass by.