I ordered new wheel cylinders, brake shoes, and a hardware kit for the rear brakes.
Pulling the old pieces off was straightforward.
The first problem was getting the old wheel cylinders off. The bolts were siezed solid, and I could not get them off. I ended up having to drill the bolts out and chisel the heads off. There wasn’t enough room to get the drill in the right position, so I used a 90* adapter, and a bit of contortion to get the job done.
I cleaned and painted the old parts that were to be reused, and then it was a simple matter of reassembly.
had replaced the hard line on one side, the line on the other side was not budging, so I cut it off and replaced it. I bled the brakes with the power bleeder, and got a good brake pedal.
The first order of business is getting the brakes working. It’s not a good idea to get it to move if you can’t get it to stop. PO installed an aftermarket front disk brake conversion, which looks absolutely brand new. After looking at some pictures online, I decided it’s based on the generic 1973-and-newer GM setup. The flex lines are new, and were connected to the original hard lines.
The rear brakes are the original 11″ x 2″ drum brakes. Everything retains the original 6-lug bolt pattern.
After trying the brake pedal a few times, it went all the way to the floor with minimal resistance. No brakes. Later I discovered one of the hard lines running from the rear junction block on the differential was leaking. After replacing that line, still no brakes.
The master cylinder was the first problem, still the original drum/drum model. The casting number on the original master cylinder is 5452310. The difference between drum and disk circuits is the amount of residual line pressure that the master cylinder maintains in the circuit after the brake pedal is released. For drum brake circuits, the master cylinder keeps about 10psi so that the shoes are slightly extended, reducing the amount that the pedal has to travel before the brakes start working. Disc brake circuits need about 2psi, and if they get more, the pads will drag on the rotors. The master cylinder needed to be changed to one that had a disk brake circuit for the front brakes.
Getting the old master cylinder off was a challenge. The hard lines were rusty and not coming off easily, but they eventually gave in.
There was no front disk brake option in 1968, so the answer is a newer master. After some research, I settled on a NAPA M36280, which cross-references to a variety of disk/drum applications.
On installing the new master cylinder, the rear connection was not exactly in the same place, and bending the rear line cracked it and created a leak, so I made a replacement line.
I couldn’t bend it the same way that the original was, but I got something that worked.
After tightening everything up, no leaks finally.
I used a power bleeder to bleed the lines.
The fronts went well, the rears were a mess. One side had the bleeder broken off, and the other side had a sheetmetal screw wedged in the hole where the bleeder used to be. The rear brakes needed to be rebuilt.
I rebuilt the carb a couple of years ago, but I hadn’t really done much with it aside from setting the idle and idle mixture. Based on what the plugs looked like, and the odor in the garage after I parked it, the mixture was rich. I decided to put in smaller jets to see if I could get that solved.
This carb has a metering block with replaceable jets in the primary side, and a metering plate with a fixed hole drilled in them. I wasn’t too concerned about the secondaries, and changing that would mean buying a new metering plate, or converting the plate to a metering block with jets.
There were #69 jets in the primary, which were the ones that were in it when I bought the car.
I decided to try #67 jets, and put in new plugs while I was at it.
The new jets were an improvement, but it still smelled rich. Also, there was a bog on acceleration, probably due to the smaller jets. I put on a bigger accelerator pump cam, and switched the jets down again to #65.
That change worked out great. The acceleration was smooth, no more bog. Also the engine was running smoother overall, and the garage didn’t smell after I parked the car.
I ordered a new kickdown rod to replace the broken one. I can’t find any sign of the rest of it, and it’s a pretty big piece that’s missing, so I can only assume it has been gone for quite a while. It’s not a very complicated piece, just a piece of wire with z-bends at the ends, but I didn’t have any wire that looked sturdy enough, so I just bought one.
Getting the rod threaded into the lever that engages the kickdown piston button inside the transmission was a bit of a challenge upside down under the car, but I got there eventually. There’s a clip/pin that the lever pivots on that needs to be pulled out so you can thread the lever onto the rod. Once that is done the pin needs to go back through the 2 holes on the bracket, and the two holes on the lever, while making sure the top end of the rod doesn’t slip out of the hole on top where the cable attaches.
Once the rod was installed, I connected the cable and verified that it worked smoothly from the carb end of the cable.
From there, I put on a new filter, and a new cork gasket. I tied the gasket on with some thread to hold it in place until I got some bolts started. I then tightened the pan bolts to the recommended 10-12 inch-lb torque. Note that is INCH-pounds, not foot-pounds. Big difference. I didn’t have an inch-lb torque wrench, so I bought one specifically for this job, since I wanted to be absolutely sure it was tightened properly so it wouldn’t leak. Otherwise, I’d have to take the transmission crossmember off again to get at all the pan bolts.
The kickdown cable is a connection between the carb and the TH350 transmission that causes the transmission to shift into a lower gear during hard acceleration. When I bought the car, the cable was not connected, and acted as though it was stuck. I assumed the sheath had melted somewhere, and that’s why it wasn’t moving. I bought a new cable, but the attachment point at the transmission was blocked by the header, so I never got around to installing it…until now.
The plan was to disconnect the right-hand side header to get access to the transmission, install the new cable, and reinstall the header.
Luckily I had help.
Headers are notorious for being difficult to install and remove. After an hour, I had the 6 bolts removed attaching the header to the cylinder head. Another hour had the 3 rusty bolts at the collector removed. The header dropped out of the way, and I had easy access to disconnect the old kickdown cable
When I took the retaining bolt off and removed the cable, it came out easily, which was bad because it’s supposed to be connected to a wire rod inside the transmission. After examining the cable, I discovered that it wasn’t melted, but the cable end was wedged up in the cable sheath, along with a piece of the rod.
In order to replace the rod, I’d have to remove the transmission pan. The original transmission in the car was a Powerglide (2-speed), and it currently has a TH350 (3-speed). The mounting points are identical between these two transmissions, but the transmission pan extends much farther back, so the rearmost pan bolts are covered up by the transmission crossmember. In order to get to those bolts, I’d have to move the crossmember out of the way.
Thankfully, the crossmember bolts and the transmission mount bolts came out easily. I jacked up the back of the transmission a little, and the crossmember slid out of the way easily.
The next challenge was getting the pan off without making a huge mess. I started with one drain pan, and quickly decided I needed a bigger one to catch all the fluid. I ended up using a big under-bed storage bin, which worked reasonably well. My wife suggested one of those pans that goes under a washing machine, I think that’s a good plan.
Once the pan was off, I expected to find the other half of the rod, but I haven’t found it yet. Maybe it was removed or lost previously. The inside of the pan looked reasonably clean, there was a very thin layer of dark (clutch?) material on it, but not a lot, so I’m hoping that’s normal. I cleaned and painted the pan because…that’s what you do when you’ve got a part off the car and have some spray paint.
I’m going to replace the filter while I have this apart, although the old filter doesn’t look very dirty. The filter kit that I got has a rubber pan gasket but some reading shows that cork works better, so I ordered a cork one because getting to the pan bolts is a problem.
Someone on the Nova board was looking for a dealer emblem for their car. here’s a 3D printed version I made for them:
Original emblemScanned image of emblem
Using the scanned image of the emblem, I used GIMP to reduce it to a pure black-and-white image using the posterizing filter. Once that was done, I hand-edited the result to clean up and straighten the noise in the image.
Foreground outline
Once the basic image was created, I used parts of it to make a background outline.
Background outline
These two pieces were traced into SVG files using Inkscape to turn them into outlines. The SVG files were then imported into Fusion360, where I filled and extruded them to form the final object.
Background and foreground extruded in Fusion360
The object was saved as a STL file, loaded into Cura, and sliced for my Ender3 printer. I used PLA filament to print it.
3D printer in actionFinal result in PLA plastic filament
It’s not perfect, but it’s a good 10-footer if it is painted with chrome paint. Another option would be using a service like https://shapeways.com to render it in metal, or https://www.gcartrim.com/ to have the plastic plated.
I’ve been driving the car more this summer since I’ve addressed a lot of the problem areas. The next item on the punchlist was getting it to ride more comfortably. The suspension felt very stiff, particularly in the rear, and going over potholes or train tracks felt like the car was going to shake apart. kaBLAM!
I didn’t want to change the ride height, so that actually limited my choices. Most of the springs/spindles/shocks available are for 2″ drop, not stock height.
After asking on camaros.net, I bought a pair of Bilstein AK2073 rear shocks. That was not the right part to order it turns out. It’s not clear on the Bilstein website, but AK2073 is for monoleaf applications, while AK2074 is for multileaf. The difference is that the multileaf has a taller spring pocket under the differential to accommodate the multileaf spring. That puts the shock mounting plate under the spring lower, so the shock needs to be a little longer.
But first…
Way back when I first got the car and was redoing the brakes, I noticed that the right rear shock upper bracket was broken, so I decided to fix that. The setup was not stock, there was a mount point extender that was bolted to the upper shock mount, and the shock was mounted to that. The extender is commonly used to adapt the shorter monoleaf shocks to a car with multileaf springs. Moving the upper shock mount position lower meant the shorter shocks would work with the lower multileaf shock mount.
I gave it a good pull with a breaker bar, but the bolts were not moving. I sprayed it down with some penetrating oil, and gave the bolts a try and more oil every day for about a week. I felt them start to budge and cranked harder…only to have the bolt snap and the head twist off. It turned out that the extender was aluminum, the bolts were steel, and they had corroded together so there was no way they’d ever come apart.
The rear upper shock mounts are two pieces. A thick plate inside the trunk with threaded holes, and another thinner plate under the car that is attached with bolts into the threaded holes in the thick plate, sandwiching the trunk floor in between. I ended up drilling the bolts out of the thick plate and cutting it away until it let loose. Not a fun job.
I could not find a similar design shock extender, so I ended up with a version that screws onto the top stud on the shock that makes the stud longer. Different design, but same effect. I put it back together with replacement upper shock mount brackets, and the stud extender on the original shock.
Back to today’s shock replacement: Remembering how difficult it had been to remove the right one, I was not looking forward to doing that same job on the left rear upper shock mount, but it had to be done. It took me 3 hours to get the mount bracket off, but I did succeed.
Removing the bracket…
Assembly:
The old shock turned out to be a no-name model marked “20818” and “POF22MC1R”, neither of which seem to turn up as the correct shock for a 1st gen F-body. It was a little shorter than the new shock, but not by much, maybe 1/2″. I had checked the travel in the new shocks, and it was about 7″
Once the new upper shock mount bracket was bolted into place, I started to test fit my new Bilstein shock, and discovered that the lower mount had been bent to fit the narrower lower eye mount of the old shock. I was able to bend the bracket back into shape. It was around this time that I discovered that my stud extender piece had a fine thread (as did the old shocks) but the new shocks were coarse thread, and probably also metric. That meant the extenders weren’t going to work on the new shocks. I decided to check the length anyway. With the car supported under the shock mount, it was at the normal ride height. I had to compress the shock about 3″ to get it seated, which worked out to about half the overall travel, which seemed correct.
Then I looked closer at the spring pockets on the diff, and realized they were for monoleaf springs, which means a) the springs aren’t properly installed, but also b) I didn’t need the longer shocks with my monoleaf bracket setup.
Given that the old and new shocks (fully extended on the workbench) were about the same length, and the new shocks had about 7″ travel, I think the 3″ shock extenders were putting the old shocks near the bottom of their travel limit. When the car hit a big bump, the shock would compress until it bottomed out…which was likely a major cause of the rough ride.
The right side was much easier since I had already replaced the upper mount.
After I got it put back together, I took it for a test drive on some bumpy roads. The roads were still bumpy, but at least the car doesn’t sound like it’s coming apart when I hit those bumps. Much improved!!!
The roof rail weatherstripping on the car is probably the original stuff, and after 55 years, it doesn’t really do its job very well. I bought a bunch of weatherstripping for the car when I first bought it, and have slowly been installing it on the car ever since. I decided it was time to do the roof rails.
The installation turned out to be very simple. The old weatherstripping just pulled out of the roof rail channel. The instructions say to add a little weatherstrip adhesive at the corner near the top of the windshield, and a little at the frontmost part with the little plastic buttons, but you don’t have to put it anywhere else.
Some of the original blue color of the car showing from under the weatherstrip:
The installation turned out to be very simple. The old weatherstripping just pulled out of the roof rail channel. The instructions say to add a little weatherstrip adhesive at the corner near the top of the windshield, and a little at the frontmost part with the little plastic buttons, but you don’t have to put it anywhere else.
The other job was replacing the outer door window ledge weatherstrip, and then fixing the window alignment so it hit the roof rail weatherstrip in the proper spot. The videos in the post about fixing the window so it rolled all the way down helped a lot here.
Getting to the window adjustments means taking off the door upholstery panel.
The panels are reproduction pieces from a company called COLAMCO that has since gone out of business. Too bad, they appear to be very well made. I wish I could read the manufacturing date, but it’s too faded.
I’m not 100% happy with the window alignment, but it’s pretty close. I still have some work to do on the rear window, and I will need to adjust both so they mesh properly.
