FEATURE ARTICLES

1937 Buick Special Business Coupe: A Restoration Journal — Part 11

By Chris Ritter

A few months ago I talked about how I disassembled my 1937 Buick's engine, checked various clearances and took some pieces to the machine shop for further work. At the time, I didn't know if the machine shop would recommend grinding the main and rod journals or just suggest polishing them. I converted my connecting rods from babbit to insert bearings and getting new inserts will be a breeze. Replacement main bearings are only babbit and very expensive. When I checked clearances the mains were within limits so I was hoping to reuse them. It turns out that I wasn't that lucky since the machine shop recommended grinding the main journals .010" and the rods .020".

Before grinding and inspecting my crankshaft the shop cleaned it and made sure it was straight. After that they checked the shaft for cracks by magnafluxing it. In brief, magnafluxing is a process where the piece being inspected is magnetized and sprayed with a special solution that contains magnetic powder. When the solution dries the piece is examined under a black light and, if cracks are present, they appear as a bright fluorescent line since the magnetic powder is drawn to the cracks. Fortunately my crankshaft had no cracks and went on to the grinding step.

At the same time I delivered my crankshaft to the machine shop I also delivered my cylinder head. I needed the shop to remove my old valve guides and drive in new ones. In addition to that work they also cleaned it and magnafluxed it — no cracks in the head either! I will resurface the valve seats using a friends Neway valve seat cutter so look forward to that journal entry later this summer.

My engine block is still scheduled to be cleaned, inspected and bored .030" over standard. I already have the oversize pistons and my replacement connecting rods so I will probably start reassembling the engine in late summer.

Aside from my engine, another project that I've been meaning to address is the removal and replacement of my rear axle seals and bearings. On the 1937 Buick, if your rear axles leak they are leaking into the same area where your brake shoes reside. When grease gets on brake shoes you can't stop very well and when you can't stop very well mayhem ensues. On my car only one of the rear axle seals had an obvious leak but I figured if I was going to go through the effort of removing and replacing one seal I should go ahead and do all of them especially when the rear end was disconnected from the car.

At the end of the rear axle housing sits the car's rear axle seal. This is pressed up against the rear axle bearing. On the inner side of the bearing is a gap for grease and then finally an inner axle seal. The axle shaft has a race on it which rides in the bearing. The rear axle seals each have a central flexible gasket that keeps bearing grease in between the two seals. That gasket also keeps any lube from the differential out of the bearing cavity. Originally this inner gasket was leather but modern replacements use rubber. Over time the material degrades hence the creation of leaks.

To do this job there are essentially three things we must remove. The outer seal is first revealed by prying out a retaining clip. This clip maintains a proper distance between the outer seal and the brake backing plate. The outer seal can also be pried out with a screwdriver but be sure not to gouge the axle housing or you could develop leaks there even with new seals.

With the outer seal removed we now have to remove the bearing to get to the inner seal. If we are going to go to the trouble of pulling an old bearing we might as well go ahead and replace that with a new one too. Buick had a special bearing puller in the late 1930s. Since I don't have access to that puller I removed my bearing with a slide hammer and rear axle bearing puller.

The way the rear axle bearing puller works is quite simple. The puller consists of threaded rod with a swiveling shaft. You insert this shaft through the center of your bearing and when it reaches the other side you draw the shaft perpendicular to the back of the bearing and then tighten a washer to the outer face. This puller is threaded on to a slide hammer which is then used to draw out the bearing. Using this tool I had my bearing and inner seal out within three minutes.

With all of the components out I cleaned and inspected the chamber for gouges. Seeing none I pressed in the new inner seal. I packed my new bearing with grease (a job that I absolutely hate) and pressed it in to place. Here I used a bearing/seal driver because it is critical that you insert your bearings straight and even. Trying to drive in offset bearings is nearly impossible and would only result in ruined bearings or gouged shafts. It was easy to determine when my bearings were in the proper position because the shaft has a lip. Once it was in this final area I added some more wheel bearing grease for good measure, pressed in the outer seal and installed the retaining clip.

At this point the brake backing plate is attached and the axle shaft is inserted into position. If you remember my earlier post about pulling the axle shafts you may remember that the shaft is simply held in place by a U-clip found inside the differential. My new bearings will ensure a smooth roll and my new seals should contribute to a properly functioning braking system.

The last subject I will talk about in this journal entry is the subject of paint. Now that warmer weather is upon us all of my attention is being focused toward paint removal and eventually priming and painting as well. Of course in between there will be plenty of sanding but my arms are already sore just thinking about that so I can address that in a different journal entry.

To apply paint in the best way possible in my work area I need to fabricate a paint booth. Ideally this booth will be non-permanent, cost effective and safe. My number one reason for painting my own car is to save money but that is only one reason for doing it this way. I also like to paint things and will take great pride is telling people I did the work.

My paint booth is inside my pole building. It is 18' X 24' and this contains enough area to work around my body/frame and have an area to set up horses for smaller parts. It uses 2X4 posts spaced eight feet apart and those posts are tied into the trusses above and more 2X4s as the base. 4-mil plastic sheeting will be hung from the posts and explosion proof fluorescent fixtures that I picked up at auction will be used for illumination.

I have a forced air respirator but still need to get adequate air flowing through the booth. You can calculate proper airflow by determining your cubic area (length X width X height) and then tripling it. I will be installing two adjustable fans with sealed motors that will create adequate ventilation. Incoming air will be filtered. Of course we must realize that too much air flow could create a jet stream but conversely too little air will result in, well, inadequate ventilation! I will have plenty of time to tweak my system when spraying my etch primer and 2K primer.

I will leave you with a little teaser on what I've been doing most recently and that is paint stripping. I started with my doors and began the process with liquid paint stripper. When that phase is complete I will go over the metal with Roloc bristle discs that are attached to a pneumatic angle grinder. These 3" rubber bristle discs are the equivalent of 50-grit sandpaper but leave no swirl. After the bristle disc I will use a dual action sander with 120-grit paper and lastly 320-grit paper. Much more on this to come in future posts. Now it is time to take stock of my sand paper, sanding blocks, and guide coat supply — painting season is here!