highcking

The 57 unit is the same as yours. But in 58, the sender unit was moved to the front of the tank just above the flange. This was done (so says the shop manual) so that the sender unit could be serviced without lowering the tank. But this means that the seal has to withstand continuous immersion when the tank is about 3/4 full or more, not just sloshing or occasional immersion due to car motion. I think I will switch to cork - I’ll check out the Chevy option. I think it may work.

I am now almost certain that “56 Buick” has nailed the leak source. For 20 years up to 1957, Buick put the sender unit on top of the tank where it could not be a leak source. In 1958, they moved the sender to the front of the tank just above the seam. The sender is attached to the tank by five sheet metal screws that will be submerged when the tank is about 3/4 full. TERRIBLE DESIGN. It sacrifices safety for service convenience. The seal is supposed to be achieved by having the screws go through holes in a round rubber flange gasket. When I installed the sender unit in my shop, I failed to test the seal by inverting the tank and filling with enough gas to cover the sender. If I had, I would have found that gas was seeping out via one or two of the screws. I checked this today by cleaning that whole area with paper towels, waiting a minute, then feeling around for fresh gas near the screws at the lower part of the sender. Gas was seeping out. This leak simulates a flange leak because the flange is bent upwards into a “trough”at this point. Gas from the gauge oozes into the trough, travels around to the drivers side and drips down. My repair shop will have to drop the tank, reinstall the sender unit with a fresh seal and using Permatex on the screws and the gasket itself. Then they can pressure test and also put gas in with the tank inverted and let it sit for 24 hours. I have to think this was a problem in 1958 unless the factory used a sealing method that does not appear in their repair literature. Thoughts welcome.

Excellent advice. As a lifelong fire protection engineer I cannot agree more. Gasoline vapor is one of the most explosive mixtures known, that’s why it makes such a potent fuel for our Buick’s!

To 56 Buick - the gas gauge seal is something I hadn’t even thought of, and it’s definitely a possibility. The gauge is out of sight unless the car is on the rack and it could be a leak point in a full tank! I installed the gauge in my shop before the repair shop installed the tank. It seemed pretty simple, but I was not happy about the screws penetrating the seal. I could have tested that on the bench. if we find the gauge to be the culprit, are there any suggestions for installation to get a good seal the way the gauge is designed? I know it was relocated to make it easy for mechanics to swap the gauge out, but thinking about it now, it’s a bad idea.

I will get a replacement from the vendor (Fusick). I then plan to have my welder solder/braze the flange and have my shop pressure test it afterwards. That should do it. In general I agree on rebuilding vs replacement, but a 62-year-old tank isn't the same as a generator or master cylinder. I hadn't thought of the testing issue but in future I will make sure to test before installing.

I'm not a welder, but in good light the weld looks like a common zipper. I believe it's leaking at the front and dripping towards the rear -- can't see the front at all. It has to be the seam somewhere because it leaked no gas with 3-4 gallons in the tank and leaks steadily along the top of the flange with a full tank. My local repair shop works on all kinds of big trucks and the manager said they're experienced at pressure and vacuum testing tanks for leaks. I like the brazing idea - I have an excellent local welder who could braze the seam of the replacement tank. Thanks for the suggestions!

Very good suggestions on testing. If the vendor provides a new tank, I can test as you suggest. I have a sniffer that could check for escaping fumes with the lines capped off. I also have a vacuum tester. I never thought to leak test a new tank - I’d assumed the vendor would do that.

Thanks for all the replies. The vendor has agreed to swap the tank, though I doubt it will be tested first. I’ll get to eat the labor cost, of course.

This week I had a brand new fuel tank ($500 with shipping) installed in my 1958 Roadmaster Buick. [Tank vendor name available on request - one of the "big" companies offering parts for Buick and Olds.] It was a good fit, no installation issues. The shop added a gallon of so of gas and then I drove to the gas station and filled it up to full. When I got home I parked it on a concrete pad for a few hours, and when I came back I saw a large wet spot under the left rear of the car near the exhaust pipe. The spot smelled of gasoline. Looking underneath, I saw that the new fuel tank was leaking steadily from the seam at the left rear corner of the tank. See attached pictures. You can see large drops of yellow gasoline along the seam. I actually watched the gas seep out at the corner. Whoever is making these tanks is not leak-testing them before shipping and does not employ competent metal fabricators. This tank was stored on a shelf in my shop for months in the original shipping box and then was carefully installed with new pads and straps. I am going to try to seal this tank to avoid having to remove it from the car loaded with 20 gallons of gasoline and having no drain plug. The seam will dry out when the gas level falls below the seam. Advice? Anyone done this kind of sealing job, and if so, with what product? Thanks in advance. Bill in Luray, VA

The doors on the passenger side fit poorly no matter what I try by way of alignment. Maybe that's the problem.

Joe - thanks for the reply. I frequently use Hometown Buick even though I have all the paper manuals. Easy to print and expand the visuals. I see the schematic you have in mind and the note that there are variations from model to model. This thought occurred to me because I have a two-bolt-hole bracket on each side of the frame where only one of the holes has a bracket for the caged nut above it. This must be a model variation. I'm putting off this project to warm spring weather. I am currently finishing the tires/springs project and the seatbelts project. Once these are done, the car will be fully drivable. It's in desperate need of cleaning and detailing too. Bill

I might be able to help if the front seat you have is the same or similar design as a 58 Roadmaster seat. It could be that the 57 Special seat has a gap between the bench and the backrest so you won’t have the problem I had. Try running your hand through or something like a plastic tool that won’t damage the seat. If there’s a gap it’s easy to do the lap belts. I did not do shoulder belts or the back seat. I installed standard GM belts for the late 50s. I can send a picture if you like. If my unused set would work for you, I’ll be happy to let you have it at no cost. if you want to pursue this with me, use my email address: highc.king@verizon.net. Bill in Luray Va

I’ve dealt with Resto Specialties before and had the same experiences. Thanks for the reminder. I’ve been ordering weatherstripping from Steele (at amazing costs) and had them on my mind. Eventually I’ll try to replace all the body bushings I can get at. For the moment I’ll concentrate on the missing ones. I expect the new tires to arrive today (800-15 bias) and need to get them installed along with four new springs. I did manage to thread the front seatbelts between the back and seat bottom without any cutting of fabric. Very tricky task that’s easy on most old cars and trucks.

Yes, that is very helpful advice as it explains why I don't see a nut for threading the bolt into. Lots of rust in this area. It's possible that the "previous owner" broke loose the cage nuts, or they might still be there. When the Virginia weather gets better I'm going to look at this problem more carefully. I might ask two questions as this stage: (1) why does Steele carry several different body mount cushions for 1958 Buick, and (2) what is a "pointed 3/8" hex head bolt"? See pictures.

Something I noticed today while working underneath my '58 Roadmaster (doing seatbelt installation). Some (at least 2) of the rubber body cushions on each side are missing the bolts, nuts and bushings. I can provide pictures if need be. I didn't notice this issue when I had the old interior and seats out of the cabin, though I don't know if that would have mattered. Now everything is assembled down to the seatbelts. Question -- can these mounts be fixed with the car fully assembled? It looks to me that on the cushions that are present (they look original), the bolt head is on the bottom and the nut is on the top of the assembly where I can't see it. Steele carries the rubber parts. All advice welcome. Bill in Luray

I accessed this thread because of something I noticed today while working underneath my '58 Roadmaster (doing seatbelt installation). First note that the underbody of this car is pretty rusty and previous owners seem to have left this alone. I think the car was undercoated early in its history (in NY state). It has never had the body and frame removed so far as I can tell, though perhaps someone tried and stopped partway. Anyway -- I noticed that some (at least 2) of the rubber body cushions on each side are missing the bolts, nuts and bushings. I can provide pictures if need be. I didn't notice this issue when I had the old interior and seats out of the cabin, though I don't know if that would have mattered. Now everything is assembled down to the seatbelts. Question -- can these defective mounts be fixed with the car fully assembled? It looks to me that on the cushions that are present (they look original), the bolt head is on the bottom and the nut is on the top of the assembly where I can't see it. All advice welcome. Bill in Luray

I'm about to install new Steele door weatherstripping on my Roadmaster. The only sections giving me trouble are the odd-shaped end-pieces at the center post. I think these would be common to all 1958 4-door hardtops, certainly to Supers, Roadmasters and Limiteds. Can anyone provide close-up pictures of what these sections look like when correctly installed? Many thanks. Bill Luray, VA

Today I mounted the wheels on the car and then scrubbed off the blue protective film from the sidewalls. To my surprise, on three of four tires I found indelible, ugly blemishes. See attached pics. Tomorrow I'll be discussing this with Lucas Tires. Infuriating.

That's usually my method too. I'm checking because the Buick has bolts instead of lug nuts. I wonder why?

Excellent, thanks. I just didn't look closely enough at that section. That's a gorgeous Caballero! I'm looking at the "restoration saga" now. Amazing effort - congratulations!

Looking for a wheel bolt torque spec on my 1958 Roadmaster. Doesn’t seem to be stated in any of the Buick manuals I have. Note that these are bolts, not lug nuts. Bill in Virginia

The Coker Tire Company's views are here (from 2015): https://www.hemmings.com/hmw/bias-ply-or-radial-tires.html My own comparison and choice was between a genuine bias ply and the American Classic "bias ply look-alike radial." My only qualm about the latter was the whitewall width (too wide) vs. superior control and roadability of a steel belted radial. I've had steel belted radials on all my big cars over the years, including my '58 Buick Century, numerous Cadillacs, and my enormous '77 Mercury Marquis. As Coker points out, bias plies ride narrower with less road contact and have a tendency to "follow the seam" in badly-maintained roads, which is just about every road. To my mind, the only valid reason for putting on bias ply tires (other than slightly lower cost) is mechanical and cosmetic authenticity with the car leaving the factory. We all draw our own lines there. I balk at things like disc brakes and third stoplights, while other might find these are perfectly reasonable. My main worry on my '58 Roadmaster is, will the perfectly-functioning, non-leaking Flight Pitch Triple Turbine Grade Retarder Dynaflow stay healthy? Bill in Luray

I admit they would look nice in the proper whitewall width. My question is whether this construction method will hold up to handling 5,000 pounds of Buick at 70mph. The old “retreads” would frequently fall apart, on both cars and trucks alike.

I'm probably going to go with the "American Classic Bias Look Radial" at $314 each. They have the "pie crust" sidewall.

Jensen racing - I agree. Bias plies would I think deter me from driving the car at all. I sure wish some vendor made the big radials with a 2 or 2-1/2 inch stripe, though. The 3” plus style went out on most makes around 1957. Johnd - thanks for reminding me about Diamondback! I’d forgotten about them entirely.