Bill Shields

I have two identical Buick-correct AFBs, #2800s. The one I am using now came from an eBay vendor/rebuilder, the Carburetor Center in California. On receipt it had several obvious flaws (wrong setting for the starter switch as an example). I sent it back and they corrected the issues. The second AFB I bought used on eBay years back and simply put it on the car while I was doing the partial restoration. It started and ran OK, but I never drove on the road with it. Eventually I sent it off to the rebuilder National Carburetor, which had done a flawless rebuild on a big Holley 4-barrel for my '77 Mercury. This too arrived with a few problems and I sent it back. They reworked it and sent it back to me after I'd installed the one on there now. Both of these carbs were complete and not dirty basket cases. I chased down an accelerator pump rod for one of them. I assumed that factory Carter settings would do the trick provided the base gasket has a good seal. The carb on the car runs great at all speeds, does not leak, and doesn't bog down except for coming off idle before the choke is fully open. It's certainly not impossible that the rebuilder screwed something up. I can always do a swap and see what happens. I do not plan to get into the internals on either one. By the way ... when I first got this Buick it had a Rochester setup. I sent the carb to the gentleman who advertises in the Buick Bugle. ("Going out of business" for 3-4 years now.) My first try at running this rebuild resulted in raw gas bubbling up all over the manifold! Sent it back and he redid it. Second try, no leak but the car ran terribly. I gave up on that approach. Many years back, I had several Cadillacs, a 59 and a 63, that ran beautifully on Carter AFBs. But they were "factory original" cars impossible to find today. Bill

Many good suggestions and ideas above. Thanks to all. To Ken: I've looked at those tips before but I will look again. You're right about bypassing the idle circuit at fast idle, but the car will bog down from slow idle too if you wait just long enough for the fast idle cam to disengage. On the butterfly and the choke spring, I think they're not far off as "index" seems about the right tension to me. But this is a sensitive adjustment and daytime temps are rather high right now. See my report from today -- going two points rich and two points lean didn't seem to matter. I like the "two-finger test" except the bogging down is almost invisible under no-load conditions. Is that a clue? Vac reading is manifold, yes, vac hose feeding the windshield washer pump. I still worry about carb base leaks. The aluminum AFB requires a gasket sandwich that is really hard to seal on an old, not so smooth a manifold. I ended up using some gasket goop as part of the sandwich, as recommended in all the Cadillac shop manuals for this carb. But this suggests a test to me. I'll hook up my vacuum gauge so it can be seen in the car and see what happens to vacuum under load when the engine is stumbling. Very light throttle should not make much of a dent in curb idle vacuum of 17-18 inches. To Jon: correct factory AFB Model 2800s. I have two of these. Choke is hot air, seems to function properly. I will try your suggested procedure for retuning. Ambient daytime temperatures now are in the 80s but I'll try to do the procedure in the morning or early evening.

Tom - thanks. The '58 Buick manual asks for throttle opening of 35 - 55 degrees on the four barrel carbs. That way the engine doesn't just about explode on starting. My one "older Buick," a 1940 Limited, started on a medium throttle setting and was quite reliable. The flaw in this whole approach, it seems to me, is the flooding potential. Every time you depress the pedal, the accel pump squirts in gas. If it doesn't start right away, you're heading for a flooded condition. My '58 Century, which I owned for about 15 years, was an unmolested, low miles "used car" with a Rochester 4 barrel. I never touched the carb and it always started!

Tom - I eventually installed with a sandwich approach -- gasket on the manifold, aluminum shim, gasket on the carb. No leaks. For future reference ... do you rebuild as a business? I have two AFB rebuilds on hand from "national" rebuilders. One had the mixture screws way too far out and the fast idle screw set for no fast idle. The other had the choke set up so the fast idle screw cleared the fast idle cam with the choke fully open, hence the throttle never rests against the main idle screw. Neither rebuilder set up the starter switch properly. I'm not a carb rebuilder but these mistakes seem ridiculous for "professionals" who charge plenty. The first one I fixed myself and it's on the car, the second one I just sent back. Bill

Marty - that's an interesting idea that hadn't occurred to me. The odd thing as my pictures show is that the AFB "groove" does not line up with the manifold groove. But I need to look more carefully at that issue. FYI to all -- my rebuilder changed the setting of the vacuum start switch from correct to wrong. It's now set to activate on full throttle! Shop manual specifies in the range of 1/3 to 1/2 throttle.

I understand. I just cringe at the whole idea of removing the steering column and trying to take it apart.

Since the steel shim has no "give" to it, my thought is that it should go against the smoothest, straightest metal surface. The carb's aluminum casting base is smoother than the well-aged cast iron manifold surface. That factor and a '59 Cadillac shop manual gave me the idea to put the shim against the carb body. The manual wants gasket sealer (I assume #2) used there. I'll find out soon. I can't explain why the AFB groove is the opposite of the Rochester groove.

My solution on both of my '58 Buicks (horn had failed in both cases) was to intercept the horn ground wire where it approaches the steering column and connect it to an invisible little horn button mounted on the metal cover on the underside of the steering column. This is about a one hour task and cost of $10. The horn will blow when you want it to, just not from the horn ring. Bill in Luray

I recently sent off the Carter AFB from my '58 Roadmaster for rebuilding. It came back today in fine shape and I set about installing it. Suddenly I noticed something that struck me as odd. It's well known that in the years 57 and 58 (and maybe more), GM cars with four barrel carbs were using an exhaust gas passage to warm the carb and prevent icing. This passage was accomplished by a groove in the intake manifold and a matching groove in the carb base. (See picture Buick 1) This system apparently worked OK for the Rochester cast iron carb (see picture Buick 2). Note in picture Buick 2 that the manifold groove is towards the front of the car which matches the groove in the Rochester carb base. Now look at picture Buick 3, the base of my Carter AFB. The identical groove is there -- but it's at the rear of the carb and hence would not work, right? In picture Buick 4, I show the two carbs side by side, with the front of the carbs towards the top of the picture. Rochester, groove in front matching th manifold, AFB groove in the rear matching nothing. I'm aware of the corrosion issue on the AFB carb and the recommendation to interpose a thin steel plate at the carb base to prevent exhaust gases from coming in contact with the aluminum. The idea is to put the "paper" gasket on the manifold and the steel plate on top of it, then the carb. The Cadillac manuals state this for the use of AFB carburetors. The exhaust gas does not travel into the carb but the heat is transmitted through the plate. My question is, why does the Carter AFB, correct in all respects for 1958 Buick, have the groove for exhaust gas at the rear of the base where it could not match up with the manifold groove? Why would the Rochester and Carter carbs be mismatched in this way? I assume the car will run fine with the AFB as it did before, but should use the steel shim anyway? Bill in Luray

Do any of you '58 experts know what the correct gasket arrangement is for the Carter AFB 4-barrel carb? Today I pulled off the manifold of my Roadmaster a clean, used, but not rebuilt AFB I installed back in 2014. This carb started, idled and ran well at speed, but of recent had developed a bad flat spot coming off idle. I decided to swap the carb for an identical, professionally rebuilt unit I 've had on the shelf since last year. The issue I confronted halfway through the swap has to do with gaskets. On the car (probably since I bought it) was a sandwich of the gasket shown below (note the cutout for the exhaust passage) on the manifold side and a thin stainless shim on the carb side. This shim has no cutout for the exhaust passage, hence that feature would not work. (Frankly carb icing is not a concern for me.) I opted to drop the metal shim and just use the pictured gasket. (Note: the gasket that came with the rebuilt carb was a plain paper item, pictured below, that also would have blocked the exhaust passage.) I finished installing the rebuilt carb and started the car. It runs well at higher rpms with steady 17 inches vacuum. It runs unevenly at idle and vacuum is unsteady around 13 inches. I suspect a gasket leak, and will run some checks for that tomorrow. The question is, what gasket or gaskets/shims did Buick use? If that information is in the Shop Manual, I can't find it. Likewise zero info in the big parts books. I did find in my 1959 Cadillac Shop Manual that Cadillac in that year used an elaborate "gasket sandwich" for the AFB. All information welcome. Bill Shields (VA)

I can't count the number of parts I've tossed out only to regret it later. Keeping every original part is a good idea (now I know) because a later repro may be wrong!

Test of notification system.

duplicate posting in error

Thanks to all above who replied! I am not receiving the email notifications of replies to my post! I have to check and see why that is. I'll post some more replies tonight. While I'm here ... a question. I tested the windshield wipers (Cam-o-Matic) a few weeks back and they worked OK, somewhat. (Motor is good, a Ficken rebuild.) I was getting a sharp clicking noise on the drivers's side. I pulled the dash cover and tested again. Noise was coming from the aux transmission in front of the driver. At top speed the wipers worked smoothly, no noise. At lower speeds, this click occurred once for every pass. Cables seem tight. Something is sticking and then letting go. Is there anything to be greased? Thoughts welcome. Again, sorry about the late response. Have to check my account. Bill in Luray

The car: 1958 Buick Roadmaster. Lots of electrical work over the past few years: new harness, generator, voltage reg., etc. Everything works as it should. Puzzle 1: the ammeter hovers just on the charge side of center when the car is running. This is OK. When I activate any of the four power window switches, the window reactors fast and the ammeter jumps way up on the charge side, virtually off scale. Why does running a window motor cause the ammeter to act that way? I would have expected a momentary jump towards the discharge side. Puzzle 2: The dash cigar lighter is hooked up to power. I cleaned the inside of corrosion and tested for voltage on the center contact. The test light glowed strongly. But the lighter doesn't work and neither does a socket charger powering a USB lead. I tried the latter in the cigar lighter of my 77 Merc and it worked fine. Ideas? Bill in Luray Va.

Seeing that the summer Buick meets are gone again, I'm posting some pics of my completed 58 Roadmaster. It starts, runs and drives smoothly and quietly. Partial list: new, correct interior, factory-style seatbelts, all options work, new tires, powder-coated wheels, rebuilt suspension, fresh steering parts, rebuilt generator, fuel pump, water pump, new hoses and belts, Carter 4-barrel, new voltage reg, fresh engine harness, rebuilt windshield wiper/washer motor and pump, rebuilt speedo, speakers front and rear with factory fader, and lots of rechroming. It's by no means a perfect car, but it's a pretty rare Buick that has been preserved for another generation of Buick enthusiasts. Bill in Luray, VA

Please email photos to me at highc.king@verizon.net. Thanks. Bill Shields, Virginia

I need to remove the belt from the PS pump on my "new" 1966 New Yorker, which has the 440 cid and A/C. The shop manual talks about loosening two lower bolts to release belt tension. I found one easily enough but not the other - and the pump/bracket assembly seems pinned against the A/C bracket anyway. It can't be that hard to get the PS belt off. What am I missing? Bill Shields Vienna, VA