Good News, and Bad News

[Klawineagle]

Ok, I have been fighting a vacuum leak that I can't find.

Good News.................
I found where it is leaking. It is at the back of the carb, where all the throttle cables and brackets are.

Bad News...................
I haven't found the actual source of the leak. I can't see anything back there, lol.

I sprayed some brake cleaner back there, and the engine purrs. I know it is back there somewhere, just can't find it. Spray on the left or right side of the bracket, nothing. Right in the middle section of the bracket, bingo!!!

Any clues?

[camoit]

what bracket?

You need to pull the lines one at a time and inspect them. It's going to be a line or the carb base gasket. Or the carb nuts are loose that hold it to the manifold. We have seen that soooo many times.

[Klawineagle]

The bracket that the throttle cables, and all the adjusting screws are part of. At the rear of the carb closest to the firewall.

Ya, I don't see any lines on the back of it. That is why I was asking. Maybe there is supposed to be one, but there isn't. As for the base gasket, I thought of that as well, and had to order a couple of them. Which brings me to my next question.

If I am replacing just the base gasket, is it as simple as remove the 4 bolts at the top that hold the carb down, then lift it up? Or am I going to have to remove all the lines,and then try to figure out where they all go back together at?

[camoit]

You need to drain the radiator first. It has coolant running through the carb and removing it before you drain the radiator will fill the intake. I learned that the hard way. If you don't have any smog laws where you live we recommend getting a Weber. soooo much easer to work with.

[Acuta73]

You need to drain the radiator first. It has coolant running through the carb and removing it before you drain the radiator will fill the intake. I learned that the hard way. If you don't have any smog laws where you live we recommend getting a Weber. soooo much easer to work with.

LOL, been there, done that. Also filled my crank case once when I pulled the water pump. Ahh, the stupid mistakes we make...


I second, third, and fourth the idea of a Weber. Small pain to set up, but still beats the holy livin crap outa that Mikuni....

[Klawineagle]

If you don't have any smog laws where you live we recommend getting a Weber. soooo much easer to work with.

I would love to, however, I don't have any more money. Spent $1600 for the truck, and already dropped another $300 into it so far.

[Andy 2]

There is a vacuum line behind the throttle bracket right down at the bottom of the carb on my 88. I have to get right over top with a flashlight to see it. If you want to take the carb off just make some tags up out of masking tape and number them. Make 2 of each number from 1 to 10 say. As you pull the lines off, stick a tag on the line, and a tag on the nipple it came off. That way you can put them back in the right places. This way you can replace the gasket and check out all the lines and fittings with the carb off the manifold.

[Klawineagle]

Update. Thursday night, we pulled the carb off. Found a busted vacuum line at the back corner of the carb, by the valve covers. Replaced the line, and gasket. Put it all back together. Guess what?!?!?!?!

Wrong. Still acting the same. Squirt the brake cleaner dead center of the throttle bracket, engine will purr smoothly.

Hopefully going to pull it back in the shop today, and take the carb back off, and take a look at the back of it and try to figure out what is going on. I know everyone says to replace the carb with a Webber, but I don't have the money. I dropped my entire savings account into buying this truck and getting it to where it is today. We have nothing left, and I still have to come up with money for my trip next month to pick up my son for his graduation, which I don't see happening. But I gotta, cause he is coming to live with me.

But going through the Haynes manual. It talks about some type of "wax" valve on the back of the carb, under the throttle cable bracket? Anyone have any clue to what this is? That is about the area that we believe it is leaking from.

Someone else told me to just tap out the cover over the mixture screw. Back it out 3 1/2 turns, and forget about the vacuum leak, as that would fix it as well.

[Andy 2]

Is it possible that the throttle body is cracked or worn around the shaft, or the gasket between the throttle body and carb body is cracked?

[Klawineagle]

That is what we are thinking it maybe. I went ahead and bought 20 feet of vacuum lines. This truck still has vacuum lines from the factory, only found one bad one, believe it or not. Going to replace all of those. I bought a carb rebuild kit. Holy crap there is a lot to that carb. Not sure if I want to tackle it myself, or just pay someone to rebuild it.

Someone that I know that rebuilds carbs, of course he says he won't try to rebuild this one, told me to just unplug the mixture screw and adjust it. That will make up for any vacuum leak, and it is the easiest fix.

[Andy 2]

Have you checked the auto recyclers for a used carb off of something with less miles. car-part.com might have something listed. Even if you cant find a great carb you might be able to put one good one together out of two. If you need another throttle body that would be one way to go.

[Fordubishi]

Real stupid question for people that have the old crappy carb. Has anyone looked at the old manual 2 bbl's off a Toyota,Datsun,Chevette or 4 cyl mustang?? I did put a Chevette manual 2 bbl on an older Tercel and only had to oval the holes a little to fit onto the Toyota studs. With the manual carb we removed almost 100ft of freaking vaccume lines (ok 10 ft) and ended up with just the brake booster and Distributor line.Granted the car was a 5 speed so not sure if it would work on an auto but the Chevette carb has the linkage for the kick down no matter if it's of a standard or auto.

[originalowner]

I read these threads and as a matter of fact I am a member here because I can add the perspective of a person who bought one of these trucks brand new and still have it- 344,410 miles later. The motor has never been out of the truck. And it uses no oil...

Heck, I just recently pulled the original vacuum harness out from under hood. I never bothered to remove it when I did the Weber retrofit.

I don't know what kind of Superman kryptonite :))they made those vacuum harnesses out of, but 24 years later, the rubber is still soft and pliable. (The harness is on my workbench at da house as we speak.) So I'm with Camoit...you have a leak at the carb baseplate gasket.

Save your bucks and do the Weber thing. Once it's installed, it's basically "set it and forget it"...

http://www.webercarbsdirect.com/category_s/616.htm

The adapter kit is another 25.00 bucks...

[Klawineagle]

I will have to look into it later. I gotta get my car fixed as well. All the money I have spent to buy this truck, plus fix it up, was my car fund. lol. Gotta love having kids grow up. I am trying to work out a deal with someone and trade one of my 1991 Camaro's for either a 1988 Dodge Ram 50, or a 1988 Mighty Max. Hopefully I find something out soon. Would love to have one of these as my own to drive, instead of driving my son's.