rebuilding a quadrajet - The 1947 - Present Chevrolet & GMC Truck Message Board Network

vmax · 01-17-2003, 12:33 PM

hello,
i have a quadrajet carb,i am having problems with my floats.
i cannot get gas to go into my carb.
does that sound like my floats sticking?
my fuel pump is working because i took off the gas line and it pumps really good.
i can put gas in the carb and it will start and it will die out after the gas burns out.
so can i buy a master rebuild kit or is there such a kit?
the truck is a `86 gmc 4+4 with a `76 gm 350 4bbl.700r-4.
i need to get my truck fixed because my wifes suburban is going in the body shop and she is taking my honda while it is in the shop. so i have to the 27th of this month to figure my carb out.
any feed back will be greatly app.
thanks in advance,jeff

J-Spec C10 · 01-17-2003, 12:36 PM

Niehoff makes a kit that covers most quadrajet rebuilds. the kits are like $20.

PHOENIX · 01-17-2003, 12:49 PM

ChevyChic just rebuilt her Qjet for the first time. Im sure she could give you some good pointers. She made it sound easy

85Silverado · 01-17-2003, 05:50 PM

If someone could do a write up with pics the next time they rebuild their q-jet that would be awesome!!!!!

PHOENIX · 01-17-2003, 06:09 PM

Paul D.:
Yes it would!

vmax · 01-17-2003, 07:48 PM

yes pictures of rebuilds would be great,and a diagram for vaccum lines too.

chevychic · 01-18-2003, 12:17 PM

The rebuild is pretty simple and straight forward. I just did my first one a week or two ago and didn't run into any major snags. You can get a rebuild kit from most any part store. They run from $12 to $24. I paid $24 for mine. It didn't include a replacement float. I think that you would need to buy that seperately if you think you need to replace yours. Might as well since you're going to be in there anyway.

As far as a diagram for vacuum lines, if you have a digital camera, take pics of all angles while the carb is on the truck. This way you have your own diagram to put it back on with.
Take pics along the way to help you put things back together.
If you don't have a digital camera, take notes. The rebuild kit comes with a fairly detailed explanation of what you need to do. It has a diagram that tells you how to take the carb apart and in what order.
I found that when you're getting ready to put everything back together, it can get hard to understand the diagram. Pictures and notes are very helpful then.

One thing the instructions don't tell you is when you're putting the carb back together, keep it upright until you get the airhorn on. Once the airhorn is on then you can move it around to get the other parts back together.
This is how I ran into my only little snag that was easily fixed.

Take everything slow and note how things go together. Set aside a couple of days to do the rebuild. You can get the rebuild done in just one day but have an extra day open for any snags you might run into.

A good tip from Mike (swervin ervin) was to tie a wire around the larger pieces when you're cleaning all the pieces with carb dip (get the one that comes in a bucket with a basket) this way you can lift the pieces out of the dip without getting your hands near it. You don't want that stuff on your skin.
Don't put any rubber or plastic pieces in that stuff either. Only metal parts can go in the dip.

When you're removing adjustment screws, screw them in all the way, counting how many turns it takes and make a note of it. Then remove them. When putting the screws back in, just screw them in all the way and then unscrew them the number of turns it took before.
The APT screw needs a special tool or you can use needle nose pliers to get a good grip on it. That worked for me.
I went down and picked up Doug Roe's Rochester Carburetor book. It's more for modding these, but it had some really good diagrams in it and it did come in handy. I decided to pick this up because I'm planning on learning more about these carbs and what you can do to them.

Anyways, that's my 2 cents. Check out Mike's site for more q-jet info http://www.73-87.com/garage/myqjet.htm
and I'm sure he'll chime in when he reads this.

If I can find where all my pics went (disappearing disk) I'll post them.

Give it a shot, you have all week to get it done. Plenty of time for a standard rebuild.

Good luck

**swervin ervin** · 01-18-2003, 01:41 PM

As far as a article, this is one of those things after it's done, you say, dang, I wish I had took pics of this and put them on the web. When I do it again, I'll be sure to document everything with pics.

If you have questions, fire away.

vmax · 01-18-2003, 04:54 PM

thanks alot guys and gal,
your help has been very welcomed.
ok heres the scoop,carb is off my truck,carb is opened up.
my floats are not moving freely,it feels like the metering rods are sticking. can they be out of wack?
everything is cleaned real well so there is no deposits in the holes.
another question, is there suppose to be a ball in the carb like a b-b size ball?
if there is were does this ball go?
and for the vaccum lines,the carb was all messed up vaccum lines un hooked so i dont know were they should all go.
anyone have a picture of the old style carb set up,no egr to hook.heat spring type choke. so i can see how the vaccum lines are hooked up.
i hope this helps out on explaination.

chevychic · 01-18-2003, 05:56 PM

There is a b-b size ball. That would be the discharge check ball, it sits below the disharge ball retainer that looks like a brass colored screw that sits below the ac pump. The airhorn would need to be removed to get to it.

I went out and took some pictures of my set up. Ignore the barney and big bird colors...I plan on redoing the hoses soon :p
However, the different color looms do help to trace the hoses to their location...so um, yeah I meant to do that....

chevychic · 01-18-2003, 06:01 PM

Here's a side view...sorry for the blinding valve cover...CHROME

Oh, and don't anyone give me a bad time about the location of my fuel filter...I needed to drive my truck and didn't have any more time to spend getting it on there. I'll be relocating it one of these days soon....

It's hard to see where the yellow hose goes so if you need a better picture I can get one for you.
My hot air choke just routes into the top of the intake.

vmax · 01-20-2003, 04:56 PM

ok i have the carb. taken apart and i dont see the small ball
below the accelerator pump. with this ball missing will this cause the fuel not to come into the carb.?

**swervin ervin** · 01-20-2003, 07:15 PM

Quote:

Originally posted by vmax
ok i have the carb. taken apart and i dont see the small ball
below the accelerator pump. with this ball missing will this cause the fuel not to come into the carb.?

No. The check ball is there to keep air from entering the pump well on the up stroke. When the pump goes down on the power stroke, so to speak, it pushes the check ball off it's seat to let the fuel go on out the pump jets. Once the pump starts back up, the ball will cover the hole up again, and it starts all over again. The only reason for the check ball is to keep air from coming in. There is a channel past the pump jets which is vented to the air horn. If this ball is missing, it will cause a bit of a lag the next time the pump is used, because of the air being sucked in.

In short, put the ball in when you rebuild it. It looks like someone has already had it apart and left it out. I bet it never did perform right after this either.

01-17-2003, 12:33 PM	#1
vmax Registered User Join Date: Sep 2002 Location: michigan Posts: 25	rebuilding a quadrajet hello, i have a quadrajet carb,i am having problems with my floats. i cannot get gas to go into my carb. does that sound like my floats sticking? my fuel pump is working because i took off the gas line and it pumps really good. i can put gas in the carb and it will start and it will die out after the gas burns out. so can i buy a master rebuild kit or is there such a kit? the truck is a `86 gmc 4+4 with a `76 gm 350 4bbl.700r-4. i need to get my truck fixed because my wifes suburban is going in the body shop and she is taking my honda while it is in the shop. so i have to the 27th of this month to figure my carb out. any feed back will be greatly app. thanks in advance,jeff

01-17-2003, 12:36 PM	#2
J-Spec C10 Whats this wire for?.... Join Date: Dec 2002 Location: Barrie, Ontario, CANADA Posts: 378	Niehoff makes a kit that covers most quadrajet rebuilds. the kits are like $20. __________________ Kyle CANADIAN CONNECTION '82 C10 Resto-Custom--> * 2 1/4" manifold back dual exhaust with Hooker Aerochambers & High Flow Cats Taylor Ignition Wires Centerline 15" Telstars with 32"x10" mudders

01-17-2003, 12:49 PM	#3
PHOENIX Registered User Join Date: Oct 2002 Location: Phoenix, Arizona Posts: 4,703	ChevyChic just rebuilt her Qjet for the first time. Im sure she could give you some good pointers. She made it sound easy __________________ * AVOID: LOPER'S PERMORANCE / LOPERSPEED.COM OF PHOENIX, AZ & COTTMAN TRANSMISSION *

01-17-2003, 05:50 PM	#4
85Silverado Registered User Join Date: Dec 2002 Location: Milwaukee, Wisconsin Posts: 198	If someone could do a write up with pics the next time they rebuild their q-jet that would be awesome!!!!! __________________ Paul D. '78 C20 Scottsdale 350ci 3 speed with granny gear 14 bolt rearend My trucks are "Car-Guy safe".......which pretty much means death trap in the hands of a normal civilian.

01-17-2003, 06:09 PM	#5
PHOENIX Registered User Join Date: Oct 2002 Location: Phoenix, Arizona Posts: 4,703	Paul D.: Yes it would! __________________ * AVOID: LOPER'S PERMORANCE / LOPERSPEED.COM OF PHOENIX, AZ & COTTMAN TRANSMISSION *

01-17-2003, 07:48 PM	#6
vmax Registered User Join Date: Sep 2002 Location: michigan Posts: 25	yes pictures of rebuilds would be great,and a diagram for vaccum lines too.

01-18-2003, 12:17 PM	#7
chevychic Registered User Join Date: Oct 2002 Location: Chanhassen, MN Posts: 1,061	The rebuild is pretty simple and straight forward. I just did my first one a week or two ago and didn't run into any major snags. You can get a rebuild kit from most any part store. They run from $12 to $24. I paid $24 for mine. It didn't include a replacement float. I think that you would need to buy that seperately if you think you need to replace yours. Might as well since you're going to be in there anyway. As far as a diagram for vacuum lines, if you have a digital camera, take pics of all angles while the carb is on the truck. This way you have your own diagram to put it back on with. Take pics along the way to help you put things back together. If you don't have a digital camera, take notes. The rebuild kit comes with a fairly detailed explanation of what you need to do. It has a diagram that tells you how to take the carb apart and in what order. I found that when you're getting ready to put everything back together, it can get hard to understand the diagram. Pictures and notes are very helpful then. One thing the instructions don't tell you is when you're putting the carb back together, keep it upright until you get the airhorn on. Once the airhorn is on then you can move it around to get the other parts back together. This is how I ran into my only little snag that was easily fixed. Take everything slow and note how things go together. Set aside a couple of days to do the rebuild. You can get the rebuild done in just one day but have an extra day open for any snags you might run into. A good tip from Mike (swervin ervin) was to tie a wire around the larger pieces when you're cleaning all the pieces with carb dip (get the one that comes in a bucket with a basket) this way you can lift the pieces out of the dip without getting your hands near it. You don't want that stuff on your skin. Don't put any rubber or plastic pieces in that stuff either. Only metal parts can go in the dip. When you're removing adjustment screws, screw them in all the way, counting how many turns it takes and make a note of it. Then remove them. When putting the screws back in, just screw them in all the way and then unscrew them the number of turns it took before. The APT screw needs a special tool or you can use needle nose pliers to get a good grip on it. That worked for me. I went down and picked up Doug Roe's Rochester Carburetor book. It's more for modding these, but it had some really good diagrams in it and it did come in handy. I decided to pick this up because I'm planning on learning more about these carbs and what you can do to them. Anyways, that's my 2 cents. Check out Mike's site for more q-jet info http://www.73-87.com/garage/myqjet.htm and I'm sure he'll chime in when he reads this. If I can find where all my pics went (disappearing disk) I'll post them. Give it a shot, you have all week to get it done. Plenty of time for a standard rebuild. Good luck __________________ *ChevyChic* 86 Chevy K-10 If I can't be a good example, then I'll just have to be a horrible warning. "You're braver than you believe, and stronger than you seem, and smarter than you think" - Christopher Robin

01-18-2003, 01:41 PM	#8
swervin ervin You get what you pay for Join Date: Dec 1999 Location: Cherryville, NC Posts: 4,798	Here's all the pics I took for Heather. http://www.73-87.com/photos/tech/hangrod.jpg http://www.73-87.com/photos/tech/hangrod2.jpg http://www.73-87.com/photos/tech/hangrod3.jpg http://www.73-87.com/photos/tech/idlemix.jpg http://www.73-87.com/photos/tech/idlemix2.jpg http://www.73-87.com/photos/tech/idlemix3.jpg http://www.73-87.com/photos/tech/aptpowin.jpg http://www.73-87.com/photos/tech/aptin.jpg http://www.73-87.com/photos/tech/aptpowin2.jpg Heather covered everything real well. It's not hard, and it sure don't take brain surgery to do. If it did, I couldn't do it for sure. Not sure about Heather. As far as a article, this is one of those things after it's done, you say, dang, I wish I had took pics of this and put them on the web. When I do it again, I'll be sure to document everything with pics. If you have questions, fire away. __________________ Mike 1985 Chevy C-10

01-18-2003, 04:54 PM	#9
vmax Registered User Join Date: Sep 2002 Location: michigan Posts: 25	thanks alot guys and gal, your help has been very welcomed. ok heres the scoop,carb is off my truck,carb is opened up. my floats are not moving freely,it feels like the metering rods are sticking. can they be out of wack? everything is cleaned real well so there is no deposits in the holes. another question, is there suppose to be a ball in the carb like a b-b size ball? if there is were does this ball go? and for the vaccum lines,the carb was all messed up vaccum lines un hooked so i dont know were they should all go. anyone have a picture of the old style carb set up,no egr to hook.heat spring type choke. so i can see how the vaccum lines are hooked up. i hope this helps out on explaination.

01-18-2003, 05:56 PM	#10
chevychic Registered User Join Date: Oct 2002 Location: Chanhassen, MN Posts: 1,061	There is a b-b size ball. That would be the discharge check ball, it sits below the disharge ball retainer that looks like a brass colored screw that sits below the ac pump. The airhorn would need to be removed to get to it. I went out and took some pictures of my set up. Ignore the barney and big bird colors...I plan on redoing the hoses soon :p However, the different color looms do help to trace the hoses to their location...so um, yeah I meant to do that.... Attached Images __________________ *ChevyChic* 86 Chevy K-10 If I can't be a good example, then I'll just have to be a horrible warning. "You're braver than you believe, and stronger than you seem, and smarter than you think" - Christopher Robin Last edited by chevychic; 01-18-2003 at 07:34 PM.

01-18-2003, 06:01 PM	#11
chevychic Registered User Join Date: Oct 2002 Location: Chanhassen, MN Posts: 1,061	Here's a side view...sorry for the blinding valve cover...CHROME Oh, and don't anyone give me a bad time about the location of my fuel filter...I needed to drive my truck and didn't have any more time to spend getting it on there. I'll be relocating it one of these days soon.... It's hard to see where the yellow hose goes so if you need a better picture I can get one for you. My hot air choke just routes into the top of the intake. Attached Images __________________ *ChevyChic* 86 Chevy K-10 If I can't be a good example, then I'll just have to be a horrible warning. "You're braver than you believe, and stronger than you seem, and smarter than you think" - Christopher Robin Last edited by chevychic; 01-18-2003 at 06:08 PM.

01-20-2003, 04:56 PM	#12
vmax Registered User Join Date: Sep 2002 Location: michigan Posts: 25	ok i have the carb. taken apart and i dont see the small ball below the accelerator pump. with this ball missing will this cause the fuel not to come into the carb.?



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