Charlotte - A Stock 1970 K10 Build

[Love 70 Chevys]

Reassembled the pump. The kit came with a new (blue) seal, spring and retaining clip. I'm sure the old clip and spring were fine and the seal did not look all that bad, but I put all the new parts in.

[Love 70 Chevys]

Installed the pump into the casting using the new return spring that came with the kit.

[Love 70 Chevys]

The kit came with a plastic bushing to better guide the pump operating lever. There was not one there when I took things apart, and I did notice some wear on the lever near the top. I liked the improvement and it snapped into place very nicely.

[Love 70 Chevys]

Installed the pump operating lever.

[Love 70 Chevys]

Reattached the pump lever and power piston links. They were a little stubborn, but I finally got them to behave.

[Love 70 Chevys]

Installed the pump check ball, spring and guide. The kit came with all new parts. I replaced the guide and spring, but I used the old check ball. Not much can go wrong with a steel ball and I trusted the tolerances and fit on the old ball more than I did the new one.

[Love 70 Chevys]

New needle, seat and gasket installed. Old parts are on the bench, new ones in the plastic bag. Seat has a screw driver slot for easy installation. Needle also comes with the tiniest clip you ever saw. It attaches to the float to make sure it comes out of the seat when the float goes down. Another nice addition I liked.

[Love 70 Chevys]

Next the float was installed and adjusted. I didn't have enough hands to show the adjustment and take a picture at the same time. The way it is done, pressure is put on the float right above the needle so it seats, and the float pivots up. (Shown in down position in picture.) When it comes up, it contacts the bottom of the white scale. There is a specific measurement from the top of the float to the top of the bowl when it is in the up position. For 1970 trucks w/ 250 motors the dimension is 1/4". You achieve the 1/4" by bending the float at the pivot where it is thin. I had to do some tweaking, but got it after a few iterations.

[Love 70 Chevys]

Next adjustment is for the height of the metering rod where it goes into the main jet. For a 1970 truck w/ a 250 the distance from the bottom of the rod holder to the top of the bowl is 5/64". I used a drill bit and had to bend the holder down a bit to get the right setup.

[Love 70 Chevys]

Next step was to reinsert the idle tube assembly. It just drops right in.

[Love 70 Chevys]

New bowl cover gasket and the bowl cover goes back on. There are six screws of varying lengths that hold the cover on. Luckily I bagged and tagged them. There is also a tightening sequence that should be followed to prevent warping of the cover.

[Love 70 Chevys]

Kit came with new vacuum break diaphragm. Assembled it onto the link,
fed it through the hole and attached it to the tang on the choke plate. Secured the cover with two screws being sure the vacuum hole in the diaphragm lined up with the hole in the casting. (Pretty much idiot proof.)

[Love 70 Chevys]

Reassembled the automatic choke lever onto the choke plate shaft. One screw and there is a flat on the shaft.

[Love 70 Chevys]

Reinstalled the throttle (RPM) adjustment screw. Initial set-up is to screw it in until it just touches the throttle linkage (with tension spring installed) and then turn it another 1/4 turn. Further set-up has to be done with the motor running.

[Love 70 Chevys]

Put the idle mixture adjusting needle and spring back in. Initial set-up is to bottom it all the way out and then turn back out 3 turns. Rest of the tweaking needs to be done with motor running.

[Love 70 Chevys]

Installed new fuel filter spring and new nut gasket. Did not have a filter, so I need to write myself a note to get one! Only hand tightened the nut until I get it.

[Love 70 Chevys]

Put air cleaner stud bracket back on with two screws and installed the new air cleaner gasket that came with the kit.

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Put idle stop solenoid linkage (first pic) and spring bracket (second pic) and throttle spring back on.

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Reassembled the rest of the linkage parts.

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The fast idle cam, choke rod and special fast idle cam shoulder screw were not on the carb when I started. Luckily, all three parts were available at quadrajetparts.com. They carry parts for many Rochester carburetors, not just the quadrajet. Part numbers Q3130-M6 and 4213. Opened up the box and put on the shiny new parts. There is an adjustment for the cam. Couldn't do it and take pictures at the same time, but I have included the instructions. For my truck, the gap between the choke plate and the throat was 3/16". I did need to bend the rod to get the right gap. There is also an adjustment for the vacuum break that I forgot to mention. (instructions below) I did not need to bend the link to get that right gap.

[Love 70 Chevys]

Before and after pics. This was a fun little project and I learned a lot. Can't wait to get the truck running in the spring and having a freshened carburetor is a good first step!

[landarts]

Really nice work you are doing on the K10. I love where you are going with this, it will be a beautiful truck.

[Love 70 Chevys]

Next little project is to rebuild the master cylinder. It probably would have been less expensive just to buy a new one, but I was able to buy an aftermarket rebuild kit on E-bay. The master cylinder was the original Delco and I just can't give up on anything that is original to the truck. This is what it looked like to start.

[Love 70 Chevys]

First step of disassembly was to pop out the c-clip that holds all the guts in. No matter what small pick or screwdriver I used, I could not get it out. So I drilled a 1/8" hole in from the side and then I could pry it out with a small diameter drift pin so that I could get a hold of it with needle nose pliers. Used a bolt and a big squeezy clamp to push in the plunger and relieve the spring pressure on the c-clip so I could drill and pry. Rebuild kit came with a new c-clip.

[Love 70 Chevys]

Took out all the old stuff. The seals were pretty gummy and things were coated in semi-solid old brake fluid. Luckily, the bore still looked pretty clean with only some very minor pitting. Cleaned it all out, soaked the casting in evaporust to get rid of external corrosion and then used brake fluid and a honing bar to clean-up the bore and make it smooth. The new parts and springs were an exact fit and sealed very nicely.