Discs-G0-Rear
Q: I have an '01 GMC Sonoma regular-cab pickup with the 4.3L V-6 and five-speed manual transmission. I've lowered the truck and fitted it with 18-inch wheels and tires. I have the 3.42:1 Posi-traction rearend. I like driving fast on country roads, so I've taken kind of a sports car approach to the truck. I'm happy with the suspension and engine, but I'd like to upgrade the brakes by installing rear disc brakes. I don't care for the rear drum brakes.

Would it be possible to install the rear disc brakes from an S-10 or S-15 4x4 on my truck? Can I still my current brake lines and emergency-brake cables?
Matt Brown,
Dallas

A: The general answer is yes, with a few cautions. Your drum-brake truck uses the same style four-bolt backing plate flange as those used on disc-brake rearends. You need to be sure that the axleshaft end is the correct diameter to fit tightly and align the rear discs. If the fit is either too tight or too loose, some machine shop work will be necessary to get a proper fit.

You will need some new brake lines along the rear axlehousing. Just like your front disc brakes, the new rear discs require short lengths of flexible brake hose between the hard line and the calipers. With your current drum brakes, the hard lines go all the way to the back of the wheel cylinder.

You can most likely use your current parking-brake cables. There is probably enough slack to handle any minor differences between your old drum brakes and new disc brakes. If your old cables won't work, replacing them with correct cables isn't a big deal. You can buy new cables at your local GM parts department or get some wrecking-yard cables. We'd spend a few more dollars and get new cables.

When shopping for your rear disc brake assemblies, try to find a wrecking yard that understands what you're doing. Explain your project and be sure you can trade for another set in case there are any unexpected fitment problems. A knowledgeable dismantler has the reference sources that should be able to pinpoint the right donor vehicle. You're most likely to find the rear disc brakes on a 4x4 pickup or SUV, but you might also find them on some extended-cab two-wheel-drive pickups.

It's possible to find an entire disc-brake rearend and install it. If you go this route, be extremely accurate about your measurements. You should be able to use a rearend from a '99-'01 4x4 or a '98-'02 two-wheel-drive S-series truck or SUV.

Less Lugs
Q: I have a '92 Nissan King Cab pickup that I'm trying to build on a tight budget, since I'm still in school. One of the first things I'd like to do is convert from six-lug to five-lug wheels. A friend told me that the trick deal is to swap for Toyota hubs. If this is so, how difficult would it be for a novice like me to do? Is the swap the same for both ends of the truck?
Jeremy Johnson,
via e-mail

A: The good news is that Toyota five-lug hubs will fit on many mini-trucks, such as Nissan, Mazda, and Mitsubishi, because they use the same front wheel bearings. The bad news is that we wouldn't recommend that a novice do this swap. Any time you're dealing with front suspension and brakes, you're dealing with your safety. We suggest you find an experienced shop that has done this swap before.

For your truck, an '89-'95 Toyota five-lug hub and rotor will bolt right on your spindle. You need a grease seal to adapt the Toyota hub to your spindle. A good old-fashioned auto parts store (the kind that still does machine work in the backroom) should be able to find the right seal. Your truck will also need a spacer between the spindle and the brake caliper so the caliper will bolt up properly. Depending on the spacer thickness, you may also need longer mounting bolts.

Out back, you have two choices. The less expensive course is to find a competent machine shop (notice how important a good machine shop is to this whole swap) that can re-drill your existing axle flanges to the Toyota five-lug pattern. The more expensive option is to install a complete Toyota rearend.

The easiest choice of all is to find some six-lug wheels that you like. When you consider the cost and hassle of converting hubs, some of those six-lug wheels might start to look a lot more attractive.

Disappearing Emblems
Q: Is there an easy way to remove the factory Silverado badges from my truck? I know they are adhesive, not bolted on, but I don't want to ruin them or damage the paint.
Mike Dumoniere,
via e-mail

A: Relatively thin fishing line is the key to easy adhesive emblem removable. The fishing line is used to "saw" between the emblem and the adhesive. Take a length of line that allows sufficient room to grasp the line on both sides of the emblem. Something in the 18-inch range should do. Wrap the ends of the line around two sticks or clamp the ends in a couple Vise-Grip pliers.

The adhesive residue can be rolled off with your fingers, or you could use an art gum eraser. If you really think you might ever want to reattach the emblem, take a few reference measurements or a photograph.

Broken Teeth
Q: Our family vehicle is a customized '94 Chevy Astro. It has been lowered, fitted with 17-inch alloy wheels, and covered with a multicolored paintjob with some pretty wild graphics. I like the van, as it serves my young family and it still looks pretty cool.

My problem relates to the starter and flexplate. The Astro has the 4.3L V-6 and automatic transmission. I've had to replace the flexplate once and the starter twice due to starting problems. It seems like the teeth are meshing properly. I have broken off several teeth on both the starter and the flexplate.

Replacing a starter is a pretty easy task on Chevy products, but the flexplate is more involved. Everything is nice and clean. I haven't noticed any obstructions that might be causing an alignment problem. I'm getting very tired of damaged starters and replacing them. Can you suggest a way out of this problem? Thank you.
Vaughn Meade,
San Diego

A: Our first guess is that you're having an alignment problem. Starter and ring gear teeth don't just starting falling off if they are properly meshing. Check the teeth for a noticeable wear pattern. The pattern should be uniform, not too close to the edge and not too deep. The distance between the starter and flexplate or flywheel should be 0.018 inch as measured with a wire gauge.

If the gap isn't up to spec, shims can be used to correct things. These thin shims are often included with starters or they can be purchased separately. If the starter pinion gear is too close to the ring gear, use a 0.015-inch shim between the starter mounting pad and the engine block. Using a 0.015-inch shim will increase clearance by 0.0050 inch. If the first shim doesn't solve the problem, try adding another 0.015-inch shim.

If the gap needs to be decreased, shim only the outer mounting bolt. The 0.015-inch shim should decrease the gap by approximately 0.010 inch.

Even though you've replaced two starters, it doesn't mean they were perfect. We've had cases where it took three or four "economy" rebuilt starters to get a truly good one. It's tempting to pick the least expensive starter, but that's not always the best long-term value. Sure, these budget starters often come with "lifetime" guarantees, but so what? The savings aren't worth all the aggravation and wasted time. When shopping for a replacement starter, ask what parts are new and which ones are just refurbished or simply reused. We've had the best results with brand-new made-in-the-USA starters.

Those compact gear-reduction starters are a good idea. They have the extra capacity to start engines under adverse conditions such as hot engines on hot days.

You mentioned that you didn't see any obstructions on the mounting pad, but you probably didn't check the threads inside the block. It would be a good idea to chase the threads with a tap. If there is any significant debris inside the thread bores, that could affect the bolt's ability to seat completely. If the starter isn't secure, it can move and lead to damaged or missing teeth.

Filter, pump, or what?
Q: I'm having fuel system problems with my '94 GMC Sierra pickup, which is equipped with the 5.7L V-8 and the automatic transmission. It seems to be starved for fuel. It hesitates or stalls completely. My friend Jim suggested that this era of GM trucks have had problems with the fuel filters, so I changed the filter. It was much easier than changing a fuel pump.

Changing the fuel filter didn't cure the problem. I checked to see if the fuel pump was pumping fuel, and it was. When I had the fuel filter off, I blew compressed air through the disconnected lines and nothing unusual came out. So, the fuel filter is new, the fuel pump works fine, and there aren't any restrictions in the fuel lines. I use additives and fuel-drying products during the winter months, so there shouldn't be any excess moisture in the tank.

Could my problem be something other than a fuel system one, or did I overlook something? I hope you can help me.
Evan Mitchell,
via e-mail

A: It sounds more like a fuel pump problem than a fuel filter issue. Just because a fuel pump moves fuel, doesn't mean it is doing it at the proper pressure. You should check or have it checked by a mechanic. The fuel pressure for your truck should be in the 9-13 psi range. If your readings are less that specified, driveability problems can be the result.

GM has a technical service bulletin (66-63-09) related to hard-starting or no starting problems. This service bulletin discusses the possibility of a ruptured fuel pump pulsator. That can lead to decreased or no fuel pressure. Either case could cause the symptoms that you have described. The fuel pump pulsator is a flexible connector that is located between the pump and the metal fuel line in the gas tank.

You mentioned that you use wintertime chemicals (such as ethanol) in your fuel system. While they may dry the fuel, they can also damage the flexible part of the fuel pump pulsator. The pulsator can also deteriorate with age. The GM recommended replacement fuel pump pulsator is made with Viton, which is more resistant to the additives.

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