Mustang MonthlyHow To Tech Qa
1966-1967 Mustang Hardtops - Beyond The Basics
Vintage Mustang Tech Advice From Bob Aliberto
All Screwed UpA couple of years ago, I paid $1,400 for a '67 Mustang hardtop for my stepson. It's about 90 percent done, but I've noticed the screws that retain the dash pieces aren't even close to being correct. A previous owner used any screw in certain-and very visible-holes. I would like to purchase an interior screw kit, but the holes are now larger than original, thanks to the ingenuity of the previous owner. Any tips or ideas about how I can remedy this situation?Curt CusimanoVia the Internet
Depending on the size of the oversize holes, you can likely substitute #10 screws, which have a larger root diameter than the original #8 screws used by Ford. A local autobody supply store should carry them. They're available chromed with oval heads, similar to the #8s. I keep a supply of the #10s on hand because I often run across stripped-out holes during a restoration, especially the screw holes for the doorsill plates.
Power DrumsI have a '67 Mustang with manual drum brakes. I would like to keep them, but make them power-assisted. I have a brake booster from a disc brake car. Will it work with my drum brakes?
Also, I have the power brake pedal support, but not the pedal. Is the pedal for disc brakes the same as for drum brakes? If not, can I modify the manual pedal to work? Jack SheetsVia the Internet
Power drum brakes were available as a dealer-installed option for '67 Mustangs. It's a good addition to a stock braking system.
The swap is straight-forward using the parts you already have. The pedal for a power-disc setup is the same for either power-brake system. The booster assembly is fastened to the firewall with studs that pass through the pedal support instead of bolts that thread into the pedal support, as with your stock master cylinder. You can install the power disc support or drill out the threaded inserts in your stock support while leaving it otherwise intact. In either case, you'll have to work under the dash because the brake pedal will have to be inserted into the pedal frame. I usually remove the driver seat and steering column to gain access.
Once the booster and pedal are mounted, the master cylinder can be installed. Use the drum brake master cylinder because it contains a check valve needed to keep the drum brake wheel cylinder cups expanded. Disc brake master cylinders don't have the check valve. Check the length of the pushrod that actuates the master cylinder and adjust it as necessary. If it's too long, the master cylinder will not fit flat onto the booster unless the piston is slightly compressed. In that case, shorten the rod so the booster fits without any piston movement.
Missing DataI bought my '66 hardtop from the original Southern California owner in 1988. According to the VIN and the door data plate, I know it was originally an Arcadian Blue hardtop with blue interior, built in San Jose on February 9, 1966, with an automatic transmission. The axle code is blank. Is there any way to find out which axle came in my car?Ken TunnellWasilla, AR
Missing information on a door data plate isn't that unusual and can't be explained in every case. Some missing info-such as your axle ratio-can be determined, while other data-such as a build date-is difficult to determine.
To ascertain your axle-assuming the axle is still the original one-look for the metal identification tag located on one of the rear centersection bolts. The axle ratio and model, as well as ring-gear diameter, is stamped into the tag. The typical axle for a 289 two-barrel Mustang in '66 is an 8-inch ring gear with a 2.80:1 ratio. The ratio can also be observed by rotating both rear wheels and counting the number of times the driveshaft rotates. A 2.80:1 ratio will cause the driveshaft to rotate just under three times per single wheel revolution. With a 3.00:1 gear ratio, the driveshaft will rotate exactly three times. A 3.50:1 ratio makes 3 1/2 driveshaft turns, and so on.