1964 and 1967 Chevrolet Corvette - Resto Clinic

'53-'67 Corvette Tech Q&A

Jeff Bernhardt Dec 1, 2006 0 Comment(s)
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'55 Corvette October '06 Feature Story

Bang The Drum
With today's fast-paced traffic, I am sure many readers (for those of us driving our C2 midyears before disc brakes) may wish to upgrade to power disc dual-cylinder front brakes. I can't seem to get a kit from anyone, and I was wondering who might have this available, and like our musclecar brothers, have a bolt-on kit that will allow us to keep our drum spindles.Maggie Simon, Via e-mail

I've addressed this question before, and I knew I would have to beat this drum at least one more time. In an earlier writing, I suggested to the car owner they copy the factory blueprint and install the components from a disc-brake version midyear car. The parts are all available, including complete trailing arm assemblies that you can just bolt on. Then someone wrote back and pointed out that the disc-brake Corvette frames have a recessed area just behind the kickup to allow for disc-brake caliper clearance. Well, yes they do, but I'm not sure how necessary that small indentation is, maybe if you set your rear wheels for maximum toe-out and haul wood in the back of your car.

That said, I also stand behind my original opinion that the '63-'64 Corvette brake systems are world class (for the period) and allow these cars to stop every bit as well as a classic sports car should. If yours doesn't, then something is wrong with a component of the system, not the system design. Look at your front brakes; they have large diameter wheel cylinders and wide brake shoes for a reason. I owned a nonpower brake '63 340-horse convertible for seven years and never had a problem stopping it. Step on the brake and the car comes to a stop. Step on it harder and all four wheels lock up. You have to feather the brake pedal somewhere in between to achieve the best stopping power without locking up the wheels, which only causes you to skid a longer distance. This is the best you can do without an onboard computer and ABS technology. I've converted my current '65, which has disc brakes, to power-assisted brakes so it stops as well . . . no, make that as easily as my '63 drum-brake car did. I've done the same for many of my clients' cars that have disc brakes. The disc brakes for midyears were designed to require power brakes, but GM's upper management nixed the notion in order to offer the final product at a reduced cost. This I got from one of the engineers on the original design team for Corvette disc brakes that started the project in December 1963.

Would I convert my drum-brake midyear to disc brakes? Nope, but I would certainly make sure the system was fresh and working efficiently. Are disc brakes superior in competitive-type racing? Yes, of course they are, but this is something entirely different.

Opinions are plentiful and widely varied, but I try to base my opinion on fact. I drive a lot of midyear Corvettes since I'm in the business that I am, and I know when I'm behind the wheel of a properly working '63-'64 (and some 300 early '65s), the drum brakes will stop me if they are called upon to do so. Drum-brake midyear owners should take solace in knowing that when they are cruising down the highway next to an '06 Peterbilt model 379 tractor-trailer with a 600-plus horsepower C15 Caterpillar diesel engine and a flatbed trailer maxed out on weight with a load of logs, he has all the stopping power he needs to get that rig down to zero miles per hour if he needs to, with drum brakes all the way around. Enjoy the glow in knowing that your parking brakes work a lot better than your disc-brake cousins.

Be sure to maintain your brakes that are so often ignored. Based on average driving of a collector car, flush and change the fluid every three years. Inspect shoes, drums, and hardware each time. Rebuild the cylinders and change brake hoses every five or six years.

Lift And Tuck
I have a '65 Vette, and I am in process of installing new S/S brake lines. Everything is fine until you try to install the one that goes from the master cylinder to the back left block. It looks like you have to raise the body to tuck the line in position. Is this the only way to do this? Can I get away with lifting the left side of the body high enough, or will I have to lift the whole body up equally? One more question: Can you recommend a place to buy a complete new frame?John Lira, Via e-mail

Your '65 has a 31/416-inch brake line that gets clipped in and runs along the top of the left framerail. On a nonpower brake car, the brake line runs from a four-way brass block in the front to a three-way brass block in the rear. You didn't indicate if yours was power brake or not, but you did mention the line goes from the master cylinder to the block in the back, so I'll assume yours is a power-brake car. The '65 Corvettes were the first regular production Corvettes to use dual-line master cylinders when you ordered the power-brake package. The inner floor of your car swoops (that's a technical term) down inside the side rails of the frame, almost to the lower edge. I'm not sure you'll be able to raise the left side of the body enough to accomplish this brake line replacement the way the factory did it, at least not without pulling the steering column, disconnecting the seatbelt cables, removing the bumpers and brackets, disconnecting the clutch linkage and various other assorted connections so you can raise the body up quite a bit. This would happen only after you removed all the left-side body mount bolts (for which you will have to cut a couple of them, I guarantee it) and back out all the right-side body mount bolts. You'll need a new body-mount kit because you won't want to put these rusty, nasty bolts and split, deteriorated cushions back in. If you stop and think about it, you're not very far from pulling the body completely off and getting it out of the way.

Or you can follow suit of the '67 Corvette and install the brake line at the bottom of the inner wall of the left framerail. In 1967, the factory ran an armor-wrapped brake line along the lower edge of the inner frame wall, through a notch-type opening in the crossmember and clipped it in place. You have the same opening in the crossmember of your '65 frame, so you're all set. You can't use the '67 brake line because it's the wrong size, so you'll need to stick with your '65 brake line, which isn't armor-wrapped. Be aware of the exposure of the brake line if you drive a lot of gravel roads or cross a lot of creeks and corn fields.

Contact the folks at America's Finest Corvettes in Ramona, California, for your frame needs. They can be contacted at (888) 318-3883 or www.corvetteusa.com, and can supply you with a bare frame or a complete rolling chassis. If you do end up replacing your frame, you certainly won't have any trouble doing the brake lines properly.

Steering You in the Right Direction
I have a '64 Roadster with manual steering. The steering column seems to have a lot of play. I mean that if I pull the steering wheel towards me, (turning to get into a parking space) my horn will make contact and sound. There is also a little up-and-down play, but not much. I have tried to shim around the base with rubber pieces but that did not help at all. I see new steering columns advertised by Flaming River but if my column can be repaired, I would rather do that. Would the coupler in the engine compartment be causing the excess play? I don't know if it's ever been changed. I have had the car since 1995 and have been replacing parts as needed.Ken, Via e-mail

I don't believe the play in the column has anything to do with the mounting of the column, but rather, the bearings that hold the shaft in check with the mast jacket. A little up-and-down play is not good. Certainly check your coupler (rag joint), but that's not the culprit either. A wiped-out rag joint isn't going to cause your horn to blow. Excessive play between the steering shaft and the mast jacket will. The first step is to remove the steering hub from the steering shaft. No need to remove the steering wheel from the hub. After the nut and washer are removed, use a steering wheel puller to draw the hub from its pressed fit on the shaft. You'll see the upper bearing sitting in the center of the turn-signal switch. There will be quite a lot of slop in the steering shaft at this point because there is no preload on the upper bearing assembly. This preload is a result of the mounting of the steering hub with the turn signal canceling cam at the upper column, and the lower bearing retainer and spring at the lower end of the column. What you can do is check the upper bearing's condition. Look for any missing balls from this ball-bearing assembly, or a dry or deformed cage resulting from excessive play. This bearing is available from Long Island Corvette Supply at (800) 466-6367 under PN 18-21B for $11.50. While you're in there, check your turn-signal bowl to make sure it's tight and secure to the mast jacket. The lower bearing is located on the portion of the steering column under the hood, just forward of the firewall. A clamp, spring, and spacer hold a preload on this bearing, which is serviceable once the steering column assembly is removed from the car. Check to make sure all these parts are in place and holding upward load on the bearing assembly (the spring is compressed between the clamp and the lower bearing). If there is play at this bearing, remove the column from the car to replace this bearing. It is available at Long Island under PN 18-30A for $15.00.

Igor Was Here
I own two Vettes: a '78 Indy Pace car and a '65 Red/Red roadster; it's this Vette that I have a problem with. It's not a numbers-matching car, which is no concern to me, but I have engine numbers that I can't identify in any GM manual. I was told the motor was from a '67 Vette and all numbers match up except for the engine suffix numbers, which I can't find. It's a 327/350 hp with a four-speed tranny Block casting number:3892657, Saginaw, MiBlock casting date: A 237, Jan. 23, 1967Engine numbers: V0124 HT, Is this build date Jan. 24?

I don't understand the rest of the numbers. They are: I B D 7109674.

This is what I believe these numbers are: 7 is the year and 109674 is the serial number of the car this was in? Is this correct? I don't get the IBD prefix. Can you help?
Gary D. Brown, Bangor, ME

You've done a good job at deciphering your engine numbers. I've seen engines built the very next day after they were cast on many occasions. The blocks were cast by the Grey Iron Foundry in Saginaw, just a short distance from the Flint Motor Assembly Plant. Assume yours was cast in the wee hours of the night shift of the 23rd, and assembled late in the day on the 24th. There could be well over 30 hours between the two events. The 3892657 casting number was used in a variety of Chevrolet vehicles, but the HT suffix is exclusive to the Corvette.This engine was originally installed in an early February '67 Corvette. The IBD is nothing I've seen before, and likely nothing that was stamped at the factory.If this engine had a problem during assembly, they would "tag" the engine to go to repair by way of paperwork, not with a stamping on the pad. If the engine were halted from completion for more than a day, there would be a "grind-out" of the date and a restamp over it. At the final assembly plant in St. Louis, the engine arrives as a complete assembly, and there would be no reason to stamp anything other than the VIN derivative of the Corvette that the engine is installed into. The gang holder is designed to hold those seven digits evenly and in a row, so that one swift strike with a hammer sets the impression of the numbers deep into the engine pad.I don't believe there would have been room in the holder to place three more digits, especially with spaces as you've indicated in your e-mail.This leads me to the conclusion that these digits were hand-stamped individually.I've seen machinists and machine shops stamp the pad with their initials, dates, or other "markings" so they can identify engines they've worked on; thereby ruining the originality of the pad.Look for a guy named Igor that may have rebuilt your engine once upon a time.

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