New caretaker/owner of a 1967 Roadster - Have some questions

['67Vette]

Hello all, and thanks for clicking on my first thread here. My Stepfather passed away nearly two years ago, and my Mom inherited his 1967 Roadster, in Marina Blue, with bright blue interior. It has the white soft top, and a Marina Blue hard top. It has some problems I could really use some help with. Here are a few pictures:

I know very little about this Corvette's history, other than my Stepfather came back from Vietnam and bought this '67 with a different 427 tri-power than was original, the engine numbers never matched, but I remember it having the triangular air filter a decade or so ago.

I don't know why the replacement 427 tri-power (with non-matching numbers) has also now been removed and sold. It now has a fresh 489 c.i. installed, with a Tremec 5 speed, as of about 4 years ago. As the old saying goes, it is what it is - a driver now.


Be that as it may, I was able to get it running with this engine, and the MSD spark and distributor it had on it:

Here's the first problem I'm trying to figure out. The master cylinder does not have the brake booster installed, it's completely manual, and the brake pedal inside the cab is higher than the other pedals as a result:

Is the brake booster missing because there is now no more room for it? Is there an aftermarket brake booster that could fix this problem?

Thanks again!

 

[Toms007]

First off, Welcome to CAC! . Beautiful mid-year you have there.

As for the power brake booster, do you know that it HAD power brakes originally? My 64 didn't. I know it was available but the "Big" big block it has now, darn sure, takes up the space of the booster/master cylinder. Not sure if there is something out there to alleviate the problem. Maybe Tom Bryant, one of our resident experts on C1 & C2s can help with this question.

 

['67Vette]

Thanks for the reply!

I'm not certain if it had power brakes, the rubber pad on the pedal is gone now too, that may have said something on it. Is there a way to know if it did come with power assist brakes? I was under the impression that 1967 was the first year of four wheel disc brakes, and power assist - I really don't know. It has all 4-wheel discs and calipers, that look brand new nearly, but stock, the emergency brake between the seats, will need adjusting in the rear drum/disc too.

The thing that made me think it had a booster originally, is the way the firewall mount looks, as compared to a stock booster and the mounting point on it, and the way the pedal is now an inch higher than the other pedals. The brakes are horribly stiff, I'm 190lbs 6' 2", and I'm pressing my hardest at times to get it to stop. Definitely feels wrong, as if a booster would've been there. I drove this with the replacement 427, the muncie-4 speed, and stock brakes years ago, and I would swear I don't remember the brakes being anywhere near this bad.

I really think the brakes were an afterthought to jamming the biggest motor in this thing possible. My Stepdad was 6' 5" 315lbs, former Marine, and liked all things powerful.

If anyone can confirm if this had stock 4-wheel disc, and power assist brakes from the factory, that would be very helpful. If there's any more detail that I can provide, please let me know. Thanks again!

 

[Toms007]

Well, Power brakes were available earlier than that, pretty sure 1963 (maybe earlier than that) and Disk brakes (4 wheel) were first offered in 1965 (became standard, although drum brakes were offered as an option for a credit). After the stockpile of leftover drum brakes was used up, Disk brakes were the standard. But power was an option.

A quick check of my Corvette Black Book verifies my thoughts, Power brakes first offered in 63 (option J50) and continued to be an option in 67 (same option number) Disk brake delete, early 1965 (option J61) was a $64.50 credit.

As far as the heavy brake pedal, That era of disk brakes were well known for having problems with the calipers, I'm wondering if your calipers are the problem. I believe I would start with the basics, master cylinder, brake lines and calipers.

 

['67Vette]

Under the car looks brand new, I'll get some pictures next time I'm over there of the calipers and discs, it's spotless.

It's only the master cylinder that looks old, in fact that's the only part that looks to have any patina on it, everything else has been replaced. I'll get some measurements of the room available to a booster, as I'm certain that I want to put one on.

Where would I need to drill the intake manifold in order to supply vacuum to a booster?

 

[Tom Bryant]

There was close to 23,000 Corvettes built in 1967 but only 4760 were equipped with power brakes. It's quite likely that your car had manual disc brakes originally. I had a 65 with manual brakes that had a very hard pedal even after going through the brake system and rebuilding the calipers. I did stop well though, so I lived with it. Also had a 427 67 coupe with manual discs and it didn't have a hard pedal. I can't remember if the pedals were even or not. If your car was converted to manual brakes, it might have the wrong master cylinder or push rod. If the booster was removed and the power master cylinder was bolted back in place and if it has a smaller bore than a manual cylinder it could be much harder to push. I'll dig in a little deeper on this in the morning.

Tom

 

['67Vette]

Really appreciate that, thanks Tom.

 

[Tom Bryant]

To address the height of the brake pedal pad from the floor there is some room for adjustment at the clevis where the master cylinder rod connects to the brake pedal arm. With the clevis hole in the brake pedal arm being close to the top pivot and nearly a foot from the pedal pad, a little adjustment at the clevis will move the pedal pad a good amount. First loosen the jam nut on the master cylinder rod then remove the clevis pin from the pedal arm. Then turn the master cylinder rod a few turns further into the clevis, shortening the rod, and reinstall it to the pedal arm. Check the pedal location to see if it's close to where you want it. When you get it right, reinstall the clevis pin retainer and tighten the jam nut. Hopefully there are enough threads on the rod to get it where you want it. Watch that you don't screw it in so far that it contacts the pedal arm.
There is only one master cylinder used for both manual brakes and the standard J50 power brakes. It had a casting number of 5455509 and is stamped DC. It has a 1 " bore. There is an optional J56 Heavy Duty brake package that only 267 people ordered for an additional $342.30 that used a different master cylinder casting number 5460346 stamped PG that had a 1 1/8" bore and a bleeder on both line bosses on the casting. This was used with special 2 pin calipers on the front wheels. Most people that bought this option were serious racers as this was a lot of money for an option in 1967. The master cylinder in your picture is not a J56 and really looks like it has been on the car since day one.
As for the stiff pedal, there are a couple of things that come to mind. It can't be a bad proportioning valve because you only got one of those with the J56 option. If your brakes are not dragging at all with the pedal released, the master cylinder is probably ok. I would inspect the hard lines for pinched areas or damage, especially in the engine compartment since we know the engine has been out a couple of times. Next, old brake rubber hoses can deteriorate internally, and the inner lining can collapse and block the flow of fluid. If they look old or even original, I'd replace them. A set with hardware is about $60.00 from one of the Corvette parts houses like Corvette Central or Zip. You could also step up to braided stainless hoses for $80.00 to $130.00 depending on which set you choose. These will give you better brake response and feel.
If you change your hoses, now would be a good time to flush the brake system with brake system cleaner to get the crud out and refill with DOT3 fluid. Make sure you open the bleeders on the calipers to flush the crap out of the caliper chambers. It has a habit of settling in the bottom so be sure to open both top and bottom bleeders. With the system open you can take a stiff thin scraper and slide it between the pad and rotor and pry the pad back towards the caliper. This way you can see if the caliper pistons are retracting. If you have one or more that aren't moving it's time to rebuild the calipers or exchange for new stainless sleeved remanufactured ones. Stuck pistons can also be your stiff braking problem. The easiest way to bleed Corvette brakes is with a pressure bleeder. I bought one a few years ago when I did the wife's 81 and I wish I had bought it many years ago. It's almost too easy and a one-man job. Most autos stores like Auto Zone or O'Rielly's loan them out.
Just for fun, what is your tach red line? I'm interested to see if your original 427 tri-power was a 400 or 435 horse engine.

Tom

 

['67Vette]

I'll go over there this coming weekend, and get pictures of all angles of the MC and the firewall, the calipers, and the gauges, as I'm not sure where the red line is, it seems really high compared to the sound the 489 makes. I take it as easy as possible and barely drive it, until I know more about it. There are some timing questions, and exhaust pipe questions incoming, but I'll get good pictures of all of this soon.

Thanks again for your knowledge and time, Tom.