# To Convert to Disc Brakes or Not



## red68gto-Joe (Mar 10, 2006)

I have a 98% stock, numbers matching, low optioned 1968 GTO "survivor" that has manual drum brakes front and rear. To say the least, it is an adverture to stop it. I bought it to drive but do not want to ruin its investment value. Here is a question for discussion: How much will it de-value the car if I keep it otherwise stock but retrofit it with a power booster and front disk brakes. I would clean and save all the original parts that I take off of the car when converting it.

I welcome opinions, comments and advice.

Thanks

Joe


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## SANDU002 (Oct 13, 2004)

Joe,

You would be doing yourself and any future owner a big favor by installing disc brakes. It should not have any effect for any show purposes. I put disc brakes on my '67 and it really makes a difference.


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## 67gtolvr (Mar 11, 2006)

Joe,
I just joined this evening and thought I would offer this. I am the original owner of a '67 with manual drums ( how could they let this happen?). I am starting to restore the goat and found it (for me) very expensive to convert the system. Why not just add a power assist to the existing system? It seems like a much more economical way out. 

By the way, what does matching numbers mean? My car has the orig. engine and auto. trans. What else could be matching?


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## red68gto-Joe (Mar 10, 2006)

67gtolvr said:


> Joe,
> I just joined this evening and thought I would offer this. I am the original owner of a '67 with manual drums ( how could they let this happen?). I am starting to restore the goat and found it (for me) very expensive to convert the system. Why not just add a power assist to the existing system? It seems like a much more economical way out.
> 
> By the way, what does matching numbers mean? My car has the orig. engine and auto. trans. What else could be matching?



To 67gtolvr; 

You are lucky - I wish that I still had my highly optioned 68 GTO that I bought at Broad Street Pontiac in Newark NJ in 1968. I sold it for my first of many Corvettes in 1970. I loved that car but was lured away by a Corvette convertible. The GTO had power drum brakes. They were much better than my present car's non power drum brakes. It stopped pretty well but I do remeber a lot of brake fade.


Adding power assist does seem to make sense, but most catalogs that sell replacement power boosters do not recommend it. I do not know why. I'll research it via the GTOAA experts and via companies that sell the boosters. 

Regarding numbers matching: In 1968 and later Pontiac stamped the last 8 digits of the VIN number on the front of the block and on the trans so for these later GTO's it is easy to verify it is the original engine and trans (that would be a numbers matching car). For earlier cars you need to be sure that the casing dates on the block, intake manifold, carburetor, etc are relatively close to the build date of the car (on the info tag that has the VIN, paint codes, plant of mfg, etc.) and the block casting ID (e.g. WT means 350hp with manual trans) matches the PHS build records. You can also replace missing original parts (tossed away when the car was serviced or traded in as cores) with parts that are have the right manufacturing dae (like I need to do for my missing Quadrajet carburetor).

You are in a very good position, being the original owner of a car with the original engine and trans you can prove have a numbers matching car with service records. 

With a 1967 and earlier a person could "counterfit" a numbers matching car by finding an engine and trans with the correct casting dates. Ir sometimes thay maching away the incorrect number a re-stamp it with the "correct" number. Unfortunately, this is done a lot of times to counterfit Corvettes.


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## red68gto-Joe (Mar 10, 2006)

Are they power or manual disc brakes?


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## basarowich (Apr 4, 2006)

*brake conversion*

i also have a 1968 gto with drums. I have bot a set of spindles and J brackets to convert to discs. I would be interested in the part numbers you obtain and if you are going to go with the single (69) or dual (68) calipers.


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## kerno (Apr 6, 2006)

If you're going to do the disc brake conversion, I think you'll be happier with the 1969 and later single piston calipers than the 1968 four piston calipers. The 1968 units did not float, so the pistons had to move in and out to accomodate any rotor runout. Additionally, the fluid crossover holes in them were really too small to allow rapid enough fluid flow.


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## louis Andrew (May 18, 2006)

Joe,
I have heard of a company out there that sells special drum shoes that suppose to work as good as a STANDARD single caliper disc system. I believe they adverstise in Hotrod or Hemming Muscle Car Review. I preffer disc myself, but my car is not number matching.


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## Ragtop70 (May 18, 2006)

red68gto-Joe said:


> I have a 98% stock, numbers matching, low optioned 1968 GTO "survivor" that has manual drum brakes front and rear. To say the least, it is an adverture to stop it. I bought it to drive but do not want to ruin its investment value. Here is a question for discussion: How much will it de-value the car if I keep it otherwise stock but retrofit it with a power booster and front disk brakes. I would clean and save all the original parts that I take off of the car when converting it.
> 
> I welcome opinions, comments and advice.
> 
> ...


Converting to discs will not affect value one way or another. It may make the car more desireable when you sell causing it sell quicker. No potential buyer is going to come check out the car and say -nice car but no thanks, I'd buy it if it still had the tiny drums on it!


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## MKS_68 (Feb 17, 2006)

red68gto-Joe said:


> I have a 98% stock, numbers matching, low optioned 1968 GTO "survivor" that has manual drum brakes front and rear. To say the least, it is an adverture to stop it. I bought it to drive but do not want to ruin its investment value. Here is a question for discussion: How much will it de-value the car if I keep it otherwise stock but retrofit it with a power booster and front disk brakes. I would clean and save all the original parts that I take off of the car when converting it.
> 
> I welcome opinions, comments and advice.
> 
> ...


I have a 68 as well & converted to front disc a few years back (used the Original Parts Group SS brakes kit). Conversion went without problems and I was amazed at the difference. Felt like a different car! Last year I also converted to rear discs - (this was more of a pain as I ended up having to take the rear out entirely to replace the thrust washers that fell out of my Moroso diff. when the axles were out!). They look great, matching front & rear drilled discs, but there was no noticable difference in stopping power by the addition of the rears. Also, the parking brake has nowhere near the holding power of the drums so keep this in mind if you are considering doing the same. I would say rear disc conversion is a "looks only" thing. BTW, if anybody wants to buy my old complete F&R power drum set let me know... everything has LT 500 miles wear (except spindles which are original)


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## lars (Sep 28, 2004)

I did an article years ago for one of the Pontiac magazines. I tested a manual drum brake 68 GTO against a power disc brake 69 GTO in 60mph-0 brake testing (using a Vericom performance computer to document results). Here's what I found:

First baseline tests were with both cars in the "as-received" condition with well-used, but servicable, brakes. The drum car initially stopped within just a few feet of the disc car, but stopping distance starting increasing significantly after the third 60-0 test (tests were done quickly back-to-back to get the brakes rediculously hot). The disc brake car outperformed the drum car by a bit of a margin after the brakes were really hot, but not when the brakes were cool.

We then did a complete brake rebuild on both cars. We turned drums and rotors, installed pads on the disc car, and installed all new springs, shoes and hardware on the drum axles. We used top-of-the-line semi-metallic shoes (they were Accel shoes - since discontinued), and we bled the brakes.

With the good quality shoes and a fresh rebuild, the drum car performed identically to the disc car, even after 6 (six) 60-0 fast tests. Braking distance was limited only by the driver's ability to modulate the brakes to avoid complete lock-up. The drums never faded with the new hardware installed, and both cars stopped straight, safely, and with no pull or erratic behavior. We actually did several of the drum tests with hands-off the wheel during braking.

You'd have a hard time justifying switching from drums to discs from a safety point of view if you have a well-rebuilt set of drum brakes with good-quality shoes, unless you're involved in some type of competition driving where you're going to get the brakes glowing red hot for a period of time. On the street, discs look cool, but that's about the extent of the advantage.:cheers


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