# Drum to disc brake swap help



## 704dorlemans (Oct 15, 2013)

Hello. I am planning to do a drum to disc brake swap on the front of my 1970 lemans. It seems like a daunting task and has me a tad freaked out. I have been trying to find online directions on how to do the swap and have been unsuccessful. Does anyone know the steps to do this swap? If so please let me know it would really help me get a grasp on how i am to do the swap


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## WhittP (Jun 19, 2013)

I recently did the swap on my 67 GTO from front drums to front discs. It was simple and straightforward. I used the kit from Right Stuff but I know there are a lot of options. I used the stock set up for a 68-72 since they are superior (I've been told) to the 67 and parts are widely available.

I already had power brakes but my kit came with a new booster/master cylindar, front lines, new proportioning valve, and all the brake hardware you'll need.

I'd highly recommend the kit and the results of this project. Say goodbye to those scetchy stops!


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## PontiacJim (Dec 29, 2012)

Check out the video on U-Tube called, "1968 Pontiac Catalina Drum To Disc Brake Conversion". The video has 16 parts and will help you to understand what you are getting into. Watch it, then throw out a few more questions to us and we can go from there.


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## Jared (Apr 19, 2013)

I've been considering this upgrade as well so I happen to have this bookmarked. I am planning on swapping just the front while retaining manual brakes. I may have to wait since my wife has decided to take next year off and go back to school so the extra funds for this type of project are just not there right now.

Summit posts the instructions for the SSBC front disk install:

http://www.summitracing.com/parts/ssb-a123-a/overview/year/1970/make/pontiac/model/lemans


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## wonbad66 (Oct 16, 2015)

Jared said:


> I've been considering this upgrade as well so I happen to have this bookmarked. I am planning on swapping just the front while retaining manual brakes. I may have to wait since my wife has decided to take next year off and go back to school so the extra funds for this type of project are just not there right now.
> 
> Summit posts the instructions for the SSBC front disk install:
> 
> 1970 PONTIAC LEMANS SSBC SuperTwin HD Disc Brake Kits A123-A - Free Shipping on Orders Over $99 at Summit Racing


New to the GTO game, would the above kit fit a 66 GTO? (flame suit on FYI)


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## Bigfoot21075 (Oct 12, 2015)

wonbad66 said:


> New to the GTO game, would the above kit fit a 66 GTO? (flame suit on FYI)


I THINK the above will, but I know this one does AND you get the Tandem Master. *EDIT* I see you get the tandem with either kit

https://www.opgi.com/gto/CH28690/

This kit allows for 14" wheels. If you have those make sure the kit you get will work with them like this one.


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## Pinion head (Jan 3, 2015)

Disc brake subject been covered many times before, should be a search function. i personally converted over twenty '65-72 GM A bodies and '67-69 F body's tp '69 up style disc calipers/caliper brackets. Have shipped out conversion parts for many more such disc changeovers. 

Parts needed include nice used '69-72 disc spindles, or can mill, drill and tap the bosses on your current drum spindles. The use of nice used GM spindles is to minimize problems by using the offshore disc spindles. 
-'69-72 nice used caliper brackets
-rebuilt or offshore calipers, caliper pin bolts, QUALITY wheel bearings, and rotor srease seals from local parts store
- disc brake hoses and rotors and pads from local parts store
- nice used or repro hose brackets, or open up your drum hose brackets with Dremel grinder.
-Lines and master ...what are you wanting I run? A booster, no booster? 
GM did not use a true proportioning valve til '71 models. previous factory disc brakes used a combination of a distribution block, a metering valve, and eventually a residual pressure valve. Easiast, non stock appearing proportioning valve solution is to plumb an adjustable proportioning valve into the line going to the rear brakes.
-on boosters, many of the offshore reproduction boosters, the bracket design mtg to the cowl will require washers on the studs between bolster bracket and the cowl. For a stock restoration booster, have found its better to have a nice condition Delco Morraine booster rebuilt/replated.

Will ck in after dark, have to make hay while the sun shines.


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## chui1980 (Jun 5, 2013)

Is like making rice and beans. I have done it in all my cars. Right stuff has the right stuff. Just pick your budget and lets roll


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## xWoodx (Oct 23, 2015)

Do you guys find that new, oem front disc brakes are enough stopping power? Going to need to redo the brakes on my 70 which has power / front disc brakes and am unsure if new stock stuff plus maybe rear disc is enough for a street car that may have 400hp, maybe 450 someday.


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## Pinion head (Jan 3, 2015)

xWoodx said:


> Do you guys find that new, oem front disc brakes are enough stopping power? Going to need to redo the brakes on my 70 which has power / front disc brakes and am unsure if new stock stuff plus maybe rear disc is enough for a street car that may have 400hp, maybe 450 someday.


On the street, the need for much improved braking all comes down to ones driving style and habits. If one drives their near 40-50 year old musclecar like an absolute !d!ot on the street, can bet eventually they will feel like they never have enough braking power. In that position, it's also nice to have a close relative as the municipal judge, to own your own body shop, and have money to burn. 

For a good majority of the rest of us, '69 style disc/drums with upgraded rear brake shoes will provide more than enough braking power. Having cut my teeth, driving like an !d!ot on the street, along with autocrossing and driving the expensive Goodyears off a modified 4wheel disc equipped Pontiac, the 4wheel discs are nice, but short of driving on the ragid edge, they are not needed. Have also assembled rear drum backing plates with special matrix rear shoes, stiffer springs, cryo'ed rear drums, and once bedded in, the stopping performance was on par with the '79-81 rear disc I'd grown accustom to. On two of my keeper '71 HO cars, both are factory 4 wheel drum cars, and when their restorations are complete, both are slated for national show use and then the Pure Stock drags. Neither are getting "upgraded", lol, to factory disc. Have used the same special matrix shoes, etc, quite a few times and the decreased stopping distance has benefitted too many of my friends and customers drum brake equipped 13 sec to mid 11 sec 1/4 mile A bodys and F body's, needless to say on the quicker cars, well over 400 hp between the frame rails, closer to 500.


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## xWoodx (Oct 23, 2015)

I know all too well that "upgrades" are not always better and often a step backwards for various reasons. Doesn't stop them from selling the crap out of these "upgrades".

Unfortunately the car is not able to be driven and I know in their current state, the brakes on this 70 are garbage. What I want to avoid is re-doing the brakes only to find out they're not very good in new condition.

I've never much been a fan of drums on a car, especially a performance vehicle - so at the very least I'm doing 4 wheel disc unless it's prohibitively expensive. 

Most muscle cars from this era were notorious for having bad brakes and poor handling, but that doesn't mean I need Wilwoods and poly everything suspension with coil overs to accomplish my goals.


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## fairran (Dec 12, 2015)

Kind of hijacking this thread but I thought my question relates close enough to not start a new thread. I have looked the forums with no luck. I am working on getting my moms 1965 gto road worthy and I planned on doing the "junkyard" disc brake conversion. My dad says that along with replacing the spindles from a later model they also take either the upper or lower control arm to change the camber making the handling a little better but he can't remember which. Can anyone confirm this and/or elaborate this.


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## 88redconvert (Nov 24, 2015)

you can do a search for conversion kits on ebay and gather info. Some of the vendors will include their phone number and state that they are available to answer questions. Then decide where to buy. That's what I did.


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## willyscool (Sep 19, 2021)

Anyone have a Part # for a manual disc brake master cylinder need a 1" to 1 1/16 piston ?


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