Drum to Disc swap question - Second Generation Pontiac Firebird (1970 - 1981) - Firebird Nation

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Drum to Disc swap question


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4 replies to this topic

#1 msammy93

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Posted 2 weeks ago

So I have 2 10 bolt rear ends. The one on my daily driver is drum brakes while the other is disc. If I was to swap the disc components to the drum brake car would I need to remove axles or anything?

I believe I would also need to swap over some sort of disc brake distribution block for the fluid as well as the parking brake lines. Are those the only 2 things other than the stuff on the axle I need to worry about?

#2 NOT A TA

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Posted 2 weeks ago

Disc/Disc master cylinder, disc/disc combination valve, disc/disc pedal (or modify), and specific rear disc park brake cables are all needed to do the swap properly. And yes axles out to swap,  IIRC.

 

The rear disc cars also came with a dual diaphragm power booster.

 

Note: The disc brake parking brake cables MUST be installed and adjusted properly for the brake system to function.


Edited by NOT A TA, 2 weeks ago.

John Paige

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#3 msammy93

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Posted 2 weeks ago

 
Note: The disc brake parking brake cables MUST be installed and adjusted properly for the brake system to function.


Is this true for drum brakes too? On the car with drum brakes I broke my parking brake cable on one side. I know the parking brake doesn't work anymore, but will the rear drums still work? With all the trouble the swap is going to be I'm just going to keep the drums.

#4 JoePeek

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Posted 2 weeks ago

I do not believe old school drum brakes need to have the e-brake adjusted to work. The brake pads (shoes) starting position is set by the star wheel through the backing plate. Something tells me from a long ago memory that you can also adjust drum brakes by backing up and hitting the brakes several times.



#5 NOT A TA

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Posted 2 weeks ago

Joe's correct. Drum brakes do not require the park brake to be functioning for the drums to work. And the automatic adjustment of drums occurs when the brakes are applied while going backward. That is the function of the star wheel mechanism. Slamming the brakes while going faster than normal in reverse was often used to free stuck star wheel mechanisms, not the proper way to fix the issue though.

 

If the park brake cables for the rear discs aren't connected AND ADJUSTED PROPERLY the front brakes don't function properly either because most of the pedal travel is used up moving the rear pads.


Edited by NOT A TA, 2 weeks ago.

John Paige

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