1980 Firebird MC upgrade.

CoraZuki

CoraZuki

Well-known member
I put a set of Dana 44s on my Zook and needed a better MC to operate the brakes.  I got this idea from someone else on here and thought I would share how to do this.  I looked at the Subaru setup but finding parts was kinda hard, and the MC was not cheep.

The nice thing about the 1980 Firebird MC is that the reservoir is built in, you can get them brand new for a reasonable price, and they come setup for disk front drum back or disk front and back.  The only bad that I could find was that the MC is kinda big but that's it.

I would only recommend this swap if you are swapping out to larger axles with larger brakes.

This was easy. 

#1.  You will need to slot the mounting holes on the MC in about 1/8" on each side.  I did this with just a drill and a normal drill bit. 

#2.  Get 2 o-rings that fit over the flange that fits into the power booster.  I found these at O'Reilly Auto Parts.  You will need 2 in order for it to seal properly, plus I used a thin coat of RTV.

#3.  Bolt it up, without sealing it yet, using the stock push rod and check it for play.  There should not be much play, but if there is just adjust the play out.  You may need to put the large end of the push rod in a vice to hold it when adjusting the rod.

#4.  Once the play is adjusted out, put the 2 o-rings on with a little RTV, and bolt it up. 

#5.  You will need adapters for your brake lines.  This will change depending on what brake lines you are using.  I ran all new brake lines so I got adapters for AN3 lines.  I got all my fittings, steel braided, and hard lines from Speedway racing. 
http://www.speedwaymotors.com

#6.  You will want to get one 2psi residual valve for the front disks and one 10psi residual valve for the rear drums.  You may also want an adjustable proportioning valve for the rear.

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The brakes work great!  I have a 4.3 with dana 44s on 35s and this thing has no problem stopping.  ;D
 
i was under the impression you didnt need any residual pressure on a disc setup.... im going to be doing this either the weekend or next week

im doin disc/disc with sammy calipers in the front and nissan maxima calipers in the rear and just going to put a manual proportioning valve but the m/c
 
Freebird01 said:
i was under the impression you didnt need any residual pressure on a disc setup....
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You will want to install a 2psi residual valve for disk brakes.  A friend of mine did a disk swap/MC upgrade on his Jeep and had major brake problems until he installed a 2psi residual valve. 

Some of the MCs have this built in but why take that chance.  My friends new MC was made for disk front, but he still needed the residual valve.  What will happen without the residual valve is the caliper piston can work its way back in when driving.  This will cause you to have to pump the brakes the get them to work, and that's bad on the trail.  A 2psi residual valve will not cause the brakes to drag.  This valve will also keep the brake fluid from running back up the line if the calipers end up higher than the MC.  This can happen on steep inclines.  They are relatively cheep and easy to install.  Looks like you are running disk front and rear, so you will only need two 2psi valves, one for the front and one for the rear. 
 
CoraZuki said:
You will want to install a 2psi residual valve for disk brakes.  A friend of mine did a disk swap/MC upgrade on his Jeep and had major brake problems until he installed a 2psi residual valve. 

Some of the MCs have this built in but why take that chance.  My friends new MC was made for disk front, but he still needed the residual valve.  What will happen without the residual valve is the caliper piston can work its way back in when driving.  This will cause you to have to pump the brakes the get them to work, and that's bad on the trail.  A 2psi residual valve will not cause the brakes to drag.  This valve will also keep the brake fluid from running back up the line if the calipers end up higher than the MC.  This can happen on steep inclines.  They are relatively cheep and easy to install.  Looks like you are running disk front and rear, so you will only need two 2psi valves, one for the front and one for the rear. 
Click to expand...

yea i understand what they do and that ill need 2 of them....i just didnt think you needed them with discs is all...though tit was for drums only....but ill be lookin for a pair tonight on ebay

thanks for the very detailed reply ;D ;D

i got sidetracked by bad wheel bearings from my front end install and decided to install the MC. i drilled the ears to 1/2" then used a rotary file in a die grinder to slot the holes....worked like a charm...i didnt even have to change the push rod length
 
Freebird01 said:
yea i understand what they do and that ill need 2 of them....i just didnt think you needed them with discs is all...though tit was for drums only....but ill be lookin for a pair tonight on ebay

thanks for the very detailed reply ;D ;D

i got sidetracked by bad wheel bearings from my front end install and decided to install the MC. i drilled the ears to 1/2" then used a rotary file in a die grinder to slot the holes....worked like a charm...i didnt even have to change the push rod length
Click to expand...

No prob,

Glad to hear that it's going together for you.  :)
You can find adapters, residual valves, and more at http://www.speedwaymotors.com
 
i ended up buying these...

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWNX:IT&item=280332354008
 
Freebird01 said:
do you remember offhand what the thread in the m/c are? are they 3/8"-24 IFF?
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ok the rear port is 9/16" and the front is 1/2"

did you do anything with the stock splitter or the stock rear prop valve?
 
Freebird01 said:
ok the rear port is 9/16" and the front is 1/2"

did you do anything with the stock splitter or the stock rear prop valve?
Click to expand...

Sorry for not getting back with you sooner on this.  You are correct on the sizes and yon can get adapters to run AN3 steel braided brake lines off that if you want. 

The only parts of the original brake system left are the power booster and the brake peddle.  :) I ran all new lines with an adjustable proportioning valve for the rear.  I used a t-fitting to split the front left and right and I used another t-fitting on the rear axle. 
 
CoraZuki said:
Sorry for not getting back with you sooner on this.  You are correct on the sizes and yon can get adapters to run AN3 steel braided brake lines off that if you want. 

The only parts of the original brake system left are the power booster and the brake peddle.  :) I ran all new lines with an adjustable proportioning valve for the rear.  I used a t-fitting to split the front left and right and I used another t-fitting on the rear axle. 
Click to expand...

yea i need to get me a t-fitting for the rear....im sure i have an older style splitter block on a frame here that i can plumb in to change the biased from diagonal to front back
 

https://www.helpavetshine.us/help-a-vet-shine
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