Master Cylinder Upgrade

[76 PTO]

Hey guys I have a 76 cruiser with the stock disks up front and drum rears. I discovered that my master cylinder was leaking a little and wanted to up grade to the 80 series master. I would also like to convert to rear disks in the future. I bought a 1994 80 series non ABS master. Should I install the new master cylinder with the stock proportioning valve in place? When I convert to rear disks, remove the stock proportioning valve and replace it with an adjustable one?

Thanks,

 

[mtquivr]

The problem isn't your proportioning valve, the problem is your master won't have a residual pressure valve for the rear drums. This would cause more pedal travel or you might have to pump the brakes to get the rear shoes out. You can probably buy a valve for drum brakes and plumb it into the rear circuit.

 

[Shark56]

I did this upgrade on my 74 with 79 front disk axle. I only had to adjust the push rod slightly. Been running it for two years now.
I didn't need to put a residual valve in. I can't remember what year master I used but I think it was a 95 OEM.

 

[76 PTO]

Maybe I will wait to put the new master in until I do the rear disks. I thought people were using this master with drum rear brakes.

 

[Shark56]

I did. I have a 79 disk front 74 rear drum.

 

[76 PTO]

Did you keep the proportioning valve under the Master?

 

[Rock_Hugger]

I'm thinking about putting an 80 series master on my 40 with discs all the way around, what's the best year to get the master from?

 

[Tools R Us]

... I bought a 1994 80 series non ABS master. ...

On the NA '80 series, the non ABS master is a rear drum application, the ABS master is 4 wheel disk.

 

[Blue77FJ40]

So... for those of us who installed an rdb conversion on our '40s, the ABS master is the FJ80 mc of choice?

 

[Shark56]

Ok, I apologize for this. Feel free to flame me.

I did not use the 94 FJ80 Master cylinder. I went out to my shop today to see which one I bought and saw the new one still in the box. Then I remembered!
What I did use was a master cylinder from a 94-ish Pick-up that had disk fronts and drum rears. I had bought it for a steal for the power booster attached. The master cylinder looks exactly like the FJ80 one.
I just re-bent the lines to work with the booster and proportioning valve.
I bought the FJ80 MC as a 94 "with out" ABS. From some reading on line I'm still not sure if it has the residual valve for the rear drum. Seems that some 93-94's came with drums. Some with disk. My guess is to use the Newer style Master Cylinder for from disk and rear drums then it should be from a P/U, FJ80, 4Runner ect.
I'm gonna use the FJ80 on one I'm rebuilding but it will be a while before that happens. Sorry for the confusion.

Pic of Pick-up master cylinder I used.

It leans down because of the Mallotte Tub firewall being uneven. Pic was just after rinsing engine compartment.

 

[76 PTO]

I did some searching earlier and read that a 94 non abs 80 series was the one to use when doing a rear disk swap. I was just wondering if it would work until I did the rear disk swap.