I know it's possible to use the drum brake master cylinder on the rear disc models, but I don't know exactly what I need to change. I remember something about removing a check valve(?) but not sure where this is or what removing it entails. Any light that you all could throw on the subject would be greatly appreciated, as it always is.

 

probably are thinking of the bias balancing valve. it should be mounted on the side of the master cylinder. the brake bias on the all disc is different then drums.

 

Is that a fairly easy thing to remove/mod/whatever?

NimrodTT seemed to know about this when it came up a while ago, so I'd like to hear from him too.

Anyway, I'm about to go pick up the master cylinder and look at it in person.

 

yeh, its just bolted on the side with brake lines running to it.

 

Redwood - I don't know what is involved with this switch but please be careful. Brakes on a vehicle are designed as a system, annd if you change a component without know what those changes will do to the system it can end your life (or somebody elses). Why not just get the right master cylinder and know you have a perfect braking system?
Sorry to but in, but liability laws are changing fast.

Digger

 

ANY modification to the brake system should be checked in a safe environment, whether swapping parts or replacing parts.

 

Cool, sounds easy enough.


Simply, I cannot access the correct master cylinder in any reasonable way, but have access to many drum master cylinders for a very low cost. Therefore, I will modify this one (by removing one thing) and use it. I guarantee my car will stop well and there won't be a problem (it won't even hit the streets for another month).
Don't get me wrong, I have no problem with you interceding. In fact, it is nice to have a reality check when doing something like this. But in this case, I feel that the risk is minimal and the gains decent.
Thanks for the concern, digger. I feel the 1st gen love strongly from this one

 

Definitely

 

Any valves that would be different are not physically part of the master cylinder. Swap away!

 

The drum brake master has an additional check valve behind a large nut which must be removed if swapping rears.

 

if you want to get technical, you can through a wilwood brake balancer in for $50 and some labor. then you can control your brake bias. i did this in my camry (actually routed it through the firewall and under the dash beside the steering wheel) and dialed full forward (75f/25r split) would stand the car on its nose. i would just adjust it to the level of grip i was driving on. takes a little while to get used to, but is really nice when changing from dry tarmac to wet tarmac to gravel.

 

where is this nut? on the mc?

 

Located in the yellow circle.

 

you have a purolator filter by your carb too. kickass.

 

i just bolted in the rear end and went ripping the tires up and down the street,

jeremy was there,

but in all seriousness if my master cylinder wasnt blown then i wouldnt even bother swapping the stuff.

i have heard people with problems and people without,

so its up to you,

also there is a diference is a gsl rear end and a gsl-se rear end,


if your upgrading to a gsl i wouldnt even bother swapping anthing around the master in less you have problems,

but if your going all out gsl-se then the back disc is bigger and the front disc are also bigger,
not to mention im pretty sure the calipers are also diferent,in this case i would swap the master and coponents around it.

i will be swapping mine today.

 

here are som pics to show the visual diference in the two masters,

this is a 1985 gsl-se master

 

here is the 1984 gs

 

My problem stems from having a master cylinder/brake booster that is not in very good condition (read: many leaks). The reason I would perform the swap is because I can get a master cylinder/brake booster for about $10 at my local yard, but they do not have a single rear disc 1st gen (or single piston 2nd gen). I'll pick up the stuff tomorrow and probably order the bias controller on Monday, seems like a solid investment. You'll hear the results when I install it and take it for a test coast (hard to drive with no engine). Thanks for the help guys.

 

just did my master cylinder a couple hours ago,
it took all of 10 minutes.

two bolts and a couple of brake lines,

simple and easy to get to everything.

didnt change the booster though