Hey Wacky, your mailbox is full so I figure I'd start a thread on this...

Today I took apart the brake master cylinder on my '73 RX-3 in hopes of resolving the mushy brake problem I've been having.

I found that mine has the pressure relief valves under both the rear and front banjo nuts! It's just a little rubber piece around a metal disc with holes through it and a spring behind it. The front does have a slightly larger rubber opening on the back side, but I thought it was strange that there are valves in both. Does this sound right?

I might take them both out and see if my problem goes away. Maybe it's not supposed to be like this at all and that's the source of my problems. I'm also going to take apart the MC on my RX-2 to see if it's set up the same way.

I will snap some pics of those valves if anyone'e curious.

Mike

 

Yeah, just the valve for rear brakes.. Leave the front alone.

 

Isn't that valve for drum brakes only?

 

That's what I figured, which is why I thought it odd that I have one @ the front line also. I suppose the previous owner could have added it but that seems unlikely, you never know though. Anyone ever taken one apart that can confirm they have the valves in both front & rear lines?

thanks,
Mike

 

The M/C including GLC came equipped with pressure relief valve on both front and rear. I upgraded to a GLC as I decided to do a rear disc brake conversion. The engine is "IN" but no exhaust yet. Have to wait til then before I can tell you if its worth it OR not.

 

I was having some brake issues with the 78 Cosmo. Mr master cylinder also had that same thing in the front. I ended putting a 79 RX-7 m/c and capped one of the front outlets. It's working fine.......

 

True. I used the GLC since it has larger bore than the 1st gens/old school RX. It may not make any difference due to small brake booster but I just have to try it and hopefully it works

 

Very timely thread!

I've got my M/C out of my RX3 and need to upgrade it as I too have converted the rear to RX7 disk brakes and will be installing the 4 piston drag brake kit from the racing Store on the front.

Is the GLC M/C a direct bolt up??

What are people doing with the equalizer valve that came originally with the RX3? This is the valve that receives both the front and rear brake fluid stream, divides the front for left and right brakes and has the switch for the brake lights!

 

GLC is a direct fit. The RX3's stock proportioning valve located in the firewall IS JUST A JUNCTION BOX and has no effect on the rear brakes. It only split-up the line for the front brakes.

 

^Thanks for the info on the GLC master Wacky. I was going to use a SA22 master on my Duece but now I'll use the GLC master instead.

One question though... anybody still sell GLC master cylinders new? I haven't seen a GLC in years, not even in a wrecking yard.

 

Just looked on ebay. No GLC masters.

 

Napa should have them.
https://www.rx7club.com/old-school-other-rotary-63/73-rx-2-brake-master-cylinder-603285/

 

I got mine brand new but it didnt come with a brake fluid reservoir. Since I have mnay spare RX-7 parts, I used the brake fluid reservoir from a FB.

 

What year M/C from the GLC are you guys using???

 

i got a 81 glc the other day for 20 bucks its a running car and ac works

by other day i mean like 3 months ago