No parking brake?

[infernosg]

Originally Posted by FC Zach

This issue happened to mine once before as well as only one wheel engaging, I bled the calipers and had no further issues. It's been years since worked with this but I believe there were two bleed screws and I opened the upside-down one on the bottom, I remember that because it didn't make any sense to me.

Anyways I figured this all out after needlessly replacing a caliper that ended with the same results as before. Looked into it and it was too simple

I thought the parking brake was purely mechanical.

I never understood why the calipers have two bleed valves. Ironically, the passenger's side is the only one I attempted to bleed with the bottom valve out of curiosity. I still bled both rears with the top screw but hopefully it's coincidence that the passenger's side isn't working. I've probably bled the whole system 5 times now with a Motive pressure bleeder and the traditional 2-person method and no luck.

[FC Zach]

Originally Posted by infernosg

I thought the parking brake was purely mechanical.

You would think!

I'll double check my manual, I could be wrong.

[Pete_89T2]

Interesting... I thought the bottom bleeder screw was there simply there to help purge accumulated crud out of the caliper when pressure flushing & bleeding. Given the way this caliper is designed and oriented on the car, you can see there's a low point that would tend to trap & accumulate crud, so I figured the extra bleeder was there to deal with it.

Whenever I flush & bleed brakes on the FC, for the rears I open the bottom screw first (top closed) to flush out the crud. When fluid flows out clear & clean from there, I close the bottom screw & open the top one to purge the air out.

[FC Zach]

Double checked my manual and found this but nothing in detail regarding why the bottom is used. .

[infernosg]

Originally Posted by FC Zach

Double checked my manual and found this but nothing in detail regarding why the bottom is used. .

Interesting. Is that in the Haynes manual? I have a paper copy of the FSM and I don't recall seeing that. I'll give it a try because I definitely fall into the category of having "overhauled" the calipers. The worst that can happen is the parking brake still doesn't work. I've discovered some older RX7 racecars have deleted the parking brake system so I'm not too concerned at this point.

EDIT: It shows up in the FSM for the '88 MY but not in the FSM for the '89 MY. More interesting...

On a somewhat related topic does anyone know how to actually adjust the brake pedal "free play?" I've swapped to the 929 MC and booster and the pedal free play is out of spec according to the FSM. The FSM instructions for adjusting pedal height and free play are the same. In order to get the free play in spec I have to adjust the brake pedal all the way out, which puts the pedal height out of spec. I don't see how to get the free play in spec without violating the pedal height spec. Maybe the 929 free play specs are different...

[RETed]

Originally Posted by Pete_89T2

Interesting... I thought the bottom bleeder screw was there simply there to help purge accumulated crud out of the caliper when pressure flushing & bleeding. Given the way this caliper is designed and oriented on the car, you can see there's a low point that would tend to trap & accumulate crud, so I figured the extra bleeder was there to deal with it.

+1

I agree - it's due to the orientation of the brake caliper being almost vertical.


-Ted