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bat-stang
06-22-2007, 12:52 PM
Recently did the GLORIOUS Cobra brake upgrade on my 93 however I had to totally equalize the proportioning valve. The rear feels like it isn't participating in the stopping party. I already have the rear Cobra brakes on my car with about 1/2 pad left. This is all of the time--no special high temp issues. Help.

jimmysidecarr
06-22-2007, 06:50 PM
How many miles since the change?
Any bedding in done on the rears?
Can you lock the rears on a hard stop?
The 93s are non-ABS right?

No possibility of air still in the lines?

Is it possible that everything is ok and perhaps the fronts have so much more brake torque NOW than before that it just seems the rears are not participating?

You can lock the fronts ... right?
When you do some test stops (lock em up) can you check the tire marks to see if the rears are leaving marks too?

bat-stang
06-22-2007, 11:10 PM
How many miles since the change?
Any bedding in done on the rears?
Can you lock the rears on a hard stop?
The 93s are non-ABS right?



No possibility of air still in the lines?

Is it possible that everything is ok and perhaps the fronts have so much more brake torque NOW than before that it just seems the rears are not participating?

You can lock the fronts ... right?
When you do some test stops (lock em up) can you check the tire marks to see if the rears are leaving marks too?Hey Jimmy, long time no hear! I'm still on the same rears that I have had for about 2 yrs; I CANNOT, that I can tell, lock the rears. And no , I don't have ABS. I could have air in the lines; I have speed bleeders and have bled them but twice could be the charm. And, can I lock the fronts? MAN can I! I think that with my proportioning valve I should be able to modulate my brake pressure...? There are far too many fox cars with this upgrade for my situation to be the norm. Fact of the matter is this could have been an ongoing problem that was masked with my 99 gt calipers; the stock distribution valve could be at fault, I didn't defeat it so it could have been done wrong.

jimmysidecarr
06-27-2007, 02:11 PM
Try a good old..... "old school" 2 man bleed just to be sure.

Curious what you find...

You could try putting the rear of the car on jack stands and running it in gear... just to see how much pedal effort it takes to stop just the rotating weight of the driveline... just to make sure the rear brakes are doing .... something. Not a very good indicator since the brakes are not stopping the weight of the car... but just a diagnostic tool.

bat-stang
06-27-2007, 07:14 PM
Thanks Jimmy I'll try it in the AM.

johnbasf
06-27-2007, 11:59 PM
Thanks Jimmy I'll try it in the AM.

Send "BOC-beau" a PM. Tell him John sent you. Beau races AI and is a great mechanic.

bat-stang
06-28-2007, 10:43 PM
I bled them this morning and I think that my rotors are glazed and the pads are glazed: I jacked the car up and did the stop-the-wheels-with-the-brakes and they are working. Then I bled the calipers and took it for a test drive. The pedal pressure felt higher (like the bleeding helped), front braking seemd to require more pedal (like the rears were using some of my front bias) but the back end did'nt seem to be pulling down. Also below are more interesting issues:

The previous owner 'defeated' the distribution block beneath the mc--however I think that both of the springs were removed instead just one? I essentially have the M2300 set up and how My PV is set now my back end should be locking up.

Oh yeah one more thing: while bleeding the rear I noticed that the rear pot of my SVO MC reservoir was the level that was falling--not the front as I was supposing...


Thanks for the info on 'BOC-beau'. If my rear rotor upgrade and pad replacement doesn't help, I'll hit him up. Thanks for all of your help.

Batman

bat-stang
06-28-2007, 11:05 PM
Oops, double post...