quote:Originally posted by LF - TP 2511:
...So with the exception of a well-maintained stocker, I'd say toss the proportioning but retain the shuttle...
I'm in agreement with Larry. However, if you want to improve the performance of the oem brake system, remove the proportioning valve, in every situation. A proportioning valve does not belong on the front brakes ever. It is one of the designs of the Pantera, along with the cooling system, that makes me think to myself "what in the hell were the designers smoking?".
A proportioning valve reduces its hydraulic output pressure in relation to its input pressure, above a certain setting, which creates a knee in its output curve. Under no circumstances do you ever want to reduce the pressure to the front brakes, the driver does that with his/her foot. Proportioning valves belong in the rear break circuit to balance the pressure to the rear brakes to avoid rear brake lock up.
My Wilwood brake system has no proportioning valve at all, but because the pistons in the rear calipers are smaller than the pistons in the front calipers, the rear brakes have never locked up on me yet.
If a Pantera works OK with a proportioning valve in the front brake circuit, and none in the rear brake circuit, it is obvious that rear brake lock up is not a problem with the oem brake system. Removing the proportioning valve in the front brake circuit will not hurt a thing. It is one of the oldest Pantera improvements there is, owners have been doing this since the early seventies.
cowboy from hell