[Shotimes] rear brake questions

[Leigh Smith]

I agree with Ron that it would help re-distribute the braking load. 
However I still feel (IMHO) that it is a "band-aid" fix and makes the 
car inherently unstable under full braking. If the ABS ever fails,  the 
rears lock, and it could quickly do a snap spin on you in a turn. The 
safest way to re-engineer the system is to tune the brake proportioning 
so the fronts lock just slightly before the rears.

Having the rears lock first is a tuning method that should be left to 
professionals who know what they are doing. Obviously Ron likes it. I 
personally know many national champion Autocrossers that tune their 
brakes that way, but only for an auto-cross. (If you drive agrressive 
enough, it helps to rotate the car). But for the street or a high speed 
track, ... never.

I just can't in good conscience recommend this mod for the average 
driving caliber of a SHOtimes lister. And I feel honor bound to speak 
up. Yes, it will feel good, and you will "probably" be O.K....99.9% of 
the time. But I would not want to be the one who manufactures components 
for this mod, or recommends it, in our lititigious world today.

I'll get off my soapbox now. Just don't want anyone to get hurt 
unnecessarily.

My .02
Lee


Ron Porter wrote:

>Well, I do like the plugs in the rear, and rely on the ABS at the track to
>work as it should. When I had the plugs in my '95, the ABS was not always
>functioning, and it was not an issue on hard stops. The back would lock
>slightly ahead of the fronts, but not objectionably so.
>
>The suspicion is that the valve was originally there on Tauri for the front
>disk/rear drum setup, and is not of particular value for all disk. On the
>track, though, I had rotor temps of 630/front, and 550/rear after one
>session, with mild dusting on the rears. It really does help to distribute
>the braking load, IMHO (this is with a '96 upgrade).
>
>Ron Porter 
>
>-----Original Message-----
>From: shotimes-admin@autox.team.net [mailto:shotimes-admin@autox.team.net]
>On Behalf Of Leigh Smith
>Sent: Wednesday, July 23, 2003 11:16 AM
>To: van Oss
>Cc: shotimes@autox.team.net
>Subject: Re: [Shotimes] rear brake questions
>
>
>Joseph;
>It's possible the two problems are connected. When the proportioning 
>valve arm is disconnected, it will almost close, leaving you with very 
>little rear brakes.
>It will also maintain pressure on the piston when it tries to release.
>Test for this condition by releasing parking brake, and then crack open 
>a bleed screw and see if the pressure release solves your retraction 
>problem.
>
>I would try to get the proportioning valve working again. There is a 
>somewhat popular mod on the list of defeating it and relying on the ABS 
>to prevent  rear brake lock-up. Personally, I would not rely on this. I 
>would not put my life in the hands of a (old, & reliable?) Ford 
>electrical system. The mechanical / hydraulic system is there (in part) 
>to keep you from spinning the car in a sudden stop. Ever had a car go 
>backwards on you at 70mph? BTDT.
>Lee
>
>
>van Oss wrote:
>
>  
>
>>I have been refurbing the rear brakes on my 91.  Replaced the parking-brake
>>cables, both rear calipers, pads, hoses, and had the rotors ground.
>>
>>One problem:  The return spring on the Left Rear caliper seems not to be
>>strong enough.  When I release the parking brake, the lever on the caliper
>>does not return to position.  I can pry it up, releasing the rotor, but it
>>will not release by itself.  Did I get a bad caliper?  Has anyone
>>experienced this?  Anything I can do to correct it?
>>
>>Also, I never noticed this before:  I seem to have parts missing from the
>>proportioning valve.  The valve body itself is not in any way connected to
>>the lateral arm.  Is that a bad thing?
>>
>>Joseph van Oss
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>>    
>>
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