[DeTomaso] Wilwood Brakes WTF????

[Kirby Schrader]

Whether this helps the issue or not, I doubt it.... but here ya' go anyway.

I have never had the biased wear that Mike shows in his pictures...

I've been running Quella's Wilwood system since 1985 with the reverse
pressure valves with no problems.
The RVP good/bad gets beat up every now and then on the list, but I
still have them.
:-)

I have had issues twice with the brakes shaking after hard use on the
track, but this always occurred just after I'd put new rotors on.
The rotors obviously warped (although some people have told me that
doesn't happen) because once I had the rotors turned down after a
track weekend, they were fine again and never gave any further
problem. It was only the fronts, too.

I did have one other bout of shaking at TMSR one year. The effect was
much different than the 'rotor warping'. The brakes would be fine
braking hard into a corner initially and then they would start really
shaking. I wrote that off to boiling DOT3 brake fluid.
Once they cooled off just a little, everything went back to normal.
I use the ATE stuff now and haven't had a problem yet, but it's been
awhile since I have pushed the Pantera that hard.

I did change the front 4 piston calipers to the mini six piston set
up. This was a direct swap and made a very nice improvement to the
overall braking.
The car stands on its nose so hard now you can feel the ass end waving
around behind you.
Tom Upton says he has the same problem with his race Pantera and
figures he needs to lower the engine to move the CG down...

Personally, I plan to install a proportioning valve and see how much
more rear brake can help. But, as everyone knows, too much rear will
have you sliding sideways very quickly. Ask me how I've proved it....

Oh, and the GT40 has a VERY similar 4 piston caliper Wilwood system on
front and rear, but I've never found any reverse pressure valves...

FWIW,
Kirby


On Mon, Apr 15, 2013 at 1:13 PM, Tomas Gunnarsson <guson at home.se> wrote:
> The fact that virtually all cars on the road uses non-floating rotors
> and work well without the RPV indicates that there's something wrong
> with the installation rather than a system requirement. If you have
> little runout all you get  is slightly dragging brakes.
>
> Tomas
>
> <-----Ursprungligt Meddelande----->
> From: MikeLDrew at aol.com [MikeLDrew at aol.com]
> Sent: 15/4/2013 7:30:32 PM
> To: pantera at cox.net
> Cc: detomaso at poca.com
> Subject: Re: [DeTomaso] Wilwood Brakes WTF????
>
> In a message dated 4/15/13 4 58 23, pantera at cox.net writes:
>
>
>> I bought a set of Wilwood brakes from one of our local vendors back in
>> the 1990s. and when checking the runout ("wobble") of the installed
> rotors,
>> several were found to be in excess of 0.050", over 10 times the usual
>> working range.  This will produce the juddering you spoke of.
>>
>>>>I had the same issue, and fixed it by having the rotors turned on the
> car. I have zero runout now. The juddering I experienced on the track
> was
> short-term, caused by the problem that I had picked up.
>>
>> >Thanks again to S O Bill for the help, we spent a lot of time on his
>> lathe correcting the misgivings.  It seems that although the kit was
> stamped
>> "Wilwood", the rotors were actually cloned by a pacific rim company,
> not
>> sourced from Wilwood.
>>
>>>>I have to wonder where my rotors (which came as part of a kit from
> Pantera Performance Center) really come from? I do intend to upgrade
> them to
> curved-vane, slotted discs. Just not this week!
>>
>> >Also, get rid of the 2 psi residual pressure valves ASAP, they belong
> on
>> a car that has the master cylinder physically lower than the calipers,
> as
>> in the 'ol T-bucket street rods. They will typically drop the master
> brake
>> assy below the floor so as to hide it and present an uncluttered
> firewall.
>>
>>>>Dennis included them with his kit. I have to say that I drove a
> Pantera that had a Hall JFZ system (which is effectively the same)
> without these
> valves, and it suffered greatly from pad knockback. If you drove down
> the
> road for ten minutes, the first time you stepped on the pedal it would
> go
> halfway to the floor, as the initial travel was used to reposition the
> pads
> against the discs. Subsequent stops would deliver a nice, firm pedal,
> until
> you drove for some distance without using the brakes. It was very
> unnerving
> not really knowing where the braking was going to begin. The RPVs
> totally
> eliminate that, which I suspect is why they were included in the system.
>
> There are probably better ways to handle the situation; one would be
> fully
> floating rotors. I will probably be upgrading my brakes at some point,
> and
> slotted, curved-vane, floating rotors are high on the list, along with
> six-piston calipers.
>>
>> >Hope this is of some help.
>>
>>>>Indeed!
>>
>> >Congrats on the upcoming nuptials, BTW,
>>
>>>>Thanks! Have to make sure both Panteras are there to celebrate with
> us!
>
> Mike
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