[Fot] TR4 dual circuit brakes - restrictor valve

[TR4 Tony]

Hi all

I run a dual circuit system and no external valves on Beastie and no problems
with what I call 'pad knock off' , caused by the stub axle flexure.

I'm currently using avast of the southwick fat alloy hubs and stub axles  as
they take much more of a pounding without the need for intervention, but prior
to this I used the shim and conical washer kit that TR enterprises can supply.
Big improvement over the standard set up as this stops the stub axle flexing
quite a lot, so for most this might be enough.

The fat hub kit with big stub axles removes the issue completely, no soft
pedal or high bearing wear rate, no nylons flying off and 3 wheel motoring
etc. So for me this was the way to go as my nerves get frayed quite enough as
the scenery flies by very close .

Regards

Tony

Sent from My iPhone

On 20 May 2011, at 00:29, "Randall" <tr3driver at ca.rr.com> wrote:

>> Disk brakes generally need a
>> residual
>> pressure valve which keeps a bit of pressure on the pucks to prevent
>> them from
>> being withdrawn too much by seal elasticity.
>
> In the case of the TR3-4, I believe it was done for a different reason: the
> front spindles flex enough under hard cornering to push the caliper pistons
> back and cause a low pedal on next application.
>
> I don't recall the change point offhand, but the factory deleted the RPV at
> some point (during TR4A production maybe).
>
> Having run for some 25 years with the RPV removed from an otherwise stock
> TR3A, I do not believe that seal flex is a significant issue with these
> calipers.  But spindle flex definitely is.  For my car and my driving (on
> the street), I find that I can just live with a low pedal after hard
> maneuvers.  It's never been low enough to need a pump, just enough to be
> disconcerting if you aren't expecting it.
>
> I believe it was Jack Drews that came up with the spacer fix instead.
>
> -- Randall
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