Re: Spider front brakes spongy

[Dick Stachowiak <stachowiak@domain.elided>]

> Date: Mon, 15 Oct 2001 16:11:35 +1000
> From: Marty Wilson <martin.wilson@domain.elided>
> Subject: Spider front brakes spongy.
>
> Greetings,
>
> My 5 year rebuild and conversion of my Ex USA Spider is down to the last
> job. The bloody brakes.
> The braking system has been rebuilt with resleeved and rebuilt underfloor
> master cylinder and rebuilt dual booster. However the brakes were spongy and
> not up to the standards of fellow 105 dual booster systems.
> I checked where the fault lay by clamping off the flexible hose to the rear
> brakes, no difference, still spongy so therefore fault in front brakes.
> Clamped off front flexible brakes hoses one at a time, still no great
> improvement.
> Clamped off both front hoses near callipers, fantastic, lovely hard pedal.
> Deduced front callipers the problem.
> Rebuilt a spare set of calipers and put them on the car, bled the system
> till the cows came home and no air coming out when bleeding. Tested brakes,
> absolutely bloody hopeless, still spongy and crappy.
> Clamped off both flexible hoses again next to calipers, beautiful hard
> pedal.
> I can only conclude there is still air in the calipers, they are up the
> right way with the bleed nipples at the top.
> What am I missing here? Anyone had this problem before and solved it? Can
> anyone fault my logic?
> Any contributions gratefully accepted.
>
> Marty Wilson
> Newcastle Australia
>

I had avery similar experience with my 66 Gulia Sprint GT.  I tried everything and ended up adding a residual pressure valve to the system.  This keeps a pound of pressure in the system at all times to keep the calipers from retracting away from the rotors.  This solved my problem and didn't seam to have any negatives.  The valves
are advertised in the magazines that cater to the hot rod and custom car crowd.  Hope this helps.

Dick Stachowiak

71 Spider
71 GTV

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