Spongy Brake Pedal

[Dean Peterken]

I have a '74 RHD 2000GTV which, after 6 years in off the road is finally getting close to being back on the road. Over the last 12 months I have rebuilt the suspension and brakes, had a small amount of panel work done and am half (the easy half I fear) through recovering the seats with used but genuine leather skins. I have some photos to post shortly.
The BB has been a huge help with the work I have done so thanks to eveyone who contributes.
Now to the point of all this, the spongy pedal. Like so many others I had a very spongy pedal after following the posted bleeding procedure. I was tempted to try the mysterious "pump up and hold pressure overnight with a stick method". Before I tried this I was looking, thinking and checking everything I had done. I noticed that the rear brake pads were a little loose in the calipers compared to the front ones. During the rear caliper rebuild I noticed the rear pistons had a kind of spring clip inside them which fitted over a pin in the caliper body. So I got to thinking, maybe the spongy pedal is the rear pistons moving in air. I removed the pads, pumped the pedal a little to move the pistons out, pushed them back a little so the pads just slipped in and to my imense satisfaction I had a nice firm brake pedal.
So my theory is the pressure overnight trick actually gets the spring clips to seat in a correct position rather than the seals yielding to the pressure.
Has anyone experienced the same fix? What do you all think?

[spannerman]

Hi.
Ive hade the same thing happen on my GT Junior and have seen it where ate calipers have been used on other cars. I did the same thing with moving the pistons in and out a few times to bring up the pedal. My thoughts have been that maybe the modern seals that go in are slightly different in some way to what they should be for that application and that a bit of a "massage" helps them bed in so they dont suck the piston too far back in.
I have also thought of trying the rear calipers without the centre pin and spring arangement. Can anyone tell me what that mechanism does?
Cheers...

[lowmileage]

Without answering your question - what is the age of your brake hoses? Rubber hoses in these cars become a maintenance item and have to be replaced periodically. They may "look" good but when pressure is applied, they may expand and could contribute to your spongy petal. I don't know what the cut off is but if they are older then 10 yrs, I'd replace them.

[Dean Peterken]

Thanks for the reply, but all the rubber hoses are new, I would rather be sitting in my Alfa driving it than under it fixing up a half done job!