Spongy brake pedal - finally fixed

[paulheritage]

Been putting up with this for a while in the '76 red TR7, and although the brakes work very well the pedal is very low before it starts to work. Most of the brake parts have been renewed in the last few months inc. the master cylinder, brake PRV, rear cylinders, rear pipes, front caliper pipes but couldn't get it right - even had my local professional use some of the new bleeding gear in case I wasn't getting trapped air out but didn't work either.

This weekend I bought a couple of lengths of Cupro Nickel pipe, new connectors and a professional flaring tool and decided to replace the main copper brake lines to/from the PRV to the master cylinder, front calipers and rear brakes. Wasn't looking forward to this job as the current copper lines looked fine but the only thing I hadn't done myself and wasn't really sure if it would make any difference.

After completing the job and bleeding the brakes again it seems to have fixed it and now have decent brakes with correct pedal travel.

Not really sure why this would have fixed the problem but pleased I did it anyway and shouldn't need doing ever again!

Cheers Paul,

1976 TR7 2.0 FHC, ACG 2367 - Carmine Red (on the road)
1980 TR7V8 3.9 DHC, Orient Blue (on the road)
1977 TR7V8 4.0 FHC rally car, ACG 35005 - Tahiti Blue (complete, no MOT)
1976 TR7 2.0 FHC, ACG 3115 - Java Green (now sold)

www.TR7.co.uk

[Hasbeen]

Interesting.

I have always found that it takes 3 bleedings, with a few miles between them to get the brakes really solid.

It is surprising that the 7 & the 8 both exhibit this characteristic. Only the pipes & the distribution valve are original parts on the 8, all the other bits have been upgraded.

Perhaps the pipes are the cause, but as you say, why?

Hasbeen