Locking brakes

Hi
I?ve got a problem with my 69 S4 dhc brakes, they hold on after applying, just for a fraction of a second, the pedal dose not appear to be sticking.
I have flushed and bled the system, but the pedal is still long on first pump. The car pulls up reasonably straight from 70 mph with no probs,
The servo looks like new, however the car has had very little use over the last 10 years since an extensive restro @ Mike Millers. I bought it in September last year while looking for parts for my S3 on ebay :open_mouth:
Thanks in advance
Chris.

It is most likely the servo sticking, you need to get it serviced.

I had the same problem but worse on my +2 with twin servos; if fact, the wheels were locking up. It turned out the air bleed valve in both servos, whcih like yours look new, were sticking through lack of use. This is quite easy to fix, by removing the plastic cap, the rubber valve, and the sticking item is the little piston in a bore. Clean that our, lubricate the bore, and then with a little screwdriver ease it back down as someone lifts off the (applied) brake pedal. If that works you dont need to re-bleed. Otherwise its a servo overhaul job

good luck

Thanks, I’ll have a go at the air bleed valve, I’ll let you know how I get on. :slight_smile: Regards, Chris.

My original brake caliper pistons sometimes formed rusted areas on their surface due to lack of use. Years ago, I switched to stainless steel pistons and haven’t had a problem since. May be worth a look…

Gary
'71 Elan Sprint
Miami, Fl

I assume it’s a Lockheed servo. AP told me it’s a common problem. As another reader said it’s almost certainly the air valve sticking. If I recall correctly there’s a mod using a spring under the air filter push on cap and the valve itself. A suitably sized/strength spring is fitted over the top centre of the valve (towards the outside of the servo ie not under the diaphragm and the filter cap snapped back into place. Every car I’ve had with these servos has had the same problem. It’s only a minor fault but annoying.

John