FINALLY….. after much gnashing of teeth, the brakes works…. in one direction at least.
I’d spent some time trying to bleed and the air out the new brake system… the odd hour here and there with my (long suffering) third foot to push the brake pedal wasn’t really working.
After following the manual to the letter, the pedal still went straight to the floor…. time after time after time.
Was there air behind the piston in the master cylinder ? Front end was put up on axle stands as high as they could go. Master cylinder bled (there was some air in it) … still didn’t work.
Plus, I had a other problem, the original shared fluid reservoir had a leak (clutch and brake fluid) so there seemed little point in tying to eliminate the air form the system if I was to replace the reservoir and running the risk of getting air back in the lines again.
So I bought a Gunson pressure bleed kit, a replica reservoir and proceeded as follows. I used the pressure bleed kit of “blow” all of the brake fluid out of the lines at each cylinder (and clutch slave) and removed the wheels and brake drums to expose the wheel cylinders.
Once this was done, I refitted the replacement reservoir (taking care to keep the residual brake fluid off the paintwork), filled the reservoir with new fluid and bled the clutch slave cylinder in about 10 seconds. Proof of concept?… lets call it that.
The same was then done with each of the brake cylinders and the master cylinder. Pretty confident that all the air was out but pedal still went to the floor.
Over a cup of tea and digestive biscuit a eureka moment occurred. The manual showed a clear diagram of the spring arrangement at the wheel cylinder and I was pretty sure I had not done it like that. After a quick cross reference on the Series 2 club forum, I knew I’d got it wrong.
10 minutes later and the springs in the correct location….. BRAKES 🙂 I’d fitted the leading shoe spring from the leading shoe to the rear shoe. This meant as I pressed the pedal, both shoes are pushed outwards BUT as I release the pedal, the spring pulls them all the way back in again. (this would explain the pump up effect as I was pumping faster than the spring could retract the pads and eventually making contact) The rear shoe should not have a spring attached. So with the leading shoe springs attached to the posts on the backing plates, I had a set of functioning brakes.
That said, they now bind when I reverse out of the garage to such an extent, I have to reverse out in low range. Some judicious sanding of the leading edge should help but thats for another day….. when I can be motivated to take all the wheels off again.