seized brakes!
Discussion
Finally I got it on the road yesterday.
She started immediately, with en enormeous rattle until the tappets were filled with oil.
I stopped after driving for about 20 min. at a local mecanics to ask for a check of the steering geometrics (toe-in).
When I wanted to leave, the breakes had seized. We first thought that I had over pulled the handbrake, since parked in a hill. The mecanics said that I should drive slowly, so that the brake would break free. I did so and after 3 minutes I was back as the brakes seized more and more. (Engine would starve in 2nd)
It were the front discs that started to smell. Then the mecanics asked, wether I had tried to remove all the freeplay from the brake. I did in deed regulate the pushrod of the servo a bit and replace the bolt between pedal and servo fork.
The mecanics released the hydraulic pressure by opening the brake pipes at the brake master a bit, and the seize was gone. I drove home with the nuts fixing the master to the servo released by a few turns.
At my place I turned the pushrod in by 2 turns again. No problems this moring when I drove to work for 45min. Problem solved hopefully.
So to anybody concerned about a "direct brake pedal feel".
Do not push this issue to far. These brake masters need some freeplay towards the servo, in order to allow the pistons to move back under all circumstances (thermo dilatation etc.) I dono if there is a bottom valve in this master or not, but I know that my mecanics made me save to drill a hole into my knee.
Cheers Patrick
>>> Edited by roulli on Tuesday 2nd April 10:07
She started immediately, with en enormeous rattle until the tappets were filled with oil.
I stopped after driving for about 20 min. at a local mecanics to ask for a check of the steering geometrics (toe-in).
When I wanted to leave, the breakes had seized. We first thought that I had over pulled the handbrake, since parked in a hill. The mecanics said that I should drive slowly, so that the brake would break free. I did so and after 3 minutes I was back as the brakes seized more and more. (Engine would starve in 2nd)
It were the front discs that started to smell. Then the mecanics asked, wether I had tried to remove all the freeplay from the brake. I did in deed regulate the pushrod of the servo a bit and replace the bolt between pedal and servo fork.
The mecanics released the hydraulic pressure by opening the brake pipes at the brake master a bit, and the seize was gone. I drove home with the nuts fixing the master to the servo released by a few turns.
At my place I turned the pushrod in by 2 turns again. No problems this moring when I drove to work for 45min. Problem solved hopefully.
So to anybody concerned about a "direct brake pedal feel".
Do not push this issue to far. These brake masters need some freeplay towards the servo, in order to allow the pistons to move back under all circumstances (thermo dilatation etc.) I dono if there is a bottom valve in this master or not, but I know that my mecanics made me save to drill a hole into my knee. Cheers Patrick
>>> Edited by roulli on Tuesday 2nd April 10:07
quote:
Finally I got it on the road yesterday.
She started immediately, with en enormeous rattle until the tappets were filled with oil.
I stopped after driving for about 20 min. at a local mecanics to ask for a check of the steering geometrics (toe-in).
When I wanted to leave, the breakes had seized. We first thought that I had over pulled the handbrake, since parked in a hill. The mecanics said that I should drive slowly, so that the brake would break free. I did so and after 3 minutes I was back as the brakes seized more and more. (Engine would starve in 2nd)
It were the front discs that started to smell. Then the mecanics asked, wether I had tried to remove all the freeplay from the brake. I did in deed regulate the pushrod of the servo a bit and replace the bolt between pedal and servo fork.
The mecanics released the hydraulic pressure by opening the brake pipes at the brake master a bit, and the seize was gone. I drove home with the nuts fixing the master to the servo released by a few turns.
At my place I turned the pushrod in by 2 turns again. No problems this moring when I drove to work for 45min. Problem solved hopefully.
So to anybody concerned about a "direct brake pedal feel".
Cheers Patrick
>>> Edited by roulli on Tuesday 2nd April 10:07
It's a known problem, the first tiny travel of the pedal cuts the brake circuit off from the reservoir and seals it. If the master cylinder can't move back all the way (because the adjuster is too tight) the circuit remains sealed when the brakes are off, and as soon as the fuid heats up it pushes the brakes on. There are two common types, I think the Lucas type has a small rubber flap valve that is held closed by the hydraulic pressure plus a spring, and pulled open by the last mil of piston travel. If you stop hard the circuit can build up so much pressure from thermal expansion that the valve stays closed despite the pedal coming back to the normal position. Stamping hard on the brake pedal several times usually releases it, and you need to clean the master cylinder or slacken off the adjuster to stop it happening again. The other sort has a channel that is closed off by the the piston and here it's simply a matter of making sure the piston comes back far enough.
Hope this makes sense,
Peter Humphries (and a green V8S)
Gassing Station | S Series | Top of Page | What's New | My Stuff