brake bleeding

[rossbraithwaite]

Hello All, apologies for the newbie question on a subject extensively covered on the forum. With regards to the textbook process for bleeding brakes; two people, hold pedal down while nipple is closed, release pedal etc.
If the S1 Girling calipers have the ball bearing correctly fitted under the bleed nipple should it work effectively as a non-return valve for brake bleeding? If so, is there any need for a non-return valve bleed tube? Or for the two person bleed technique?
At the bottom of pedal travel when fluid flow stops the ball bearing should drop back into position and prevent return fluid flow. Am I missing something?
Thanks, Ross

[mgcjag]

Hi Ross....i dont know about the ball in the bleed nipple......but it really isnt a big deal to bleed the brakes even single handed.....open nipple push pedal down....hold it down with a length of 4x2 wedged against the seat...close nipple.....repeat.....Steve

[rossbraithwaite]

Thanks Steve, my question is why is it necessary to close the nipple for the pedal release stroke? The BB under the bleed nipple should prevent return. I have done as you describe on a Land Rover but that had no BB under the nipple.

[abowie]

The BB under the bleed nipple should prevent return.

I don't think that it does.

All you are doing is changing one sealing surface for another when the screw is tightened.

[288gto]

Andrew, the ones I've seen have a small spring pushing the "ball bearing" against the outlet hole so that it acts as a non return valve. My Fosseway brakes came with them but I'm m not convinced how effective they are. I bled mine using a combination of vacuum bleeder and traditional foot method.

Note to Ross the OP, mine a complete new system did take a lot of bleeding including slackening the union on the servo to get a good pedal. There's lots on here about bleeding the brakes.

Simon

[mgcjag]

The OP gives the impression the ball bearing is a standard fit on the Girling caliper....he dosnt mention aftermarket bleed nipples......Steve

[rossbraithwaite]

yes, the BB under the bleed screw is standard on S1 brake calipers

[christopher storey]

I think some confusion is creeping in here : S1 original calipers are not Girling, but Dunlop . S2 calipers are Girlings .

[rossbraithwaite]

Sorry, mea culpa. I meant the S1 Dunlop caliper

[abowie]

Andrew, the ones I've seen have a small spring pushing the "ball bearing"

Simon

The original ones don't. They just have a small dished section at the end of the screw.

[288gto]

Thanks Andrew, you learn something new every day, I know which ones you mean now. Without a spring, presumably you are just relying on gravity for it to act as a non return valve?

Simon

[abowie]

As I said, I don't think it does act as a non return valve.

All it does is gives you an annular sealing surface rather than a "needle and seat" one.

Presumably this doesn't give a real advantage as modern cars all use the "needle and seat" design.