Why does my brake pedal go to the floor

[SilverBeast]

I can't think of a reason either, unless they aren't standard calipers, though I'd still expect some sort of seal.

I think the odd boo boo is going to happen in 7,001 posts. I'm sure I've made more than you already!

[Clifton]

Could have too much movement in a drum. You can lightly clamp the rubber line, one corner at a time. It would rule that out.

[BDA]

I think the odd boo boo is going to happen in 7,001 posts. I'm sure I've made more than you already!

Thanks for the vote of confidence, Silver! I am positive we are all trying to be helpful to each other and I am also positive that we will make mistakes from time to time. I just hope nobody's counting mine! 

[dakazman]

  Have you tried to cap off the rears and see what happens.then do the fronts , then side to side?

Dakazman

[Sparkrite]

The rears have been done so no issues there. In answer to brian ,when I pump the pedal rapidly the pressure does build up but then quickly fades. I have yet to pull apart the calipers but out of curiosity pulled out the old slave cylinder pistons and whilst they were not re used, they were not too bad.

[EuropaTC]

hmm, that sounds a bit ominous. although it's a bit messy, perhaps the next step is to remove the closing plate for better access and then fit 2 bleed nipples in place of the front/rear circuits coming out of the m/cyl (assuming you are still on a dual circuit system). If you can't get a hard pedal it does point to a failed internal seal.

If it looks ok then replace the circuits one at a time and see how you go.

Another thing that did come to mind, if the previous owner removed the servos and just bridged the pipework in the engine bay then you have the complex arrangement of pipes going from front to rear and then back again for the front circuit. Lots of potential for air to get caught in a high point loop with that arrangement and if that's what you have then I would be tempted to simplify it.

Brian

[mike alain]

well,  the reason I looked at this post was I was going to bleed my system the day after, well I tried,  used the tool for it to suck the fluid , i get lots of air from all corners, no pedal, NO leaks anywhere,   new units in back and rebuilt calipers in front (with no place for o ring) and I will prove with a pic later,  now I am wondering if I used wrong fluid, I used DOT 3,  not girling,
the new triumph master is in, I suspect that 2 things may be wrong,   1st, I did not pre bleed master (stupid),  2nd , should I have used girling on the new master I bought on ebay 
this is a total rebuild car, with all new lines, I have been restoring cars for 50 years and never had this problem,  note, I left the triumph top on master and make sure level stays up,
I am sure that this could not be the problem.  bleed systme agin next day,  get LOTS of air, really suspect bad master.  but will take off and bleed it, then reinstall,  really fed up and this is a lot of work.  make walk away for a few weeks, this one really has me stumped.   Mike.

[jbcollier]

Pressure builds and then goes away + no leaks and no change in fluid level = bypassing master

[Sparkrite]

I have managed to remove the calipers and the bores are good, so just a very good clean and then new pistons and seals.
If I've come this far then I will have to remove the master cylinder , hopefully it should not be too difficult.