Re-reading the thread, I don’t see any mention of a new slave/booster. Correct?
The slave booster is also new. I put everything new hoping to avoid any issues. So much for that idea.
Start with the basics. Check if the free play is at the foot pedal, using your hand push and pull on the pedal and try and determine if the connection to the master is tight or if there is a lot of free play before the cylinder operates. (Look up in the footwell and watch what’s happening) I’m trying to understand if you have the correct master (or the correct rod) between the pedal and master.
The free play is definitely in the pedal to the master cylinder.iI believe I used the original rod. I got the master shall Endo from Welsh jaguar and they seem to know what the correct parts are. But it does seem like a possibility that the rod is too short. I’m not sure what exactly could be done about that.I keep assuming That the brakes were in bled completely and match why there is slop in the masses sound of but now thinking about it that doesn’t seem right.
If the brake pedal firms up with a quick double pump it’s indicative of an air bubble.
Noting you’ve just done a rebuild, have you made sure your feed lines are correctly connected? The front reservoir feeds the rear circuit.
Something not right here. The fronts are very easy to bleed, and the output should be robust. If the shaft isn’t too short, then the master piston is sticking. One more problem not cured by power bleeding.
Mike I agree with you 100%. It seems very weird to me that I should not get a robust flow. I’m beginning to think that you are right about it being the master cylinder in period I guess even a new one can be defective. It’s funny cause now when I press the brake pedal there’s like a gurgling sound coming from the master cylinder. Why is it that you think the simplest things are gonna be easy.
I double checked all of my line connections using the Bentley manual.
When you do get to the point where resistance starts, can you continue pressing the pedal and getting it to go down further? Or is like it hits a hard stop?
There are two variations of feeds to the front and rear circuits from the slave cylinder on the vacuum booster, depending on earlier or later 4.2 S1 cars, one the reverse of the other. Both arrangements are shown in the Bentley manual.
I have always found the rear circuit more difficult to bleed than the front. If not feed lines then perhaps an issue with how the master and/or slave cylinder kits have been assembled?
That’s never good. You likely have air in the master again. Is your fluid level holding? If not, reach up under the dash and feel for fluid at the top of the brake arm. Were you doing this without the engine running? It’s a whole lot harder to bleed the brakes without vacuum assist, so at least start the engine from time to time and let the vacuum canister evacuate.
Fluid level stays the same. I did not bleed with engine running. To me the weirdest thing was that while trying to bleed I never got a free flow of fluid like you usually do, either front or rear brakes. I tried using positive pressure on the reservoir, using the pedal and using A compress of power and bitey my document. At no point did I get good flow of fluid out of the caliper.
Now that I’ve got to see… 
A couple of thoughts concerning the lack of flow - have you checked that you don’t have a sealing ball bearing stuck in the bleed nipple orifice?
If you have a new master cylinder, I would also check that you have the brake pedal stop adjusted correctly to allow free play to guarantee that the cylinder can return far enough to allow fluid in from the reservoir. If not, you will just be pumping fluid out and not replenish it from the reservoir.
I do not follow. You stated this is a new master cylinder. So lots of air front and back circuits. And you are now bleeding the brakes to get all that air out. You started at the rear brakes and got a nice firm pedal. Great. Then trying the fronts, you lost the pedal. So you are saying that before you ever bled the front brakes and only bled the rears, the pedal was good, even though with a new mc the fronts were not even bled yet??? So you are reporting that after having the firm pedal (after only bleeding the rears) now that you open the fronts which already had air in them, you lost the pedal? I feel like I am missing something.
Also, if you indeed did have a good pedal after only bleeding the rears, that indicates your free play is at least in the ball park. But then you report that maybe there is a lot of free play. But I missed if you ever confirmed that the free play is now proper. That should be a first step.
Tom
This could be caused by irregular sticking of the master cylinder piston.
If this is the case the excess pedal travel will occur when the piston seal sticks part way down the bore. Should the piston seal be sticking in the bore, it will not allow the cylinder to recuperate fluid fully after each stroke making bleeding difficult at best.
In the latter case it might be possible to encourage the cylinder to recuperate fully, by pausing a few seconds, at the top of each stroke, during manual bleeding.
I am not intimately familiar with the E type brake system, but my own Jaguar has a similar system. When looking over that system in some detail it seems obvious to me that the fluid supply and piping size and routing, from reservoir to master cylinder, is undersized. This in itself will promote slow recuperation of fluid and may be a reason for frequent brake bleeding troubles.
Just suggestions….no more
Charles I have noticed on a couple of your posts that the wording is a little strange. Possibly you have a grammar checker or spell-checker or something modifying what you are posting.
Sorry about that, it’s close I use voice to text. I will watch it more closely
This is the crux of the problem. Start the engine and bleed the brakes. Without vacuum assist, the flow is poor. I’m surprised you were able to get anything at all out of the rear brakes, but maybe the reservac was fully charged when you started.
Thanks Michael , I will try re bleeding the brakes with the engine running and see how that goes.
I wonder if the MC has been overstroked? I.e the piston has been pushed so far forward that it is now stuck?