The 'E' Type Forum

After a spirited run out a few months back, i have only just noticed that there seems to be a transfer of brake fluid happening. The front brake circuit reservoir seems to be depleting and filling the rear brake reservoir. Anyone come across this before? and what's the normal cause?

Leaking seals in the servo shuttle is the most likely cause, I'm afraid

Hi Chris,

Whereabouts is the shuttle located as the brake servo is brand new - supplied by SNG

Jason

Ok, so in my terminology - brake master cylinder :-)

I guess it's a case of, remove and get a replacement under warranty as i purchased the complete assembly brand new only a few months ago
:(

Ah, no, it's not the brake master cylinder. That is the hydraulic device which is connected to the pedal. The servo shuttle ( as I call it ) is just that : it is a vacuum /hydraulically operated shuttle which delivers servo assisted hydraulic pressure from the main supply ( which comes from the master cylinder and from the second fluid reservoir ) and sends it to the front and rear brake lines

Thanks for clarity Chris. It appears that i've a "new" faulty unit which luckily is still under warranty

Actually, I've had a thought . Before you take the whole servo out and send it back, disconnect the secondary fluid bottle B at the servo unit and check what I think is a one way valve which ( IIRC ) screws into the top of the servo unit . It is probably a white plastic device. It is item C in the diagram of the servo . Note that B and D are often transposed - the factory altered them from time to time, but the transposition seems to make no difference

Thanks Chris - i'll have a look this weekend

Jason

Hi Chris,

No sign of any one way valves UNLESS, these are the large nuts that the rear reservoir and rear brake circuit screw into on the cylinder?





There are four connections on the cylinder and the two nearest the front of the car (rear brake circuit and rear brake reservoir) screw into large adaptors? that in turn screw into the cylinder. Are these one way valves?

The trap valve is fitted under the outlet connection at D. It is a little plastic casting with a spring under it.

As the threads on the 4 holes in the cylinder body are all different it would be difficult if not impossible to misassemble it. I suppose the spring and casting could be fitted under the inlet connection at C but it would be too small to do anything.

I have never understood what this valve actually does in normal usage; it is too weak to prevent flow against braking line pressure and in any event if it did it would interfere with brake function. I assume it is there to do something if the front circuit fails?

Hi Andrew,

Had a look and i definitely do not have any plastic casting. Are we talking about the bolt at the end of the cylinder which affixes the cylinder via a bracket to the engine frame?

If i remember correctly, if you unscrew this bolt there's a spring behind it?

Valve is #29

Thanks Andrew - that's a big help. I'll report back when i've replaced

Jason

Bad news - SNG don't supply this part separately :(

Any ideas where to source one?

You could try Past Parts, or maybe just try cleaning the components; there is not much to it that can go wrong.

I thought you stated your servo was a recent purchase; is it not guaranteed?

Paul

Yes Paul, it's under warranty. As i have the system currently drained i might just disconnect and return it

I've got the same going on. People suggesting the servo. Let me know if you find out any more. Thanks

Rayloud : this thead is nearly 9 years old, so you are unlikely to get any feed back