Where has all the fluid gone

[mopoole]

Don't take the Stag out in winter unless the roads are salt free as I have a yard in which I can run the Stag around, forward and reverse till it all warms up then after a while back to the garage. No problems at all with the brakes. Went for a run this morning and gradually the brakes started to go soft with increased pedal travel so cut the run short and back to base. On opening the brake fluid reservoir the rear compartment is totally empty and the front only half full. Been underneath as I have a pit and no telltale leaks seen or puddles of fluid. Using silicone fluid bytheway.

Any advice/suggestions gratefully received and possible remedies.

Many thanks
Maurice

[sujitroy]

Classic sign of fluid leaking inside the brake servo.

[stagwingnut]

Yes , master cylinder seals have gone

[richardthestag]

Chamber closest to the servo is front brakes, the seal that stops fluid getting drawn into the servo under vacuum may have failed.. start the engine and the servo will slowly draw fluid from the master and into the servo.

Remove the master and see if the pushrod is wet with brake fluid. if not check inside the servo. if that is bone dry then one of the brake lines, flexible hoses or front calliper has failed. fluid can get soaked into the underseal or stoneguard and may not be instantly obvious that it is leaking. however ancient underseal that appears all fresh and shiny is likely because it in full of brake fluid.

[mopoole]

Thanks Guys.
Presumably, at least the seals in the master cylinder will need replacing(the cylinder is only a few years old ?chinesium). What about the servo? Drain as much fluid out as possible? Will the seals there need replacing? There's no fluid in the footwell.
Thanks again
Maurice

[jbuckl]

Its not usually worth fitting just a seal kit to a stag master cylinder.
Often need re-sleeving the bore.

New cylinders are available, but a resleeved, tested Lockheed part is probably the best option.

The servo can survive the fluid usually, do try to wick out the fluid though.

Heres a place that supplies a service for lockheed cylinders:-
(youll need to supply a core though)

https://cbccarspares.co.uk/triumph-stag-original-lockheed-brake-master-cylinder---gmc218-6712-p.asp

Although rimmers seem to be offering a new lockheed item now.....

https://rimmerbros.com/Item--i-GMC218

[richardthestag]

Good old cheapo chinesium

Tony white should be able to help you with a donor lockheed master to get rebuilt. Be sure it is the master though

[mopoole]

Thanks all. Have bit the bullet and gone for ?Lockheed replacement from The Brothers.Will spend the W/E swopping and bleeding
Thanks again for your imputs
Maurice