Disappearing brake fluid

[NigelW]

I've got a problem with the brake fluid vanishing from the reservoir, no leaks visable anywhere. I'm thinking it might be the servo filling up but there is none of the usual smoke when the engine is running and the peddle is still hard. Anyone got any thoughts on this?

[sulzeruk]

If is is disappearing and no leaks, it will be filling up the inside of your servo. They can occasionally fill up without the fluid being sucked into the engine. How much is it loosing? I had the same on an old Lotus ELan
Alasdair

[NigelW]

Thanks for your input. Just what I'm thinking, I suppose it would only smoke if the servo diaphragm was split. I've lost two full reservoir fills in the last few months. Had a look on the archived forum and Cass mentions an uprated servo that's available so that's what I going to replace with. I think I'll leave it till the new year as it's just too cold at the moment to work on cars, I'm not driving it at the moment due the council dumping salt on the roads.

[Jose]

does anyone rebuild these Servos? I have mine and two extra ones.

[NigelW]

I'm sure they do, quite a lot of Jaguar parts specialists sell them on an exchange biases. I had my original one rebuilt about 35 years ago but it only lasted another 10 before I had to get another one.

[NigelW]

I think I've finally tracked down the fluid loss problem. I pulled the carpets up under the pedal box and found the felts were soaked in fluid leaking from the master cylinder, good job I use silicone fluid or a repaint would be in order.

Looking today for a new one has thrown up two types, one costs about £45 and another it seems only available from D Manners without a few more parts that I don't need, (costing another £50) a TRW item costing £99 listed as original equipment. I went for the latter as the cheap one looks like a far East part that I have less than full confidence in based on past experience.

[Jose]

please post a photo of it and let us know how it works.

[NigelW]

Will do, should be here tomorrow.

[NigelW]

New master cylinder from David Manners.

Note it has the Lucas script on the side, will fit asap.

[NigelW]

Finally got the new M/C fitted. I kinked the the brake pipe going to the servo removing it form the old M/C union but as luck would have it I had a new pipe of the right length with the correct ends on that had been stashed away in my shed for the last twenty five years. It was a bit of a struggle to fit with the bends along the engine bay and into the servo. I had to make up and fit new under carpet felts that were ruined with brake fluid from the leaking M/C. Took it out today for a test drive and the brakes are so much better, the new uprated servo really coming into it's own with increased stopping power.