Brake servo/master cylinder replacement.

[atc40]

Just noticed brake fluid level has dropped on the rear section of the reservoir and brake fluid dripping off the bottom of the servo.
So it looks like a replacement master cylinder is required, should I remove the servo at the same time to check for fluid inside?
Both servo and master cylinder have lasted for 21 years using Automec silicone fluid, so cannot complain.
I have read that replacing the seals in the master cylinder is a difficult job and does not last long, is it better just to buy a new replacement as they still seem to be available?
How difficult is it to replace both with a BMW unit, what model BMW do replacements come from? Is it worth it?
TIA.
Andy.

[Phil S]

Not been there YET but from the problems others have had go for a stainless sleeved cylinder.
I've looked at a bmw E30 master cylinder and servo. You need to create a bit more space by putting a dish(dent) in the inner wing and sort out stud mountings, if yours is a manual I believe the clutch fluid supply needs to be moved.
euro car parts were a reasonable price for the bmw bits

[DMT]

Just done this myself recently.

I did and would recommend, fitting new standard master cylinder and servo. The servo will exchange. There are many good deals from the reputable gang and should last for another 21 years.

The newer BMW options are I am sure are better but you have a great British icon, keep it that way,

Sorry if I sound like a wally.

Dave

[022Dave]

The newer BMW options are I am sure are better but you have a great British icon, keep it that way,

Let's not forget that BMW own the rights to the Stag and its logo, along with other British icon names......

[wilf]

FItted a new master cylinder from SOC spares not too long ago, easiest to take servo and MC out as one, then separate. They can be "reluctant" to part. Didn't need a new servo myself, no fluid had got in it, but I am at a loss to know where the lost fluid did actually go - the level in mine was dropping steadily.

[DMT]

I have the same problem wilf.

Eventually found rear outer and inner front pipe connections leaking. Not obvious for ages.

[DMT]

Let's not forget that BMW own the rights to the Stag and its logo, along with other British icon names......

I did not know that. You learn something every day, but I am sure they are happy for us to be a original as possible. I say this with a multitude of non original mods!

[DJT]

I fitted a new TRW master cylinder and exchange servo from Robsport 5 years (19,000 miles) ago. All fitted and bled easily. However, I have been aware for quite a while that the fluid (Dot4) in the m/c went dark after a while, with what seemed to be tiny particles of rubber in the bottom. Changing the fluid worked for a while, but not for long.

A few months ago I was doing work on other parts of the system so I bought a m/c seal kit from LD Parts. I removed, stripped, rebuilt and refitted it without disturbing the servo. So far, so good except that I noticed fluid seeping from between the reservoir and the m/c body, despite replacing the seals. I siphoned the fluid out of the reservoir and removed it to find that the bottom face of the reservoir was distorted. It didn’t leak before I stripped it. I was able to flatten the base using glass paper on a flat surface and refit it. No leaks so far.

Time will tell if the darkening fluid problem returns.

[jbuckl]

Cbc in Quinton Birmingham have supplied a good re-sleeved Lockheed master cylinder (exchange and tested) has to be Lockheed and has to have reservoir on.

[atc40]

Thank you for all your replies. Have decided to stick with the standard servo.
Have now ordered a new master cylinder from SOC Spares.

DJT - How did you manage to remove the master cylinder from the servo whilst still in position on the car? I have just been looking at what’s involved on mine and cannot see how to undo the lower nut on the master cylinder.

[Lingen]

It isn't too difficult if you make a spanner for the job. I "Cannibalised" an old 1/2" AF one by cutting one end off to make it short enough to get at the nut..
Mike.

[DJT]

Thank you for all your replies. Have decided to stick with the standard servo.
Have now ordered a new master cylinder from SOC Spares.

DJT - How did you manage to remove the master cylinder from the servo whilst still in position on the car? I have just been looking at what’s involved on mine and cannot see how to undo the lower nut on the master cylinder.

1/4 inch socket. As I said above, the m/c is a TRW unit which may have a slightly narrower casting the the original Lockheed item. These are about the only ones available new nowadays. TRW, Lucas, Lockheed are all the same company now I believe.

[wilf]

You might finagle a spanner to get that nut off, but having done that, the servo might not want to let go of the MC. This was why I took the combined servo/MC out- it took a lot of pulling and prying to separate them - it's only 4 relatively easily accessed nuts after all.