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MG MGB Technical - Hydraulic fluid leak -clutch

On the last run out of the season before my B goes into the garage for a winter sleep I noticed a (sudden) decrease in the level of hydraulic fluid in the clutch reservior. Sure enough there was a lot of fluid under the car as well.

Before I rush in just a couple of questions. I have so far checked the hose to the slave and found no signs of leaks. Given it is minus 2 outside and I dont want to spend hours in the cold, I thought I make a plan first.

1. Has any one else experienced this and if so where did you look first?

2. Is a revsion of the seals in the cylinder a viable DIY option (I have copies of both Bentley and Haynes)if it should come this far?

3. Am I missing anything else blindingly obvious?

For the record it a 67 BGT

pAul
Paul

I had a similar problem on my 79 GT which was due to the steel hydraulic pipe rusting through at the junction to the flexible pipe. It is very exposed to the elements and is almost certain to fail there eventually.

I replaced it with a copper pipe and a new flexible hose. Access is very difficult unless you have very long arms and small hands and bleeding the slave cylinder afterwards required the use of an Ezibleed to get all the air out.

Hugh

Hugh Adamson

Paul-
If you couldn't find brake fluid leaking in the area of the clutch master cylinder, then the most likely suspect is the clutch slave cylinder. Rebuild kits for this are readily available. If the pipe is rusted as Hugh suggests, avoid the use of copper pipe. They're prone to cracking after prolnged exposure to vibration and they're illegal in many countries. Instead, use stainless steel.
Steve S.

Paul. Top up the clutch master cylinder. It should still work properly. Then, place a piece of cardboard, or, if you have a garage or flat parking space, a large piece of paper, under the car. Work the clutch pedal several times, then look under the car to see where the cardboard or paper is staining. This will give you an idea of where to begin your search.

Yes, you can rebuild the slave cylinder and master cylinder at home if the bores are not pitted.

Replacing the flex line is much easier if you remove the starter from the engine. Disconnect the battery before doing so.

Pure copper lines are, as Steve S. notes, often not allowed in various countries. There is, however, a copper-nickel (cupro-nickel) line made, I believe, by Automec. This is the type of lines used in Lindsay Porter's mgb restoration book. I have seen them for sale here in the US, thus believe that they are probably acceptable most places. Les
Les Bengtson

FWIW, stainless lines are prone to cracking also as stainless is brittle and work hardens from vibration too. I will be using copper nickel brake piping as used by Mercedes and Volvo in Europe as they don't rust. According to my European friends the Cu Ni lines are dirt cheap there - not so here. It's nice to have foreign friends to do you favors and vice versa.
datsooonmike

I guess the replacement pipe I described as copper probably was copper nickel. I bought it from Brown & Gammons so I'm sure it would have been both legal and safe.

Hugh
Hugh Adamson

When the MC leaks it ususally does so into the cabin, so this is almost certainly the slave, hose or possibly the pipe. Whichever, unless either or both are fairly new replace the hose if you replace/rebuild the slave.
Paul Hunt

This thread was discussed between 08/12/2002 and 09/12/2002

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