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MG MGB Technical - clutch leaking

i have a 1968 mg b roadster and the clutch master cylender is leaking from some where because the fluid is gone after about a week. i'v looked every where through that line and can't find a leak. can any one help me with some suggustions.

thanks
scot
Scot

I'm hardly an expert here, but there are only a couple of places where it could be leaking, that is, if the hardline isn't damaged, although I've never heard of that. If the leak is coming from the master cylinder itself or the connection to it, often there will be fluid that runs down the clutch pedal, or damaged paint around the pedal box. The flex line running from the hardline to the slave cylinder is another place to check, along with the slave cylinder itself. Make sure the bleed screw is tight too.

A little more info from you might be helpful here. Are you driving the car and using the clutch, or is it sitting and leaking all on it's own? When you press on the pedal is it firm, or soft, does the clutch disengage all the way? Have you had somebody else operate the clutch for you while you look for the leak? Have you pulled the cover off the pedal box to look for fluid? It will be much easier to find a fresh leak if the surrounding areas are clean from old dirt, oil and grime.
Jared Snider

Jared. "I'm hardly an expert here". Could not tell that from your response. Good job. Les
Les Bengtson

I've had this one, too.

The clutch worked fine and I could drive around all day without fuss. But, leave the car sit for a couple
of days - and the clutch MC reservoir would be nearly empty.

Externally, the MC and slave were dry, as was the garage floor.

The flex hose was damp from engine oil changes, so I wiped it clean. Pressurizing the system would
help me detect any leaks so I pushed in the clutch pedal and held it down with a stick wedged against
a 2x3x18 block of wood that is held up against the seat frame.

A tiny, tiny trickle of fluid came from the hose were it is inserted and swedged into the threaded fitting.

Changing the hose is another matter. It's very difficult to get to the hose fitting on the bracket that is
attached to the car frame. Removing the starter helps a bit - but it is still difficult to gain access to the
fitting with a pair of wrenches (you'll need to somehow get two wrenches on the fitting to untwist it).
Having a set of stubby (extra-short) combination wrenches would help here.



Daniel Wong

I've recently replaced the master and slave cyl, as well as the clutch hose from the slave. My mc reservoir was going dry after a couple days. The rubber caps/diaphragms deteriorate and get gunked up over time. Moisture plays a role too, and the metal parts get rusty. I didn't have to remove the starter on my 79. There's a window in the firewall under the dash with a removable rubber panel(at least on late models), that allows a bit of access. The bottom bolt near the firewall is a bear to get to. As Daniel says, access is difficult. I've now changed out everything but the clutch pipe. Until I replaced the slave, master, and clutch hose, there was fluid running down my clutch pedal.
Sam C

Scot emailed me over the weekend and told me that he still can't find the leak. Here's the text:

the car is sitting
the peddel is firm
the clutch disengages
and i have had someone pushing the peddle down well i looked
and i have taken off the cover

any more suggustions


Does anybody know if there is a dye that can be added to the hydrailic fluid to help pinpoint the leaks. I know they do this with coolant, and the dye shows up under a UV light. Is anything like this availible for the clutch, would it be safe, and most importantly, would it be cost effective?
Jared Snider

Okay, just so I don't get any comments about about my priorities here, I'd like to switch safety as being more important than cost-effectiveness.
Jared Snider

This thread was discussed between 01/02/2002 and 05/02/2002

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