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MGB 1978 MGB clutch is out..!

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Guywith2Mgs

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Car ran great 2 years ago but sat. It starts fine but clutch is to the floor. Not an expert here but can figure stuff out pretty well. Any first checks before i jack up the car/go crazy on this thing? thank sin advance and love this place already!
 
Hydraulics, most likely. To do it right the first time, rebuild or replace both master cylinder and slave and replace the flex line. A pain, but then there's no guessing. And if it sat that long in other than climate controlled conditions you should consider doing the same with the brakes.
 
I'm with Doc on this -- start with the hydraulics first. Straightforward enough to do if a little fussy. Hopefully it's not anything with the clutch itself, as that requires engine-out to fix.
 
The MGB clutch slave is really easy to do - I did one in an on-street parking spot in front of an Italian resturaunt once because thats where it died (put the right side front wheel up on the curb to get a little room and did it in an hour or so). I know its basic, but check for fluid. If theres no fluid in the master, and no suspicious evidence of fluid under the master (inside or out), then I'd change the slave 1st. If you have fluid, then its not leaking and may just need a good bleeding. Complete replace or rebuild will certainly eliminate any doubts, but a simple bleed or slave swap could get you down the road quick if the master isn't failed.

I'm looking at the same problem on a 1984 Jeep XJ and it is NOT easy - the clutch slave is on top of the transmission and can only be accessed by dropping the trans (or cutting an access in thru the floor). I'd rather do a dozen MGB clutch slaves than one on that Jeep.
 
Easiest/quickest is Moss Motors. Don't forget the flex line.
 
One word of advise. If you care about originality, keep the ones you are removing and send them out to be sleeved.
The replacement units will be generic units and will work fine but will not look like the originals.
As Doc says, Moss sells a complete kit with all the bits you require. I believe the part number is 180-718 and sells for less than 60 USD.
 
Grantura_MKI said:
One word of advise. If you care about originality, keep the ones you are removing and send them out to be sleeved.
The replacement units will be generic units and will work fine but will not look like the originals.
Click to expand...

Hence my: "Easiest/quickest" comment.

Grantura_MKI said:
I am a guy with three MGs.
Click to expand...

And experience with dozens more! 😉

I'd be for sleeving the originals in any event, if the MG in question is a pre-'68. :devilgrin:
 
Hello - similar problem - acquired a 77 MGB - clutch pedal goes to the floor. Removing the slave cylinder rusty/watery oily mess spilled out taking off the boot so waiting on a new one ordered. Question - The master cylinder contains full / clear looking brake fluid - when removing the slave I was expecting the flex hose to start draining out the master fluid - but nothing came out. Could this be due to lack of pressure or could the entire line be clogged somewhere?

Thanks for any insight!
 
not likely clogged - might just be that the Master isn't vented and therefore the lack of opportunity for air to ingress is holding the fluid back. Also the fluid itself doesn't always flow that quickly.

You could try taking off the MC filler cap to see what happens - though even then it won't be quick, more like drips.
 
Bendure said:
Hello - similar problem - acquired a 77 MGB - clutch pedal goes to the floor. Removing the slave cylinder rusty/watery oily mess spilled out taking off the boot so waiting on a new one ordered. Question - The master cylinder contains full / clear looking brake fluid - when removing the slave I was expecting the flex hose to start draining out the master fluid - but nothing came out. Could this be due to lack of pressure or could the entire line be clogged somewhere?

Thanks for any insight!
Click to expand...
Since the system is already "opened" a suggestion would be to replace the flex line as well. The old "ounce of prevention" paradigm. 😉
 
And you could try cracking the line at the master and having your helper push the pedal down. Close the line before pedal is released.
Bob
 
Cracked the line moving pedal does not seem to cause any fluid to move or escape - sign of a bad master cylinder?
 
Bendure said:
Cracked the line moving pedal does not seem to cause any fluid to move or escape - sign of a bad master cylinder?
Click to expand...
Is there fluid in it?
 
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