MGB & GT Forum
Strange clutch problem
Posted by Kats Bee
Topic Creator (OP)
Apr 26, 2015 06:49 PM
Joined 15 years ago
2,411 Posts
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The clutch in our '77 MGB has me scratching my head. In the morning when it is cool outside the clutch pedal pretty much goes straight to the floor, making me shut the car off, engage reverse and then restart the engine so I can back out of the driveway. No problems with the forward gears. Later in the day when the outside air has heated up, the clutch does not present ANY problems at all. The pedal is good and high, engaging and disengaging as it should. I have checked the fluid level many times and it is topped up to with in 1/2 inch of the MC top. Could the MC be by-passing fluid internally when the engine bay is cool and operating normally when there is heat in the system? Jim
Apr 27, 2015 06:42 AM
Joined 19 years ago
6,499 Posts
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Maybe! It is very difficult sometimes to know which part is defective.
How old are the master, slave and hose?
My guess is the master, however I am from the "replace all three" schools of thought.
In 43 years I have never been towed.
L.W.(Larry)Baygents
63B
77 Spit
How old are the master, slave and hose?
My guess is the master, however I am from the "replace all three" schools of thought.
In 43 years I have never been towed.
L.W.(Larry)Baygents
63B
77 Spit
Topic Creator (OP)
Apr 27, 2015 06:56 AM
Joined 15 years ago
2,411 Posts
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Apr 27, 2015 07:12 AM
Joined 19 years ago
6,499 Posts
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Replace or service the copper gaskets!
In theory they are not reusable. Many do. Many have bleeding issues.
Easily annealed.
In a new 72 B the brake master failed at 30,000 miles. Others last forever. This was when I allowed others to touch my car.
I use only 1 brand of brake fluid, LMA and have been lucky. Stick with one. Being from the world of chemistry we do not like mixing stuff.
L.W.(Larry)Baygents
63B
77 Spit
In theory they are not reusable. Many do. Many have bleeding issues.
Easily annealed.
In a new 72 B the brake master failed at 30,000 miles. Others last forever. This was when I allowed others to touch my car.
I use only 1 brand of brake fluid, LMA and have been lucky. Stick with one. Being from the world of chemistry we do not like mixing stuff.
L.W.(Larry)Baygents
63B
77 Spit
Donthuis
Don van Riet
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Apr 27, 2015 11:19 AM
Top Contributor
Joined 10 years ago
13,281 Posts
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The clutch MC is the most temperamental in the whole chain of parts. The seal on the piston also acts as a valve mechanism, therefor as a minimum change all the seals with the MC in place.
If you do not mind the expenditure just replace the whole MC by a new one and indeed renew the copper washers on the banjo junction or anneal them.
"Slave cylinder often gives up in sympathy with the master" says Porter, but I myself have replaced many MC's/seals and very few SC's. Hoses last for a very long time
PS Afterwards prepare yourself for the bleeding, which may go easy or not. See the numerous posts on clutch bleeding variants
If you do not mind the expenditure just replace the whole MC by a new one and indeed renew the copper washers on the banjo junction or anneal them.
"Slave cylinder often gives up in sympathy with the master" says Porter, but I myself have replaced many MC's/seals and very few SC's. Hoses last for a very long time
PS Afterwards prepare yourself for the bleeding, which may go easy or not. See the numerous posts on clutch bleeding variants
RAY 67 TOURER
Ray Marloff
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Apr 27, 2015 07:58 PM
Top Contributor
Joined 14 years ago
17,477 Posts
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Topic Creator (OP)
Apr 27, 2015 08:35 PM
Joined 15 years ago
2,411 Posts
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