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T-Series Hydraulicless clutch

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Bob Claffie

Bob Claffie

Jedi Knight
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I'm starting to work on the family '72 MGB which has zero resistance in the clutch pedal. It's been sitting for most of the last 10-12 years. We've tried basic pump, pump, hold to no avail. The reservoir is full but fluid only dribbles out of the slave bleeder, not under pressure. We replaced the flexible hose as a precaution but had no effect. I know bleeding these things is problematical and I don't expect miracles but am looking for others success stories. Also, looking for the thread size of the slave bleeder in case I have to "inject" fluid from the bottom. Thanks, Bob
 
When I did my Sprite I used a Mityvac to pull some fluid through first before I tried the pedal method, that worked. After tht many years of sitting the slave cylinder may be shot as well.
 
I use an eezibleed which makes bleeding brakes and the clutch about as easy as it gets. Fill the bottle with fluid, attach to the master, pressurise, crack the bleeder till the bubbles stop and you're done.
 
Setting that long, both the master and the slave should be rebuilt. I pump fluid back through the slave to fill the master reservoir and never have an air problem. PJ
 
Paul...Mechanically, how do you set up a way to "pump it back through the bleeder"? I'm having the same problem with my clutch. Thanks.
 
Gary, I pull the bleeder out, wrap a couple turns of teflon tape on the threads, put the bleeder back and screw it in just enough to allow fluid to pass back through. The tape helps keep the fluid from passing back through the threads. Even so, a small amount will more than likely drip until your done. Have someone watch the reservoir to make sure it doesn't overflow, tighten the bleeder and done. Any hand pressure pump will work as long as you can attach a hose to it and the other end over the bleeder. This is also how I fill a new, dry, brake system. On a brake system, I unscrew the bleeder out of the farthermost wheel cylinder and screw in a modified bleeder with the seat removed, pump until fluid comes into the master cylinder, pull out the modified bleeder and screw in the proper one. Very little fluid is lost during the change over. Then go to the next wheel cylinder until all 4 are done. As before, you have to watch the master cylinder reservoir. I have no problems doing it this way. But your going to get others who say their way works better and maybe it does, so I'll just leave it there. :peaceful: PJ
 
Regardless of how difficult it is to bleed the system and get all the air out, you should be able to pump fluid through it easily from the master cylinder. Probably the master cylinder is in bad condition. You really shouldn't even try until you've rebuilt the MC and slave.
 
Considering how inaccessible the master cylinder is, replacing it is waaaay down on my list of priorities. The chances of getting the fitting out without destroying the frozen pipe are slim to none. I may go to the extreme of putting a kit in the slave and see what happens (or doesn't). I have a Mityvac on order and I hope that will get fluid in all the places it is supposed to be, and under pressure when needed ! Bob
 
If the system was dry before you started then the seals wil have had a chance to dry out. They rarely recover and even if you get it working odds are against it lasting long as they just don't rewet well.
 
When you say that the MC is inaccessible--do you mean the slave cylinder? I don't have an MGB, but as I remember, the MC is above the pedals in the engine compartment, quite accessible. You probably can replace the internals of the slave without removing it from the car. Ideally, you'd want to hone it out and check for pitting, but still, just replacing the piston seal would be better than nothing.

The thing won't keep working just because it's inconvenient to service it. You're risking finding yourself stalled in the middle of an intersection 75 miles from home in the rain.
 
Bob
You have found the correct way to bleed the clutch when you say"Inject" fluid from the bottom. This the best and only way according to my belief. since the air in the system trys to go up you just need to encourage it to go all the way to the top.


I get a good trigger oiler put a peice of transparent tubing securely over the nozzle pump it till fluid comes out of the tube and slip it over the bleader fitting open the fitting and pump untill bubbles stop coming out at the master cylinder and then close the fitting valve.

I bleed brakes the same way.
 
Well, color me surprised. Yesterday I rebuilt the slave cylinder. It didn't appear to be mal-functioning but it was full of crud inside. The bore was fine and I cleaned it up with some 1200 paper and put it back together. Result--- still no clutch but I had eliminated another possibility. As i had been spraying PB Blaster on the fitting at the MC in anticipation of having to service it, that paid off as I was able to break loose the fitting. Before tackling that evil job I hooked up my new MityVac to the bleeder on the slave cylinder and started pumping. By gollly here comes fluid and bubbles, what do you know ? After topping up the master a couple times and continuing to suck fluid through the system I actually have a decent pedal. The big test was to put the car in gear with the clutch depressed and crank the engine over. Yes ! The engine really is disconnected from the transmission with the clutch in. Many thanks for the suggestions and comments .
 
Nicely done!
 
PAUL161 said:
Gary, I pull the bleeder out, wrap a couple turns of teflon tape on the threads, put the bleeder back and screw it in just enough to allow fluid to pass back through. The tape helps keep the fluid from passing back through the threads. Even so, a small amount will more than likely drip until your done. Have someone watch the reservoir to make sure it doesn't overflow, tighten the bleeder and done. Any hand pressure pump will work as long as you can attach a hose to it and the other end over the bleeder. This is also how I fill a new, dry, brake system. On a brake system, I unscrew the bleeder out of the farthermost wheel cylinder and screw in a modified bleeder with the seat removed, pump until fluid comes into the master cylinder, pull out the modified bleeder and screw in the proper one. Very little fluid is lost during the change over. Then go to the next wheel cylinder until all 4 are done. As before, you have to watch the master cylinder reservoir. I have no problems doing it this way. But your going to get others who say their way works better and maybe it does, so I'll just leave it there. :peaceful: PJ
Click to expand...

I forgot to mention that this is how we recharge aircraft brakes at times to make sure all the trapped air is out. :encouragement: PJ
 
I like the pumping from the bottom idea and may purchase a new oil can pump for when I put my own new MC. I'll probably flush the system top down first because my MC reservoir showed some pretty gunky residues.
 
Swapping out the clutch master is probably best, but I don't blame Bob for trying everything else first.
They are a pain to remove on an MGB and the hard line is often fused solid to the unit.

Might be worth a shot to do other stuff first, since the clutch master isn't really safety related.

On the other hand, if your brake master cylinder has been sitting that long and is also "dry", I'd bite the bullet and pull them both out.

It's no fun....that's for sure!
 
Actually this is my sons MGB I am merely "assisting" in getting it roadable. Neither cylinder went dry over the storage period and both responded to simple fixes. Wheather they last a day or a decade remains to be seen. According to my son this car is to be the "Friday night ice cream trip" vehicle. I'm guessing 200 miles a year would be a miracle. He admitted this week he drove his '99 Miata approx 350 mile in the last year ! Too many other choices. Bob
 
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