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TR2/3/3A Tr3 a clutch hydraulics problem, again.

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Expatriot

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Having replaced all the components from reservoir on down, on the clutch system, from Moss,
find i have a similar problem to many of the posted threads,
have tried almost everything to fix the issue.
I think i adjusted the slave pushrod according to manual. Appears to be correct stock length.
The slave cylinder is in the correct position installed from the engine side, the bleed screw up.
Return spring hooked up, pushrod in the middle position.

Bled normally and got constant stream of little buubles that never quit while bleeding. wrapped teflon tape around the bleed screw.
got a nice tight fit over the bleed nipple with bleeder hose.
Pedal feels great on first try.
After more tries pedal goes almost to the floor.
Tried vacuum bleeding from the slave.
Tried pressure bleeding from the slave up to the reservoir.
Tried the Moss video bubble trapping idea.
At first every one of these methods achieved what felt like a good pedal and clutch worked just fine for about 50 miles.

Replaced the new slave with another new slave from Moss. Did all the bleed methods again.
Still after a-day or two of the car just sitting the clutch pedal goes almost to the floor.
no loss of fluid in the res. And no sign of any fluid leaks. Anywhere.

if i pump the pedal five or six times, have nice firm clutch. drive off, alls well for a bit, then pedal goes soft.
Pump pump pump, nice pedal, etc etc. drive home.
Leave it overnight, pedal is soft again.
Have pumped at least three containers of new fluid through the system with different methods above,
and still no clutch after a day or two of sitting
Read all the threads on this and other forums.
seems like air is getting into the system.?
Have bled many an English car clutch system just fine.
Tried everything suggested.
What am i missing?
thanks everyone for any suggestions.
 
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I'd check for fluid inside the boots on the pushrods of both the master and slave cylinders to confirm that there is no leak. Re-check all your hydraulic connections as well. All your symptoms symptoms point to a leak.
At one point people were having issues with the reproduction master cylinders but I don't know the specifics.
Tom
 
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Hi Tom, thanks for that. Agreed there has to be a leak somewhere.
I did actually check behind the boot on the slave this morning after posting the question.
found a very tiny amount of fluid behind the slave Boot. I mean a very tiny amount.
Its new, the second one from Moss that i have replaced.
Could it be a whole batch of these Chinese made slaves are bad?
will contact Moss on that.
one thing that bothers me if you are familiar with the tr3 is my slave cylinder pushrod does not go into the slave barrel straight in but at slightly canted angle. The mounting bracket dictates that, which does not appear to be bent in any way.
Any idea if that could cause the slave piston to not seal properly?
 
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I had a new MC on the brakes that did about the same thing. Good brakes most of the time and always good after a couple of pumps. Sometimes the pedal would go to the floor first pump then be fine on the second pump. Not a good feeling coming up to a stop sign.
New MC fixed the problem.

David
 
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+1
I am afraid to jump in, because there have been so many of these threads this year. Normally I would say it's a bleed or linkage adjustment problem. But with the rash of bad repro parts we've had I would lean towards a defective MC.
 
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CJD said:
+1
I am afraid to jump in, because there have been so many of these threads this year. Normally I would say it's a bleed or linkage adjustment problem. But with the rash of bad repro parts we've had I would lean towards a defective MC.
Click to expand...
Thanks for the comments And jumping in.
Talked with Moss and they agreed there should be zero fluid behind the rubber boots in both mc and slave cylinders.
apologized for my troubles.
Sending me a free replacement slave cylinder. Good for Moss.
When asked if they had a rash of returns of these items, the rep, couldn't say.
this will be the 3rd slave cylinder tried, all exhibiting the same symptoms.
however one is eternally hopeful that the brand new part in its way will cure the problem,
since the only tiny leak of fluid in the entire system was found behind the slave boot.
 
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Every reference to which hole to mount the pushrod tells you to use the middle hole but if you have the owner's handbook that came with the car the picture of the operating leaver shows it in the bottom hole. With it mounted in the bottom hole the pushrod lines up with the slave piston and the pedal is easier to push so that's how I did it. As far as the hydraulics go, if you have the original parts you will never be disappointed if you get them rebuilt by a brake shop, I gave up on aftermarket parts that don't work.

Graham
 
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Graham H said:
Every reference to which hole to mount the pushrod tells you to use the middle hole but if you have the owner's handbook that came with the car the picture of the operating leaver shows it in the bottom hole. With it mounted in the bottom hole the pushrod lines up with the slave piston and the pedal is easier to push so that's how I did it. As far as the hydraulics go, if you have the original parts you will never be disappointed if you get them rebuilt by a brake shop, I gave up on aftermarket parts that don't work.

Graham
Click to expand...
Hiya Graham, thanks for that refrence to the bottom hole mounting. Did notice the orig. drivers practical hints handbook shows that.
When i got the car it was in the middle hole. When installing the aftermkt slave, loads of other blokes were recommending the middle hole.
sadly i tossed the slave that was on the car. But looking at it, didn't look like the original.
when i lost the clutch intially thought it was hydraulics, and replaced the whole lot.Turned out to be a sheared taper pin.
i will try mounting in the bottom hole when good people at Moss send a free replacement slave.
Reading the myriad threads about clutch hydraulics on the tr3 this must be a recurring issue . Thanks again Graham.
ted.
 
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I have been chasing a clutch issue for some time with zero results other than new parts installed :rolleyes: Looks like a trans pull is in store this winter. Good luck with yours.
 
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The slave cylinder is just a cylinder, piston, and seal. Not much that can go wrong with it, except leakage. Even if it leaks, the fluid will be replaced until the reservoir in the master cylinder is empty. But if you had that much leakage, you'd know it.

Once you have a hydraulic system bled properly, air doesn't magically reenter it. So, repeated bleeding probably won't fix it. But if you are still concerned that it's not properly bled, try using the old-fashioned two-person method where one person pushes the pedal and another operates the bleed valve. I've never been able to get a really good bleed any other way.

The master cylinder, however, has a "valve seal" between the cylinder and the reservoir. That part prevents the cylinder from forcing fluid back into the reservoir instead of into the hydraulic line. It's not a great system, as even a little leakage past that seal could cause, well, just what you are seeing.

I'd replace the master cylinder yet again, but obviously the one Moss is selling is trash. Try to find another make, if it exists; the recommendation of Rimmer is probably a good one. Another option is to rebuild it yourself. If you do that, take a good look down the cylinder and make sure that the surface where the valve seal sits is OK.
 
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Hi Obi, good ideas there thanks. My only clue to any leaksge was the small amount of fluid behind the rubber boot in the slave.
nothing behind the master boot at all. Every other fitting is bone dry and no detectable loss of fluid in the reservoir .
i have tried the two person bleed method more than once. Tried the reverse bleed and the vacuum bleed.
Will first bench bleed the new slave from Moss which they are sending for free. Then one more try at installing that one. If no luck, wil replace the master, hopefully Rimmers has a decent one.
Im getting so used to being under the car, its quite cozy under there, have my sandwiches, cup of tea, radio.
sp53 said:
I still think the problem is the Master and not the Slave cylinder. What diameter slave are you getting, 1 inch is for the tr3
Click to expand...
 
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