T-Series Clutch - shifting problems - help?

[eschneider]

OK, I'm stumped.

Slave took a dump, so I replaced the master, slave, and hose. I cleaned the lines out with alcohol and blew it dry with compressed air.

Now it won't shift into reverse or 1st without grinding.

Here's the weird part. If I start the engine with it in first gear and drive, the clutch disengages about halfway to the floor. The car will roll to a stop.

I know the first suggestion is going to be re-bleeding the clutch. Did that. The next suggestion is going to be to check the linkages. Done -- everything is tight. The next suggestion will be to look at the range of motion on the slave cylinder rod. I'm getting at least 1/2" (only spec I found was 10-12mm)

question 1) what could cause this as a result of changing the slave and master cylinder and hose?

question 2) why will the clutch disengage while driving - enough that the car will roll to a stop ---- but won't disengage enough while sitting still to shift into gear?

It seems to me like there is something sticking ever so slightly in the clutch, enough to get the input shaft spinning so that the gears won't engage..... But that couldn't have happened as a result of changing the hydraulics......????

My brain hurts.

 

[Bruce74B]

As you said, I would rebleed it again...very slowly and methodically. If there was no problem before, it is not likely that the syncros are suddenly bad, but is it just first and reverse??? Does it shift into other gears while sitting still alright? Does it help to double cluth...that could be a temp solution until it works out the gunk in the system...but again, I would bleed it with patience and a helper to cure the easy problem first. I have had to rebleed several systems multiple times before they worked right...after all, it is 30 years old. JMHO

 

[DrEntropy]

Have you recently changed the oil in the trans? Straw grabbin' here.

Have you tried the old method of stopping the mainshaft by:

1) Depress clutch.

2) Move shifter partially into second (engages balk ring).

3) Select first or reverse.

That used to be routine with my B.

 

[marinmg]

Why did the first slave fail?

 

[eschneider]

Why did the first slave fail?

Why? Age, I suppose. 'Twas leaking fluid past the seals, and after cleaning it up, the piston was fairly loose in the bore. I'm told that happens with old age.....

 

[eschneider]

Thought I'd follow up.

Problem solved!

Trans fluid (less than a year old) was low, so I changed it. Wanted to make sure there were no metallic slivers of woe and doom anyway.

When I originally installed it, I reversed the bleeder and hose locations. I switched them and re-bled the system.

Not sure which actually fixed the problem, but perhaps this will help someone in the future.

 

[DrEntropy]

When I originally installed it, I reversed the bleeder and hose locations.

Ummm.. AIR will go to th' TOP...


I'm just curious why ya did that.

And highly happy it works now!

 

[kennypinkerton]

They come in the box with the bleeder in the wrong hole. Just so it all fits in the box.

 

[eschneider]

Ummm.. AIR will go to th' TOP...
I'm just curious why ya did that.
And highly happy it works now!

I usually bleed slave cylinders before I bolt them to the transmission. I lock the piston/rod with a steel band so that the fluid moves, rather than the piston. So with the slave in my hand, I just pointed the bleeder "up", not paying attention to the way it mounted to the car.....

Stupid, I know. I've done stupid-er.

Theoretically, it shouldn't have mattered which port the fluid entered, but I'm content with the result anyway.

 

[eschneider]

I spoke too soon. Was silky-smooth, then the problem returned after 25 miles. Clutch slave movement hasn't decreased. No leaking fluid. Won't shift into any gear while idling.

 

[DrEntropy]

hmmm...

Which car is this, Eric? It sounds like you have some sort of mechanical failure. Cover plate springs? maybe the "spigot" bearing is dry/galled and the first motion shaft is kept spinning?

The fork is pinned on MG's with a special bolt, they can become worn and then kinda resemble a crankshaft. Fork bush wear, T/O bearing... Lookin' like you need to do some teardown and inspection.


...rats....

 

[eschneider]

Update....

Got a borescope into the bellhousing. Clutch carbon is GONE. No trace of it left. I'm guessing it was worn, and the last bits disintegrated suddenly.

I'm guessing when that happened, the slave piston extended into a rough section of the cylinder bore and failed.

 

[DrEntropy]

GAH...

R&R unit indicated.


To motivate ya: The removal, once practiced, can be reduced to under an hour.

 

[eschneider]

The removal, once practiced, can be reduced to under an hour.

Oh, WELL, then. I'll have to practice by doing the job at least 3 times. Seems that's the way things are going recently..... <sigh>

 

[Stewart]

I've done 2 now with #3 coming up shortly. I'm having the same issues your having with my 73. 1st time engine removal and reinstall went quick. Even had the rented engine hoist returned in less than an hour. Second time hour and a half to get it out and 6 hours to get it back in. Not looking forward to doing this one.

 

[DrEntropy]

Six hours, Stew?!?! What th' heck happened THERE?!?!

 

[Stewart]

Transmission crossmember decided to not fit after 33 years of fitting. It also learned kung fu in that time and beat 2 people into pulp. The engine was done and ready to run in an hour. That was a long day.

 

[eschneider]

Geez, I was gonna drop the trans, not pull the engine?

 

[DrEntropy]

R&R as a unit, Eric. It's easier to pull it out all at once. Thrutchin' around trying to just remove the trans is a true PITA. It CAN be done but believe me, taking it out with the engine is FAR easier.

waitaminnit.... we ARE talking MGB here, are we not?

 

[eschneider]

R&R as a unit, Eric. It's easier to pull it out all at once. Thrutchin' around trying to just remove the trans is a true PITA. It CAN be done but believe me, taking it out with the engine is FAR easier.

waitaminnit.... we ARE talking MGB here, are we not?

<laugh> Yes, MGB. No, it's not mine.

Thanks for the tip.