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Clutch Spin

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jvandyke

jvandyke

Luke Skywalker
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Just got my '63 Midget back together. Gearbox swap. First time. Went okay. Has all four gears and reverse.
Now, it has what I think is clutch spin. It had it before the swap too. I noticed a drip of fluid on the clutch slave dust boot, wiped it, it came right back so, I'm hoping all I have to do is rebuild the slave.
Symptoms: crunch into 1st (at a dead stop) crunch into reverse from a dead stop, very little pedal travel, take up is almost immediate as you release the pedal.
I've grounded the car as I don't want to hurt this gearbox!!!
Am I on the right track?

PS
What size flare nut wrench is correct for that line?
 
Yes. 7/16" You should only need a 7/8" cup available at many local parts stores, and you can usually remove the piston, clean, and install cup without removing the slave which is a HUGE time saver.

Peter C.
 
Air.
I noticed some PO had (I don't think this is OEM) 3 or 4 coils of line on the way to the slave. Too lazy to get the right length? Or are those coils useful somehow?
I asked at NAPA about just getting a 7/8" cup, NO.
Found place in town with the "kit" cup and dust boot, for $10 which is silly but oh well.
Did I mention I got the new gearbox in and engine reinstalled and I DROVE IT! Pretty happy with myself......so far.
 
Concur. Slave seal is FUBAR. You can get that cup from a local NAPA if you get a counter person with a clue. Bleeding the system is a pain but BE PERSISTENT! If you can get a second body to sit in and operate the pedal, have them push the pedal to the floor ONE time and hold. Measure that travel, cylinder bore end to fork extension... then have the "pumper" stroke the pedal thru full travel at least three and better four strokes and hold it to the board again. Measure that distance from slave to fork again and if it exceeds the first measurement you have air in the line. More bleeding. It can be a process, but patience is the answer. Capture the fluid with a small hose and bottle from the slave so you can "recycle" the fluid and keep the M/C level up. If the M/C sucks air, you gotta start all over again.
 
My kids know the bleeding routine! Napa guy was not interested in the 7/8"s cup. Too bad I didn't add that to the two orders from VB I got last week. I have a set of hard lines in the pile o' parts from the PO, maybe one is the right length for the slave. Don't see them in the VB or Moss catelog. Usually I won't disturb a line if I don't have too, the one going into the slave looks like it was done without a flare wrench and I'm loath to touch it because that means I'll replace it so, a rebuild "in situ" sounds good to me. Hopefully you can bleed through the passenger footwell inspection hole?
 
Ummm... yeah, but "kids' hands" are more suited to the space allowed... unless you've owned/maintained a Lotus in the past. :smirk:
 
jvandyke said:
I noticed some PO had (I don't think this is OEM) 3 or 4 coils of line on the way to the slave. Too lazy to get the right length? Or are those coils useful somehow?
Click to expand...

Those coils are actually supposed to be there. It is a hard line right? Those coils are supposed allow for movement of the drivetrain vs the body.
So, be happy, if not original, then the PO knew what they were doing when they replaced it! (good sign!)
Good job on the tranny..that is one thing I have not dared to venture into yet..
 
Cylinder rebuilt and bleed. I got a rebuild kit (cup and dust boot) from a local shop off the shelf (they specialize in old stuff) for $10 which is no bargain, but not paying shipping and not having to wait is worth it.
Rebuild went fine. I measure about 1/4" of travel before I started. Once done and bleed I hoped to see improvement but it seems pretty much the same amount of travel to me. Maybe the master is begging for a rebuild too.
No road test yet as it's too late now. At least it wasn't leaking anymore.
BTW bleeding through the inspection plug was easy, probably why it's there. I took an old 7/16" wrench and bent the box end a bit more so it angled right through the inspection hole, clear tube to old 20oz. pop bottle. Stopped bleeding when fluid was clean again and no bubbles, refilled master (with fresh fluid) twice during the process, hopefully it never got low enough to suck air!
 
Bummer, no better. How much movement of the slave push rod is expected? Hopefully it's just a bleeding issue and I have air yet. Or read somewhere (here?) yesterday that the linkage can wear at the master.
 
Not so much wear at the master as maybe an adjustment of the rod length!! But check (and double-check) bleeding first...never fully done on the first try!!!! :thumbsup:
 
By rod length do you mean push rod from the master, up against the stop screw on the pedal box? Isn't that just pedal free play? Maybe the main cup in the master is letting fluid leak past, not external, just not creating sufficient pressure? I had this on my Opel's brakes. I guess I'd better rebuild the master too. I just rebleed with the extremely competent help of my 8 year old son. I've pushed a lot of fluid through it and see no bubbles, not that there can't be air trapped somewhere and the fluid just goes right past it but I did try the 40 rapid pushes method, which I read can dissipate the air bubbles and hopefully help them past the high spots. No luck though, clutch simply isn't engaging enough to keep the gearbox from spinning. I can sit at idle (in gear) with the clutch in fine but going into gear from neutral brings grinding, at low idle I can slam it home and go but that isn't cool. Going into other gears doesn't seem as smooth as it should be either. Master rebuild I guess, then bleed like a mutha again and see where I'm at. Shoot, was really hoping to drive it again.
 
If there is too much free play you will not get the right stroke. It should be fairly tight with just a smidge of free play! I would wager that there is still a bit of air in the system yet though (It <span style="text-decoration: underline"><span style="color: #FF0000">IS</span></span> a bear to bleed thoroughly!!)
 
bugimike said:
If there is too much free play you will not get the right stroke. It should be fairly tight with just a smidge of free play! I would wager that there is still a bit of air in the system yet though (It <span style="text-decoration: underline"><span style="color: #FF0000">IS</span></span> a bear to bleed thoroughly!!)
Click to expand...

Free play is okay then. With the pedal up, I set the stop screw with just a bit of clearance so pedal free play is minimal. Which didn't help at all of course. Either the master needs help, there is air (and I don't know how else to bleed it more thoroughly, I know there's devices to help but I'm not convinced they're any better than the two person method.

What's expected range of motion of the slave pushrod? I'm only getting 1/4" inch worth. No idea what to expect there.
 
i know exactly how u feel...same problem here.
i think 1/4" is expected, but it has to STAY there..

i took my master cylinder loose from the
mounts and hand bled it while holding
it above the car somewhat.. cap off.
lotsa bubbles came out.....squeeze slow,
as itll shoot everywhere if u arent careful...

mine still doesnt work , but im gonna
rebuild the master next......z
 
I kinda think it should be more. Have you looked at the rod and pedal linkage at the master to be certain the holes of the pushrod and pedal aren't "ovaled" or the pin worn? Excess wear there translates to a LOT of motion *lost* at the slave. And I've seen pins worn to a point they look like mini crankshafts. They will feel reasonable when in the "freeplay" position and spin 90* with pedal pressure which shortens the distance the master cylinder is depressed.

Just one more thought.
 
my master is/was new...
no pin problem here, nice and tight.....

im thinkin bout adding some length
at the slave rod and checking the results.....
ill still rebuild the master though....z
 
Umm, changing the length of the slave rod wouldn't do anything for distance the slave traveled. It's the swept area/stroke of the master wot determines the stroke length at the slave, it'll still move the same distance with either length rod. Only thing more length would be needed for would be if the rod & arm were loose (too much freeplay from slave "zero" position to where the T/O bearing begins to engage the clutch). If the freeplay down there is excessive, then I could see the need.
 
good point Doc.
my whole system is new or rebuit
except for the master....
kinda points fingers, dont it? :wink: ....z
 
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