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MG Midget and Sprite Technical - Clutch Spin

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?
J Van Dyke

J,

Hydraulics seem likely to me, especially since you said it did it before you took it apart. Could be the master or slave.

You might try a fill and bleed because that might verify that it is not something else, even though you may end up rebuilding or replacing the hydraulics for the final fix.

Charley
C R Huff

I rebuilt the slave last night, although I was a bit unsure of which way the seal is supposed to go in. Cross sectional view in Haynes shows the flat side outward toward the piston. Went with that. Bleed extensively but no joy, still wants to grind trying to get into first. I measured 1/4" movement of the slave pushrod before I started and still only had 1/4" when I was done, but it wasn't leaking. So, either the master needs work, or there is still air in the lines or the clutch parts internally aren't happy (just had it all out last week and they all seemed in good order to me, sure hope I don't have to pull the motor again).
How much movement of the slave pushrod is expected?
J Van Dyke

Does it grind going into other forward gears?
Does it grind when you are at a stop going into first or only when the car is in motion?
Did you put an all syncro box in there, if not how many (if you know)?
Rick Bastedo

Only grinds going into first (non-synchro) and reverse (also non synchro) from a dead stop. I'd expect a fight (grind) going into 1 or reverse while rolling and it does that too of course. Other forward gears don't grind.
It's a standard ribcase tranny. Clutch disk and release bearing looked great. Pretty sure it's a hydraulic thing.
Rebuilt slave, no improvement. Extensive bleeding, no change. I ordered a master cylinder rebuild kit this morning. Hope that does it, hate to pull the motor again.
J Van Dyke

When I recently did my clutch (New Cover/Plate, rebuilt slave cylinder, new relase bearing/new fork bush) I ended up with not quite enough movement on the clutch pedal - resulting in the same symptons - difficulty with 1st/reverse. There was some free movement at the top of the travel.

My assumption was the clutch wasnt fully dis-enaging. Enough that the synchros masked it on 2/3/4th. But 1st & reverse showed it up.

I made an adjustable slave cylinder push rod to get the movement of the pedal/slave to match exactly where I needed the movement for the actual clutch.

Worked perfectly and the clutch is behaving itself now.
Dean Smith ('73 RWA)

Yes, I love the adjustable push rod!

Is there any slack in the rod area there J?
8-)




ON THE CAR!!! (gee)
Rick Bastedo

The pushrod may need to be longer? 1098 takes the shorter one I believe. I remember there was a bit of play in it, some freeplay. Should there not be? Wondering now about the clutch lever bushing, I used the lever that was in the gearbox, seemed okay......uh oh?
J Van Dyke

No pushrod slack (on the car, or anywhere else, thank you very much!)
Crawled underneath, rod is tight against lever (although I should note the proper pin and stuff is gone (push rod to lever connection), there's a bolt/nut on it that I kept a bit on the loose side (proper stuff on order).
So I used my great strength to force the pushrod back into the cylinder. Went back to pedal and pumped it back up. Is it normal than for the slave, when "at rest" to have the push rod about 1/2 way (rough guess) through it's travel already?
Anyway, I ordered up rebuild kits for all the hydraulics, MC and Slave and proper pins and clips for the pushrod to lever connection.
J Van Dyke

when you bleed you need to have the piston on the slave cylinder right back in the body, cable tie the push rod back to the rear of the slave cylinder body and then bleed out the air.
Alex Sturgeon

Alright, I'll give that method a try while I wait on parts (that I may not need)
J Van Dyke

I tried rebleeding with the slave pushrod tied back, must not have tied it well as when I was done, it had pushed off the cable tie. Have since gotten my MC rebuild kit from VB and stripped down the MC. This could certianly be my problem, no? It's pretty filthy as seen here:
http://gallery.mac.com/jvandyke#100153&view=grid&bgcolor=black&sel=4
Also, one push rod is a bit bent, hmmmm.
Will clean vigorously, rebuild, rebleed and hope for the best.
J Van Dyke

P.O. gave me a 2000 University Motors technical manual, I think they used these at weekend seminars they host(ed) on all things MG. There's a section in there about clutch hydraulics and the symptoms match my issues exactly so hopefully I'm on the right track!
J Van Dyke

This thread was discussed between 24/06/2008 and 03/07/2008

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.