PDA

View Full Version : clutch question: Slave push rod length?



thixon
08-21-2010, 09:11 AM
It appears that the clutch slave cylinder push rod I have is too short. I'm unable to adjust the rod out enough to get to the recommended 2 7/8" distance from the cylinder mating surface to the bottom of the top nut on the rod. my truck is a '66 IIa. I know there are two pushrods (II/IIa and III) are these different lengths?

Rineheitzgabot
08-21-2010, 09:19 AM
Travis,

Sorry I can't help, but I am keenly interested in others' input on this, as I am very close to the end of my pushrod, and I have to be careful when tightening the jam nut in such a way, to prevent the pushrod from walking out, since there are only a couple of threads left.

So, in essence, I have the same problem, only I have just enough left on the pushrod to actually function, and I have always wondered if this was common. I have already had it walk out, once. It took about 500 miles, but I certainly don't want to have to deal with that again.

Hope you get some useful input (not just for my sake).

-Gary

scott
08-21-2010, 09:34 AM
not much help but i just found that series i & ii have different push rods than & iia. i & ii 537601 - iia 576751

thixon
08-21-2010, 01:22 PM
Thanks guys. Just as a test, I cut the head off a bolt, and joined it to the pushrod to lengthen it. Not permanant, but enough to see what happened. It served to lengthen the rod, and increase the throw, but the tranny is still spinning with the clutch to the floor. I will play with the adjustment and see what happens.

If anyone can measure the overall length, and the length of the shaft that's threaded that would be great. If I can get those dimensions, I'll just make one. Hell, if I can't I'll just make one, and wing the adjustment.

lrdukdog
08-21-2010, 02:56 PM
push rod I have is too short

Travis, Travis, never admit that your push rod is too short :p
Jim Wolf

bpj911
08-21-2010, 04:03 PM
:O

I had a similar issue with my truck when i got it. I bled it, bled it, adjusted it, bled it,cursed it, cursed myself.

I felt like it was too short as well although it measured to spec. No matter what I did I couldn't get it to work. I cut a piece of all thread and used that a little longer, didn't really help either despite being longer.

I never fully resolved it except all i did was disassemble the slave cylinder and put in a new cup and bleed it out. Still wasn't very good and I frequently had to double push the clutch pedal.

That all being said, after I drove the truck for awhile it started to move the pedal up towards the middle of the stroke. I can only assume that there was air in that bastard somewhere as it has been fine for months. Quite a mystery and a pretty irritating one at that.

thixon
08-21-2010, 08:53 PM
I have a good solid pedal to the floor. Event though I've lengthened the rod, I still can't get it to shift well. It will grind in every gear, even third and fourth. Obviously, there's still some clutch contact in there somewhere, otherwise I would'nt have a spinning gearbox! I'm able to drive it by double clutching, but I have to double clutch every gear. Annoying. The other thing its doing is lurching in first and reverse from a dead stop. If I slip the clutch quick I can avoid it. This may be caused by slop in the drive train though. It needs new u joints, and the slip joint in the rear shaft has some play.

Oh well, any thoughts are appreciated.

Rineheitzgabot
08-22-2010, 06:47 AM
How is your master? Is there any possibility that it needs replaced/rebuilt?

Terrys
08-22-2010, 06:56 AM
The other thing its doing is lurching in first and reverse from a dead stop. Oh well, any thoughts are appreciated.

The lurching and the dragging together are making me think friction plate is bad.

thixon
08-22-2010, 10:17 AM
Rine,
Mast is brand new, but it could still be pedal adjustment at the master. I'm gonna try that today.

Terrys, I'm hoping your wrong, but the same thoughts crossed my mind before I started tinkering hard with the adjustment. The clutch parts are all supposed to be new. Here's where I get scared. The guy I bought the truck from was a doofus of the highest order. I've had to redo almost everything else he did, so this would be par for the course. He had receipts for all the parts, but that may not mean anything. The good news is that I have to pull the body off again to finish painting anyway so I could check then.

I'm gonna try and adjust my pedal so I get more throw today and see what happens.

Nium
08-22-2010, 10:23 AM
The dimensions I have for the slave cylinder push rod are

4 1/8" Total length of rod for IIA with hydrostatic clutch mechanism not the early clutch mechanism
1 1/4" Threads to bottom of nut at top of threads
2 5/8" Smooth part of rod above top of nut
1/4" Nut height

thixon
08-23-2010, 07:44 AM
Thanks Nium.

I'll pull the rod tonight, and measure and report back in. It'll be interesting if Mine matches up. If it does, I suppose that means I have to think about taking a look inside the bell housing.

warrenperkinson
08-30-2015, 06:13 PM
The dimensions I have for the slave cylinder push rod are

4 1/8" Total length of rod for IIA with hydrostatic clutch mechanism not the early clutch mechanism
1 1/4" Threads to bottom of nut at top of threads
2 5/8" Smooth part of rod above top of nut
1/4" Nut height

I know this is an old thread, but I have just found this information particularly useful - these sIIa pushrods are now hard/expensive to find. I've been able to use these dimensions to fabricate one from an old handbrake rod (part# 277921) - excellent!

Cheers,
Warren.

Star27buck
08-31-2015, 09:58 AM
If the clutch has been sitting for some time, sections of the friction material can adhere to the clutch face and fragment and become wedged between the friction surface and the clutch plate or flywheel. I couldn't see a way to resolve this other than to separate the transmission and replace the (relatively new) clutch plate. I labored under the impression that the hydraulic mechanism was at fault and replaced most of it before discovering the loose bits.

kb1iaw
09-03-2015, 08:37 AM
FWIW, I ran into the same issue you are having and posted this to another forum last fall:

"Have any of you ever run in to this? I installed the tubing and hose between the clutch master and slave on my 71 IIA, bled it, set the adjustments and gave it a try. The throw out bearing shaft moved but not enough to disengage the clutch. After re-bleeding the system, and double checking the adjustments it still didn't work correctly. The slave push rod didn't look right and I couldn't make the adjustment specified in the manual so I removed it and compared it to one removed from a 70 IIA parts car. There is a significant difference in the lengths. After installing the longer of the two and setting the adjustment to spec the clutch throw out now seems to work fine."

I got this one reply:

"Yep. It's pretty common on most brit cars to find varying length push rods. Moss makes an adjustable length piece for triumphs and I think a couple others. I generally just make em out of round stock, round off one end and thread the other. The one on my IIa is one I made"