Clutch "issues"

Tony Radford · #1 (**permalink**) 10-30-2004, 06:31 AM

OK, I had my clutch upgraded to a Ram 900 series "street/strip" kit with sintered disk. I'm running a Mcleod hydraulic actuator and aluminum flywheel. I realize that a bit of "chatter" is unavoidable and I can live with that at least for now. But the overall action of the system seems to be a bit inconsistent. When everything is cold, it seems to be ok. But after a while, I experience a bit of coarsness when shifting (not real smooth) and reverse is difficult. I rerouted the hydraulic line away from the header and replaced the DOT 3 with DOT 5 (for the heck of it). I don't think there's any air in the line as I've bled it numerous times. I've adjusted it all over the map. I've accepted that I probably went a bit too far on the upgrade, but I'd like it to be useable for at least a few thousand miles. Any ideas?

T

Big-Foot · #2 (**permalink**) 10-30-2004, 08:08 AM

The sintered disks engage and release very quickly which is why they are preferrable for racing applications. Right now, I think your issue might be in the hydraulics yet. Measure the travel of the throw-out fork when cold and hot to see what the delta is there, if any. Believe it or not a difference of .030" on the end of the fork will make a big difference in the way it feels.
Temporarily adjust any freeplay out of your slave cylinder to throw-out fork and see if that works better when hot as well.
I'm not a big fan of aluminum flywheels as they tend to "grow" when hot as well.. There are other reasons I don't like the aluminum wheels as well, but have found that the discussion of them is akin to discussing religion.
You may have multiple things working against you here.

Excaliber · #3 (**permalink**) 10-30-2004, 10:38 AM

Aw come on Randy, get that can opener out and release that alloy can of flywheel worms.

I've never heard the pro's and con's of the flywheel worm hole theory. Whats your take on it?

RIght NOW I have my engine and tranny out, if I'm gonna buy an alloy wheel, now is the time!

strictlypersonl · #4 (**permalink**) 10-30-2004, 11:28 AM

Tony,

When you release the clutch, how far up is the pedal when the car start to creep?

If the creep starts more than two inches from fully depressed, you could have either a misaligned transmission, bent (or damaged) driven disc, or a bad pressure plate.

BruceT · #5 (**permalink**) 10-30-2004, 12:23 PM

Tony,
I'm having the exact symptoms. Mcleod clutch came with the engine from Roush with an alumimum flywheel. Cold engine all's well but hot it's either hard (nearly imposssible) to get into reverse and like you have been all over the place with adjustments. One turn either way at the fork will cause slipping or hard to get in gear (and shift), really gets notchy and a grind once in a while. I adjusted the pedal to give me a little more throw and it did help some but there is still a tremendous difference between hot and cold. I'm concerned about going with more throw, I don't know what will happen mechanically with the diaphragm mechanism. Is there a concern of going too far? When it's cold it pops & snaps when I depress it all the way (engine off). It's also real jerky feeling as it nears the floor and watching the fork it gets jumpy at the same time. Did you notice any change with the dot 5 fluid?
I gotta agree that something is growing when it gets hot, Randy probably answered that for me, the flywheel. Hope someone has some suggestions for us. My car is new, 250 miles but I don't think this is something that"s gonna "break in". More likely - burn up.

BruceT · #6 (**permalink**) 10-30-2004, 01:54 PM

One more note:
When I am adjusted so there is no clutch slip (in 3rd) it will creep in low gear at stops so I kick it in neutral to keep from letting the clutch drag - wear and get hot. When it is cold in the morning I have 1 - 1 1/2 inches off the floor to engagement (no grind in reverse)- hot it will creep with the clutch in the carpet.

RICK LAKE · #7 (**permalink**) 10-30-2004, 02:54 PM

Tony Radford Tony what is the air gap between the disc and pressure plate or flywheel when you have it engaged? On an alum flywheel, .060" to .080" in the min spec. It may be larger with an iron disc. Call Mcloed and ask Red. Has far as the chatter that's a given. Titlon has a 3 disc clutch with the same problem either in or out, NO SLIPPING IT. A high preformance clutch for a 3400 lb car is all your car should need. I would take that one out and put a HD in there with the spring hub on the disc. Set the air gap on the pressure plate to .040-.055" and your problem will be gone. Give me a call if you want to talk about this. 1-732-254-3536. Rick Lake

Tony Radford · #8 (**permalink**) 10-30-2004, 03:16 PM

Thanks guys. I think I know the problem. Shortly after I had the clutch professionally installed, I re-routed the hydraulic line and put in the DOT 5 fluid. I was pumping the pedal, holding it down and opening the purge fitting. Now that I'm bleeding it right and replacing the original DOT 3, I'm noticing that it is all but impossible to get the air bubbles out of the system. I'm considering pumping the fluid into the system though the bleeder fitting on the slave. We've been trying to pump the air out with the clutch pedal for the past two hours and I'm still getting air bubbles in the drain bottle tube. I feel confident that this is my problem.

Tony Radford · #9 (**permalink**) 10-30-2004, 05:22 PM

I was hoping I could come back to you guys with my new designation "self-proclaimed genious". I picked up a syringe, connected it to the bleeder fitting and sucked the fluid through the system. I got the air bubbles out with no problem. But I just took a brief test drive and it ain't quite right. At least I got the air bubbles out!

SCOBRAC · #10 (**permalink**) 10-30-2004, 10:53 PM

Did you grease the input shaft at the pilot bearing? Are you using a bearing rather than a bushing. It sounds like there is a bit of friction in the works.

Michael C Henry · #11 (**permalink**) 10-31-2004, 12:21 PM

My car came with a external slave cylinder and a tilton 7/8" master cylinder.It didn't have enough travel for complete clutch release and free travel for the throwout bearing. I ended up going to a 15/16" master cylinder . It is a little stiffer pedal but now I can have free travel for throwout bearing release and complete clutch release for finding reverse and such. I bought a 1" kit but never installed it.

Tony Radford · #12 (**permalink**) 10-31-2004, 04:03 PM

I give up. I've run a quart of DOT 3 through the system and now I have no clutch at all. Air seems to be getting into the system but it isn't leaking anywhere. The fluid level in the reservoir doesn't change. Is it possible I destroyed my slave cylinder when I filled it with DOT 5? When I put the syringe on the bleeder fitting, I can pull air along with the fluid forever. Mike, I'm inclined to agree that I don't have enough travel with my new "long-throw" pressure plate. Is it possible to change the slave to one with a longer travel without changing the master or would I need a master with longer travel as well? This is bumming me out. I'd much rather be cruising that slinging DOT 3 all over my garage. And it tastes pretty bad too.

RICK LAKE · #13 (**permalink**) 10-31-2004, 05:15 PM

Tony Radford Tony try this. Put the rod of the slave cylinder all the way in. You will have to crack the bleeder. Put dot 3 back in the system. If you can't move the slave rod in by hand the seals are swelled and you need new seals. with the slave piston all the way in close the bleeder and pump the clutch pedal slowly in. Get someone to watch the slave rod extend. Make sure you have fluid in the res. Do this slowly as not to let air bubbles get into the line. After you have done this a couple of times you should see the fork move. Reset the linkage so that the return spring holds the throwout bearings off the pressure plate. Tap on the slave cylinder with a wrench a couple of times easy to help remove any air left in the system, crack the bleeder for a couple of seconds. then stop if you see no air bubbles in the bleeder. You may have to do this a couple of times. If after the 3 rd time still have no clutch. Call back. You may have alot of air in the system so do this way 2 times. You can collect the dot3 and use it again as long as you keep the dirt and wet out of it. Give me a call if you still cann't get it. 1-732-254-3536 Rick Lake

Tony Radford · #14 (**permalink**) 10-31-2004, 05:43 PM

Thanks Rick. I do have a fair amount of rod movement. It just apparently isn't enough. I bled the system yesterday and it seemed to work great for a few minutes, then gradually stopped working (well). It got progressively worse as I messed with it today. Not matter what I did, there seemed to be plenty of air in the system despite the fact that I was pulling fluid from the reservoir. Is it THAT hard to get trapped air out of one of these things? I've purged all the DOT 5 out of the system and replaced it with DOT 3. There is a fair amount of pressure on the slave piston as I had to extend the rod a bit (loading the pressure plate) in order to get the clutch to release sufficiently. Air has got to be getting into the system somehow, but it isn't leaking any fluid. Is the possible?

Cobrabill · #15 (**permalink**) 10-31-2004, 06:19 PM

DOT 5 will ruin McLeod seals.No synthetic fluids can be used.If i were you,i'd pull it now and send it back to McLeod.

Tony Radford · #16 (**permalink**) 10-31-2004, 06:51 PM

Bill, what about the master? Does it really need to go back to the manufacturer? Is it hard to replace the seals?

Michael C Henry · #17 (**permalink**) 10-31-2004, 08:30 PM

If you adjust all the free travel out of the pedal and master cylinder you will more that likely move the master cylinder piston off its natural stop and cover up the tiny hole that lets the actual master cylinder rerfill from the resivior.Make sure that the piston is resting at the end of the master cylinder against the snap ring and not against the pedal.Also let gravity and time help .Let the air settle out of the fliud and don't get it airated again. Keep the resivoir full.Air will try on, it's own ,to work it's way to the top.Brake fliud it viscus and the bubbles will linger a while.

Michael C Henry · #18 (**permalink**) 10-31-2004, 08:47 PM

The throw out bearing doesn't care or know what gear your in.What you described is not enough clutch release. Just different gears with different leverages.When you get complete clutch release you'll see the difference. It won't try to creep .You can shift it to any gear and no lurch.My problem was with the original Tilton 7/8' master cylinder i could either have release or free travel but not both. I gave up leverage for more slave cylinder travel. I bought a 1" kit but later decided to go inbetween with a 15/16" master cylinder kit.Works great.

trularin · #19 (**permalink**) 11-01-2004, 05:36 AM

Mike H, how did you compensate for the increase in required pressure at the pedal when you went to the 1".

I was at 1" and dropped it to .7" to get better pressure. Ended up with more travel, but great pedal pressure.

Just wondering.

Michael C Henry · #20 (**permalink**) 11-01-2004, 08:44 PM

I bought an 1" kit ,but never installed it.I had been given warnings that with the increased volume at the slave cylinder ,I may have to install a pedal stop on the master cylinder pedal. I only needed a little more travel at the slave cylinder and with the greater master cylinder diameter and volume, I was losing leverage. So I deceided to split the difference and just go up to a 15/16" diameter master cylinder.The pedal is slightly harder to push than with the 7/8" master cylinder.I never drive with bare feet and with shoes on I can hardly tell the difference. After all it has been a long time since it last ran and it is just the way it works .Given I have the same clutch( presurplate, lever and slave cylinder) as before and the clutch pedal is as before. it doesn't mater how you approach it or what parts you change .You have a throwout bearing tring to move the levers on a pressureplate with a given spring rate a specified distance . In my case I only changed how far the throw- out bearing traveled so my reactive pressure stayed the same but required more fliud to travel farther.If I increase the volume of the master cylinder ,It will take a little more pedal pressure to move the master cylinder the same distance as before but more fluid is being moved,due to the larger diameter of master cylinder. Everything is a trade off .If I would have gone with a larger diameter master cylinder the more pedal pressure that would have been required.Without changing any other componets By changing the master cylinder diameter a 1/16" ,I got the needed extra travel of the slave cylinder at the expense of a little more pedal pressure. They have formulas for all this stuff but given that I was just buying a little larger diameter master cylinder and all the math would not have changed anything.