new clutch feels like crap

[Wyomingcowboy]

I just replaced my clutch with a LuK 05-101 and now my pedal is waaay soft and doesn't fully disengage. I have to start it in gear or mash the pedal to the floor and jam it in gear. I re-used the hydraulics and made sure the little rubber boot was on the end of the slave cylinder push rod. Do I have to upgrade hydraulics too, or can I just get a little longer push rod? I know these are non adjustable clutches and I REALLY don't want to pull it all apart again.



I'm hoping GCroyle or some other expert reads this!

I rebuilt transmission about 60k ago at 110k but reused clutch as it looked and felt ok then. After the rebuild the truck ran and felt the exact same. Why is this so different?!?!:{

 

[Wyomingcowboy]

I drove home (about 23 miles) after that last post and the shifting and starting in gear has improved but there is a vibration in the floor that wasn't there before. I first noticed it on the hwy at about 70 mph and 2k RPM.

I've had a very stiff clutch pedal since I've owned it, both before and after the transmission rebuild. I can get used to the softer pedal and the vibration but I really don't want to! (Actually I kinda like the pedal feel)

Any thoughts?

TIA

 

[RustyJC]

At first blush, the vibration would indicate a balance problem, but there's another possibility that I ran into when I had a South Bend CON O/FE clutch installed in my 2002. Following South Bend's instructions, the shop sent the flywheel out to a machine shop to have the face reground. Unfortunately, the machine shop didn't index correctly off the face of the crankshaft mounting flange, and we finally found a . 050" runout on the friction face of the flywheel. This was enough to throw the clutch mounting off to produce a SOLID 1 per revolution vibration through the floorboard that you could even feel at idle. The flywheel had to come off and be reground correctly before the vibration was eliminated.



Just another possibility to keep in the back of your mind.....



Rusty

 

[NIsaacs]

Sometimes the input shaft can wear in the spline area and installing a new clutch you can get a mis-match with the splines and a dragging disk will result. If/when that happens, every time you release it, it might sometimes not be exactly centered upon re-engagement and you can get an intermittent vibration.



I would like to know why this clutch is softer on the peddle also. My '01 has been hard from day one but other trucks I have driven are soft. Mine is so stiff that if I get in heavy stop and go traffic my knee gets tired.



Nick

 

[GCroyle]

I just replaced my clutch with a NEW CLUTCH and now my pedal is waaay soft and doesn't fully disengage. I have to start it in gear or mash the pedal to the floor and jam it in gear. I re-used the hydraulics and made sure the little rubber boot was on the end of the slave cylinder push rod. Do I have to upgrade hydraulics too, or can I just get a little longer push rod? I know these are non adjustable clutches and I REALLY don't want to pull it all apart again.

Wyomingcowboy,



Two different issues presented, lets take the easy one first.



Pedal effort.



If you have a truck with a normaly worn out "thin" disc and JUST replace the DISC and release bearing only reusing the old clutch cover, your pedal effort will be reduced. This is a characteristic of a standard diaphragm clutch. We can back this up with test graphs. Couple that with a new release bearing (the rotating part is not the issue, the SLIDING part is) that goes on with new grease in the grease groove, a cleaned up guide tube with a film of grease, dab of grease on the pivot points and your pedal effort is back to AS DESIGNED. Lets test your new clutch, easy pedal and all. Take it for a test drive, get it into 5th and in a section of road that is an uphill grade, make like you are passing a truck, nail it.



Q. Did the RPM and MPH remain syncronized? If yes, clutch did not slip, try again with loads, still holding? Enjoy the easier pedal.



Not releasing cleanly. Many possible issues, lets hit the hydro's first.



The 13" clutch used in the NV5600 needs about 1/2" of bearing travel for release. Easily delivered by a correctly functioning standard hydro system. I don't have your trucks clutch/hydro's etc history, but I sure do like to rule out ANY chance that this is an external problem rather than an internal problem first.



We have done quite a bit with the hydros at work and these systems can be confusing, I admit. First no bleed screws or vent, I actually like this because in this application, that means we are not going to WASTE DOT 3. It is a simple process to test the hydro's independant of the clutch, we have a video on youtube showing the procedure, really it is a bleeding, make that burping procedure that ends with a test. Basically you use a steering wheel puller (after removing the S/C but still hooked to the pressure line remove its pushrod and boot) to block the piston, simple. Now the test, push on the pedal with your HAND (use your hand, we don't need to pressure test is as much as we need to do an effiency test) this system will go rock hard in 1/8" clutch master cylinder pushrod travel with a couple of pounds applied at the pedal with your hand. If you have an air bubble it will get hard but it will travel further before it gets rock hard. This loss of effective travel is what KILLS a system from releasing completely. I recently demonstrated a Ford Ranger system (No. 1 problem system) and actually added via a T and some brass parts the ability to run it w/o any air in it and then with the T and a valve to a trapped section of clear plastic incorporate a SMALL air bubble into the pressure line, it stopped releasing on the spot. Maybe next week, I'll take a picture to show the setup. We used it for training demonstration.



How to fix if it fails.

1. Look for leaking or weepage, if found consider R&R of that component.

2. Chasing the bubble out. Best to remove the entire system as a complete unit, not hard at all. Take to bench.

3. Watch youtube video Bleeding w/o bleed screws.

4. With M/C positioned with p-rod pointed down at 30 degrees or so, remove cap.

5. Slowly compress S/C by hand and have someone watch for bubbles in M/C reservoir. If bubbles, repeat several times. Tap on S/C, line and all the way up to M/C. Chase the bubbles out the top.

6. Test for 1/8" to rock hard.



NOTE: Will not be effective if the M/C is horizontal, this prevents air from getting to the exit in the M/C fluid flow path.



Longer S/C push rod IMHO and experience will not do anything. It is the VOLUME of fluid displaced by the M/C that determines how far the S/C pushrod will extend.



Other possibliities for no release exist, but lets start with this, let me know what you find.



Nick:

We did an R&R on an '04 that they didn't grease the sliding portion of the bearing, pedal effort was off the chart and I actually broke the M/C to pedal pin trying to push the pedal.



RustyJC:

The F/W has a flange that centers it on the crank, but for resurfacing they as you describe must use the crank contact surface as a reference, not the projecting flange, ouch.



WC, good luck.



Gary

 

[RustyJC]

RustyJC:

The F/W has a flange that centers it on the crank, but for resurfacing they as you describe must use the crank contact surface as a reference, not the projecting flange, ouch.

Gary,



That may have been what happened on try #1. :{ As you state, you have to reference off the face that seats against the crankshaft.



Rusty

 

[NIsaacs]

Nick:

We did an R&R on an '04 that they didn't grease the sliding portion of the bearing, pedal effort was off the chart and I actually broke the M/C to pedal pin trying to push the pedal.





Thanks Gary,



That might be the issue, however wouldn't the engagement suffer also, the return of the bearing? It never slips. That might be why I have had two failures on the hydraulics tho...



Nick

 

[Wyomingcowboy]

I drove up a grade in 5th as Gary suggetsed and mashed the throttle several times and RPM's and MPH's seemed to be in sync. and there seems to be no slipping. I'll try again in a little while with a heavy trailer. However, when pulling up to a light this morning in neutral and clutch fully disengaged I was able to slip into 1st with very little effort.

I don't know how any air could have gotten into the hydraulics but I guess I can go there next. Gary actually talked me through that about 3 years ago on the phone. I had to replace the slave when putting it all back together as the pedal got pushed on the floor and shot the piston across the room. All I did was replace the slave at that time and I had no problems after.

 

[Wyomingcowboy]

One more thing: I did notice that the new TO bearing looked a little different from the original. I didn't think to measure it though... . might that have something to do with it? How likely is it that LuK put the wrong TO bearing in?

 

[GCroyle]

Thanks Gary,



That might be the issue, however wouldn't the engagement suffer also, the return of the bearing? It never slips. That might be why I have had two failures on the hydraulics tho...



Nick



Engagement is just allowing the pressure plate to clamp the disc with the process under your control, you're taking the pressure off of the release system, there is no active PULL FOR ENGAGEMENT part of the process.



We are trying to overcome the force required to push the diaphragm spring forward to the F/W by about 1/2" the actual force is for discussion say its about 350+ lbs peak at the face of the bearing. Problem: The fork at the bearing contact is moving in an arc motion. At the junction of fork to bearing carrier fork moves in arc, bearing moves straight. A wiping motion of the fork to carrier. This is a bit of a mechanical conflict. Any lack of lube at the required points, fork to pivot ball, fork to bearing carrier, bearing grease groove (in the cast iron carrier) fork to S/C pushrod will only add to the force that your leg has to overcome. Wasted effort. Sometimes I describe it as an old pickup that has king pins. When all greased up, works great, no problem. Forget to grease it and it gets real tough to turn the steering wheel. Grease the pins and bushings, life is good.



One thing that I think we are really lucky about on our Dodge clutches and release systems is the style of clutch release bearing and the size of the guide tube and materials. The carrier is cast iron and one of the longest carriers in current applications that I know of (P/U and cars only) with a large grease groove and all of this helps prevent binding. In cases of the shorter length release bearings and in many aluminum trans cases they can even snap the integral guide tube snout clean off in a bindup and stomp situation.



I have never removed a broken (worn a bit, yes) Dodge Ram clutch release fork, but Ford had to revise their '99 and up 7. 3L fork, they broke against stock clutches and they are using nylon bearing carriers.



I think the release load should be enough to match the vehicle type (these are full size trucks) give you the necessary pedal feedback but not be so heavy as to be uncomfortable to drive in stop and go traffic. Think of a guy in Minnesota in Feb wearing long johns, jeans and snowmobile pants put him behind an import pass car feeling clutch pedal, heck, he'll will not be able to get any feedback off of that light pedal.



When we did the '04 installation video (the one that I broke the pushrod pin in) I asked the owner to get in the truck but DO NOT push the pedal. I started the camera, started talking, OK push the pedal. He was darn near speachless it was that easy. We didn't do any magic, just detailed it.

 

[GCroyle]

One more thing: I did notice that the new TO bearing looked a little different from the original. I didn't think to measure it though... . might that have something to do with it? How likely is it that LuK put the wrong TO bearing in?

Wrong bearing in the LuK kit, not likely.



This is a unique size and configuration. Don't forget EACH supplier should be able to offer you Tech Support, in doubt C A L L the supplier.



The original bearing was made by BCA, cast iron, two retaining clips, flat face and self aligning. Most all versions match that I can think of, except one. Aetna Bearings in Chicago IIRC has a version with a bigger looking bearing based on their style for that size and type. Looks a bit different but dimensions and performance are what count, not cosmetic differences.



Hey, one other thing about our clutch release forks, you can put them on "flipped" swapping ball stud side for pushrod side, yup. Dodge part number is lower left as viewed facing trans. Flip it and you loose the curved crown, goes fork flat spot to bearing carrier flat spot, not good.

 

[Wyomingcowboy]

Went and pulled my 4 horse steel trailer up the same grade and there appears to be no slipping... ... .

Do I go with hyd. next?



I'm certain the fork is on correct as there was only one clip and that was on the pivot and I know for certain that is the way it went back on.

 

[Wyomingcowboy]

How likely is it that I just pulled a little air in the through the SC? It just hung there semmingly harmlessly

 

[GCroyle]

How likely is it that I just pulled a little air in the through the SC? It just hung there semmingly harmlessly

Don't know for sure but if you do not have any reserve travel (pedal comes up ~1 1/2" or so before clutch starts to engage) difficult gear selection from standing start, mushy rather than crisp and solid, might be good to test and check.



2nd and 3rd Gen hydro's (except G56) use a "O" ring seal and the line and O ring are held in by a 1/8" roll pin. Works pretty darn good. Did you pick up a bubble, don't know, test and recovery procedure previously detailed.



FWIW the G56 hydro's use an external spring clip, IMHO a "looser" connection.



Remember, we're assuming a completely useable, correctly installed clutch that we're working with.

 

[Wyomingcowboy]

Remember, we're assuming a completely useable, correctly installed clutch that we're working with.

This is also my concern



I'll pull the hydraulics and check for air but it won't be for at least a week probably. I'll be sure to check back in.



Thanks for all you do, TDR members!

 

[NIsaacs]

Thanks Gary,



That might be the issue, however wouldn't the engagement suffer also, the return of the bearing? It never slips. That might be why I have had two failures on the hydraulics tho...



Nick



Engagement is just allowing the pressure plate to clamp the disc with the process under your control, you're taking the pressure off of the release system, there is no active PULL FOR ENGAGEMENT part of the process.



When we did the '04 installation video (the one that I broke the pushrod pin in) I asked the owner to get in the truck but DO NOT push the pedal. I started the camera, started talking, OK push the pedal. He was darn near speachless it was that easy. We didn't do any magic, just detailed it.

Gary, I guess what I am thinking is if the release system is so dry as to make it bind and push hard, it would also return hard?? Maybe that is not the case? If that is all that is wrong, then I have ignored it when I should have fixed it. I just assumed it was the nature of the beast, but other trucks like it that I have driven are easy so maybe I should just pull it and give it a good inspection. I am seeing a real small drip out of the bellhousing that I am sure is engine oil so I think my rear crank seal is leaking. It is too dirty to be transmission oil.



As soon as I check it out I will report back, thanks!!



Nick

 

[GCroyle]

Nick,



A side by side comparision would be helpful, with one additional issue. Both need to have basically the same clutch OE version vs OE version. Once you compare a stock OE to almost any other HD version, the direct comparison value is lost a little bit.



Gary

 

[NIsaacs]

Gary,



Here are some pic's of my clutch. It is gunnysacked, wore out! The pilot and throughout are both dry but still rotating ok. The clutch disk is up to the rivets and the fingers are paper thin. Also the flywheel looks funny. If you can see the red area in the pic's, that is still machine marks from original. It is like the hot spots have swelled and is holding the disk off the flywheel at that point. The throughout bearing slider housing is almost dry, very sticky. The fork ball/socket seems fine. The torque springs in the disk are loose as a goose. The input shaft spines look great. It looks like the cosmoline is still on it.



Actually I am kind of appalled, I thought it would look better. Maybe my driving is not as good as I thought:-laf It has 211,000 miles. It also had 34,000 when I bought it so I will blame the previous owner



Nick

 

[GCroyle]

Nick,



That should be covered under the Red Carpet special owners we take care of you warranty policy, no problemo.



"It is like the hot spots have swelled and is holding the disk off the flywheel at that point"



Nick w/o seeing the F/W hard to be for sure. But as the cast iron gets REALLY hot from use and yours shows that. The iron is transformed into something called Martensite. Martensite has a very bad habit, it expands in volume it makes high spots on the surface. OK, take it in for a grind, machinist does his magic, looks great. Install, life is good... ... ... for a while. We have taken a bunch of calls with resurfaced F/W's at the core of the job and 2-4 months later (F/W gets reheated seeds sprout) the caller is reporting CHATTER. Why? Chatter is difficult to pin down to one thing over the phone w/o seeing the parts. But the Martensite got its top resurfaced, but the roots are still in the F/W. Use it, heat it up and like weed seeds they grow back and EXPAND -> UP and create new high spots, bad stuff.



Ever see a brake drum with hard spots in it that show up as bumps?



Now please don't rip me on this as a guy in the clutch business trying to sell product. There are a bunch of suppliers out there and we all face this potential problem. Remember, the machinist's job was to create a cleaned up surface, but not to take too much off right? The roots are still in the casting.



What to do? Make a decision. Inspect carefully does it have heat checks/cracks in it, ring gear condition, time and effort required to get it resurfaced etc. Please don't make me post pic's of custom resurfaced F/W's roloc pad, disc grinder, lathe with a loose attitude about the cutter etc.



Nick, the single biggest aid to a sucessful clutch installation it the installers attention to detail, period.



Ok, I want to back one thing up, the Martensite stuff. I didn't make it up, we consulted with one of our corporate companies, Webb Wheel, talked with their cast iron guru many years ago. Yup, thats Martensite bad stuff and he continued and continued. He actually authored a small write up for us about it. FWIW we are part of Marmon Highway Technologies which includes Marmon and Fontaine and Webb and too many others to list in the family forest.



Good luck and thanks for the pic's.

 

[NIsaacs]

Nick, the single biggest aid to a sucessful clutch installation it the installers attention to detail, period.



Ok, I want to back one thing up, the Martensite stuff. I didn't make it up, we consulted with one of our corporate companies, Webb Wheel, talked with their cast iron guru many years ago. Yup, thats Martensite bad stuff and he continued and continued. He actually authored a small write up for us about it. FWIW we are part of Marmon Highway Technologies which includes Marmon and Fontaine and Webb and too many others to list in the family forest.



Good luck and thanks for the pic's.

Gary, thanks for taking the time to explain Martensite. I have never heard that before but it makes perfect sense. I used a straight edge on the F/W and it shows what you said, it is bad. The hot spot at about 0900 o'clock is really high. I think it has been there a long time because you can see and feel the wear as the disk wore it back down.



I have already dropped off the F/W at the machine shop and will pick it up this morning. This might have been a perfect candidate for a new one. I will definitely remember this in the future. The ring gear is fine.



I will report back after install, thanks again!



Nick