Looking for ideas on why my first clutch installation failed, and tips to avoid the second time. Transmission, bellhousing and clutch are all out of the car. Need to press out the pilot bushing with the play-doh or grease trick.

Did an engine swap, prior to that transmission and clutch worked fine.

Issue: Clutch would not disengage. Wheels turned with clutch pedal fully pressed down. When trying to shift into gear with engine running, was like the gate to the transmission was blocked. Shifter would not go into gear unless I matched the RPMs up just right.

New Parts:
Clutch Fork
LUK Clutch Kit, including friction disk, clutch release plate, and throwout bearing
National PB-656-HD Pilot Bushing

Only original part was the pivot pin. Have a replacement now on order.

With a helper, fully bled out the master and slave cylinders. Was able to see the throwout bearing press against the clutch fingers and overall movement of the clutch fork measured at the slave cylinder was 16.5mm - FSM calls for 14.7 minimum, if I recall correctly. The bleeding did help firm up the pedal feel, but still zero disengagement of the clutch.

One thing I did NOT do during the first installation is have a helper push down on the clutch pedal while sliding in the transmission. We were both underneath the car helping to guide it into place.

Took these pictures after pulling everything today. I could see no obvious signs of damage. The only odd thing I noticed was the bolts holding the clutch to the flywheel were only snug. Torque specs are 35 ft/lb. Mine didn't feel that tight. Maybe I just answered the issue?

Would greatly appreciate any and all thoughts. Certainly want to avoid doing this a THIRD time!


Flywheel side of the friction disk. Printing still clearly legible.

National PB-656-HD pilot bushing. I have a replacement coming in, thought maybe the marks on the face were from the input shaft. However, I see no corresponding marks on the shaft.

No markings on input shaft where it fits into bushing. Only about the first two-thirds enters the bushing, judging from the grease line.

Throwout bearing alignment

 

That pilot bearing looks like what I'd expect if you guys were having an issue or 2 trying to get it to line up. It's brass for a reason, you shouldn't see any marks on the input shaft from it.

Put your friction disc up with the pilot tool.
Place your pressure plate up. Use the clutch bolts (they are different than other bolts) and evenly tighten them in a criss criss pattern. DON'T crank one down then move to the next. Torque to spec. Thread locker is advised.
Put the bellhousing and clutch fork on. Torque to spec. You don't need to have the slave hooked up at all. I've been there a bunch and have never hooked it up first.
Putting the trans up there, I use a jack under the front of the trans and bench press the back of the trans. A helper is useful, not entirely necessary, sometimes no room for them anyway. Better for safety if anything. Make sure you go through the bearing and friction disc smoothly and wiggle forward to line up the bolt holes. I've only had it once or twice where the input shaft just slipped into the pilot bearing. I usually get the bolt holes as lined up as possible and slowly bring it in evenly with the trans to bellhousing bolts. As long as it goes smooth and doesn't bind, you should be on the money.

 

The marks on the pilot bushing look like it was hammered in with a socket. NBD.

Bigger issue though, is lack of grease in it. It needs grease. LOTS of it. Enough to fill up the cavity in there, but not so much that it comes out when the clutch gear slides in, because then it will get all over the disc & flywheel.

However, looks to me as though the pilot was beat on a bit too much and too hard. It's REAL SOFT; beating on it will distort the metal and make the hole too small. The burr of molten metal thrown up around the hole confirms that. The fit is too tight. If you kept on driving it, it would eventually smooth out; but its life would be short.

Try taking a small amount - emphasis on SMALL - off of the bushing bore with some sandpaper. Might even want to measure the pilot on the clutch gear, and the ID of the bushing, and open the bushing up to maybe .010" or so of clearance.

And grease it... I'd suggest Mobil1 grease.

Flywheel bolts should be around 55 ft-lbs or so. Clutch bolts around 30. Tighten the clutch bolts in a circle, a half-turn or so on each one, so that the clutch gets pressed onto the flywheel evenly and straight.

 

Thanks guys! Really appreciate the comments. Sounds like the pilot bearing install is the root cause of my issue, so a few follow up queations (a new bushing is on its way, better to start fresh)

1) I had it in the freezer for several days before installing. Is there a recommended way for installing? I dislike beating on things to get them to fit, but I remember this being VERY tight.

2). Sofakingdom: to clarify, I should fill the cavity behind the bushing with the Mobile1 grease?

I have a transmission adapter for my old Craftsman jack for this removal and install. Went like butter on the way out, hoping it will be as useful foe the install.

Thanks again for the pointers!

 

No other way to get it in that I know of other than brute force. The fit isn't usually close enough that freezing really would make all that much difference; would be a bigger factor if it was a tight tolerance like a bearing. The trick is to use something to drive it in that contacts it only at the outer edge. A hammer and a socket works fine, as long as it's almost as large as the bushing, and is kept centered on the bushing while driving it. Maybe put a hose clamp on the bushing to hold the socket centered. Another way to apply force other than beating might be a 3-jaw puller with something between the drive screw and the bushing to spread the load. Grease in the crank bore will help.

Yes the cavity should be filled and some left on the bushing bore. Don't put in so much that the pilot tip on the gear "hydraulics" the bushing out of the crank. Additionally, leave a light schmear on the transmission's clutch gear bearing retainer or the inner bore of the throwout bearing, since the bearing slides along the retainer during operation.

 

No one has yet addressed why the first I stall would not work... The issues discussed so far should not be the issue.

Is it the right clutch fork? How does it compare to the original?

Was the clutch disk in backwards? One side says toward engine or flywheel.

Is the slave cylinder moving enough to actuate the clutch?

 

All great questions. The clutch fork is the one appropriate for this CouldAMS CF133) from Rock Auto. I no longer have the original (broke cardinal rule of don't get rid of ANYTHING until project complete!) but recall comparing the two at the time of installation and they appeared identical.

Clutch disk was not installed backwards. Verified that the side marked "flywheel" was indeed facing the flywheel.

Slave cylinder had very good travel, both before and after bleeding. Factory service manual calls for around 14.5 mm travel at minimum, mine was over 16mm. Could see the throw out bearing compressing the clutch fingers.

Tried for an hour to remove pilot bushing with grease and an extra input shaft alignment tool. Sucker would not budge. Heading to O'Reilly's now to rent the slide hammer and pilot bearing puller. Really hoping I don't have to chisel it out.

 

Clutch fork pivot pin arrived today. Shows the amount of wear on the original one. Worked fine before pulling the transmission, but could the slightly shorter height and rounded top be the issue?

 

Stopped at AutoZone and picked up both the screw out and slide hammer style pullers. Love these rental programs! Over 105 in South Central Texas, so left in garage to tackle in the morning. Fingers crossed that it comes out without too much of a battle tomorrow!

 

Both styles of rental tools were a complete fail. The puller style couldn't grab the back side of the bushing, so it just came out on its own. I had higher hopes for the style of jaws on the slide-hammer attachment, but the claws are too wide to get through the bushing.

Left with no other options, broke out the drill and chisel...

Started with 1/8", then increased it where I had clearance to not hit outer wall. Needed two slots to break out a chunk with the chisel.

Out! Working on cars means life is never easy.

 

The pivot ball shouldn't make any difference at all to the matter at hand. The old one does look like it was run dry for a real long time though, probably wise to replace it regardless.

 

I'd wiped the grease off the pivot ball from my first install, wanted it to look good for the picture!

Just ordered an inner spring caliper from Amazon to measure the crank snout where the bushing rests. My bronze bushing measures 1.095" on the outside, and I believe the interference fit should be 0.001 - 0.002". No idea what the crank dimension is, so this will help me find out. Friend up the street has a mini lathe if it needs to be turned down any. Based on how hard it was to pound the first bushing into place, I'm leaning towards it distorted the inner diameter enough to come into contact with the input shaft on the trans. Logical?

 

When I took my recent car apart, there was no pilot bushing!!!.. but I did replace one on my previous car... They are a pain to remove and install... I did end up dinging the face during install but that shouldn't affect proper operation.

Since everything seemed to be installed right... I have to wonder if it's the right clutch... I ordered one recently and the box was marked right... But inside was a clutch for a six cylinder car... I would check part numbers...

 

That is a GREAT idea! Will certainly double check the numbers when I'm back in the garage.

I'll know lots more tomorrow when measuring the crank hole against the bushing diameter (1.095"). That might shed a lot of light on the situation too.

 

Sometimes I wonder about these clutch kits... On my 88, someone did put a new clutch in before I bought it... Old throw out bearing left in... the clutch pedal was really high... Usually a symptom of a worn clutch, not a new clutch. I took it apart... The clutch was clean and new... Replaced it with a zoom brand clutch, new throw out bearing. Now, it comes in perfectly... The valeo clutch that was in the car just seem to come in at a totally different place.... Hated it.

Now I run two cars with the zoom performance clutch and I really like the feel of both.