Poor clutch hydraulics problems same, but different - JeepForum.com
 
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post #1 of 8 Old 07-01-2020, 07:16 PM Thread Starter
fishadventure
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Poor clutch hydraulics problems same, but different

In continuation of four or five recent posters in probably three or four threads discussing poor pedal with new clutch parts such as here https://www.jeepforum.com/forum/f12/...4380939?page=4 I thought I’d post a new thread.

My nephew’s’88 4.2 needed a new throwout bearing, and the flywheel looked awful being that the clutch had worn into it .030-.035”.

So we put a new flywheel on in addition to a LUK clutch, pressure plate, and throwout bearing (internal slave). I bled everything, got pressure in the pedal, but once I started the motor the resistance went away just like it had air. A pint of fluid later I’m sure there’s no air.

I concluded that since the slave was new, $40 for a new master was worth it. It wasn’t - same problem. Bleeds to pressure, but start the engine: no disengagement pressure. New slave bad? Maybe. I’m just stumped.

The pedal barely released the clutch when jammed to the firewall, and no feel. Grinds into reverse badly. So I guess I’m pulling the trans- again.

Q: should I just pull it apart and do the slave? Or play Adjust My Length

Second problem is the third Autoxone starter grinds in the flywheel teeth and I’m frustrated with the stupid thing. Any thoughts on either welcomed and requested as I’m frustrated with the stupid thing


[size=3]Shackles & D-rings are different things.
Cranking IS turning over
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post #2 of 8 Old 07-02-2020, 11:31 AM
1project2many
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Internal slave can be tough.
Have you pulled the transmission yet?

Air can sit in the slave cylinder. Sometimes it takes a bunch of work to pump up the pedal enough so air can come out when you open the bleeder.

Let's assume the air is gone... what else could be the issue? Pressure plate? Very little will cause this to act differently when engine is running than when engine is off. Disk? It's possible that a rivet or two holding the friction disc to the hub is broken and starting the engine causes a problem. Mismatch or problem between bearing and fork? This is a definite possibility. What about loose transmission to engine bolts? Yep... this can happen. The weight of the trans / xfer case hanging off bolts keeps it from moving with engine off, but vibration from engine running can cause an issue. But we tightened everything... Most likely the clutch fork is not seated on a pivot ball properly or has a problem.

Finally, some folks say flywheel has a special shape. Supposedly FSM backs this up. I'd confirm with FSM then check for "flat" flywheel if nothing else jumps out.

Good luck.
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post #3 of 8 Old 07-03-2020, 06:23 AM Thread Starter
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Well of course there is no pivot ball. Or fork. Internal slave...

I haven’t pulled it yet (jeep is at his house 140miles from home for me)

I think I’m going to bleed the fitting at the top again for fun and games and see if I get any air. I just don’t get how I can get peddle resistance and have it feel good and then start the motor and have nothing. This makes absolutely no sense to me.

I just don’t want to do the slave pulling the transmission again Uggh

I am sure the bolts are all tight and torqued though. And I actually did use a pry bar and check for crankshaft end-play (the starter grinding BEFORE the throwout bearing went is why we bought a flywheel before I even pulled the driveline for the clutch and throwout bearing)
So that’s the wild card that’s making me more confused

[size=3]Shackles & D-rings are different things.
Cranking IS turning over
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post #4 of 8 Old 07-03-2020, 06:25 AM Thread Starter
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This is an 88 with AX15; are there different starters for AX15 vs. BA510?? I want so much for the two issues to be unrelated.

[size=3]Shackles & D-rings are different things.
Cranking IS turning over
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post #5 of 8 Old 07-03-2020, 06:10 PM
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Quote:
Well of course there is no pivot ball. Or fork. Internal slave...

Yes, of course.

Quote:
I think I’m going to bleed the fitting at the top again for fun and games and see if I get any air. I just don’t get how I can get peddle resistance and have it feel good and then start the motor and have nothing. This makes absolutely no sense to me.
I would likely bleed it again also. I would also try cranking the engine with the clutch pressed. That might cause the "engine running" problem to show up without actually having the engine running.

Quote:
And I actually did use a pry bar and check for crankshaft end-play
An alternate way to check for crank end play would be have a helper press the clutch while watching balancer/belt/pulley. This would include the dynamic problem which doesn't occur when the engine is off.

Quote:
(the starter grinding BEFORE the throwout bearing went is why we bought a flywheel before I even pulled the driveline for the clutch and throwout bearing)
Did you look at the starter ring gear or starter drive gear teeth? Did you see definite wear or damage? Location of the damage might help understand what's happening.

Did you mention the symptom or problem with original slave? Low pedal? Leaking? Blown out??

Give me a bit to look up starters just to see if there's a difference.
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post #6 of 8 Old 07-05-2020, 05:04 AM Thread Starter
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The flywheel AND starter are both brand new so those were not suspect.

The old flywheel teeth were ground off in a way that indicates to me that the starter gear is too close to the flywheel because ther were damaged to the root. But the starter bolts in parallel/inline with the starter throw so there’s no adjustment so I’m not inclined to say that’s the issue.

On the other hand, that damage could also be caused from not enough starter throw, or it not extending completely.

When I get back down there I’ll do a two-person end-play check as you suggest but I’d expect and hope that it’s fine. It would blow mind a little to have the motor run so well and have the 1/4-3/8” end play I think it would take to cause this issue!

[size=3]Shackles & D-rings are different things.
Cranking IS turning over
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post #7 of 8 Old 07-05-2020, 12:47 PM
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The end play came to my mind also.

If you cannot fix it with a hammer then it has to be an electrical problem.
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post #8 of 8 Old 08-02-2020, 05:21 AM Thread Starter
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I haven’t pulled the trans again to measure end thrust- I suppose I could do so at the front, too, but have not tried.

I did get it shifting with some minor trouble with first and reverse and was hoping it would ‘break in’ but it went back to ‘impossible’ after a mile or so. Bleeding produces no air bubbles.

I did get the clutch hot on purpose once by slipping it in fourth gear hoping to get some settle down but that didn’t change it.

In the past I’ve seen a couple flywheels I’ve pulled on jeeps with a spacer between the crank flange and flywheel, maybe .080-0.090” or so. I always assumed this was a previous owner installment error as more often a similar spacer is on the clutch side under the bolt heads. Admittedly I’ve not installed one ever...

Would that 1/16”+ make a difference (if I sourced one) if I used it to ‘shorten’ the travel of the throwout bearing?

Is there supposed to be a spacer there? (my nephew’s jeep, like most, didn’t have one on disassembly)

These are all new parts, making me nuts. I’ve installed used parts on all my stuff, saved “good” parts from partouts, and never had trouble. I put new parts in and I’m beating my head on a wall...

Of course there’s still the end thrust variable untested.

[size=3]Shackles & D-rings are different things.
Cranking IS turning over
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