Project Eagle: Diagnosing a Driveline Problem

When I last spoke of this Eagle, it was a mere introduction — both of myself and of this project. I hinted vaguely at its “some kind of clutch problem.” Honestly, that’s about all I knew at the time. Shortly after, my dad came over for a visit and we spent a couple days yanking the transfer case, transmission and front axle out to see what was up.


I found a like-new ATV jack at an estate sale for dirt cheap. I don’t have a motorcycle or ATV, but it works very well as a transmission jack.

There was no feel in the clutch pedal for sure, and the clutch master cylinder “reservoir,” such as it was, wasn’t holding fluid. That problem was obvious. But it also seemed to not be clamping at all: I could slot the shifter into any gear without depressing the cluth, even with the engine running, and it wouldn’t move. There was a bit of a clanging sound though coming from somewhere underneath, and we also couldn’t figure out how to engage the front axle — the unreliable vacuum-operated system was long ago removed. We decided to pull the transfer case, transmission and front differential to inspect them and the clutch. It’s a good thing we did.

All the major components were fine, but there were some unpleasant surprises. The transfer case mounting bolts were missing. It was just resting on the crossmember. The front differential vent had come off. The diff had probably a gallon of water in it, and maybe a pint of oil. Luckily, no rust: The ring and pinion were like new. The clutch was in fine working order too, in new condition as promised by the previous owner.
The clanging I had heard was simply because the transfer case was neither in 4WD or 2WD. The other vacuum-operated device that worked the transfer case, like the one for the front axle, was long ago removed. To engage it, I have to crawl underneath and flip the lever myself. I just never pushed the lever hard enough.
So, though all that work wasn’t strictly necessary, it did put confirm a lot of good parts and expose a few other problems. While we had the front diff out, my dad also found a solution to finally and permanently engage the front axle. After removing that access cover, draining the water and grime, and cleaning inside it, he found a piece of scrap pipe in my garage that fit perfectly to hold the fork in the engaged position. Now, when I select 4WD on the transfer case, it’ll actually be in 4WD! Oh, we fixed the vent, too.

20140613_180303When I have a lot of projects going at once, this tends to happen to my work area.

I also took this opportunity to replace some old, torn CV joint boots. One of the previous owners had hastily repaired them using grocery bags and duck tape. As you might expect, plastic bags aren’t strong enough to spin and flex at high speed. The joints themselves were fine, so I ordered a handful of universal CV joint boots from RockAuto.

That dirty hole on the right is the clutch master’s home. 

After mostly reinstalling the driveline (those missing bolts are still missing), I set to work on the origin of this problem: Operating the hydraulic clutch. AMC was linked to Renault at the time, so while many components for this Eagle originate with the Big Three and are as abundant as stupid tweets from teen idols, others are, well, a bit more French. This is the case with the clutch master.

If you order the wrong kit, you get O-rings and grommets instead of a new plunger.

Rebuilt replacements are usually unavailable. I got a rebuild kit, but it was the wrong one, so I ordered another. Upon receiving the right one, the rebuild was easy except for one confounding factor: The pressure line. It’s rusted to the body of the clutch master cylinder, so I took a hacksaw to it so I could remove the unit from the car. I still have to figure out how to remove that fitting without destroying the unit. I might just drop it off at a machine shop and ask the professionals there to remove it.
As for the reservoir, I did come up with a solution for that. It came from the world of motorcycles. I’ll simply mount up a cheap remote reservoir to the cowl and run a hose down to the clutch master cylinder. No more hassle with filling. No uncertainty as to the level. No water in the system.
I’m optimistic it’ll work. The hard part is finding time to do it.
[Photos Copyright 2014 Hooniverse/Alan Cesar]

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  1. Hatchtopia Avatar

    Grocery bags and duct tape? I don't even…

    1. mdharrell Avatar

      "Or" doesn't work well, either. Trust me.

  2. MrHowser Avatar

    The CMC looks very similar to the one from my Comanche – Auto zone had them for $30. Might be worth a look.

    1. Alan Cesar Avatar
      Alan Cesar

      The one I'm seeing for a Comanche has an integrated reservoir, which simply won't fit in that cramped spot. Or, if it did, I wouldn't be able to reach the cap, ever, without removing the brake master.

  3. Batshitbox Avatar

    Make sure your remote reservoir is connected to your master cylinder by a length of EPDM rubber hose and not simple vacuum hose. It's about a buck twenty five a foot from Mc Master. Brake fluid will go right through Buna-N rubber, and you'll see it sweating out. Then it gets contaminated with moisture, which it wicks right back in. Then it boils in the line under pressure (after it gets past the master cylinder, of course). Then you have problem.

    1. Alan Cesar Avatar
      Alan Cesar

      Since this is a hydraulic clutch that won't see much heat at all, I don't think I would actually have a problem if the fluid got wet. But I appreciate the information, and I'll be sure to order up some EPDM rubber hose for this.

  4. nanoop Avatar

    "The hard part is finding time to do it."
    Totally right. I envy you already for the phrase "my dad came over for a visit and we spent a couple days "…
    Two people! For DAYS!
    And you achieved a lot!
    Keep her on the road!

  5. FЯeeMan Avatar

    components for this Eagle originate with the Big Three and are as abundant as stupid tweets from teen idols, others are, well, a bit more French
    Your snarkasm fits right in and is greatly appreciated.

  6. topdeadcentre Avatar

    You brave, brave souls. Once upon a time, I had an AMC Hornet wagon, followed by an AMC Concord sedan. They were no more than twelve years old each when I owned them, and parts availability (where things didn't come from someone else's parts bin), and certain parts were already hard to get. I salute your efforts!
    <img src="; width=400>

    1. danleym Avatar

      I have a Spirit. Most parts are available if you know where to look- there's a number of AMC specialist vendors that have popped up, and generally one of them will have most things you need. They might be used, or they might be N.O.S. and stupid expensive, but they can be found.

  7. wilco40 Avatar

    Excellent on the front axle engaging pipe. Did the same thing on my '86 4spd. Cherokee with copper tubing slit and rebent around the shift fork shaft. A wheelchair bound friend of mine had 8 Eagle wagons, all with automatics. I welded the TC engaging can on the last two so it was always in 4X4. Got rid of a pile of vac lines, and mounted an offroad light switch panel where the 2W/4W vac selector was in the dash. Lost a couple of MPG, so what. They were meant to be full time 4X4 anyway. Front axle history goes all the way back to FF Jensen Interceptors, along with the viscous coupling. Good luck with the 'ol girl.

  8. 71MKIV Avatar

    50/50 mix of atf and acetone, enough to plonk the whole mc in. Cover and go away. Come back days or weeks later. Mild persuation should remove th e offending part

  9. hyvolt Avatar

    Heat it cherry hot, let it cool then repeat. I have never had it fail. Just heat the fitting.