So I got my truck at 160k, now she's at 235k. As far as I know, it's the factory clutch (PO sold it because he didn't want to throw $$ at ball joints ).
I suck out the clutch reservoir every spring and refill with fresh DOT4, no other maintenance.

I've smoked it 3-4 times when in a pinch (as in smell and visible smoke), and when I've needed to slip it (trailer, getting another car unstuck, etc.) I slip it.
Otherwise I take it really easy on takeoff, and rev match/shift without it.

So...as I was rocking the truck free this morning, I started to wonder-how much am I tempting fate? If it goes, I'll be riding my lawn mower to work.

__________________
$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

With well over a million miles of clutch experience, I believe that clutch life is HUGELY determined by how it is used. It sounds like you are onto the most important key to it and that is preventing heat. Under any load slip the clutch with the lowest RPM and load as possible to get to a point where the clutch pedal is released, thus having solid connection as soon as possible without lugging the engine.

In more severe loading like you describe, you have to do what you have to do, but just try to produce as little heat as possible.

BTW, as far as the hydraulics go, you would be much better served to use an assistant at the pedal so you could flush a few stroke of fluid through the system.

Hope this helps.

__________________
2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

Simply a wear item. Treating it easy generally is the normal way to extend the life but they will still eventually wear out as they were designed to.

I still had the original clutch disk in the 240D at about 250k miles. It finally failed via the release bearing self-disassembling, not via wear of the wear surfaces.

235K is impressive for a clutch in a passenger truck, particularly one you use for towing.

The old, traditional test for the clutch is a simple one. Tested at normal operating temperpature, put the front bumper firmly against an immovable object (or have a helper to stick a foot over firmly on the brake pedal) and set the parking brake fully, then put it in 4th (not OD, just whatever is next down from OD), rev it to 3,500 or so, then slip your foot off the clutch pedal (no gradual release, immediate, full engagment). To pass the test the engine should die IMMEDIATELY. If it bogs and starts to rev back up, obviously get off the gas pedal and push the clutch pedal down, and start planning for replacement.

That said, if you're planning to keep the truck, I'd just plan to replace it anyway. It's not the toughest job you'll ever do, and then you're good for another 235K or so. Do the works when you do it, pressure plate, clutch plate, TO bearing, pilot bushing. It just sucks to have to go in and re-do one of those later, since all the labor is the same.

My fears are absolved, I'll wait until she pops and then replace. I do have a nice Fidanza flywheel that might fit...

__________________
$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

I would never test a clutch like that (in my own car).

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

What kind of truck out of curiosity?

For what its worth, I've driven mostly manuals my whole life, I prefer them. And worked in a range of professional auto repair facilities namely on BMW's. I've changed a lot of them! Clutches seen to fall into 2 categories when the actual clutch fails. One is they just become so worn they can't hold the power and they slip, pretty simple. The other is somewhere close to or within that realm of wear, the friction lining becomes so thin/weak it shears away from the rivets and usually jams up in the pressure plate and then the dang thing won't disengage no matter what you do, pedal pressed hard to the floor! I've changed a bunch that did that! You probably already know this but always replace the pressure plate, pilot bearing, throw-out bearing, etc. Get an entire clutch kit. The LuK Repsets are excellent kits if available. I also recommend having your flywheel resurfaced if it has a lot of heat marks, grooves, crazing. Sometimes getting the last miles out of a clutch means the rivets end up eating away at you flywheel.

__________________
87' 300D, Currently undergoing an OM606 swap/build! SUPERTURBO!!!
03' 2500HD Dmax + goodies!
82' 300SD, parting out!
93' 300TE 4matic, parting out!
83' 240D Project Cheap Drive
89' 300E, parting out!
74' Datsun 510 wagon
88' RX7 10thAE, 13B track car build soon

Skippy~ As for perception: Drive what you like and can afford. Those who don't like it can supply vacuum to one of your components. LOL

If you need parts, I have some!

1998 Ranger, 2.5L SOHC, M5OD, 2wd. The littlest of little trucks.

__________________
$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

Considering that you only do it maybe a few times over the life of a vehicle (and only once you suspect it to begin with) it's really not that drastic. And if the clutch is good, then you also find out if your motor mounts are.


A while back I needed to pick up something for the GF and a friend at church offered his old Nissan 4x4 "if you can drive a stick." No problem there, so I go over to pick it up, I think it's about 215K on the clock, drive off. Get a couple miles away and enter the freeway, sitting in 4th (out of 5) at about 40 in the weave/merge lane, step on the gas (about half-throttle) and hit the turn signal and then engine revs way up while truck barely accelerates. Oooooops. I went back to his house and he's like, "what do you mean the clutch is slipping." We go out to the freeway and he's simply winding it out through the gears before he shifts, so he's never accelerating much in 4th or 5th. But he said go ahead and take it, so I was just really careful and gentle with it. Darn thing was slipping badly enough it also used more than a 1/4 tank to go about 60 (nearly all freeway) miles. Sheesh.

But no, I didn't need to do the slip test outlined above on it.

I do recall going with a friend to go look at a high-mile import of some kind back in the 80s (he asked me to come along because I actually knew something about cars). I felt the clutch slipping just on a gentle drive with him in the passenger seat, and I pulled into a grocery parking lot and did the above test. The parking brake worked well so I didn't even go for an immovable object (besides which I knew it wasn't going to need that). I rolled it up to 3 grand and dropped the clutch and the engine barely changed RPM. Now THAT is a worn-out clutch.

Ug! there is a better way to do this. 3rd or 4th gear 1/2 throttle up hill at a speed just above lugging the engine, push the clutch down until it slips, motor flares to 2,500 let clutch up normally ( don't dump ) motor should rapidly pull back down to preslip speed.

As for clutch life, some of these has a self adjusting pressure plate that gives a variable height peddle as it malfunctions. No, not the auto adjusting release bearing but actual springs / wedges in the clutch cover apparently intended to reduce clutch release cylinder wear. This can be replaced with a regular clutch cover

The release bearing hydraulic unit is self adjusting and can leak.

Changing the clutch on this is easy and new clutch parts not expensive even for OE like Valeo or LUK. Be sure to get the flywheel resurfaced, a warped flywheel will cause the clutch to drag. Also change the master and slave hydraulic unit at the same time. I'm big on lifeing parts and changing them near end of life rather than waiting for something to break at random.

The test I've heard is to go into fifth at 30 MPH and floor it. However, the Corolla clutch is slipping occasionally and that test still comes up just fine, so maybe it's not the best...?

__________________
"Senior Luna, your sense of humor is still loco... but we love it, anyway." -rickymay ____ "Your sense of humor is still loco... " -MBeige ____ "Señor Luna, your sense of humor is quite järjetön" -Delibes

1982 300SD -- 211k, Texas car, tranny issues ____ 1979 240D 4-speed 234k -- turbo and tuned IP, third world taxi hot rod

2 Samuel 12:13: "David said to Nathan, “I have sinned against the Lord.” And Nathan said to David, “The Lord also has put away your sin; you shall not die."

I didn't say there weren't alternatives, and I wouldn't really say yours is better (or mine is). All I know is that the one I posted has been around for decades, and will never pass a clutch that isn't in good condition. True, it strains some other components as well, but it does test the clutch.

Nor would I.

__________________
2001 SLK 320 six speed manual
2014 Porsche Cayenne six speed manual

Annoy a Liberal, Read the Constitution

Ah! I had a 93' Ranger, 4.0L 2wd, M5OD and had also done a clutch in it plus a clutch in my friends which was about the same as yours. Its not too bad of a job but the slave cylinder in those trucks tends to suck. Its internal to the bellhousing and mostly plastic. The hyd. line going to it can be a pain in the @ss to release too. Theres a special tool but its not that great. You have to push a plastic sleeve into the coupler to release the line. I had to replace the slave unit twice because they wouldn't hold a bleed, after a while the thing would gradually suck in air and with the clutch pedal to the floor, the clutch would drag enough it would be very hard to get into gear while stopped. If yours works good in that regard, leave it be and keep a spare. You can replace the bearing on it. Also check/replace the shifter bushing halves and pins, very commonly trashed on these Mazda 5spds. If you have any Q's let me know, I have more experience on these than I would like

__________________
87' 300D, Currently undergoing an OM606 swap/build! SUPERTURBO!!!
03' 2500HD Dmax + goodies!
82' 300SD, parting out!
93' 300TE 4matic, parting out!
83' 240D Project Cheap Drive
89' 300E, parting out!
74' Datsun 510 wagon
88' RX7 10thAE, 13B track car build soon

Skippy~ As for perception: Drive what you like and can afford. Those who don't like it can supply vacuum to one of your components. LOL

If you need parts, I have some!