2.9 to 4.0 swap completed... now i have no clutch!

I posted in the transmission section, and hate to be the guy that posts two threads for one question... Just hoping to figure this out ASAP and I'm afraid no one cruises the transmission section much. If it's an issue, no problem deleting a thread.

I just put a '94 4.0 with mazda 5 speed in my '86 Bronco 2.
Pulled the engine and trans from a parts truck, and was told by a honest lookin' dude that the engine and trans worked great, and trans had a fairly new clutch.
Engine runs great indeed.

Well I went to drive it and quickly found out the clutch is not disengaging at all. Clutch in, try to shift into reverse, gnarly grinding. Won't go in any other gear unless engine is off.

Pulled the slave master and made sure it was bleed properly, no air in the pocket of the master cylinder or anywhere else. Pedal feels good.

Read about people having problems with clutches freezing/rusting together after sitting. My transmission sat outside for a bit so figured i'd give it a shot. Started it in gear, drove it around revmatching gears , bogging and stomping throttle with clutch pedal depressed trying to free it up. I don't think this is the issue, it surely would have freed with the abuse i gave it doing all this.

I can get under it and watch the throwout bearing move as my buddy pushes the clutch pedal. Is it moving as far as it should though? Couldn't say. But i can see the diaphragm getting pushed in.

Only thing i can think of is if the bronco 2 2.9's master cylinder doesn't move enough fluid volume as the 4.0 master cylinder. After hours of research though, this does not seem to be an issue.. or atleast in the hundreds of 2.9 to 4.0 swap threads, i've never seen it mentioned, and you would think surely someone would bring this up.
Regardless, i welded an eyelet off of another master cylinder pushrod to the end of my eyeley, and used the new extended eyelet to see if 3/4" longer pushrod would push more fluid and disengage the clutch. No difference.


I'm lost, and getting pretty frustrated. Afraid to drop the transmission because i can't think of what would be wrong in the bellhousing. I was checking out the throwout bearing when i had them separated and would have noticed if something was obviously wrong.

Thanks fellas. I'm going crazy over here.

I'm not a pro by any means, but if the slave cylinder is working properly, my guess would be that the pressure plate is stuck. If it was sitting outside, it might have gotten rusted to the shaft.

That's just what I can guess.

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Ok, I'm an idiot, I misread that last part where you said you had them separated.

Maybe it's binding on the shaft?



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So you had the engine/transmission separated before you installed them?

Have you bled the whole system? Have you tried pumping the clutch pedal?

He's checked to make sure it's bled

Did you actually disassemble the entire clutch pack? Removed everything from the flywheel?

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Because if you haven't, everything in there could be rusted up. Or even the pilot bearing could be seized, locking the flywheel to the input shaft. I doubt it, but it's possible.

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You need to take out your mater cylinder and bench bleed it, I usually have to do this part a couple times to get it right, n I've done it about 20+ times


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Look up a video on YouTube, you have about 80% of the air out you need to get the other 20% out or you will never get her working properly


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I'm aware of the air pocket in the master, I have bench bled it. There is no air in the system.

I never pulled anything dealing with the clutch apart. Simply unbolted the trans from the engine and re-bolted in the bronco.

I drove around for a half hour (started in gear and rev matched thru gears) smashing the throttle repeatedly in all gears with clutch pedal floored (and pumped). Did this incase the parts rusted together like mentioned. Surely they would have free'd after the hell i gave it doing this for so long.

Watched my buddy's throwout bearing move while he pushed the clutch to compare to mine. Need to look at mine again to refresh my memory, but his throwout seems to engage the diaphragm a decent bit more than mine does.
His master cylinder looks to be the same as mine as well, so there's more evidence to figure on that not being the issue here.
Going to bleed it one more time, and check my throwout bearing movement compared to my buddy's. If still no luck (not counting on it), I'm going to drop the transmission tonight and have a look-see at everything. I got a new clutch and slave cylinder in case something is goofed. But of course, i may as well just put them on instead of even considering my parts to be good and returning the new parts.

Yeah, swap that stuff out.

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Watched my throwout bearing engage. It engages the same as my buddy's.

Something is wrong with the clutch. Commence tranny drop and clutch job. Should be up and running with new parts in a few hours, hope it shifts!!

Let is know

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Lost Bushman said:

Let is know

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Click to expand...

*us

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Lets just say it took a sledge hammer to get the clutch off of the flywheel....
Dropped trans in 25 minutes, got the new clutch and slave on, putting tranny back in for good.

Maybe if we beat the hell out of it all night long we could have broken it free but with all the rust im glad its getting fresh internals!!