I press the clutch and the engine stalls

[KMinAF]

Last Thursday the clutch pedal got "hung up" and wouldn't return by itself. I popped the pedal back up with my foot. Now everytime when I press the clutch pedal I hear what sounds like a failing TO bearing. Also, at an idle when the clutch pedal is pressed the engine loads up and stalls as though something is dragging. I removed the access plate, pulled out the fork and spun the TO bearing and did not hear any grinding/rumbling and it seemed to spin freely (all be it without a load). There was no debris i.e. clutch or bearing pieces.

Both the master and slave cylinders were replaced last year, I am using a SPEC stage III clutch, I rebuilt the engine last year and it idles and runs perfectly except for this clutch issue.

Anyone else experience a similar situation?

 

[Poodles]

is the pressure plate or clutch fork worn (like they have been contacting)?

have someone hit the clutch while you look at the front crank pully, does it move in/out when the clutch is pushed?

 

[gaboonviper85]

replace your master and slave...and use toyota parts (aisin).......

 

[Facime]

replace your master and slave...and use toyota parts (aisin).......

Im not exactly sure why your advice is to throw parts at it without having the faintest clue whats actually wrong with it, not to mention I really doubt replacing the hydraulics will help at all with something that sounds like its grinding, loading up, and causing the engine to stall.

to the OP: there have been several documented failures of Spec clutches on here lately. I would initially suspect the pressure plate. You are probably going to have to drop the trans to see anything though. With the clutch pedal pressed can you spin the crank by hand and look and listen though the inspection holes for any further information?

If poodles test reveals play you are looking at serious failure in the thrust washers, not a good thing, and means engine rebuild time.

 

[Poodles]

or failure of the throwing bearing assembly, as I've been through far too many times...

 

[KMinAF]

I am leaning toward a faulty TO bearing possibly binding under load. So next week I will drop the tranny and see. My reasoning on TO bearing is because the TO bearing is the only thing engaged when the pedal is pressed. Am I right or am I missing something?

As a side note, the issues with SPEC clutches, are they legit or urban legends exagerated by each telling party?

 

[Facime]

I dont think the guys one here who exploded their spec clutches recently would call it urban legend. In the last month I have seen that name mentioned several times in conjunction with frustrated buyers. I know nothing more than that. They may have abused 'em I dont know.

 

[Poodles]

don't drop the tranny yet, do the check of the front pulley that I told you...

 

[KMinAF]

Crank thrust bearing wear is nil i.e. no fore aft movement

The noise / loading happened suddenly with no prior warning or indication that something was amiss.

The slave cylinder is new from http://www.toyautoparts.com/ and is Aisan the master is new from Checker Auto (I believe this to be the cause of the pedal hanging up problem) and will be replaced shortly.

I took the trans out and except for the disc being worn out enough to warrant replacment, I dont see anything wrong. (SPEC stage III) The TO bearing is quiet with all of it's retaining washers in place, no unusual wear is evident on the pressure plate springs (but then would I be able to see a fault?) and the pilot bearing spins easily.

 

[Facime]

wierd. so any ideas?

 

[Poodles]

Pics of all parts?

Tech help is so much easier when it's in front of you...

 

[Facime]

so with the transmission in gear and the clutch out, no binding and car drives or can you even test that since it dies when you want to put the clutch in? What Im wondering is if the binding was in the transmission itself. Does the input shaft turn freely?

 

[KMinAF]

The input shaft does turn freely (done by hand) and prior to removal, no noise was heard at idle with the trans in neutral. The car drove / sounded normal at all speeds in all gears. I had entertained the same thought regarding the trans, but concluded that with the clutch pedal pressed the trans would / should be disengaged from the engine eliminating it as a factor.

I will take some pics and post them soon.

Never a dull moment when you own a Supra

 

[KMinAF]

Since I couldn't find anything wrong with the clutch or trans I went back to crank movement. Upon close inspection of the backside of the pulley I could see where it had rubbed against the timing belt cover. This time I used a pry bar and was able to unfortunately, move the crank fore and aft. Thanks to all for your input.

 

[Facime]

bummer, sorry about the bad news. Good excuse for an upgrade? :naughty:

We dont talk about crankwalk here on SM much but it can happen to any motor. Any idea what caused it?


edit: btw, good call poodles.

 

[KMinAF]

When I assembled the engine last year the crank felt a little tight although I could still turn it fairly easily using a wrench. Against my better judgement I left it as is instead of trying a different thrust bearing set. I am wondering if this possibly caused a lack of lubrication resulting in it's failure. I will pull the pan on Wednesday after work and see how bad it is. As far as upgrading, Dr J is giving me a sweet deal on a flywheel and clutch assembly so I will try and make the most out of an unfortunate situation.

 

[super.secret.supra.club]

Any update as to what the problem may have been. Did you find and replace the crank thrust washer to be the problem?

 

[KMinAF]

The problem was from a thrust bearing that had fallen out due to extreme wear. The bearing had actually worn a groove in the crankshaft! I believe it was due to improper clearance between the bearing and crank surface, being too "tight" it was starved for oil. The fix was "simple", remove engine and replace crankshaft. I used a factory thrust bearing this time and have not had any problem since. At this time I am using a stage three clutch and have disabled the clutch switch so that the engine is always started without depressing the clutch. I have also switched to full synthetic oil. The moral of the story is to never assume that the end play is going to be correct just because you are installing new bearings.