GodSpeed

great job getting it running.
now how bout some pics

Matt Sheppard

Good on ya, Team!

I dont quite understand the whole O2 sensor excursion, but I am glad you have won the battle (how sweet it is).

Time to start sorting brakes and suspension before poaching any 16 psi runs. Please, we like having you around here.

teamking

Alright, well I've had a busy week, so no time to work on the 944 really until tonight.

I decided to try to take it for a low speed road test up my street ('up' being key. I can go 1/4 mile up hill and roll all the way back if necessary). So I got the car down off the cinder blocks that its been on for the past 6 months and fired it up. Unfortunately, I couldn't get it into gear with the engine running. If I really tried to muscle it into gear (say 3rd), the car would start to creep forward.

With the engine off, there is no trouble getting the car into gear.

So, seems to me like the clutch. I got underneath and watched while my daughter pressed the clutch and could see the slave cylinder piston move about half way across the inspection port.

Any way to differentiate a hydraulic problem from a worn clutch, other than to bleed it and see if that fixes it? BTW, the clutch pedal feel pretty soft to me, but I've got no experience driving the car to compare it with. But it's soft relative to my S2000 and T100 clutches.

Any thoughts?

teamking

Very briefly: a 3 wire O2 sensor is just a 1-wire O2 sensor plus two more wires for a heating element. The heating element brings the O2 sensor up to temp faster. The car can run in open loop mode before the O2 sensor warms up, and closed loop after.

If the heating element fails, it creates a short circuit, and blows whatever fuse it's on. It happens to be the same fuse that runs the fuel pump. By completely disconnecting the O2 sensor, I've removed the short, and now my fuel pump runs, and the car runs in open loop mode. If I snip the wires to the heating element of the O2 sensor and reconnect the other wire, then my car will run in closed loop once it has warmed up from the heat of the exhaust, which is just fine in my book.

***

Thanks for the words of wisdom, and I will definitely work up the speed (and boost) in this car slowly. Trust must be earned.

teamking

Somone asked for some pictures, so...

teamking

I took another look at the inspection port this morning, and measured the distance from the front of the port to the edge of the slave cylinder piston and got about 30mm, which is OK according to clarks-garage.

I guess I'm going to try to bleed the system.

Since the fluid is 10 years old, I really ought to flush it along with the brakes at the same time, so I guess that will be my task for the weekend.

Any other good ideas before I get started???

Matt Sheppard

That's the best trick to try at this point. Bleeding the clutch and brake system is cheap, perhpas you will get more travel out of the cyl. and after 10 years, obviously needs to be done. Do all the brakes like you have the car now - flat. Then, make sure to follow Clark's proceedure on clutch bleeding particularly about having the nose down low and the rear jacked up.

Hey, thank you for explaining the O2 thing. I see the wisdom now

black944 turbo

One thing you may want to try is, put the car in gear and press the clutch while rocking it back and forth, or put the car in gear and start with the clutch in it will probably move the car, but if the petal is left in and you go up a hill it will probably break loose. My clutch on corvair ( sat 30 years) was frosen, which is what you are describing and I tried those methods and all was ok.

teamking

That's great advice.

Today (with my in-laws over), I managed to get the brake fluid flushed and the starter off and the rear end way up in the air--everything short of the clutch bleed. I'll finish that off this week (hopefully), and give your ideas a shot as soon as it's down on the ground.

Thanks!

ClassJ

I am betting on the clutch being rusted frozen to the flywheel and pres plate myself.

I say put the car in first with a lot of room in front of it. Depress the clutch, and turn her over. Be ready to kill the engine in case it does not work itself free.

xsboost90

yeah i had this on an 82 924 i bought. Got it running but the clutch was frozen on- we pushed it up a hill, rolled it down and i put her in gear and dropped the clutch- bam! popped it loose.

pjburges

Whenever a clutch locks up on any of my old motorcycles I just start it up and drop it into gear and ride it up and down the street with the clutch lever pushed in, and it will usually slip free

kinda the same thing xsboost did - cept I was using the motor instead of gravity

teamking

OK, I'm going to try to break the clutch free this morning.

I've been thinking about this, I want to do this as gently as possible.

My thought was that since I've got the starter off anyway (to bleed the clutch slave cylinder), maybe I should just replace it with the flywheel lock. Then, I can put the car in gear, depress the clutch, and use my truck to tow the car (and break loose the frozen clutch).

Sound like a good plan?

1986951

Hold it!

You said the Inspection Hole showed "about 30mm" and you thought that was okay, according to ClarKsgarage...

A new clutch will show 18mm distance between the back side of the clutch Throwout Arm (where the Slave Cylinder pushrod seats, only on the opposite side) and the far edge of the inspection hole.

In my experience, a 'Used UP" clutch plate will show about 28mm when taking that same measurement, which means the Wear Surface on a clutch disc is about 10 mm... Sounds about right... Measure it by finding the largest socket that will fit in the above space without moving the Clutch Arm, and then measure across the diameter of the socket, outside to outside edge...

Now your clutch COULD be rusted to the flywheel and pressure plate, but it is also probably GONE, for all intents and purposes, so don't expect miracles if you get it freed up...

If you want to try breaking it free by towing, do it in short 'Jerks"... i.e. depress the clutch (ignition OFF) and have the person operating the tow vehicle give you a smart "Tug" for say 15 feet, and then repeat... after a couple of pulls, the rear wheels should break free and start rolling on their own... If that doesn't happen, sounds like something else has locked up in the tranny...

teamking

Interesting. I just double-checked and Clarks-garage does say 34mm, and I had figured I probably had 15,000 miles left in the clutch, plus or minus.

What will be my symptoms if the clutch is indeed 'Used up': slipping under power?

***

As far as breaking the clutch free: what if I just have the rear wheels off the ground and start the car in first gear. I put the clutch in and use the emergency brake to break the clutch free?