'90 CQ 7A manual trans shifts only when engine off

[cgharibo]

What needs replacing/fixing when a car shifts fine with engine off and does not shift with engine running?

Thank you!

[Tractor Dave]

Sounds like the clutch.

[K Simmonds]

Clutch or release mech 100%

[cgharibo]

The car has less than 100,000 miles. How do I check the release mechanism?

Thank you!

[Tractor Dave]

I've seen a clutch go at 25k when abused.
Not really easy to check mechanism without pulling things apart. It's very difficult to see what's happening through the tiny window in the bell housing. You could remove the slave and check that's good.

[5cylinderman]

Has the car been off the road for any length of time? The clutch plate could have stuck to flywheel with a bit of rust. I've seen it many times before.

[K Simmonds]

Assuming the pedal is opperating correctly I'd start by popping the slave cylinder out to check it's not leaking, though you'd have noticed a considerable drop in fluid and a puddle if it is.

As said above if the car has been stood for ages then the clutch could be frozen as we call it in the trade or to be precise rusted up. This can be fixed in seconds with extream care...

Put the the car in fifth with the engine off. Check the brakes work, apply the hand brake anyway, push the brakes firmly on. Whilst holding the brakes fully on depress the clutch pedal and just breifly flick the starer. It's best to disconect the king ignition lead or pull the the fuel pump relay before trying this for the first time.

[newsh]

This happened to my friends dad's camper van that was left out in a field over winter, the clutch got stuck. It was pretty bad and rocking back and forth in a high gear wouldn't free it. He was an old school engineer and knew what to do in an old school way.
He took a hose from a boiling kettle on a gas burner and piped the steam into the bell housing through the hole in the bottom, he topped up the kettle a couple of times and would rock the van back and forth in gear, after a while the clutch popped free and was fine, they then drove it to the south of Spain.

[K Simmonds]

I like the steam idea, that's good thinking. Once free they tend to be fine it's just a case of shocking it into life.

[cgharibo]

Hi there, here is an update on the 7A with frozen clutch:

I replaced the master and slave cylinder and bled the system. The clutch pedal feels fine but the clutch is still frozen.

I kept the car idling for 30 mins and let it heat up well and the clutch is still frozen.

I pulled the handbrake, applied my foot on the brake and attempted to start the care a few times while braking it in place and the clutch is still frozen.

I applied my foot on the brake and started the car and drove about 50 feet and braked. The clutch is still frozen.

I have no convenient way to pump steam in.

Any other thoughts to free up the clutch?

Thank you in advance!

[Tractor Dave]

That's a bad case of a seized clutch! Last thing to try. Get someone to tow you. Put the car in first gear with clutch depressed. A slow tow (tractor is good) for a few hundred yards.
If that doesn't work you will have to remove the gearbox.

[cgharibo]

I may just try the tow method.

How about if I removed the speedo sensor and pour boiling water in?

[K Simmonds]

That sounds like one serious seized up clutch or a knackered pressure plate... Dave's suggestion is worth a shot but if that doesn't work the box will have to be removed as he says...

You can get steam in by removing the starter but it sounds like it's gone beyond that point as the starter motor acting on the flywheel has a lot of mechanical advantage.

Do you know why the car was parked up? There is a large thin round band/spring on the outside of the pressure plates finger springs, if this snaps it will jam operation and no amount of force will free it off. BTDT a couple of times with these cars for customers.

The five speed box isn't too bad to pull out and refit, it can be done on axle stands with a trolly jack and quite a bit of time by yourself, the six speed is much heavier and pig to do alone. Regardless I suggest getting a second pair of hands involved for safety's sake even if you have access to a lift.

If you do have to get in there change the rear main seal and gearbox input shaft seal along with the complete clutch kit as sods law one of these will start to leak as soon as one puts it back together. Try and get a Sachs clutch kit, LUK are made by Sachs and pretty much identical.

The flywheel will very likely need to be resurface if it's corroded, no big deal a decent shop will do it for less than £50 over here.

Good luck!

[K Simmonds]

I may just try the tow method.

How about if I removed the speedo sensor and pour boiling water in?

I think you mean the crank sensors, the speedo sensor runs in the gearbox and you certainly don't want to be pouring water in there. Worth a shot, at this stage you have nothing to loose though I fear your going to have to pull the box out.

[cgharibo]

Thank you for the replies.

I am not sure how the car was parked up, for > 10 yrs!

I would like to explore the large thin round band/spring on the outside of the pressure plates finger springs. Is this something I can check by slipping under the car to see if it is snapped?

Thank you everyone for all the good advice! This is a rescue car!