1800: Gear selection

[142 Guy]

Originally Posted by VolvoRoyS

It is a cable clutch. There is very little free play at the fork end so would have thought increasing it to 3-4 mm wouldn't help. Got my wife to operate the clutch from within the car while I watched underneath. Lever moved; didn't seem to be broken. I had backed the car out of the garage last week without this problem. Inside, the clutch feels normal. So what else could have broken?

Roy

The 3-4 mm specification applies to the early hydraulic clutch. The later cable operated clutch is adjusted by measuring the travel of the clutch pedal. It is described on page 4-5 of this document

https://volvo1800pictures.com/docume...0_140_1800.pdf

The specification for the 1800 is 5.5" of pedal travel. If the pedal travel is more than 5.5" that indicates too much free play in the cable which results in the clutch failing to get complete release. It can also be the result of a clutch cable 'issue'.

The design of the attachment of the clutch cable to the pedal mechanism on the 1800 and 140 is exceedingly poor and subjects the inner strands of the clutch cable to a lot of bending where they exit the outer jacket at the pedal end of the cable. This results in fraying of the strands and early failure of what should otherwise be a very robust cable. If you can, squeeze under the dash and try and get a look at the cable attachment point to the top of the clutch pedal. Check for broken inner strands close to the cable attachment point. This may require that you use a pedal jack or a suitable length of wood to hold the clutch pedal in the full down position so that you can fully check the inner cable.

If the pedal travel is correct then it is not a cable adjustment or cable wear issue. The issue I mentioned earlier with the broken clutch fork occurs on the part of the fork where it contacts the release bearing. From the outside, the clutch fork movement will appear normal; however, the release bearing will not move or will move less than required to get complete clutch release because the 'inside' part of the fork is actually flexing. However, if this is occurring the pedal travel will definitely not feel normal. It will be lighter than normal.

I would also note that if the release bearing or the clutch diaphragm spring have failed the clutch pedal travel will definitely not feel normal. With the engine off and the driver's side door open, press the clutch pedal over its full range of operation. If the diaphragm spring or the release bearing has failed you should get bad noises.

[VolvoRoyS]

Originally Posted by 142 Guy

If you can, squeeze under the dash and try and get a look at the cable attachment point to the top of the clutch pedal. Check for broken inner strands close to the cable attachment point.


I would also note that if the release bearing or the clutch diaphragm spring have failed the clutch pedal travel will definitely not feel normal. With the engine off and the driver's side door open, press the clutch pedal over its full range of operation. If the diaphragm spring or the release bearing has failed you should get bad noises.

I'll try these suggestions and report back. Not getting any bad noises so maybe it is a cable issue.

Roy

[142 Guy]

Are you thinking that you might have a complete non release of the clutch as opposed to just a dragging clutch? If so, cable adjustment is not going to fix that problem. A complete non release could be a release fork / release bearing / diaphragm spring problem which are pretty much all internal to the bell housing. Short of removal of the transmission to access the clutch you would need an endoscopic camera to inspect those parts.

Just for reference, I have attached a document from IPD USA which shows the location on the release fork where cracks develop. The document also discusses other clutch issues as worn engagement pins where the fork contacts the release bearing.

If you are still uncertain as to whether the problem is a dragging / non releasing clutch, jack one side of the rear of the car up so that one rear tire is free to rotate. The other tire needs to be in solid contact with the ground. Support the car safely because for this test somebody needs to be in the driver's seat. With the parking brake off and the transmission in neutral, you should be able to rotate the rear wheel and see the drive shaft rotate because of differential action (this test will not work with a limited slip differential). Now shift the transmission into 4th gear. It should be impossible / exceedingly difficult to rotate the rear wheel because of engine braking. Now have somebody sit in the car and press the clutch pedal to the floor (or use a pedal jack) so that the clutch should be disengaged. You should now be able to rotate the rear wheel. Because of the additional drag of the transmission input shaft / release bearing / pilot bearing it will be slightly more difficult to rotate the wheel. If it is impossible to rotate the wheel or with enough force you find that you are actually turning the engine that confirms that you have a non release / severe dragging problem as opposed to some kind of shift mechanism problem. It doesn't really say anything about what is causing the problem.

[VolvoRoyS]

Originally Posted by 142 Guy

If you are still uncertain as to whether the problem is a dragging / non releasing clutch, jack one side of the rear of the car up so that one rear tire is free to rotate. The other tire needs to be in solid contact with the ground. Support the car safely because for this test somebody needs to be in the driver's seat. With the parking brake off and the transmission in neutral, you should be able to rotate the rear wheel and see the drive shaft rotate because of differential action (this test will not work with a limited slip differential). Now shift the transmission into 4th gear. It should be impossible / exceedingly difficult to rotate the rear wheel because of engine braking. Now have somebody sit in the car and press the clutch pedal to the floor (or use a pedal jack) so that the clutch should be disengaged. You should now be able to rotate the rear wheel. Because of the additional drag of the transmission input shaft / release bearing / pilot bearing it will be slightly more difficult to rotate the wheel. If it is impossible to rotate the wheel or with enough force you find that you are actually turning the engine that confirms that you have a non release / severe dragging problem as opposed to some kind of shift mechanism problem. It doesn't really say anything about what is causing the problem.

I tried a variation of this; the car will move freely in neutral and handbrake off. With 4th gear selected, handbrake off and my wife depressing the clutch pedal the cooling fan would start to rotate as I rocked the car, suggesting that the clutch was not freeing.
So then I tried a suggestion in the Haynes manual: "engage 4th gear, apply handbrake, depress clutch and start engine". I took the precaution of taking a lead off the coil as I didn't want the engine to start and also stood on the foot brake. When I operated the starter I expected the car to lurch forward, but no it didn't. So took my foot off the clutch, tried operating the starter and it did lurch forward . I had pushed the car back to give room for this movement.
Encouraged by this I reconnected the coil, started the car and found all gears normal.

So what happened? Suspect clutch disc was sticking on the splines; don't think it was stuck to the flywheel as it had been working the previous week.

Roy

[morwenna240]

God works, an sometimes old motors, in mysterious ways, tha knows.