Grinding clutch

[Doherto]

Hi everyone, again. Whilst rebuilding my 1968 240 i replaced all clutch componants with new, 8.5inch system. All was adjusted and worked fine for the few dozen times i have driven her out of the garage and along the drive, probably less than a mile in total. Unfortunately, having completed the mechanics, rewired the engine bay and moving on to the body preparation for spraying, for no apparent reason the clutch started to grind quite loudly intermittently. I checked everything i could think of but decided that i could not "spoil the ship for a hapeth of tar" so have removed the drive train to solve the problem. Annoyingly i have dismantled the clutch today but cannot find anything wrong. The thrust bearing would not turn so thought i had it sorted only to find that it is a graphite solid thrust "bearing" which i understand therefore does not rotate and is effectivly a wear part. There is plenty of graphite so not fauly but i suppose could be a sourch of the noise. The noise by the way only starts as the clutch pedal is being released and the drive starts to bite about a third the way up the pedal travel. Is this a standard thrust bearing for this late model or should she be fitted with a "propper" rotating bearing. Any other thoughts would be appreciated. I have not removed the flywheel to check the inner bearing yet but that was new with the engine rebuild too so not hopefull. Will i ever finish this project

[peterdpps]

Don’t know if This helps but I have just had the clutch replaced in my 240 after at least 32 years use and the garage I used had a problem with the thrust bearing.
The part no is HD 1099 and I obtained one from SNG Barrett’s per their parts list. When the garage dropped the gearbox and removed the old thrust bearing it was not the same as the new one. The offset of the two spigots was different with the new one much closer to the bearing housing.They showed me the difference and we looked at the parts list etc but it was difficult to see the exact difference between them. Because of the geographical location they suggested I took the old one to David Manners who were closer to them, to get one that matched.
I gave Manners the old one as a pattern, told them the car details and they matched it exactly. The funny thing is that they had it under the exact same part number!

The only thing I can thing is that Barrett’s had the wrong bearing in the box. As it happens I’m going over there today and shall discuss it with them.

It may be that you have the wrong bearing and this might be affecting the clutch engaging and disengaging.

[Doherto]

Thank you Peter for your reply. Can you remember if your thrust bearings were of the rotating type or as in my case the solid graphite non rotating type.

[peterdpps]

Hi,
My thrust bearing is of the solid graphite type in a cast iron housing and looking at a schematic seems to just slide to and fro rather than rotate.

Follow up on the wrong part! I’ve been to SNG Barrett’s and they say they know there are two different types of thrust bearing for the 240. The one listed in their parts book and a longer throw one, which mine is. Given that I did 50 miles from home to Barrett’s 85 miles round trip to source the correct bearing then another 50 miles today I think these bearings have done more miles in the boot than in the clutch!

I suggested to Barrett’s that, if they know there are two alternatives it would be a good idea to tell the customer at point of purchase. As I didn’t know at the time which type mine was I bought the listed part. If I’d been told there were two I would have bought one of each to be certain. They accepted my point and said they would put a note against this to advise customers and if they don’t know which is the correct part they have the option to buy both.

I understand that the wrong bearing and fork combination will cause problems. Hope you get sorted soon

Pete

[Doherto]

Had a funeral to attend today so not much progress. Took off the flywheel to inspect the spigot and found as per the attached photo. Will have to figure out how to remove it to see if the wear is along the shaft or just drive shaft insertion wear at the front end. Not sure if this could cause my problems but will have to be changed anyway. Discovered that apparently there are two fork arm thrust bearing combinations for the 240 so I am trying to find out more about that. If anyone has any information it would be appreciated

[piman]

Hello Doherto,

fill the bush with grease and find a close fitting drift, (Even wood will do) then drive the drift into the bush and the grease forces out the bush. I agree that I don't think the bush is your problem. I also don't think that the clutch would work with an incorrect assembly of thrust bearing and actuating arm? Was the driven plate assembled the right way around? If not there would likely be witness marks on the plate where it contacted the flywheel.

Alec

[Doherto]

Hi Alec. Yes the driven plate was the right way round as thankfully being a new Borg and beck I could read the markings for the flywheel side. The plate gives me some concern though. I have attached a picture below as it has some unusual markings on it which hopefully you can see. It was new but I never measured the thickness of the friction pads but now that I have they are only 1mm. I understand that is the point when a driven plate should be changed so do not understand why if it was thicker when installed it should have worn so quickly, if indeed it has. Finally the flywheel I expected to be shiny in the contact area but it is a very dark colour just where the driven plate makes contact. Perhaps it has not done enough work to get shiny I don’t know. I was hopeful that the point at which the grinding noise occurred, as the load starts to bite on clutch release would have given us some direction of thought perhaps not. Still scratching my head so any thoughts appreciated.

[XJR308]

Hi
I would think the worn bearing in the back of the crankshaft is the culprit. It was quite common back in the day if a car had been left standing for a while the bearing would dry out and make a Loud noise.

[Doherto]

XJR308 thank you that’s sounds encouraging as it will be changed along with other parts I suspect. I can see the standing for a long time corollation As this engine has been but not how it would generate the noise as the driven plate is being clamped. Although I am no expert and accept confirmed experience as offered

[XJR308]

The nose shaft of the gearbox ( sometimes called the 1st motion shaft) will slip inside this bearing (bush). Under load when the clutch is being engaged there will be a side ways force that will put a load on the bush. If it is worn and dry it will make a noise. Similar to a slipping fan belt but not as high pitched.

[piman]

Hello Doherty,

that plate doesn't look as it's even bedded in yet, certainly I don't believe it has worn any. You don't really need a marking on the plate, Lokked at from the side it is assymetrical in section and the larger projection always goes into the clutch cover.
See how you get on with changing the bush, clutches are pretty basic and there is not really that much to go wrong as long as the clutch release, grips and does not drag.
By the way, carbon thrust bearings were the norm in the fities and sixties, at least on U.K. cars. and work well and quietly, unlike ball races occasionally.

Alec

[Doherto]

Thank you everyone for your help. Bush ordered fingers crossed. I will put the drive train back together but will not be putting it back into the car for a few weeks as I am going to prep the bodywork for spraying. I will update this post with the outcome as soon as I have her running again. Thanks again

[Doherto]

Hi all, reporting back as promised. The grease trick didn't work unfortunately, as with using bread which was another demonstration on you tube. I bought a pully but it broke that too. Ended up drilling it out then making two longitudinal hack saw cuts 180 degrees apart and then very very gently tapping out the remains. Thank fully after freezing the new one it was installed without much of a problem. And, body work prep finished and the engine is back in now and the clutch is working fine, no noise

[peterdpps]

Hi Doherty.
Glad to hear you seem to have solved your problem. Just an update on my clutch situation which is something of a mystery.
A couple of weeks after my clutch was replaced I did the JEC Wonders of Wales run and on the first day when I stopped the car wouldn’t go into reverse with the engine running, just made a loud grating noise so I guessed the clutch was not disengaging. After several very noisy attempts I decided to switch the ignition off, engage reverse then start the engine with the clutch depressed. This worked perfectly and gear selection has been smooth and quiet ever since!
No idea what caused the problem but my guess is that it was either something to do with the thrust bearing and fork installation or maybe an airlock in the slave cylinder.
Having it inspected next week so may know more then!

[Doherto]

Peter, your problem sounds intreging and will be good to get your feedback post inspection. Also i, and i am sure others, would be interested to understand how an inspection will be carried out. I know there are two access
"Holes" in the bell housing but i do not know what it is possible to check / measure through them, or do they use mini cameras or something. Looking forward to hearing your feedback