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Clutch release bearing
Posted: Sun Apr 12, 2020 8:35 pm
by jagnut66
Hi,
I saw this advertised on eBay, as a replacement for our standard carbon release bearings:
https://www.ebay.co.uk/itm/NEW-MORRIS-M ... Swhe9doxAu
I just wondered what people on here might think of it, would Phosphor Bronze be superior or wear quicker for example?
Best wishes,
Mike.
Re: Clutch release bearing
Posted: Sun Apr 12, 2020 9:18 pm
by simmitc
The important thing is that it is a roller/ball race bearing, the phospher bronze will not ne subject to wear. For most people, the advantage of the roller type bearing is simply that it won't wear when sitting with a foot on the clutch, which seems to be a modern lazy bad driving habit. In my view, if you stop the car then the handbrake should be on and the box in neutral with the clutch up. That way, the carbon bush does not wear, and if your foot slips then the car does not jump forwards.
Re: Clutch release bearing
Posted: Mon Apr 13, 2020 7:46 am
by philthehill
There is one major drawback with these type of bearing when used with a BMC release arm in that whilst the thrust moves in an arc the clutch cover pressure pad does not.
Therefore the bearing when depressed and loaded against the pressure pad the movement between the two is in the form of oscillation which can lead to wear of the release bearing. The carbon thrust is able to compensate for the oscillation in that it is able to relate in more than one direction at a time without problem..
That is why Ford (and other manufactures) have the release bearing firmly centred on the gearbox front extension shaft.
To overcome the oscillation problem when using the BMC clutch release arm some modifications have a certain amount of float in the release arm pivot pin bush to compensate.
My own Ford gearbox with BMC clutch release arm has this problem but I have allowed sufficient slack between arm and carrier to allow for full concentric operation of the roller release bearing.

- clutch release.jpg (403.45 KiB) Viewed 662 times
Re: Clutch release bearing
Posted: Mon Apr 13, 2020 1:01 pm
by GavinL
In support of Phil's post, back in the '80s when roller replacements first became available I fitted one to my 1275 Midget. It never worked properly, and dragged, the only way I could get the hydraulic clutch to work was to pump it ( the hydraulic system was all in good condition). A mechanical clutch might overcome the problem i had, but I'd still personally be wary of the direct swap type roller release bearing for the reasons Phil describes.