Centurion shock absorber question

[Mike Cecil]

Australia changed from oil to grease: perhaps Canada did the same?

Were the plugs, plugs or those flat, slide-on type grease nipples (don't remember the name)

Mike

[rob love]

Originally Posted by Mike Cecil

Were the plugs..... those flat, slide-on type grease nipples (don't remember the name)

Mike

Alemite button head fittings?

[Mike Cecil]

Thanks, sounds about right, Rob:the grease gun had a head that slid onto the flat nipple from the side and clicked into place.

Mike

[Malcolm Towrie]

Originally Posted by Mike Cecil

Australia changed from oil to grease: perhaps Canada did the same?

Were the plugs, plugs or those flat, slide-on type grease nipples (don't remember the name)

Mike

Hi, Mike,
I found the pivot arms between the road wheel stub axles and the suspension units were converted to grease. These are hollow and were originally filled with oil to lubricate the bushings. The oil fill plugs were simply drilled and tapped for the weird (and in my opinion hopeless ) British grease fittings. Perhaps that's is what you are thinking of? Because the shocks need a thin oil to pump through small orifices to do any damping, rather than a grease.

The shock reservoirs just have a large fill plug.

I made the executive decision from a maintainabilty point of view to convert all the British grease fittings to standard grease fittings. It's an easy conversion as the British fittings use 1/8"-28TPI BSP threads which are so close to 1/8"-27 NPT they thread right in.

Malcolm

[David Dunlop]

Might be worth a quick email to Bovington to see if they have any information in their archives, on the topic, Malcolm.

David

[David Herbert]

Actually the flat topped 'button head' nipples that accept a grease gun fitting that slides on from the side are an American design, originally made in the USA by Alemite, as Rob has said. They were used in plant applications (most wartime crawlers and scraper boxes for example) and came in two head sizes and many thread sizes. These were referred to as Small TAT and Big TAT I believe, but possibly only in the UK. They were adopted by the MOD as standard and are still available commercially here in the UK.

David

[Mike Cecil]

Hi Malcolm, yes, I think you are right: conversion to grease was the road wheels axle arms, not the shock absorbers: sorry to mislead you.

The 1973 Aust EMEI Data sheet for Centurion lists shock absorbers, each reservoir, as 4 gallons of 0-134 (OM-13) oil (sounds too much? Maybe 4 gallons covers all the shocks and that is a typo?) and axle arms as XG-274 grease.

OM-13 is listed as 'lubricating oil, general purpose, petroleum, light' with a viscosity of 13 @ 38 degrees C.

XG-274: I don't have a spec for, but XG-276 is a moly grease with extreme pressure additives, and XG-279 is a general purpose automotive and artillery grease. XG-279 sounds closer to the mark.

I also looked at the maintenance book, and the shocks, when serviced off the vehicle, are filled using a special jig that works the shock back and forth to pull the oil into it. They are then topped off and the plug inserted before assembling back into the suspension unit.

Regards

Mike

[Tony Smith]

Originally Posted by Mike Cecil

The 1973 Aust EMEI Data sheet for Centurion lists ...... axle arms as XG-274 grease.

XG-274: I don't have a spec for, but XG-276 is a moly grease with extreme pressure additives, and XG-279 is a general purpose automotive and artillery grease. XG-279 sounds closer to the mark.

Mike

XG-274 is still a General Purpose Grease (I got a tin of it when I bought my Perentie Land Rover), manufactured by Shell as an Aviation grease. Specs are listed by Shell HERE.

[Malcolm Towrie]

David, thanks for the information. I stand corrected. I thought these fittings were obsolete but I see Amazon is still happy to sell me all types of them!

Mike, I suspect the 4 gallons per suspension unit is correct. Each unit is about 3 feet long, about 10" wide and the shock absorber section at the top is about 6" deep, which works out to be a volume of about 8 gallons. I'm reluctant to commit 16 gallons of oil to the 4 suspension units that have shocks without being sure that it's doing something useful. According to our expert here, the T-54 didn't have shocks either. So did they go out of fashion after the war?

What puzzles me is if you neglect the shocks because they are not effective, what happens when they'd seize up?
Malcolm