What condition should the Beech Disc look like?

Mine have dark glazed areas and smooth beech, all dry.

Two of the discs have a radial split.

PS - I can't see this topic has been covered since 2009, or before.

Location: West Cornwall

Hi Sandy, I would replace any split ones from A7 Components (£6-70 each)and lightly grease them all on reassembly. It works for my chummy.

Ian Mc.

Location: Shropshire

They are described as oiled beech wood in Austin literature Sandy, what they were oiled with I don't know but I would have thought unlikely to be completely dry. I have always had reasonable success with the hard friction material used on later cars combined with a brass disk, I should also add that I like to run with fairly tight dampers as I prefer the feel and handling that way.... seems to work for me

Location: NZ

Many thanks Ian & Ian, will be sorted this morning.

Location: West Cornwall

Am I reading this correctly? Are we saying that the working faces of the lignum discs should be greased? How does that affect the operation of the damper - I thought it was a friction device. Can someone please clarify because I'm confused. I understand the pivot pin and bushes should be lubricated but surely not the working faces of the discs. Help!

Ah, Reckless Rat, a name that had slipped my memory...
I was wondering the same thing, .

Woodrow's Manual has no guidance on this apart from cleaning the parts from grit and rust occasionally - Section F4-1.

In the A7 Companion (page 184) '.... taken apart, thoroughly cleaned... Centre pin and washers slightly smeared with grease...'. That's credited to the 'Austin 7 Handbook', which I also checked, Handbook Edition 1095 (Jan 1934) on page 54 - see A7CA Archives here
Whey Hey, I've remembered how to do it 'here'......

Location: West Cornwall

HI All, The reason for the lubrication on the discs is for a smooth movement The dampers are there to slow the movement between axel & chassis not to stop it or make it jerky
Hope that makes sense

Location: TINOPAI NZ

I have made a good few beech disks for various cars. When fitting I smear them in ordinary engine oil. Not for lubrication but to repel water and damp. If making your own leave the centre a little oversize. Eliminates the chance of cracking if and when they dry out and shrink

Location: Ireland

Location: West Cornwall

Surely if the damper assembly is locked up or its action is jerky that's down to the adjustment being over tight or there being high spots on the friction material. If the discs are greased then you will need even more tension to get the same damping effect, surely? My understanding was that the wood (or lignum) discs should be lighly sanded to remove any glazing and re-assembled dry,(apart from the pivot bush). The damper is a friction assembly just the same as a drum brake. You wouldn't advocate greasing a brake shoe to make it more effective, or at least I hope not.

My first inclination would be to use something like linseed(boiled) which would preserve and harden the surface of the beechwood. Water in wood is a bad thing. So the linseed oil would preserve the wood from repeated wettings. And wet wood will raise the grain. I can also see the point of some lubrication. It prevents possible binding and the radial cracks mentioned could be the result of that binding.

Location: TINOPAI NZ

Your comment "I suspect that pretty good discs could be made from waterproof mdf" rang a bell. 50 years ago Father's business, making clutch motors, hit a problem with the then modern clutch linings glazing. The solution was to use a good quality hardboard which worked well until his supplier supplied some poor quality hardboard.

I've yet to see anything made from MDF being described as good quality. Water resistant MDF is only so if it does not get wet.
I'm continually astonished that this rubbish is still available.
Perhaps friction discs in shockers will prove to be the one sound application for it but somehow I doubt it.
Birch ply, now you're talking my language!

It may be worth considering the properties of wood and how these characteristics may influence its use in a damper.
Wood is hygroscopic, whatever type it is, it depends on its moisture content for its integrity; to much moisture, and even if that fluid is oil, then wood will start to suffer from some sort of rot. To little moisture and it will loose structural integrity and start to split, crush or just powder. Moisture content of timber depends on the equatorial environment it inhabits.

Beech is a very hard and tough wood with good strength properties and high abrasion resistance, when it has a low moisture content it can shrink considerably and may be subject to movement.

Based on these properties, I would imagine that oiling the timber with a wood oil to ensure it maintains its elasticity and remains rot proof may be best. I would imagine that grease will increase the amount of torque required to make the damper work thereby increasing the load on the timber whist also allowing the moisture content to vary across the seasons, especially if the car is kept in a warm garage, in which case the damper performance may vary.

Regards, Mark

Location: Lytham

Back in the sixties we were advised to cut new friction discs out of solid vinyl floor tiles the ones which were thick and hard, not the modern soft sponge with a skin. No lubrication used. Non absorbent, no variation in performance. cheers Russell

Location: back in the UK in Primrose, going to guildtown !

I don't think MDF or OSB are viable options. Nor would what we call Masonite here in the US. The latter is now not true Masonite and uses injected binders, rather than using the natural binders, and is no longer baked with boiled linseed as it used to be made. Phenolic might be a good option as it is quite durable. But, given the choices, I think sticking with beech may be the best option.

I have used Paxolin successfully as an alternative, I may be wrong but thought Austin used this type of material on the later Ruby's

Location: NZ