Brakes

[ian Howell]

Whilst reading the Technical Notes from the Club website, I noticed that it says that 1930 cars had 8 inch drums, and then also adds that later back axles with 10 inch drums fitted earlier cars (well, that's my understanding), however: -

My 1930 Long Four has 10 inch drums, so does this mean the axle is not original? (A bit of a disappointment if true, as the engine and chassis numbers match so I have always expected that the car was essentially 'Original'.

Whilst relining the brake shoes, I found brass shims between the linings and the shoes!! Presumably, once the linings had worn down to the rivets, the shims were inserted to raise the 'lands' between the rivets to provide an extra few miles of wear! Possibly during wartime?

The car had obviously been derelict for some years before I bought it in 1966, so it seems possible.

Certainly it had a long, hard life at some stage because, after a severe rear end 'shunt', it was driven far enough for the bent rear chassis to cause considerable wear on the spring shackle bolts and bushes.

They never wear out, they never wear out, they hardly . . . .

[Tony Fearn]

Hello Ian. I've just had a look at the Pitmans "The Book of the Jowett" which I bought recently on eBay. The preface includes the phrase - "in the following pages, we deal with the maintenance of the various types of Jowett car produced from 1930 to date" (1937). In the chapter labelled 'Brief description of Jowett models', one of the paragraphs starts- "The four wheel internal expanding brakes operate in 10 in. diameter drums.." - I reckon that for a definitive answer, you should call our Pre-war Registrar Ian Priestley. Nevertheless, I remember him telling me that there are two thicknesses of brake linings on pre-war cars. As I remember, he said the thinner ones used to have aluminium rivets. The thicker ones, the usual brass rivets. Just wondered if the brass shims made thin shoes act as thicker ones. I have dismantled quite a few prewar brake systems on various scrap cars in the past, and on more than one occasion there have been shims under the aluminium brake shoe bearing surfaces at each end, which probably did the same job in a more agricultural way than the brass shims under the whole brake lining. Perhaps other technical boffins might comment. I.P does not have internet access as yet, but some of us are working on him. Regards, Tony.

[ian Howell]

Tony: -

Thanks for the reply - good to make contact again.

Well, that's good enough for me, and in any case that's what I've got and I don't propose to change them anyway, so it was really just academic.

However. . .

In the same notes (on the Jowett Technical site) there is also mention of the thick / thin linings. Well the drums have chalk marks inside them saying (wait for it!) 10 1/16 + .020".

So they must have been skimmed at least twice, and probably more often, in fact they might be perilously thin now, but they have been in use like that so we shall see.

However, at Beaulieu I bought some 'loose' brake linings that were too wide and too long but which have cut to size easily, and these have now been rivetted to the shoes. When I replaced the drums over the brake assembly - they fitted perfectly!

The 'old' linings (not necessarily original) were of a hard material secured by brass rivets. The shims were only about 10 thou and there were four on each shoe between the lining and the shoe, spaced out between the rivets.

Now that I have more or less finished rebuilding the mechanics at the back end, and work my way forwards up to (but not yet past) the freewheel gizmo, I can see the front springs. SURPRISE!!

The nearside links between the chassis and the ends of the springs hang straight down, but the offside ones have a distinct 'crank' in them - maybe 1/8". Also the springs appear to be narrower than the back ones. That's not a big problem, but when I made replacement bushes and bolts for the rear springs, and whilst I was on a 'roll' with the lathe, I made enough to fit the front end as well!!

Time will tell, but not this week as I am away from home for two days, my regular car is in for MOT on another day and I am off to Wales on Friday! Apart from that, my time's my own - well some of it.

[ian Howell]

Moving on from my last post about the brakes (now all linked up and set up - handbrake working for the first time in at least 40 years!), I now tackle the prop shaft.

The couplings are OK but I notice that the female centreing tubes at each end of the shaft are worn right through to one side. This has obviously taken some time to accomplish and the car must have been used in this state for ages. The prop shaft vibration must have been IMPRESSIVE to say the least, but there appears to be very little wear on the male 'ball' bolts.

I really cannot see HOW the wear got to this stage, but there it is. (See the pictures that Keith has now added - thank you. The white rim is where I 'chalked' it to show the difference in thickness around the sleeve!)

I am turning up new tubes to fit the existing three-holed carrying plates and these will be welded in place as per the originals.

Another detail - I bought a correct pattern ammeter on ebay. It was a bit 'stiff' but when I dismantled it (see what I mean about detail!), the spindle that carries the pointer had come out of its bearing at one end. I slackened the screw bearing, popped the shaft back into place, re tightened the bearing screw (not TOO much) and all is now fine!

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