something tightens up

[andrew34ruby]

I am wondering what is wrong with my Ruby, a rather strange fault.

Sometimes it’s as if something is jamming. Out of gear and brakes off, the car only rolls a couple of inches either way, then stops abruptly. Pushing the car it rocks easily backwards or forwards, but only a couple of inches. It’s as if the propshaft won’t turn and the car is just free for the amount of slack in the diff.
Try to drive the car and it’s a bit reluctant to move, then after a couple of feet it is free, and drives as normal. Drives as normal for twenty miles and more. Drives as normal when you stop and start.

I’ve figured out that from rest if you drive for just a couple of inches it locks up, either forwards or backwards, so manoeuvring is difficult, and it sometimes happens in stop-start traffic. If you never drive just a couple of inches the car drives normally.
 
After a fast (for Ruby) twenty mile drive I found both front brakes COLD. Both rear brakes a teeny bit warm. The diff, well warm. The gearbox, yikes that more than warm.
 
Any ideas?

[Ruairidh Dunford]

Brake shoe, spring or pivot etc. loose/broken?

[David Stepney]

I had a similar problem with my RP some while ago. It turned out to be a broken brake shoe.

[Anne Griffiths]

That was my first thought too.... having experienced broken pivots twice in past years.

[Barry Townsend]

I had a similar problem, the brake pivot had snapped off. A few minutes on my lathe to make a new one and voila.

[andrew34ruby]

Thanks for all the replies and ideas. Today I jacked the car up and all the wheels spin ok. Tried with the brakes part on, off, backwards, forwards, simply cannot find anything wrong. Checked the gearbox oil level and found it rather low, far below the bottom of the threads on the filler. So drained the oil and less than half a pint came out. Flushed with clean oil and a few bits of metal did come out, dull silver in colour and not magnetic. Re-filled with a bit less than a pint and left it at that.

Short of removing all drums how can I check for a broken pivot?

Took the car for a drive round - behaving perfectly now.

[Ruairidh Dunford]

You will need to remove the drums on all four wheels to check the suggestions above, Andrew.

[Duncan Grimmond]

If you want to see what's inside those drums , they'll have to come off...no biggie for a man of your calibre!

[Nick Mayne]

I have tried, at some expense, the floating brake shoe mod used a long time ago and explained to me by John Sutton (an ancient bard of A7 Racing) but after carefully setting up the brakes following good advice, when reversing out of the garage my wheel completely locked up and I repeted the sequence about three times. I have finally decided getting everything right in that approach is not so easy as it involves very careful machining and bobbin diameter sizing. I think the effect was the same as discussed by Andrew and I was replicating loose brake parts. Thus I also think your problem is likely to be in the brakes as Ruairidh says. In my case I now need two pairs of 1.125" wide shoes, new linings and the new pivots ..... any offers?
I think fitting Girling adjusters is not just a matter of the expansion cylinder ... does it need special brake shoes as well?
Keep us posted Andrew.

[andrew34ruby]

Keep us posted Andrew.

I intend to keep you all posted.

At the moment the seven goes faultlessly and I'm reluctant to investigate at the moment. Don't want to have it in bits and miss Newby Hall and Ripon old cars events coming up in July.

Taking the 1955 Austin to an event at Bradford tomorrow, at Wrose recreation ground.