3Ltr Handbrake

John Murch · Posted: Fri Apr 02, 2021 8:30 am Post subject: 3Ltr Handbrake

At the base of the handbrake lever there is a yoke with a fat pin, thought this pin, which can rotate, there is the rod that connects to the brake system. The angular movement of the pin ensures that there is always a straight pull on the rod.
A few days ago I pulled on the handbrake at a T junction on a steep hill. The rod snapped, so no handbrake.
The ensuing effort to get moving on the hill resulted in some rather clumsy clutch (cone) use which promptly jammed in the engaged position.
It took half an hour of allowing the clutch to cool and vigorous stamping on the clutch pedal to free matters.
The cause of the rod breakage was that the pin at the base of the handbrake had seized thus each time the handbrake was used it bent the rod, work hardening it until the inevitable.
So the moral of this story, ensure the pin at the base of the handbrake is free to move and give it a drop of oil from time to time.

Iain Warner · Posted: Fri Apr 02, 2021 10:39 am Post subject:

Bad luck John, but the failure did not result in any collision which no doubt you are thankful for.
At least with the hand throttle it means you do not need to have three feet to pull away in such circumstances. I wonder if the fingers on the clutch ring were the cause of it jamming in engagement and need attention with a small file?
Iain

John Murch · Posted: Fri Apr 02, 2021 10:54 am Post subject:

Thanks Iain,
I have to confess to a moments panic and forgot that I have a hand throttle.
My clutch does not have the sweetest of take ups, you may well be correct re the fingers.
John

John Robins · Posted: Fri Apr 02, 2021 3:42 pm Post subject:

John, I feel I know you well enough for a gentle leg pull.

You mean to say that you did not have a house brick stored in the car for hill starts without a handbrake?

Cheers
John

John Murch · Posted: Fri Apr 02, 2021 7:33 pm Post subject:

The problem was, being on a steep hill ,keeping a foot on the brake while getting out to put the brick in place.
I had to borrow a brick from a skip, having gently wedged a rear wheel against the kerb.
I will have to rig up a pulley with a brick for future emergencies.😀
John

DavidThompson · Posted: Sat Apr 03, 2021 4:33 pm Post subject:

Just been out to the garage to lubricate the pin, just in case, but was happy to see it all working as it should with no discernible flex on the rod. I changed the ratchet and pawl last year and gave everything a good dose of grease then, and of course C19 has restricted use of the car since.
The clutch jamming comments are of interest though. My cone clutch has a propensity to jam when used unsympathetically, for example entering a roundabout, missing second and driving out in third instead. The first time was disconcerting, but now I expect it and give the clutch pedal a good whack with my foot if it feels tight.
This has worked so far, but I live in fear that it might decide to stay jammed. Do I take it that allowing it to cool will release it?
Does "attention with a file" solve the problem? If so, how is this attention administered?
I would also say that reversing - especially when everything is hot - needs a very delicate touch to avoid lots of jerking.

DavidThompson · Posted: Sat Apr 03, 2021 4:37 pm Post subject:

Just been out to the garage to lubricate the pin, just in case, but was happy to see it all working as it should with no discernible flex on the rod. I changed the ratchet and pawl last year and gave everything a good dose of grease then, and of course C19 has restricted use of the car since.
The clutch jamming comments are of interest though. My cone clutch has a propensity to jam when used unsympathetically, for example entering a roundabout, missing second and driving out in third instead. The first time was disconcerting, but now I expect it and give the clutch pedal a good whack with my foot if it feels tight.
This has worked so far, but I live in fear that it might decide to stay jammed. Do I take it that allowing it to cool will release it?
Does "attention with a file" solve the problem? If so, how is this attention administered?
I would also say that reversing - especially when everything is hot - needs a very delicate touch to avoid lots of jerking.

Iain Warner · Posted: Sat Apr 03, 2021 7:50 pm Post subject:

David, Section 2.6 of the Technical Facts gives a good description of the cone clutch and 2.6.1 (2) details the adjustment and dressing of the fingers on the outer ring.
I note in section 2.6.2 there is the warning NOT to try to free the clutch if stuck in engagement by pressing heavily on the pedal! In order to follow the recommended method an assistant appears essential.
It is a bit of a pain to carry out the work on the ring as you have to remove the pedals and the carden shaft in order to be able to extract the clutch ring.
All part of the fun!

John Robins · Posted: Sat Apr 03, 2021 8:14 pm Post subject:

Back in the days when the buses had Gardner 5LWs, manual transmissions and handbrakes that sprouted through the cab floor, the vehicles carried a steel chock to add to the safety on sloping stands. At departure time, the driver engages first, lets out the clutch and the conductor, in one fluid movement, hops off the platform, scoops up the chock, and hurls it into the gap under the stairs with much clanging and banging meanwhile resuming his normal stance on the bottom step. (Only works facing uphill of course.)

Maybe there are still a few of those chocks doing the rounds of the autojumbles and, suitably refinished to match the green of the 3 litre, would replace the housebrick.

Cheers
John

JohnWilliams6437 · Posted: Sun Apr 04, 2021 5:11 pm Post subject: 3 Litre Handbrake

John
Should you want to give your handbrake a rebuild some time , when I rebuilt my car i got a set of works drawings of most of the constituent parts. Happy to copy for you.
Incidentally the drawing shows the hand lever top as being silver plated ! Not much left on mine.
Also on a related subject a friend passed on a tip - make up a
little wedge to drop into the ratchet and pawl space so when the car is parked some lowlife can't release it.

John Murch · Posted: Sun Apr 04, 2021 6:16 pm Post subject:

Thanks for the kind offer which is greatly appreciated, but I won’t need them.
My handbrake mechanism is in excellent order, the problem I encountered was probably due to the whole handbrake lever, including the hole in the bottom yoke, being nickel plated, it made the pin a rather too tight a fit. Hopefully I have now opened it up sufficiently. Just waiting for a replacement rod.

DavidThompson · Posted: Mon Apr 05, 2021 1:21 pm Post subject:

Thank you Iain, for reminding me to look in Technical Facts. I bought my copy second hand, and is the forth, rather than fifth edition, which seems to be permanently out of stock. I hope one day to be able to buy the up to date edition.
Whatever advice is given regarding the amount of force to be applied in releasing the clutch, I'm afraid the impulse to give it a good whack is irresistible when finding it jammed and approaching a busy roundabout.

John Murch · Posted: Tue Apr 06, 2021 12:59 pm Post subject:

Thanks Iain for pointing out the comment in TF regarding freeing the clutch, mine wasn't to hand but I have now looked.
It says
"DO NOT press heavily on the clutch pedal as this can bend the pedal shaft. To release the clutch, depress the pedal to load the clutch cone and give the edge of the cone carrying the lining a sharp blow. This will free the cone from the outer ring".
As you say, difficult when by yourself!
I'm pleased to say that Kingsbury Racing swiftly made up a replacement rod for me which I have now fitted.

Robert Craven · Posted: Thu Apr 08, 2021 9:18 am Post subject:

My clutch went through a period of often getting jammed and I got used to having a hammer at the ready and jumping out and banging it. The last time it stuck was after having to tow someone stuck in a perilous position on an incline which gave us little choice but to move quickly. Another time I yanked the handbrake on so forcefully at an uphill T junction that I couldn't release it without the passenger's help.

PS I'm finding the number of clicks to log on to the forum varies quite regularly.

John Robins · Posted: Thu Apr 08, 2021 10:06 am Post subject:

Sorry to butt in, but Noel Trewhela is looking at general forum software problems following a long phone call with me. Since he has multiple other tasks I do not think it will be a quick fix, however.

Cheers
John R

John Murch · Posted: Thu Apr 08, 2021 10:24 am Post subject:

My route to the forum always seems to be the same,
Home page, click login, enter details, log on, click ‘The Club’ sub menu Forum.
Seems a bit long winded but unchanging.

Robert, did you hit your clutch cone in any particular place? I suspect I should have hit mine a bit harder (using the copper mallet) but due to injured right wrist found it hard to do.

Robert Craven · Posted: Mon Apr 12, 2021 9:39 am Post subject:

John,
I can't quite remember. Probably on a solid looking spot, perhaps either on the rim where the clutch lining sticks out or at an angle on the centrepiece of the cone. A sharp bang or two with the wheel nut hammer was always effective and didn't seem to do any harm.