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Handbraaake!


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Take the rear cylinder out of the backplate and the handbrake lever and then look at the inside of the slot where the lever sits. It will have over time worn a vertical groove in the back plate as no one ever bothers to strip and grease them so they slide properly. Its this groove you need to weld up and smooth in. Without it the rear cylinder doesnt move properly when you pull the handbrake on and then the brake only works on one shoe not both.

Stuart.

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Sorry me for my honest words,

the grooves are one of the results of the really very poor construction of this brake.

Think about how it works and you must realise this.

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Hi Marco,

if you think about it the design is a work of genius - minimal components and a basic design that has few problems.

 

The design probably was good for a normal working life 7 - 10 years but we are now up to 50 - 60 years.

 

And as Stuart points out - how often are they regreased etc.

 

If the original design had catered for 50 years service it would have been designed differently and the cost of the car would have gone out of the window.

 

Roger

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Hi Roger,

 

handbrakes on all modern cars I know work by the same common construction:

a long leaver inside the brake drum on one brake shoe an a pushrod to the other brakeshoe.

A automatic adjuster is possible, but not necessary.

 

That´s a old, very simple and in my opinion very reliable construction.

You can find it on old / classic cars, for example from 1949 on at the more than 20 million times built VW Beetle.

Shure the construction is older.

 

Browse at Google for photos by "VW beetle rear brake".

The Beetle was a "lower middle class car", this construction would fit very well a sportscar like the TR.

 

Ciao Marco

Edited by Z320
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  • 2 years later...

Hi there,

my rear brakes are off the car because of a leak cylinder on the right side.

Time to fit new break shoes and brake drums, stored since two years in my workshop for this case.

Down under the new break drums I found my old - or new - hand brake project,

always in my mind, but what I forgot: I already have the parts....

P1150551-b.JPG.7bd95f81f962868605b7da8ae647e9dc.JPG

 

Edited by Z320
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  • 2 weeks later...

This way it could work, or similar, I hope...

P1150560-b.jpg.aaa46ebb06412bd78ccf98b763089ce1.jpg

This is a steel dummy, but here the bowden cable will come in (left brake plate),

I would not try this if this in two directions angular surface would not invite me.

P1150561-b.JPG.e9619264a2644ed611e3cf23b104f5ec.JPG

Drilling already on the right brake plate

P1150566-b.JPG.627829fe97bce59c6248459cfd1207ef.JPG  P1150567-b.JPG.f955da2ff95dc59702c13848d37ee3b6.JPG

to be continued..

 

Edited by Z320
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Very nice Marco.

Not sure this has been done before on a TR, but it makes good sense to me. Some cars, like and old Opel Kadett (abd sevaral others from that period) have a rear wheel cylinder with 2 pistons in  the hydraulic cylinder is fixed-mounted on the baseplate. Not sure what would be the difference with the TR set-up where the cylinder moves.

The automatic adjuster is like the one you have.

Regards,
Waldi

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Hi Waldi,

the double piston and leaver in the drum for me his is a very interesting and well working construction.

The earliest car I found using it was Ferdinand Porsche's "KdF-Wagen" from the mid 30-ies, perhaps it's older (the genius Hans Ledwinka/Tatra?).

It was the common construction since then for decades until today - and is still in use for new cars with rear drum brakes.

Perhaps another member can report?

Also cars with rear disc brakes use the leaver in the drum it because there is mostly a drum brake in the center of the disc for the handbrake.

But also some producers found it an interesting challenge to build rear disc brakes without drum.

I can't judge about that because I never had such a car.

Ciao, Marco 

 

 

 

Edited by Z320
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Hi Marco,

this is from a Corsa, same principle. The ratchet adjust the rod once the stroke is large enough, but I’m sure you know that:)

Waldi

D0A01002-B263-4789-81CC-6999CD1A3A6A.jpeg

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Yeah Waldi,

thanks to be with me, my ideas are this:

1st

to put the brake drum off one time it must be drilled to set the ratchet back to zero with a screw driver.

2nd

Due to the TR construction I see it will be a very bad €@);/@@?!! to put this all together behind drum flange.

3rd

There will be no space for the adjustable rod and  ratchet with my solid Goodparts hubs.

 

That's why I try with a solid rod and the TR manual adjustor.

Ciao, Marco

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Hi Marco, 

I do not understand what limits this, but that’s just me. Keep us posted. Both with or without automatic adjuster, it could be an improvement because it eliminates the awkward sliding cylinder and lever design which generates a lot of friction.

Waldi

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The rear brake cylinder only has one piston pressing either to the rear or front (not both) (Left/Right), thus the need for sliding back and forth, regardless of the handbrake mechanism.

If you want to get rid off this sliding feature, you need to replace the brake cylinder with a 2-piston cylinder (such as the Corsa or Citroen C1). But by doing this, you need to move the handbrake mechanism too, as modern cars have it.

Jochem

 

Edited by JochemsTR
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Hi Jochem, thank you for your post!

Indeed the BMW set I use (9" x 40 mm brake shoes) comes with 2 hydraulic cylinders, each with 2 pistons 7/8".

THIS would be the best solution, but this needs too much modification on the TR brake.

And in my opinion there is no real friction problem with the 1 piston cylinder as long as I only use the hydraulic brake.

The problem is with the handbrake:

In my opinion the friction problem is the bolt / axle through the hand brake leaver which has to slide on the back plate

while it is twisted by the sadly position of the cable pivot point on the trailing arm and strongly pressed on the back plate while working.

The brake cylinder itself slides without any problem.

Ciao, Marco

Edited by Z320
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Interesting Marco,  I'm watching this but have little more to add than has already been mentioned, but to encourage your enterprise. B)

Your alignment of the IRS Bowden cable (height) to brake lever makes good sense and I'm sure the use of the stiff inner clutch spring also works to keep that final bit of tension on the cable.  Together with well adjusted and suitably greased  brake cylinder, as other have mentioned, is all useful advice.   Thanks to you and those others, and also to Waldi for the invaluable moral support which has helped keep this thread alive - so a newbie like myself might see it.!

Pete

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Marco,

Good idea to keep one cylinder only. This avoids pedal increase as more oil has to be pumped. I agree with you, the original cylinder will not result in high friction since the forces are in line with the direction of movement.
Only when the hard brake is used this plays a role.

Does anyone know if Marco’s hand brake route has been done in the past?

I gave all 3 of you all 3 a like;)

 

Thanks Pete for the feedback. I like this active forum.

Waldi

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4 minutes ago, Waldi said:

Does anyone know if Marco’s hand brake route has been done in the past?

Waldi

No we just set them up properly in the first place and then theres no problem.

Stuart.

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2 hours ago, Waldi said:

Marco,

Good idea to keep one cylinder only. This avoids pedal increase as more oil has to be pumped. I agree with you, the original cylinder will not result in high friction since the forces are in line with the direction of movement.
Only when the hard brake is used this plays a role.

Does anyone know if Marco’s hand brake route has been done in the past?

I gave all 3 of you all 3 a like;)

 

Thanks Pete for the feedback. I like this active forum.

Waldi

Surely Triumph did all this in the 1970's

Why not use the rear brake assemblies (drum, backplate etc. and friction set up) from Mk 2 Triumph 2000, 2.5 PI, 2500 saloon or estate  or Stag.  These systems were self adjusting and of course use the same hub unit as the TR IRS models so the stud patterns to trailing arm and wheel are not messed up.

Mk1 Triumph 2000 and 2.5PI used the same rear brake design as TR with an adjuster, but swapped to self adjusting in 1969. Why the TR did not get this feature is a mystery.  Probably cost.

Only challenge is finding a scrap Stag.... Mk2 Triumph saloon or estate would be much easier.

The only issue I had when running these cars was the handbrake cross bar that works the shoes tended to seize and needed to be lubricated.  Self adjuster is a ratchet and pawl arrangement.

See image of Stag setup from the Rimmers web page.

Cheers

Peter W

 

.jpg

Edited by BlueTR3A-5EKT
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This are the moments when I am pleased about paint and not powder coat

P1150568-b.JPG.d71bb6ebea590ba69970bd604182d27b.JPG

did I mention soldering is my favorite, always gives a nice surface and is most times solid enough

P1150569-b.JPG.adf56577765055bb77a6a87e5fcb7f0a.JPG

Some black paint from the rattle can, both plates ready

P1150574-b.JPG.e48d9cc9170e918829030481a9bbfb0e.JPG

looks like original?

 

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