Tr4A Handbrake Upgrade, Temp guage test.

[John Morrison]

Hi all,

I've seen this more than once, but cannot, now that I need the info, find it anywhere.

I'm after the detail on re-drilling the 4A handbrake pawl, so as to increase the leverage,

anyone got the info?

Also whats a simple, hopefully in situ test for a 4A Temp Guage got one reading really high, when the engine is fine.

 

Cheers,

John.

[RogerH]

Hi John,

 the hole is quite limited in where it can go.  Mid way between the existing hole and the curve of the metalwork.

For the gauge - pop the temp sender into a pan of hot water on  a fly lead for the earth. You will need a thermometer in the pan.

 

Roger

PS - you should not be drilling the pawl etc but the hole for the cable clip.

Edited April 27, 2021 by RogerH

[jerrytr5]

Jerry

[Lebro]

Re the temperature gauge reading high - check the voltage stabiliser is connected, & working. Does the fuel gauge read correctly ?

Bob.

[trchris]

Hi John

I used a digital thermometer (the infared type) to check mine after a engine rebuild  I think Lidl have/had them on sale at around £15 recently

Chris 

[Z320]

Hi John,

indeed I often have a different view on thinks, I guess I'm "strange"...?

The TR handbrake is a very awful construction because of the assembly around the brake drum, pulling stronger on it does not improve it.

Please see my post at this handbrake lever thread and decide your own

You also could read Handbraaake (with triple A)

There I explain how to lift the cable to avoid friction and not to twist the lever, also how to added a strong spring for more more elasticity.

Finally only a swop to a "lever in the drum" construction changes everything. 

Ciao, Marco

[RogerH]

49 minutes ago, Z320 said:

Hi John,

indeed I often have a different view on thinks, I guess I'm "strange"...?

The TR handbrake is a very awful construction because of the assembly around the brake drum, pulling stronger on it does not improve it.

Please see my post at this handbrake lever thread and decide your own

You also could read Handbraaake (with triple A)

There I explain how to lift the cable to avoid friction and not to twist the lever, also how to added a strong spring for more more elasticity.

Finally only a swop to a "lever in the drum" construction changes everything. 

Ciao, Marco

Hi Marco,

our step by step change is Evolution

Your attack on the final solution is Revolution

 

Roger

[Andy Moltu]

An alternative is to fit the extensions to the levers sold by Hart on eBay. 

I know there are those who will say the standard handbrake is fine when in perfect condition.

I would argue it’s just about adequate at best. Flat back plate, good shoes, adjusted properly and new handbrake cables are ok but the extensions make it so much better.

[RogerH]

19 minutes ago, Andy Moltu said:

An alternative is to fit the extensions to the levers sold by Hart on eBay. 

I know there are those who will say the standard handbrake is fine when in perfect condition.

I would argue it’s just about adequate at best. Flat back plate, good shoes, adjusted properly and new handbrake cables are ok but the extensions make it so much better.

The extenders do make a very good improvement.

Repositioning the cable attachment pivot on the handbrake handle improves it significantly more - especially combined with the above

Marco's re-engineering of the lever mechanism is a greater leap in improvement yet again.

 

Roger

[keith1948]

attached is how to do 4A handbrake mod (you need to be logged in to see the attachment)

Improving TR4A.doc

Edited April 28, 2021 by keith1948
more info

[Z320]

Hi,

allow me to add one point about the longer levers:

you get less than you might expect from a longer lever - if you can`t also change the point you are pullng from.

Because torque is only force x the effective lever 90° to the force.

This photo is already some years old.

Red is the direction of pulling on the original lever, but the effective lever (90° to the force) is shorter.

Orange is the direction you have to pull the original lever to benefit from its full lenght, but you can't pull in that direction and the effective lenght is not much longer.

Green points from the fixing of the bowden cable to the the end of a possible end of a lever extension, but the effective lever 90° to the force is much shorter.

So yes, you will have a benefit from lever extensions, but it is less than the lever may suggest.

Ciao, Marco

[Tr4aJim]

Marco, I think I see maybe why my implementation of the lever extensions had a better result. My TR4A has a live axle. On my car the handbrake cable connects to the lever extension at almost 90 degrees (the pictures are not the best, but you get the idea).

Jim

[Z320]

Sorry me and YES,

I expect less benefit on the IRS axles, more benefit on the live axle,

let me add:

90 deg to the visible lever is no guarantee, it has to be 90deg to the effective lever,

see the orange lines: pulling 90 deg the effective lever is pasing left of the coil spring, 90 deg to what you might think is the lever is directly to the coil spring - but the wrong direction.

Please have a closer look yourself (if you want)

Edited April 29, 2021 by Z320

[John Morrison]

On 4/27/2021 at 10:25 PM, Lebro said:

Re the temperature gauge reading high - check the voltage stabiliser is connected, & working. Does the fuel gauge read correctly ?

Bob.

Hi Bob,

so the fuel guage works fine.

I'm thinking there is no real way to test the sender other than by substitution?

John.

[Lebro]

If you have access to some resistors, or a variable resistor then you can.

I would need to check on the values required for your car, or RobH may come up with them, as he has before.

Bob

[RobH]

The TR4A sender is around 240 Ohms at cold and 20 Ohms at hot according to the data I have.  

see actual figures in post below

Edited April 29, 2021 by RobH

[RobH]

Update -  I have just found the resistances as measured.   This is just one sample and as these are not precision devices there is bound to be some spread in actual value from unit to unit. 

The TR4A uses the GTR 104 transmitter:

 

temp              GTR104                  GTR101

deg C.              Ohms                    Ohms

26                     554                          909

30                     524.                         849

40                     352                          563

50.                    272                          400

60                     184                          270

70                     146                          181

80                       98                          124

90                       65                            90

99                       47                            56

Edited April 29, 2021 by RobH
added comment

[pfenlon]

So Archimedes was wrong about the lever then?????

 

[John Morrison]

Quick question chaps,

is the TR4 and 4A quage the same?

John

[RogerH]

5 hours ago, pfenlon said:

So Archimedes was wrong about the lever then?????

 

Hi Pete,

Archie Medes was spot on but the angle of dangle does take its toll.

 

Roger

[RobH]

30 minutes ago, John Morrison said:

is the TR4 and 4A quage the same?

According to Revingtons they both use the same sensor John. 

[Z320]

16 hours ago, pfenlon said:

So Archimedes was wrong about the lever then?????

 

Hi Pete,

if you post a sketch and an accurate question it could be possible to explain

(this reminds me of one of my teachers (RIP), this phrase was one of his fovorites).

Ciao, Marco

 

[pfenlon]

12 hours ago, RogerH said:

Hi Pete,

Archie Medes was spot on but the angle of dangle does take its toll.

 

Roger

Ah Ha....

[stuart]

12 hours ago, RogerH said:

Hi Pete,

Archie Medes was spot on but the angle of dangle does take its toll.

 

Roger

But he did like a good screw!

Stuart.

[RogerH]