Why did Triumph do this?!!

[dougbgt6]

I've asked at a couple of club meetings and had some theories but no one can tell me what's what!

 

The last upgrade to the GT6 towards the end of it's production included a servo as standard, previously it had been an option. Also as part of the upgrade the rear hubs and the slave cylinders were slightly enlarged improving the rear braking.

 

When the servo was fitted as an option it operated on all 4 wheels. When fitted after the upgrade, it operated on just the front two.

 

A further complication is after the upgrade the servo was a Girling. People tell me before the upgrade the option was a Lockheed. I'm told the Lockheed is a better/stronger servo than the Girling.

 

So, I have a new Lockheed do I fit it on 4 wheels or two?

 

 

 

 

[jondhm]

I would suggest you should fit it so it operates on all four wheels. If you fit it to just the front, the rear wheels will be under-braked unless you change the wheel cylinders to the later design.

I have a late GT6 with the servo operating on just the front wheels. Had to change the servo twice (bought the car in 1976), but don't let that put you off. It works fine, and means the pedal effort is more like a modern car, so easier when you switch back and forth.

[Mike Crewes]

I agree with jondhm.  The early cars had servo assistance to all four wheels because the brake balance was needed to be kept.  Later cars probably changed the brake balance, i.e. weeker servo on the front and upgraded wheel cylinders on the rear.  Perhaps the original servo was to strong and causing a brake unbalance. 

 

The front wheels should ALWAYS have more braking power, because they do more braking.  Under braking, particularly heavy braking, weight is effectively thrown forward so the front brakes need to be more efficient.  If the rear wheels lock under braking, without the fronts locking, the car will swap ends and spin out of control.

 

Try it on a push bike!  Front only braking is much more controlable than rear only!

 

Regards

Mike

[dougbgt6]

The one thing I forgot to say  is that my GT6 is late with the larger rear braking arrangement. So it looks like I should stick with the servo on the front only.

[jondhm]

Correct, fit it to the front only.

Many years ago the servo failed on my late GT6. From memory it was a Girling, and I could not get a new one at the time. I didn't fancy rebuilding the servo myself, so fitted a Lockheed servo.

Quite a tricky job, because I had to make up a new bracket so it would fit. All a bit tight under the bonnet, so I had a real game making up the bracket with two bends in it. Possibly someone sells the bracket now, which would be much easier.

You are also correct that the Lockheed servo is stronger, so less pedal effort. This is good because more akin to a modern car, so less chance of under braking when you get into the GT6. Doesn't seem to have a significant effect on the brake balance, the rear still locks up first under most conditions.

Hope this helps.

[jondhm]

And another thing!

You also have to factor in rerouting or replacing the brake pipes leading to and from the servo.

All in all, if I was doing it again, I would try and find a Girling servo. It may be now that they are available again, suggest you talk to the suppliers such as Canley Classics.

[Cookie]

Slight error in one of Doug's mails. The official optional servo available for the earlier models was also a Girling Powerstop. The Lockheed servovos are a later aftermarket upgrade as oppossed to an offical Triumph Optional extra.

 

The factory GT6 manual shows deatils of how to fit the optional extra Girling powerstop kit to the earlier cars.

 

[dougbgt6]

Thanks Andy, I'm wrong again!  I've another thread going on CT about my on going problems (and the servo! boom! boom!) Dreamt about it last night.   I think I'll take the weekend off and do some house work.