Altering The Rear Brake Line On A 1.6 Shell

[pug_ham 244 3 Cars]

I've been thining about this a few times since my last trackday at Cadwell just over two weeks ago.

 

Under hard breaking into various corners I was constantly locking the L/H rear wheel only but I think I've come up with the reason why this might be.

 

On the 1.6 front rear split system the rear line runs from the compensator to the T piece just behind the tank where it splits to the R/H side.

 

The L/H caliper is in a more direct path of fluid flow so I'm thinking it gets a higher pressure under heavy breaking (path of least resistance etc) so if I was to change the brakline to the rear wheels so the input went to the middle of the T piece & then split to each side the rear braking force would be better balance as the pressure would have to split to both sides evenly rather than a straight path to one side more than the other.

 

Logical thinking that might work or a waste of my time & effort?

 

Graham.

[Tom Fenton 1,541]

Waste of time and effort. The pressure within the braking system once the friction faces have moved together is equal in all parts of the system, providing there is free flow to all parts. If there were not free flow you would have brakes lazy or dragging so that can be ruled out. You will notice absolutely no difference doing the above.

Tom

Hydraulics (amongst other things) Engineer.

[pug_ham 244 3 Cars]

Thanks Tom, I just wondered if it would make any difference due to the fact that with the present set up the l/h rear caliper gets a more direct flow of fluid. Obviously not.

 

Oh well, one more thing to mess with when I fit a bias valve instead then. I wanted to try to avoid this so I wasn't messing with the rear balance occasionally just to see if it was better.

 

Graham.

[welshpug 1,657]

Are the rear calipers a known pair? didn't bring up any issues on the MOT brake test?

 

might be a hose breaking down or a tiny twist in one, OR if a caliper has been replaced, it might be a different piston size as there are 2 sizes commonly available, 30mm as used on the 205/309, or 32mm as used on most 306's.

[Tom Fenton 1,541]

Flow within a system makes things move, but pressure does the work. In a car braking system you have a very small amount of flow, certainly no where near enough to cause dynamic pressure changes which is what you are alluding to.

[pug_ham 244 3 Cars]

Are the rear calipers a known pair? didn't bring up any issues on the MOT brake test?

 

might be a hose breaking down or a tiny twist in one, OR if a caliper has been replaced, it might be a different piston size as there are 2 sizes commonly available, 30mm as used on the 205/309, or 32mm as used on most 306's.

Both calipers are the correct 1.9 GTi rear bendix calipers & it showed no problems at all on the MOT. Its fine on the road in normal use & stops very well without any hint of locking any rear wheel even under emergency stops. Only on track does it display this problem.

 

Hoses are all braided & under three years old so i don't expect them to be breakign down just yet & they'll be gettin changed now when i fit a bias valve & run the rear line internally sometime this winter.

 

Thanks again for your input Tom, good to see my random thoughts about an issue are just that, random.

 

Graham.