brake balance

[sean sherry]

I test drove a '79 280 SE for a friend who felt that the car was unstable under firm braking on Round - a- Bouts. But what was happening was that the rear brakes were locking up under hard application. My 280 SL which I believe has the same system , locks the front wheels and not the rears. Both cars stop well under normal firm braking.
Of course there is a significant weight difference between the cars, but should that matter ?
Should there be an balance device somewhere to counter act the rapid weight transfer from rear to front under hard braking ?
Thanks Sean

P.S> Neither car has anti lock brakes, and both are in good condition

 

[BenzBoy]

There is a brake distribution proportioning valve built into the system which should go part of the way to stopping the rear from locking up but I would expect that the rear would lock first. Not much help I know. I figure you need Helmet on this one.
Regards,
Brian

 

[Styria]

Personally, I have never struck this problem - I have never really had to apply brakes to the extent where I could discern and evaluate which end locked up first. The timers wHen Imhave had to brake hard enough to lock the brakes, it has always appeared to be the front to do so first - and that. Was on cars without a brake apportioning valve being installed.

I do know that 6.3s are fitted with this valve, and whilst I suspect that the unit is adjustable, I cannot be sure of this fact. Anyway, as I indicated, I have never been aware of the symptoms as Sean describes. Regards. Styria

 

[sean sherry]

I have now been reliably informed that this model doesn't have a brake balance valve for the Rear Brakes. Apparently there are two bore sizes in the M/Cyl. to accommodate the different pressures required for Front and Rear.
The suggestion is that the car could have the wrong M/Cyl fitted.
Identified visually or by a stamped P/N ? ?


Thanks Sean