[Vwdiesel] Was: brake bleeding hell on a VW bug-Drum brake overheating

[Kurt Nolte]

One thing to remember is that cars use brake fluid, which expands and 
adds pressure (applying the brakes more) as it heats up, while big rigs 
and other air brake vehicles use air (And increasing pressure just keeps 
the brakes from being applied).

Air brakes use the /loss/ of pressure to appy the brakes, so increasing 
the pressure in the line from heat expansion of the air won't apply the 
brakes and lock them up.

-Kurt


On 7/26/2010 12:07 AM, Tony and Lillie wrote:
> I understand that. But, the original comment I posted was that if the
> brakesa re adjusted too tightly, they will drag to the point of heating and
> nearly locking up. However, in a big rig, as the brakes heat up, they loose
> their effectiveness, to the point of completely being innefective.
>
> I just don't understand why one vehicle's brakes gets tighter while the
> other looses effectiveness. However, I've experienced both (thankfully only
> once on a big rig!), so I know it's a fact.
>
> BTW, that was a good explination.
>